U.S. patent application number 12/531904 was filed with the patent office on 2010-04-29 for metal compound coated particulate mineral materials, methods of making them, and uses thereof.
This patent application is currently assigned to World Minerals, Inc. Invention is credited to Michael Greene, Bo Wang.
Application Number | 20100104873 12/531904 |
Document ID | / |
Family ID | 39788966 |
Filed Date | 2010-04-29 |
United States Patent
Application |
20100104873 |
Kind Code |
A1 |
Wang; Bo ; et al. |
April 29, 2010 |
METAL COMPOUND COATED PARTICULATE MINERAL MATERIALS, METHODS OF
MAKING THEM, AND USES THEREOF
Abstract
Particulate mineral materials comprising at least one coating
comprising at least one metal compound are disclosed. In one
embodiment, the at least one metal compound is a metal silicate
compound. In another embodiment, the at least one metal compound is
a metal oxide compound. In one embodiment, the particulate mineral
material is perlite. In another embodiment, the particulate mineral
material is perlite microspheres. In a further embodiment, the
particulate mineral material is diatomite. Methods of making
particulate mineral materials coated with at least one metal
compound are also disclosed. In one embodiment, the at least one
metal compound may be injected into a perlite expander to form a
metal compound coated perlite material. In another embodiment, the
at least one metal compound may be applied through a low
temperature coating process to the at least one particulate mineral
material. Uses for metal compound coated particulate mineral
materials are also disclosed.
Inventors: |
Wang; Bo; (Lompoc, CA)
; Greene; Michael; (Santa Barbara, CA) |
Correspondence
Address: |
FINNEGAN, HENDERSON, FARABOW, GARRETT & DUNNER;LLP
901 NEW YORK AVENUE, NW
WASHINGTON
DC
20001-4413
US
|
Assignee: |
World Minerals, Inc
Santa Barbara
CA
|
Family ID: |
39788966 |
Appl. No.: |
12/531904 |
Filed: |
March 22, 2008 |
PCT Filed: |
March 22, 2008 |
PCT NO: |
PCT/US08/57957 |
371 Date: |
December 8, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60896506 |
Mar 23, 2007 |
|
|
|
Current U.S.
Class: |
428/406 ;
427/215; 428/404 |
Current CPC
Class: |
Y10T 428/2996 20150115;
C04B 20/1074 20130101; C04B 41/009 20130101; C01P 2004/84 20130101;
C01P 2006/11 20130101; C04B 41/009 20130101; C09C 1/28 20130101;
C04B 20/1074 20130101; C01P 2004/51 20130101; C09C 1/00 20130101;
B01J 21/12 20130101; C01P 2006/64 20130101; C04B 41/4584 20130101;
C09C 1/40 20130101; C01P 2006/62 20130101; C04B 20/1085 20130101;
C04B 41/009 20130101; C04B 41/009 20130101; Y10T 428/2993 20150115;
C01P 2006/10 20130101; C04B 35/62807 20130101; C04B 41/4584
20130101; C04B 20/1074 20130101; C04B 20/1074 20130101; C04B
20/1085 20130101; C04B 41/4584 20130101; B01J 37/0215 20130101;
C01P 2004/03 20130101; C01P 2006/63 20130101; C04B 20/1077
20130101; C04B 20/1077 20130101; C09C 1/405 20130101; C04B 20/1085
20130101; C04B 14/18 20130101; C04B 14/18 20130101; C04B 14/106
20130101; B01J 23/06 20130101; C04B 14/185 20130101; C04B 20/0036
20130101; C04B 41/4543 20130101; C04B 14/185 20130101; C04B 41/455
20130101; C04B 41/455 20130101; C04B 14/08 20130101; C04B 41/5024
20130101; C04B 41/4543 20130101; C04B 14/18 20130101; C04B 41/5049
20130101; C04B 14/185 20130101; B01J 21/08 20130101; C01P 2006/60
20130101; C04B 14/18 20130101; C04B 41/009 20130101 |
Class at
Publication: |
428/406 ;
427/215; 428/404 |
International
Class: |
B32B 5/16 20060101
B32B005/16; B32B 3/00 20060101 B32B003/00; B32B 9/00 20060101
B32B009/00; B05D 3/02 20060101 B05D003/02 |
Claims
1-70. (canceled)
71. A metal silicate coated particulate mineral material,
comprising perlite and a coating comprising at least one metal
silicate.
72. The metal silicate coated particulate mineral material of claim
71, wherein the at least one metal silicate comprises an alumino
silicate.
73. The metal silicate coated particulate mineral material of claim
71, wherein the at least one metal silicate is chosen from at least
one of a zirconium silicate, and a zinc silicate.
74. The metal silicate coated particulate mineral material of claim
71, wherein the perlite material is non-expanded.
75. The metal silicate coated particulate mineral material of claim
71, wherein the perlite is expanded.
76. The metal silicate coated particulate mineral material of claim
71, wherein the perlite is in the form of microspheres.
77. The metal silicate coated particulate mineral material of claim
71, wherein the at least one metal silicate comprises at least one
metal component and at least one silicate component.
78. The metal silicate coated particulate mineral material of claim
77, wherein the at least one silicate component is chosen from the
group consisting of tetraethylorthosilicate,
tetramethylorthosilicate, sodium silicate, alkali silicate,
colloidal silica, solid silica, alkaline metal silicates, and
sodium metasilicate.
79. The metal silicate coated particulate mineral material of claim
77, wherein the at least one metal component is chosen from the
group consisting of metal nitrates, metal sulfates, metal
aluminates, sodium metals, metal chlorides, metal alkoxides, metal
acetates, metal formates, bayerite, pseudoboehmite, gibbsite,
colloidal metals, metal gels, metal sols, metal trichlorides,
ammonium metal carbonates, metal hydrates, and metal
chlorohydrates.
80. The metal silicate coated particulate mineral material of claim
77, wherein the at least one metal component comprises at least one
of aluminum, zirconium, boron, and zinc.
81. The metal silicate coated particulate mineral material of claim
77, wherein the at least one metal component is chosen from
aluminum nitrate, aluminum sulfate, sodium aluminate, and aluminum
halides.
82. The metal silicate coated particulate mineral material of claim
77, wherein the at least one metal component is chosen from
zirconium sulfate, zirconium chloride, ammonium pentaborate
octahydrate, and ammonium zirconium carbonate.
83. The metal silicate coated particulate mineral material of claim
77, wherein the at least one metal component is chosen from zinc
sulfate and zinc nitrate.
84. A method of forming coated expanded perlite microspheres,
comprising: introducing perlite microspheres into an expander
heated to a temperature of from about 900.degree. F. to about
1100.degree. F.; injecting into the expander at least one metal
component and at least one silicate component; and, allowing the
perlite microspheres, the at least one metal component, and the at
least one silicate component to reside in the expander for a time
sufficient to coat the perlite microspheres with the at least one
metal component and the at least one silicate component, wherein
the at least one metal component and the at least one silicate
component form at least one metal silicate.
85. The method of claim 84, wherein the at least one silicate
component is chosen from the group consisting of
tetraethylorthosilicate, tetramethylorthosilicate, sodium silicate,
alkali silicate, colloidal silica, solid silica, alkaline metal
silicates, and sodium metasilicate.
86. The method of claim 84, wherein the at least one metal
component is chosen from the group consisting of metal nitrates,
metal sulfates, metal aluminates, sodium metals, metal chlorides,
metal alkoxides, metal acetates, metal formates, bayerite,
pseudoboehmite, gibbsite, colloidal metals, metal gels, metal sols,
metal trichlorides, ammonium metal carbonates, metal hydrates, and
metal chlorohydrates.
87. The method of claim 84, wherein the at least one metal
component comprises at least one of aluminum, zirconium, boron, and
zinc.
88. The method of claim 84, wherein the at least one metal
component is chosen from aluminum nitrate, aluminum sulfate, sodium
aluminate, and aluminum halides.
89. The method of claim 84, wherein the at least one metal
component is chosen from zirconium sulfate, zirconium chloride,
ammonium pentaborate octahydrate, and ammonium zirconium
carbonate.
90. The method of claim 84, wherein the at least one metal
component is chosen from zinc sulfate and zinc nitrate.
91. A metal silicate coated particulate mineral material,
comprising diatomite comprising a coating comprising at least one
metal silicate selected from at least one of zirconium silicates
and zinc silicates.
Description
CLAIM OF PRIORITY
[0001] This application claims the benefit of priority to U.S.
Provisional Patent Application No. 60/896,506 filed Mar. 23, 2007,
which is incorporated by reference herein in its entirety.
FIELD OF THE INVENTION
[0002] Disclosed herein are particulate mineral materials coated
with at least one metal compound. In one embodiment, the at least
one metal compound is a metal silicate compound. In another
embodiment, the at least one metal compound is a metal oxide
compound. Also disclosed herein are methods of making particulate
mineral materials coated with at least one metal compound, as well
as various uses for metal-compound coated particulate mineral
materials.
BACKGROUND OF THE INVENTION
[0003] Particulate mineral materials find use in a variety of
different applications including, but not limited to, coatings,
pigments, fillers, proppants, catalysts, extenders, inert carriers,
for filtration, for insulations, and for horticultural
applications. One example of a particulate mineral material is
perlite. Perlite is a naturally occurring siliceous volcanic glass
rock, generally distinguishable from other volcanic glasses due to
its expansion from about four to about twenty times its original
volume when heated to a temperature within its softening range.
Perlite particles have been found to be useful in an array of
applications, such as those mentioned above, both in their expanded
and in their unexpanded form.
[0004] The expanded form of perlite may be achieved due in part to
the presence of water trapped within the crude perlite glass rock.
When perlite is quickly heated, the water vaporizes, creating
bubbles in the heat-softened glassy particles and generally
resulting in a light-weight, chemically inert, highly expanded
perlite product. An expanded perlite product may be manufactured to
weigh from, for example, about 2 pds/ft.sup.3 to about 15
pds/ft.sup.3, allowing it to be adapted for numerous uses, such as
those previously described.
[0005] The final form and grade of an expanded perlite product may
be controlled by, among other things, changing the heating cycle
within a perlite expander, altering the size profile of an
unexpanded perlite feed material by milling, or other processes now
known to those of skill in the art or hereafter discovered. In one
expanded form, the perlite particles are aggregate particles. In
another expanded form, the perlite particles are solid
microspheres. In a further expanded form, the perlite particles are
porous microspheres. Expanded perlite in the form of porous
microspheres has, in general, fewer inner cells compared to the
relatively larger number of inner cells found in the more commonly
produced expanded perlite aggregate particles.
[0006] Perlite may additionally be milled after it is expanded.
Expanded perlite that has not been subsequently milled generally
has a foamy or bubbly structure and may include porous spheres.
When expanded perlite is subsequently milled, the bubbles in the
structure are generally crushed, resulting in bubble fragments that
are smaller and generally of a platy structure.
[0007] Another example of a particulate mineral material is
diatomaceous earth (also called "DE" or "diatomite"), which is
generally regarded as a sediment enriched in biogenic silica (i.e.,
silica produced or brought about by living organisms) in the form
of siliceous skeletons (frustules) of diatoms. Diatoms are a
diverse array of microscopic, single-celled, golden-brown algae of
the class Bacillariophyceae that possess an ornate siliceous
skeleton of varied and intricate structures comprising two valves
that, in the living diatom, fit together much like a pill box. In
one embodiment, the diatomaceous earth is freshwater diatomite. In
another embodiment, the diatomaceous earth is saltwater
diatomite.
[0008] In some applications, the compressive strength, hardness,
and/or color of the particulate mineral materials may play an
important roll in fulfilling their intended purpose. It has been
known in the art to improve certain attributes of particulate
mineral materials through surface coating or binding particles
together. U.S. Pat. No. 3,849,149 to Swift et al., for example,
appears to disclose a method of modifying the surface properties of
certain particulate mineral materials with a surface coating having
a significant number of acidic sites with pKa values less than 2.8,
so as to result in greater ease of incorporation and uniformity of
dispersion in pigment and filler end uses. As another example, U.S.
Pat. No. 4,432,798 to Helferich et al. appears to disclose
moldable, self-setting composition consisting of a granular or
particulate aggregrate held together by an alkali-aluminosilicate
binder hydrogel. As a further example, U.S. Pat. No. 5,352,287 to
Wason et al. appears to disclose a composite pigment product that
comprises a mineral nucleus coated with a substantially continuous
and uniform active paper pigment coating, which may be used to
enhance the opacity, brightness, and/or optical performance
characteristics of paper. As another example, U.S. Pat. No.
6,641,908 B1 to Clough appears to disclose inorganic substrate
materials comprising a metal oxide coating that may be formed by
high temperature plasma coating.
[0009] The present inventors have unexpectedly discovered that, by
coating particulate mineral materials with at least one metal
compound, the compressive strength, hardness, and/or color of those
materials may be improved. In one embodiment, the at least one
metal compound is a metal oxide compound. In another embodiment,
the at least one metal compound is a metal silicate compound. None
of the references mentioned above appear to teach or suggest at
least the following: (1) the use of at least one metal silicate
coating to improve the compressive strength, hardness, and/or
coloration of at least one particulate mineral material; (2) the
application of at least one zirconium or zinc silicate coating onto
at least one diatomite particulate mineral material; (3) the
application of at least one aluminosilicate coating onto at least
one perlite particulate mineral material; and (4) the coating of at
least one particulate mineral material with a metal oxide coating,
by use of low (e.g., room) temperature solution coating.
SUMMARY OF THE INVENTIONS
[0010] Disclosed herein are metal silicate coated particulate
mineral materials comprising perlite comprising a coating
comprising at least one metal silicate.
[0011] Also disclosed herein are metal silicate coated particulate
mineral materials comprising diatomite comprising a coating
comprising at least one metal silicate selected from at least one
of zirconium silicates and zinc silicates.
[0012] Also disclosed herein are metal silicate coated particulate
mineral materials comprising a particulate perlite microsphere
comprising a coating comprising at least one metal silicate.
[0013] Also disclosed herein are methods of forming coated expanded
perlite microspheres, comprising: introducing perlite microspheres
into an expander heated to a temperature of from about 900.degree.
F. to about 1100.degree. F.; injecting into the expander at least
one metal silicate; and, allowing the perlite microspheres and the
at least one metal silicate to reside in the expander for a time
sufficient to coat the perlite microspheres with the at least one
metal silicate.
[0014] Also disclosed herein are methods of forming coated expanded
perlite microspheres, comprising: introducing perlite microspheres
into an expander heated to a temperature of from about 900.degree.
F. to about 1100.degree. F.; injecting into the expander at least
one metal compound and at least one silicate compound; and,
allowing the perlite microspheres, the at least one aluminum
compound, and the at least one silicate compound to reside in the
expander for a time sufficient to coat the perlite microspheres
with the at least one metal compound and the at least one silicate
compound, wherein the at least one metal compound and the at least
one silicate compound form at least one metal silicate.
[0015] Also disclosed herein are coating, catalyst, pigment,
filler, proppant, or extender products comprising perlite
comprising a coating comprising at least one metal silicate.
[0016] Also disclosed herein are coating, catalyst, pigment,
filler, proppant, or extender products comprising diatomite
comprising a coating comprising at least one metal silicate
selected from at least one of zirconium silicates and zinc
silicates.
[0017] Also disclosed herein are coating, catalyst, pigment,
filler, proppant, or extender products comprising at least one
particulate microsphere mineral material comprising a coating
comprising at least one metal silicate.
[0018] Also disclosed herein are methods of applying at least one
metal oxide coating to at least one particulate mineral material
comprising solution coating at about room temperature.
[0019] Also disclosed herein are methods of increasing the
brightness of at least one particulate mineral material, comprising
applying by low temperature solution coating at least one coating
of at least one metal oxide compound to the at least one
particulate mineral material, wherein the b value of the at least
one particulate mineral material decreases by about 1 unit.
[0020] Also disclosed herein are methods of increasing the
compressive strength of at least one particulate mineral material,
comprising applying at least one coating of at least one metal
silicate to the at least one particulate mineral material, wherein
the compressive strength as measured by compaction resistance
increases at least about two times.
[0021] Also disclosed herein are methods of increasing the hardness
of at least one particulate mineral material, comprising applying
at least one coating of at least one metal silicate to the at least
one particulate mineral material, wherein the hardness as measured
by scrub resistance increases by at least about two percent.
BRIEF DESCRIPTION OF THE FIGURES
[0022] FIG. 1 is a scanning electron micrograph of expanded perlite
microspheres.
[0023] FIG. 2 is a scanning electron micrograph of an exemplary
zirconium silicate coated diatomaceous earth sample in accordance
with the present invention.
[0024] FIG. 3 is another scanning electron micrograph of an
exemplary zirconium silicate coated diatomaceous earth sample in
accordance with the present invention.
[0025] FIG. 4 is another scanning electron micrograph of an
exemplary zirconium silicate coated diatomaceous earth sample in
accordance with the present invention.
[0026] FIG. 5 is another scanning electron micrograph of an
exemplary zirconium silicate coated diatomaceous earth sample in
accordance with the present invention.
[0027] FIG. 6 is another scanning electron micrograph of an
exemplary zirconium silicate coated diatomaceous earth sample in
accordance with the present invention.
[0028] FIG. 7 depicts the relationship between the coating solution
to perlite ratio and 1-inch compaction resistance of perlite
microspheres tested according to Example 4.
[0029] FIG. 8 depicts the relationship between the sodium silicate
to aluminum sulfate ratio and 1-inch compaction resistance of
perlite microspheres tested according to Example 4, with an
aluminosilicate to perlite ratio of 1.
DETAILED DESCRIPTION OF THE INVENTION
Particulate Mineral Materials
[0030] The at least one particulate mineral material is a naturally
occurring or manufactured mineral material capable of receiving at
least one coating comprising at least one metal compound. Those of
skill in the art will understand appropriate at least one
particulate mineral materials for use in accordance with the
present invention. The at least one particulate mineral material
may be of one or more varying properties, e.g., composition, form,
shape, size, and/or density. In one embodiment, the at least one
particulate mineral material is any particulate mineral material
that could benefit from an increase in compressive strength. In
another embodiment, the at least one particulate mineral material
is any particulate mineral material that could benefit from an
increase in hardness. In a further embodiment, the at least one
particulate mineral material is any particulate mineral material
that could benefit from improved coloration. In yet another
embodiment, the at least one particulate mineral material is any
particulate mineral material that could benefit from improved scrub
resistance.
[0031] A non-limiting list of at least one particulate mineral
materials contemplated for use with the present invention includes
perlite, diatomite, pumice, vermiculite, obsidian, kaolin, bauxite,
bauxitic kaolin, calcium carbonate, talc, mica, oxide pigments,
silica, alumina, zirconia, sintered bauxite, andalusiteii,
feldspar, nepheline syenite, colorants, and particulate glasses
including but not limited to soda lime, borosilicate, calcium
aluminum silicate (E-Glass), and recycled-post consumer glass. In
one embodiment, the at least one particulate mineral material is
perlite. In another embodiment, the at least one particulate
mineral material is diatomite. In a further embodiment, the at
least one particulate mineral material is calcium carbonate. In yet
another embodiment, the at least one particulate mineral material
is kaolin.
[0032] The at least one particulate mineral material may be in any
suitable form, including but not limited to amorphous, spherical,
non-spherical, micron scale, non-micron scale, microspherical,
porous, solid, non-expanded, expanded, and milled. As used herein,
the term "microsphere" refers to a sphere or spherical material
that is micron in scale. As used herein, the term "solid" refers to
a particulate mineral material having a theoretical density of
greater than or equal to about 90%. As used herein, the term
"hollow" or "porous" refers to a particulate mineral material
having a theoretical density of less than about 90%. As used
herein, the terms "sphere" or "spherical" refer to a particle that,
when magnified as a two-dimensional image, generally appears
rounded and generally free of sharp corners or edges, whether or
not the particle appears to be truly or substantially circular,
elliptical, globular, or any other rounded shape; thus, in addition
to the truly circular and elliptical shapes, other shapes with
curved but not circular or elliptical outlines are included as a
"sphere" or as "spherical". A particulate mineral material may also
be considered a "sphere" or as "spherical" even though it may have
some individual particles that have agglomerated, thereby forming
non-spherical agglomerates in the otherwise spherical material, or
are otherwise non-spherical.
[0033] The at least one particulate mineral material may be of any
shape selected by the skilled artisan for the intended purpose. In
one embodiment, the at least one particulate mineral material is
amorphous. In another embodiment, the at least one particulate
mineral material is spherical. In yet another embodiment, the at
least one particulate mineral material is in the shape of solid
microspheres. In yet a further embodiment, the at least one
particulate mineral material is in the shape of porous
microspheres. In still another embodiment, the at least one
particulate mineral material is in the shape of hollow
microbubbles. In still a further embodiment, the at least one
particulate mineral material is in the shape of hollow beads. In
another embodiment, the at least one particulate mineral material
is in the shape of hollow voids. In a further embodiment, the at
least one particulate mineral material is perlite in the shape of
solid microspheres. In yet another embodiment, the at least one
particulate mineral material is perlite in the shape of porous
microspheres.
[0034] The at least one particulate mineral material may be of any
size selected by the skilled artisan for the intended purpose. In
one embodiment, the at least one particulate mineral material is
micron scale. In another embodiment, the at least one particulate
mineral material is non-micron scale. As used herein, the prefix
"micro" and the term "micron scale" both refer to a particulate
mineral material having an equivalent spherical diameter of less
than 100 .mu.m, while the prefix "non-micron scale" refers to a
particulate mineral material having an equivalent spherical
diameter equal to or greater than 100 .mu.m. As used herein, a
particulate mineral material may be considered "micron scale" even
though it may have some individual particles that have
agglomerated, thereby forming non-micron scale agglomerates in the
otherwise micron scale material, or are otherwise non-micron
scale.
[0035] In one embodiment, the at least one particulate mineral
material has an equivalent spherical diameter of less than about 10
mm. In another embodiment, the at least one particulate mineral
material has an equivalent spherical diameter (esd) of less than
about 5 mm. In a further embodiment, the at least one particulate
mineral material has an esd of less than about 1 mm. In yet another
embodiment, the at least one particulate mineral material has an
esd of less than about 100 .mu.m. In yet a further embodiment, the
at least one particulate mineral material has equivalent spherical
diameter of less than about 10 .mu.m. In still another embodiment,
the at least one particulate mineral material has an equivalent
spherical diameter of less than about 1 .mu.m.
[0036] In one embodiment, the at least one particulate mineral
material has an esd from about 0.5 .mu.m to about 10 mm. In another
embodiment, the at least one particulate mineral material has an
esd from about 1 .mu.m to about 5 mm. In a further embodiment, the
at least one particulate mineral material has an esd from about 1
.mu.m to about 1 mm. In still another embodiment, the at least one
particulate mineral material has an esd from about 10 .mu.m to
about 100 .mu.m.
[0037] The equivalent spherical diameter of a particulate mineral
material may be measured using any of a variety of methods now
known or hereafter discovered. For example, esd may be measured
using SEDIGRAPH particle size analyzer. Esd analysis may also yield
information such as a d.sub.10 (the size at which 10 percent of the
particle volume is accounted for by particles having a diameter
less than or equal to the specified value), d.sub.50 (same as
d.sub.10 but for 50 percent particle volume, as called average
particle size), and d.sub.90 (same as d.sub.10 but for 90 percent
particle volume).
[0038] In one embodiment, the at least one particulate mineral
material is perlite. In another embodiment, the at least one
particulate mineral material is non-expanded perlite. In a further
embodiment, the particulate mineral material is expanded perlite.
In yet another embodiment, the particulate mineral material is
expanded perlite that has been subsequently milled. In yet a
further embodiment, the particulate mineral material is perlite in
the form of non-expanded microspheres. In still another embodiment,
the particulate mineral material is perlite in the form of expanded
microspheres. In still a further another embodiment, the
particulate mineral material is perlite in the form of expanded
microspheres that have been subsequently milled.
[0039] In one embodiment, the at least one particulate mineral
material is diatomite. In another embodiment, the diatomite is
saltwater diatomite. In a further embodiment, the diatomite is
freshwater diatomite. In one embodiment, the diatomite is calcined.
In another embodiment, the diatomite is flux calcined. In another
embodiment, the diatomite is natural (e.g., not calcined).
Metal Compounds
[0040] The at least one particulate mineral material is coated with
at least one coating comprising at least one metal compound, such
that after at least one coating process the at least one
particulate mineral material comprises at least one coating
comprising at least one metal compound. In one embodiment, the at
least one metal compound comprises at least one metal component and
at least one other component chosen from the group consisting of
oxide components and silicate components. The separate component
materials may also be called starting materials and the at least
one metal compound may be formed from many different starting
materials by many different processes. In one embodiment, the at
least one metal compound comprises at least one metal component and
at least one silicate component. In another embodiment, the at
least one metal compound comprises at least one metal component and
at least one oxide component.
[0041] The at least one metal component comprises at least one
metal now known to the skilled artisan or hereafter discovered.
Semimetals or metalloids, such as boron and silicon, are
contemplated as at least one metals within the scope of the present
inventions. A non-limiting list of at least one metals contemplated
for use with the present invention includes aluminum, copper,
chromium, copper, iron, lead, nickel, silver, titanium, zinc,
zirconium, boron, silicon, and mixtures thereof. In one embodiment,
the at least one metal is aluminum. In another embodiment, the at
least one metal is zinc. In a further embodiment, the at least one
metal is zirconium. In yet another embodiment, the at least one
metal is boron. In yet a further embodiment, the at least one metal
component is chosen from the group consisting of metal nitrates,
metal sulfates, metal aluminates, sodium metals, metal chlorides,
metal alkoxides, metal acetates, metal formates, bayerite,
pseudoboehmite, gibbsite, colloidal metals, metal gels, metal sols,
metal trichlorides, ammonium metal carbonates, metal hydrates, and
metal chlorohydrates.
[0042] In one embodiment, the at least one metal component is at
least one aluminum compound. Examples of the at least one aluminum
compound include, but are not limited to, aluminum salts, aluminum
nitrate, aluminum sulfate, alkali aluminate, sodium aluminate,
aluminum halides (such as aluminum chloride), aluminum alkoxide,
aluminum acetate, aluminum formate, bayerite, pseudoboehmite,
gibbsite, colloidal alumina, alumina gel, alumina sol, aluminum
trichloride, ammonium aluminum carbonate, and aluminum
chlorohydrate. In one embodiment, the at least one aluminum
compound is aluminum nitrate. In another embodiment, the at least
one aluminum compound is aluminum sulfate. In a further embodiment,
the at least one aluminum compound is sodium aluminate. In yet
another embodiment, the at least one aluminum compound is aluminum
chloride.
[0043] In another embodiment, the at least one metal component is
at least one zirconium compound. Examples of the at least one
zirconium compound include, but are not limited to, zirconium
nitrate, zirconium sulfate, alkali zirconia, sodium zirconia,
zirconium chloride, zirconium alkoxide, zirconium acetate,
zirconium formate, colloidal zirconia, zirconium gel, zirconium
sol, zirconium trichloride, ammonium zirconium carbonate, and
zirconium chlorohydrate. In one embodiment, the at least one
zirconium compound is zirconium sulfate. In another embodiment, the
at least one zirconium compound is zirconium chloride. In a further
embodiment, the at least one zirconium compound is ammonium
zirconium carbonate.
[0044] In a further embodiment, the at least one metal component is
at least one zinc compound. Examples of the at least one zinc
compound include, but are not limited to, zinc nitrate, zinc
sulfate, alkali zincs, sodium zincs, zinc chloride, zinc alkoxide,
zinc acetate, zinc formate, colloidal zincs, zinc gel, zinc sol,
zinc trichloride, and zinc chlorohydrate. In one embodiment, the at
least one zinc compound is zinc nitrate. In another embodiment, the
at least one zinc compound is zinc sulfate.
[0045] In yet another embodiment, the at least one metal compound
is at least one boron compound. In one embodiment, the at least one
metal compound is ammonium pentaborate octahydrate.
[0046] In one embodiment, the at least one metal compound is formed
in the presence of at least one acid. Without wishing to be bound
by theory, it is believed that at least one acid may act to
facilitate precipitation or coating of the at least one metal
compound onto the at least one particulate mineral material.
Appropriate acids will be known or may be hereafter discovered by
the skilled artisan. Examples of the at least one acid include, but
are not limited to, hydrochloric acid, sulfuric acid, phosphoric
acid, formic acid, and acetic acid. In one embodiment, the at least
one acid is hydrochloric acid. In another embodiment, the at least
one acid is phosphoric acid.
[0047] In one embodiment, the at least one metal compound comprises
at least one metal component and at least one silicate component.
Exemplary embodiments of the at least one silicate component
include, but are not limited to, tetraethylorthosilicate (TEOS),
tetramethylorthosilicate (TMOS), sodium silicate, alkali silicate,
colloidal silica, solid silica, alkaline metal silicates, and
sodium metasilicate. In one embodiment, the at least one silicate
component is TEOS. In another embodiment, the at least one silicate
component is sodium silicate.
[0048] In one embodiment, the at least one metal compound is at
least one alumino silicate. In one embodiment, the starting
materials for the at least one alumino silicate comprise TEOS and
aluminum nitrate. In another embodiment, the starting materials for
the at least one alumino silicate comprise sodium silicate and
aluminum sulfate. In a further embodiment, the at least one alumino
silicate is formed by a sol-gel reaction. In yet another
embodiment, the at least one alumino silicate is formed by a
sol-gel reaction comprising TEOS and aluminum nitrate. In yet
another embodiment, the at least one alumino silicate is formed
from a mixture of sodium silicate and aluminum sulfate.
[0049] In another embodiment, the at least one metal compound is at
least one zirconium silicate. In one embodiment, the starting
materials for the at least one zirconium silicate comprise sodium
silicate and zirconium sulfate. In another embodiment, the starting
materials for the at least one zirconium silicate comprise sodium
silicate and zirconium chloride. In a further embodiment, the
starting materials for the at least one zirconium silicate comprise
sodium silicate and ammonium zirconium carbonate. In yet another
embodiment, the at least one zirconium silicate is formed by a
sol-gel reaction. In yet a further embodiment, the at least one
zirconium silicate is formed by a sol-gel reaction comprising TEOS
and zirconium sulfate. In still another embodiment, the at least
one zirconium silicate is formed from a mixture of sodium silicate
and zirconium sulfate.
[0050] In a further embodiment, the at least one metal compound is
at least one zinc silicate. In one embodiment, the starting
materials for the at least one zinc silicate comprise TEOS and zinc
nitrate. In another embodiment, the starting materials for the at
least one zinc silicate comprise sodium silicate and zinc sulfate.
In a further embodiment, the at least one zinc silicate is formed
by a sol-gel reaction. In yet another embodiment, the at least one
zinc silicate is formed by a sol-gel reaction comprising TEOS and
zinc nitrate. In yet a further embodiment, the at least one zinc
silicate is formed from a mixture of sodium silicate and zinc
sulfate.
[0051] In one embodiment, the at least one metal compound comprises
at least one metal component and at least one oxide component. In
one embodiment, the metal compound is zirconium oxide. In another
embodiment, the metal compound is zinc oxide. In another
embodiment, the metal compound is aluminum oxide.
Coatings
[0052] The at least one coating may take various forms. In one
embodiment, the at least one coating is in the form of a
glassy-type coating. In another embodiment, the at least one
coating is in the form of a ceramic-type coating. In still another
embodiment, the coating is in the form of a sol-gel type
coating.
[0053] The method of preparing the at least one metal compound and
the method of applying the at least one metal compound to the at
least one particulate mineral material are not critical, so long as
at least one coating comprising the at least one metal compound is
formed on the at least one particulate mineral material. In one
embodiment, the starting materials of the at least one metal
compound may be applied separately and directly to the particulate
mineral material, forming a coating comprising at least one metal
compound thereon. In another embodiment, the starting materials of
the at least one metal compound are first mixed or reacted, and
then applied to the at least one particulate mineral material to
form at least one coating. In a further embodiment, the at least
one metal compound or one or more starting materials of the at
least one metal compound, including mixtures of starting materials,
are applied to the at least one particulate mineral material by
spraying onto the surface of the at least one particulate mineral
material. In yet another embodiment, the at least one metal
compound is applied to the at least one particulate mineral
material by solution coating. In one embodiment, the solution
coating is performed at or about room temperature (i.e., about
70.degree. F.). In another embodiment, the solution coating is
performed at a temperature less than about 300.degree. F. In a
further embodiment, the solution coating is performed at a
temperature less than about 150.degree. F.
[0054] In one embodiment in which the at least one particulate
mineral material is perlite, the perlite may be coated with the at
least one metal compound at any time during and/or after the
perlite expansion process. In one such embodiment, the at least one
metal component and the at least one other component of the at
least one metal compound are applied separately and directly to the
perlite during and/or after expansion of the perlite. In another
such embodiment, the at least one metal component and the at least
one other component may first be mixed or reacted and then applied
to the perlite during and/or after expansion of the perlite.
[0055] In one embodiment, the at least one metal component and the
at least one other component, either individually or as a mixture,
are applied to the perlite while the perlite is at an elevated
temperature relative to room temperature (e.g., 70.degree. F.). In
another embodiment, the at least one metal compound is applied to
the perlite while it is undergoing expansion and it is at an
elevated temperature. In a further embodiment, the at least one
metal compound is applied to perlite after it has undergone
expansion and while it is at an elevated temperature. For example,
the elevated temperature may be from about 900.degree. F. to about
1500.degree. F. While not wishing to be bound by theory, forming
the at least one coating in accordance with the embodiments in
which the perlite is at an elevated temperature is believed to
allow the metal compound to more easily precipitate onto the
expanded perlite and/or to induce the formation of a ceramic
coating. In addition, it is believed that coating in accordance
with the embodiments in which the perlite is at an elevated
temperature may facilitate the formation of a hard metal compound
glass/ceramic coating on the surface of the substrate.
[0056] In a further embodiment, the at least one metal component
and the at least one other component, either individually or a
mixture, may be injected directly into the perlite expander. Once
again, while not wishing to be bound by theory, it is contemplated
that, to help reduce the production cost, a coating process
according to this embodiment may be employed using existing
expander equipment with no or minimum modification. In one such
embodiment, the at least one metal compound and/or its starting
materials is injected in-line into the perlite expander.
Properties
[0057] The coated particulate mineral materials of the present
inventions may exhibit increased hardness, compressive strength,
and/or improved coloration over particulate mineral materials that
do not comprise at least one coating comprising at least one metal
compound. In one embodiment, the particulate mineral materials of
the present invention exhibit an increased compressive strength (as
measured by compaction resistance). One example of a compaction
resistance test measures the compressive force in pd/in.sup.2 (psi)
required to reduce a specified column of mineral aggregate by 1 or
2 inches. In one exemplary method to determine the compaction
resistance, a Dillion TC.sup.2 Tension Compression Cyclic machine
may be used to test cylinders packed with the mineral material to
be tested. First, test cylinders are prepared by packing the
mineral to be tested into a test cylinder with 11/8 inch inside
diameter and 5 inch inside depth. The filled test cylinder is then
held on the platform of a compaction density machine and bounced 25
times. After fitting a flanged collar on the test cylinder, more
samples are added to bring the height to within an inch of the top
of the collar. The filled test cylinder is then bounced for an
additional 25 times. After removing the collar, the mineral above
the level of the test cylinder was struck off with a straight edge.
The cylinder with samples may then be weighed for a compaction
density measurement, if desired. The cylinders are then transferred
to the compaction resistance testing unit, where each cylinder is
slowly compressed with a piston at a speed of 2 inch/min to the 1
inch or 2 inch mark. The resistance of the particulate material
during the compaction can then be measured.
[0058] In one embodiment, the compressive strength is at least
about 2 times that of the uncoated material. In another embodiment,
the compressive strength is at least about 4 times that of the
uncoated material. In a further embodiment, the compressive
strength is at least about 6 times that of the uncoated material.
In yet another embodiment, the compressive strength is at least
about 10 times that of the uncoated material.
[0059] In one embodiment, the coated particulate mineral materials
of the present inventions may exhibit increased hardness. The
skilled artisan is aware of hardness attributes desirable for
particulate mineral materials in an intended use or application.
The hardness of particulate mineral materials may be difficult to
measure directly. One exemplary method of those known to the
skilled artisan for measuring hardness is a scrub resistance test
according to ASTM D 2486-89. In one embodiment, the hardness of the
coated particulate mineral material is increased by about 2%,
according to its scrub resistance. In another embodiment, the
hardness is increased by about 5%. In a further embodiment, the
hardness is increased by about 10%. In yet another embodiment, the
hardness is increased by about 15%. In yet a further embodiment,
the hardness is increased by about 20% or more. In still another
embodiment, the hardness is increased by about 2% to about 20%. In
still a further embodiment, the hardness is increased by about 10%
to about 20%.
[0060] In one embodiment, the coated particulate mineral materials
of the present inventions may exhibit improved coloration. The
skilled artisan is aware of coloration attributes desirable for
particulate mineral materials in an intended use or application.
The coloration of the coated particulate mineral materials may be
evaluated using Hunter L, a, b color measurements collected, for
example, on a Spectro/plus Spectrophotometer (Color and Appearance
Technology, Inc., Princeton, N.J.). L, a, and b values rank the
whiteness, red/green, and blue/yellow values spectrophotometrically
by measuring the reflection of light off of a colored sample. The
desired values for L, a, and b may be different for various
particulate mineral materials and intended uses; values of L, a,
and b may be considered independently from each other such that,
for example, relatively small changes in one value (such as b) may
be highly desirable even with relatively larger changes in another
value (such as L). L is numbered between 0 and 100, with 0 being a
completely black sample and 100 being a completely white sample.
The a value is the red/green value which is a positive number for
red samples (the more positive, the redder) and negative for green
samples (the more negative, the greener). The b value is similar to
the a but looks at the blue/yellow values of the material. Positive
samples are yellow, negative samples are blue. The more positive or
negative the number, the more yellow or blue, respectively. Blue
light brightness ("BLB") may also be calculated from Hunter scale
color data (L, a, b).
[0061] In one embodiment, the coated particulate mineral materials
of the present invention have a b value closer to 0 than uncoated
materials. In another embodiment, the coated particulate mineral
materials have a b value about 1 unit lower than uncoated
materials. In a further embodiment, the coated particulate mineral
materials have a b value about 0.5 to about 2 units lower than
uncoated materials. In yet another embodiment, the coated
particulate mineral minerals have about the same L value as the
uncoated materials. In yet a further embodiment, the coated
particulate mineral materials have a b value closer to 0 than
uncoated materials, with about the same L value. In still another
embodiment, the coated particulate mineral materials have a b value
closer to about 0 than uncoated materials, with a change in L value
of about 4 units or less. In still a further embodiment, the coated
particulate mineral materials have a b value about 0.5 units lower
than uncoated materials, with a change in L value of about 4 units
or less. In another embodiment, the coated particulate mineral
materials have a b value of about 0.5 to about 2 units lower than
uncoated materials, with a change in L value of about 0.2 to about
4 units. In a further embodiment, the coated particulate mineral
materials have an a value within about 0.5 units of the uncoated
materials.
Uses
[0062] The coated particulate mineral materials of the present
invention may be used in many applications. For example, the coated
particulate mineral materials may be used as pigments, fillers,
proppants, or extenders in various materials such as paints,
coatings, catalysts, stuccos, plastics, polymers, papers, potting
compounds, spackling, tape joint compounds, concretes, plywood
patches, resin based castings, water-based construction compounds,
and sensitizers in blasting explosives. In one embodiment, the
particulate mineral materials are used in paints (including but not
limited to architectural, industrial, automotive, and maintenance
paints) for, among other things, improved scrubablity, hardness,
burnish, mar, and stain resistance, corrosion resistance, and
abrasion resistance. In another embodiment, the coated particulate
mineral materials are used in filter aid/filtration applications.
In a further embodiment, the coated particulate mineral materials
are used in insulation end uses for, among other things, increased
reduced volume full resistance and increased insulation behavior.
In yet another embodiment, the coated particulate mineral materials
are used in plywood patches for, among other things, cost
reduction, sandability, and reduced shrinkage. In yet a further
embodiment, the coated particulate mineral materials are used in
polymer concretes for, among other things, higher compressive
strength, cost reduction, reduced shrinkage, and improved flow. In
still another embodiment, the coated particulate mineral materials
are used in potting compounds for, among other things, thermal
stress crack resistance and reduced shrinkage. In still a further
embodiment, the coated particulate mineral materials are used in
powder coatings for, among other things, abrasion resistance and
improved flow. In another embodiment, the coated particulate
mineral materials are used in spackling compounds for, among other
things, improved sandability and reduced shrinkage. In a further
embodiment, the coated particulate mineral materials are used in
tape joint compounds for, among other things, improved sandability
and reduced shrinkage.
[0063] In one embodiment, the coated particulate mineral materials
are used in coatings. Exemplary coatings including, but are not
limited to, architectural coatings, light industrial coatings,
industrial coatings, decorative coatings, traffic paint coatings,
automotive primer coatings, automotive top coatings, electro
deposition primer ("EDP") coatings, cross-linkable lacquer
coatings, electro-static coatings, electro-static lacquer coatings,
high solid enamel coatings, low energy coatings (including
two-component urethane coatings), powder coatings, radiation
curable coatings, water reducible coatings, solventless coatings
(including epoxy/curing agents), solventless primer coatings,
elastomeric coatings, epoxy coatings (including urethane hybrid
coatings, terrazzo coatings, and high heat system coatings),
urethane and water-based coatings (including industrial &
architectural polymer flooring coatings), wood coatings,
self-leveling & trowelable surface coatings, chemical resistant
coatings, traffic deck membrane system coatings, deck and dock
stain and coating systems, bridge deck overlays, color driveway
sealer, color roof repair coatings, pickup truck bed liner
coatings, muffler repair coatings, ship deck coatings, concrete
floor coatings, hockey stick tape coatings, workboot toe protection
coatings, rust and corrosion preventative coatings, and anti-slip
protection coatings.
[0064] In another embodiment, the coated particulate mineral
materials are used in catalysts. Exemplary catalysts include, but
are not limited to, acid catalysts (used, for example, in ammonia
& methanol applications), amination catalysts (used, for
example, in alcohol applications), ammonia synthesis catalysts
(used, for example, in amine applications), methanol synthesis
catalysts (used, for example, in carrier applications), custom
manufactured catalysts (used, for example, in cyclohexane
applications), dehydrogenation catalysts (used, for example, in
diol and poliol applications), hydrogenation catalysts (used, for
example, in flavor and fragrance applications), pre-reforming
catalysts (used, for example, in feed purification applications),
steam-reforming catalysts (used, for example, in ketone and alcohol
applications), shift catalysts (used, for example, in nylon
intermediate applications), sulfur catalysts (used, for example, in
resin and wax applications), and chloride removal catalysts (used,
for example, in oxidation and oxychlorination applications).
[0065] Other than in the examples, or where otherwise indicated,
all numbers expressing quantities of ingredients, reaction
conditions, and so forth used in the specification and claims are
to be understood as being modified in all instances by the term
"about" Accordingly, unless indicated to the contrary, the
numerical parameters set forth in the specification and attached
claims are approximations that may vary depending upon the desired
properties sought to be obtained by the present disclosure. At the
very least, and not as an attempt to limit the application of the
doctrine of equivalents to the scope of the claims, each numerical
parameter should be construed in light of the number of significant
digits and ordinary rounding approaches.
[0066] Notwithstanding that the numerical ranges and parameters
setting forth the broad scope of the invention are approximations
and, unless otherwise indicated, the numerical values set forth in
the specific examples are reported as precisely as possible. Any
numerical value, however, inherently contains certain errors
necessarily resulting from the standard deviation found in their
respective testing measurements.
[0067] By way of non-limiting illustration, examples of certain
embodiments of the present disclosure are given below.
EXAMPLES
Example 1
[0068] An in-line coating process was used to coat Harborlite
50.times.50, a commercially available perlite filler product from
World Minerals Inc., with at least one coating that comprises at
least one alumino silicate. First, 200 pounds of sodium silicate
(Brenntag N grade, SiO.sub.2/Na.sub.2O=3.22) was mixed with 250
pounds of water in a stainless steel container for 10 minutes.
Next, 38 pounds of aluminum sulfate (Brenntag) was added to the
solution. After mixing for 10 minutes, the solution was injected at
20 pds/min into a perlite expander in production of Harborlite
50.times.50. The injection point was located adjacent to the port
for the thermocouple in the perlite expander (also called
"in-line"). The temperature at the injection point was from
900.degree. F. to 1100.degree. F. The injection was started after
10 minutes of production of the control product (non-alumino
silicate coated Harborlite 50.times.50). Samples were collected
every 5 minutes. The first sample, consisting of the non-alumino
silicate coated Harborlite 50.times.50 control material, was
collected at time 0, just before the start of injection. Four
additional samples, consisting of the alumino silicate coated
material, were then collected at times 5 min, 10 min, 15 min, and
20 min. A total of 684 pounds of coated product was produced during
the run.
[0069] As shown in Table 1, the alumino silicate glass/ceramic
coating clearly and unexpectedly improved the compaction resistance
of the Harborlite 50.times.50.
TABLE-US-00001 TABLE 1 Compaction Density and Resistance of Alumino
silicate Glass/Ceramic Coated Perlite 1-Inch 2-Inch Compaction
Compaction Compaction Sample ID Density (pd/cf) Resistance (psi)
Resistance (psi) Non-Al--Si 3.1 10.4 35.3 Coated Harborlite 50x50
(control), 0 min Al--Si Coated 3.5 16.5 47.0 Harborlite 50x50, 5
min Al--Si Coated 3.3 15.5 45.5 Harborlite 50x50, 10 min Al--Si
Coated 2.9 12.8 36.4 Harborlite 50x50, 15 min Al--Si Coated 3.2
14.0 42.2 Harborlite 50x50, 20 min
[0070] The methods used for determining the strength and hardness
of the perlite material presented in Table 1 were a compaction
density test and a compaction resistance test. In the compaction
density test, the perlite to be tested was packed into a test
cylinder with 11/8 inch inside diameter and 5 inch inside depth.
The filled test cylinder was then held on the platform of a
compaction density machine and bounced 25 times. After fitting a
flanged collar on the test cylinder, more samples were added to
bring the height to within an inch of the top of the collar. The
filled test cylinder was then bounced for an additional 25 times.
After removing the collar, the perlite above the level of the test
cylinder was struck off with a straight edge. The cylinder with
samples was then weighed for a compaction density measurement.
[0071] To determine the compaction resistance, a Dillion TC.sup.2
Tension Compression Cyclic machine was used to test cylinders
packed with the perlite produced according to this example. During
the test, the cylinder was slowly compressed with a piston at a
speed of 2 inch/min to the 1 inch or 2 inch mark. The resistance of
the particulate material during the compaction was measured.
[0072] It is believed that the slight downward trend in density and
compaction resistance of the coated particulate material was due to
a gradual increase in the homogeneity of the Al--Si coatings formed
on the samples. This homogeneity was most likely caused by large
agglomerated/melted chunk material that built up in the expander
after expansion. It is believed that the Al--Si solution was
concentrated on some spots in the expander at the end of the
expansion, thus resulting in an Al--Si coating on the substrate
that gradually became thinner and thinner, thereby gradually
decreasing the density and compaction resistance of the
samples.
Example 2
[0073] An expanded perlite microsphere product different from
Example 1 was used as the substrate for an alumino silicate
glass/ceramic coating. Prior to coating, the non-coated alumino
silicate perlite microsphere product was measured to have an
average particle size of 46 microns, a 1-inch compaction resistance
of 22 psi, and a compaction density of 9.1 lb/cf. FIG. 1 shows the
scanning electron micrograph of this starting, non-coated
sample.
[0074] To coat the starting perlite microsphere product, first, 20
grams of sodium silicate solution (PQ Corporation N.RTM. 38,
SiO.sub.2/Na.sub.2O=3.22) was mixed with 10 grams of water for 10
minutes. Second, 1 gram of aluminum sulfate (Alfa Aesar,
Al.sub.2(SO.sub.4).sub.3.XH.sub.2O, X.apprxeq.14-18) was added to
the silicate solution. That solution was mixed for another 10
minutes. Next, the solution was sprayed onto 80 grams of the
substrate perlite microspheres. After drying overnight in the air,
the alumino silicate glass/ceramic coated sample was tested for
compaction resistance as stated in Example 1. This alumino silicate
glass/ceramic coated sample had a 1-inch compaction resistance of
44 psi and a compaction density of 9.4 lb/cf.
[0075] In practice, it is often times desirable to obtain a product
that exhibits higher strength at lower densities. In general, a
thicker coating yields a larger or greater increase in compaction
density. Since only a relatively small sample of expanded perlite
microspheres was used in this Example 2, as compared with Example
1, it is believed that a greater percentage of the expanded perlite
microspheres were substantially fully coated, thus leading to a
higher degree of homogeneity than in that Example 1. Notably, while
the applied alumino silicate coating was not thick enough to
significantly increase the compaction density of the expanded
perlite microsphere sample, it did result in greatly and
unexpectedly improved strength characteristics, as measured by
compaction resistance.
Example 3
[0076] Example 2 was repeated except that 60 g of the perlite
microspheres were used. The alumino silicate glass/ceramic coated
sample had a 1-inch compaction resistance of 51 psi and a
compaction density of 9.8 lb/cf, measured by the techniques used in
Example 1. The Al--Si to substrate ratio in Example 2 increased to
21:60 from 21:80 in Example 1. It is believed that this Example 3
resulted in a thicker coating than in Example 2 and lead to both a
higher compaction density and a higher compressive strength, as
measured by compaction resistance.
Example 4
[0077] Samples of perlite microspheres were coated with
alumino-silicate coatings according to the present invention to
evaluate the increase in compaction density and compaction
resistance. Samples of commercially available perlite microspheres,
Harborlite PA1000 and Harborlite PA116 (from World Minerals Inc.)
were coated with an alumino silicate coating. The alumino silicate
coating comprised aluminum sulfate and sodium silicate. For coating
the Harborlite PA1000 samples, the sodium silicate to aluminum
sulfate ratio in the coating solution was fixed at 20, and the
coating solution to perlite microsphere ratio was varied from 0.3
to 2. For coating the Harborlite PA116 samples, the sodium silicate
to aluminum sulfate ratio in the coating solution was varied from 5
to 60, and the coating solution to perlite microsphere ratio was
fixed at 1.
[0078] To coat the perlite microsphere samples, first, the desired
amount of sodium silicate solution (PQ Corporation N.RTM. 38,
SiO.sub.2/Na.sub.2O=3.22), reflected in Table 2 below, was mixed
with 10 grams of water for 10 minutes. Next, the desired amount of
aluminum sulfate (Alfa Aesar, Al.sub.2(SO.sub.4).sub.3.XH.sub.2O,
X.apprxeq.14-18), reflected in Table 2 below, was added to the
silicate solution. That solution was mixed for another 10 minutes.
The solution was then sprayed onto the specified amount of the
substrate perlite microspheres, as reflected in Table 2 below.
After drying overnight in the air, the aluminosilicate
glass/ceramic coated samples were tested for compaction density and
resistance.
[0079] Compaction density and 1-inch compaction resistance of the
uncoated perlite materials were measured as stated in Example 1 and
compared with the compaction density and 1-inch compaction
resistance of the same material after coating with an alumino
silicate coating in accordance with the present invention. In
addition, the ratio of aluminum compound to silicate compound and
alumino silicate coating solution to perlite material were varied
in order to evaluate the impact of those concentrations on the same
parameters. Finally, for purposes of comparison, three additional
uncoated glass microsphere products, 3M Company's Scotchlite glass
bubble K-1, K-15, and S-22, were also evaluated to determine their
compaction density and 1-inch compaction resistance. The results of
those tests are shown in Table 2 below.
TABLE-US-00002 TABLE 2 Compaction Density and Resistance of Alumino
Silicate Coated Perlite Microspheres Na.sub.2SiO.sub.3/ Al--Si
solution/ Compaction 1-Inch Compaction Sample ID
AL.sub.2(SO.sub.4).sub.3 .times. H.sub.20 Ratio Perlite Ratio
Density (lb/cf) Resistance (psi) 3M K-1 (control) 5.7 57 3M K-15
(control) 6.6 74 SM S-22 (control) 8.6 125 PA1000 (control) 11.4 23
Al--Si coated PA1000 20 2 15.0 135 Al--Si coated PA1000 20 1 14.5
73 Al--Si coated PA1000 20 0.5 12.0 49 Al--Si coated PA1000 20 0.3
11.0 44 PA116 (control) 10.2 20 Al--Si coated PA116 5 1 14.6 178
Al--Si coated PA116 10 1 10.7 35 Al--Si coated PA116 20 1 11.5 45
Al--Si coated PA116 40 1 12.1 57 Al--Si coated PA116 60 1 11.4
51
[0080] As can be seen from Table 2, the samples of perlite
microspheres coated with the metal silicate (alumino silicate)
coatings according to the present invention exhibited a marked
increase in 1-inch compaction resistance, with minimal effect on
compaction density as compared to the uncoated control samples. In
addition, it can be seen that increasing the ratio of alumino
silicate coating to perlite material had a minimal effect on
compaction density, while compressive strength (as measured by
compaction resistance) was dramatically increased.
[0081] The results demonstrate that compaction resistance increased
linearly with increasing coating solution to perlite ratio. Without
wishing to be bound by theory, it is believed that the coating
layer on the perlite microsphere surface became thicker with larger
amount of coating solution, thus leading to higher strength. This
relationship from the above testing is depicted in FIG. 7.
[0082] In addition, at an alumino silicate to perlite ratio of 1,
higher strength was observed at low silicate to aluminum ratio
(<5), while higher silicate to aluminum ratio (>5) had no
significant impact on the strength. This relationship from the
above testing is depicted in FIG. 8. Moreover, as compared to the
commercial glass microsphere samples K-1, K-15, and S-22, the
testing results also demonstrate that the strength for the
aluminosilicate coated perlite microspheres according to the
present invention were at least comparable to that of the
commercial products.
Example 5
[0083] In Example 5, samples of perlite microspheres were coated
with zirconium silicate coatings according to the present invention
to evaluate the increase in compaction density and compaction
resistance. Samples of Harborlite PA116, available from World
Minerals Inc., were used for the samples of perlite microspheres.
To coat the perlite microsphere samples, first, the desired amount
(17 to 40 grams as reflected in Table 3 below) of sodium silicate
solution (PQ Corporation N.RTM. 38, SiO.sub.2/Na.sub.2O=3.22) was
mixed with desired amount (17 to 33 grams as reflected in Table 3
below) of zirconium sulfate solution (Aldrich, Zr(SO.sub.4).sub.2,
35%) for 10 minutes. In some cases, additional water was also added
into the solution. Next, the solution was sprayed onto the desired
amount of the substrate perlite microspheres as reflected in Table
3 below. After drying overnight in the air, the aluminosilicate
glass/ceramic coated samples were tested for compaction resistance
and density using the techniques of Example 1.
[0084] Measurements of the compaction density and 1-inch compaction
resistance of the uncoated perlite materials was measured and
compared with the compaction density and 1-inch compaction
resistance of the same material after coating with a zirconium
silicate coating in accordance with the present invention. In
addition, the ratio of zirconium compound to silicate compound and
zirconium silicate coating to perlite material were varied in order
to evaluate the impact of those concentrations on the same
parameters. The results of those tests is shown in Table 3
below.
TABLE-US-00003 TABLE 3 Compaction Density and Resistance of
Zirconium Silicate Coated Perlite Loose 1-Inch Zr--Si Weight
Compaction Compaction Perlite H.sub.2O Zr(SO.sub.4).sub.2
Na.sub.2SiO.sub.3 Na.sub.2SiO.sub.3/Zr(SO.sub.4).sub.2
Solution/Perlite Density Density Resistance (g) (g) (g) (g) Ratio
Ratio (lb/cf) (lb/cf) (psi) Control 8.9 10.2 10 (PA116) 50 0 23 17
0.7 1 10.8 12.6 18 50 0 25 25 1 1 12.6 14.7 71 50 0 17 33 1.9 1
12.8 15.5 100 50 10 7 33 4.7 0.8 9.8 11.6 29 50 10 10 30 3.0 0.8
11.6 13.6 85 50 10 15 25 1.7 0.8 11.7 13.8 78
[0085] As can be seen from Table 3, the zirconium silicate coated
perlite samples exhibited a dramatic increase in compressive
strength as compared with the uncoated perlite sample, while only a
slight increase in compaction density. In addition, as the ratio of
zirconium silicate coating to perlite material was increased, the
compaction resistance was also increased. The tested samples were
found to exhibit the greatest strength at a
Na.sub.2SiO.sub.3/Zr(SO.sub.4).sub.2 ratio between 1 to 3.
Example 6
[0086] In Example 6, samples of diatomite were coated with various
metal silicate coatings to evaluate their increase on scrub
resistance. Samples of CelTix diatomite, available from World
Minerals Inc., were treated with the various coatings. The
diatomite samples were coated with zirconium silicate and
boron-silicate coatings according to the present invention and
compared with an uncoated diatomite sample and samples of diatomite
coated with an ammonium zirconium carbonate (Zr(AZC)) coating not
in accordance with the present invention.
[0087] To coat the CelTix, first, the desired amount of ammonium
zirconium carbonate solution (Aldrich,
(NH.sub.4)ZrO(CO.sub.3).sub.2, 14-16% Zr as reflected in Table 4
below) was mixed with 20 g of water for 10 minutes. Next, the
solution was sprayed onto 200 g of CelTix. After drying at
120.degree. C. overnight in the air, the ammonium zirconium
carbonate coated samples were tested for scrub resistance.
[0088] CelTix was also coated with zirconium silicate using
zirconyl chloride and ammonium zirconium carbonate as the starting
materials. For zirconyl chloride coating, first, 3 grams of sodium
silicate solution (PQ Corporation N.RTM. 38,
SiO.sub.2/Na.sub.2O=3.22) was mixed with 15 grams of water for 10
minutes. Second, 6 grams of zirconyl chloride solution (Aldrich,
ZrOCl.sub.2, 30%) was mixed with 15 g of water for 10 minutes and
then added to the sodium silicate solution. Next, the Zr--Si
coating solution was sprayed onto 200 g of CelTix. After drying at
120.degree. C. overnight in the air, the zirconium silicate coated
samples were tested for scrub resistance. For ammonium zirconium
carbonate coating, first, 5 grams of sodium silicate solution (PQ
Corporation N.RTM. 38, SiO.sub.2/Na.sub.2O=3.22) was mixed with 30
grams of water for 10 minutes. Second, 40 grams of ammonium
zirconium carbonate solution (Aldrich) was mixed with 20 g of water
for 10 minutes and then added to the sodium silicate solution.
Next, the Zr--Si coating solution was sprayed onto 200 g of CelTix.
After drying at 120.degree. C. overnight in the air, the zirconium
silicate coated sample was tested for scrub resistance.
[0089] To coat the CelTix samples with borosilicate, first, the
desired amount (2-5 grams) of sodium silicate solution (PQ
Corporation N.RTM. 38, SiO.sub.2/Na.sub.2O=3.22) was mixed with 10
grams of water for 10 minutes. Second, desired amount (5-10 grams)
of ammonium pentaborate octahydrate (Aldrich,
(NH.sub.4).sub.2B.sub.10O.sub.16.8H.sub.2O, >99%) was mixed with
desired amount (3-45 grams) of water for 10 minutes and then added
to the sodium silicate solution. The ammonium pentaborate
octahydrate to sodium silicate ratio was varied from 1 to 5. Next,
the borosilicate coating solution was sprayed onto 200 g of CelTix.
After drying at 120.degree. C. overnight in the air, the
borosilicate coated samples were tested for scrub resistance. The
scrub resistance of the uncoated diatomite material and ammonium
zirconium carbonate coated diatomite materials were measured and
compared with the scrub resistance of the same material coated with
zirconium silicate and boron-silicate coatings in accordance with
the present invention. The results of those tests are shown in
Table 4 below.
TABLE-US-00004 TABLE 4 Scrub Resistance of Metal Silicate Coated
Diatomite % Increase of Scrub Sample ID Resistance CelTix (control)
0 12% (NH.sub.4)ZrO(CO.sub.3).sub.2 coated CelTix -12 24%
(NH.sub.4)ZrO(CO.sub.3).sub.2 coated CelTix 14 Zirconium silicate
coated CelTix 12 (ZrOCl.sub.2 to Na.sub.2SiO.sub.3 ratio of 2)
Zirconium silicate coated CelTix 17 ((NH.sub.4)ZrO(CO.sub.3).sub.2
to Na.sub.2SiO.sub.3 ratio of 8) Borosilicate coated CelTix 14
((NH.sub.4).sub.2B.sub.10O.sub.16 to Na.sub.2SiO.sub.3 ratio of 2)
Borosilicate coated CelTix 7 ((NH.sub.4).sub.2B.sub.10O.sub.16 to
Na.sub.2SiO.sub.3 ratio of 1) Borosilicate coated CelTix 2
((NH.sub.4).sub.2B.sub.10O.sub.16 to Na.sub.2SiO.sub.3 ratio of
5)
[0090] As can be seen from Table 4, each of the samples treated
with the coatings according to the present invention exhibited
increased scrub resistance as compared to the uncoated control
sample, regardless of the loading concentration. In contrast,
meaningful improvement on scrub resistance within testing
parameters for the ammonium zirconium carbonate coating was only
seen at a loading of 24%. In addition, scrub resistance improvement
was seen for the zirconium silicate coatings regardless of the
zirconium compound starting material (17% improvement for the
ammonium zirconium carbonate starting material and 12% for the
zirconyl chloride).
Example 7
[0091] In Example 7, samples of diatomite were coated with zinc
oxide coatings to evaluate their change in coloration. Seven
samples of CelTix diatomite, available from World Minerals Inc.,
were treated with the zinc oxide coatings in various weight
percentages, at various temperatures, and for various particle
sizes of the base diatomite material as reflected in Table 5 below.
To coat the CelTix with zinc oxide, the desired amount (6-24 grams
as reflected in Table 5 below) of zinc sulfate (Mallinckrodt,
ZnSO.sub.4.7H.sub.2O, 99.3%) was mixed with 20 g of water for 10
minutes, and then the solution at about room temperature was
sprayed onto 200 g of CelTix. The coated samples were then dried at
120.degree. C. overnight in the air. As reflected in Table 5, many
of the dried samples were additionally heat-treated at 300.degree.
C. for 15 minutes. The coloration of the resultant zinc oxide
coated diatomite materials were evaluated for improved coloration
using Hunter L, a, b color measurements collected on a Spectro/plus
Spectrophotometer (Color and Appearance Technology, Inc.,
Princeton, N.J.). The coated samples were then compared to the
uncoated control sample. The results of those tests are shown in
Table 5 below.
TABLE-US-00005 TABLE 5 Improved Coloration of Zinc Oxide Coated
Diatomite Drying/heat- treatment Temperature Blue Light Celtix (g)
Zn(SO.sub.4) (g) (.degree. C.) d10 d50 d90 L a b Brightness Control
4.91 13.57 28.78 93.16 0.20 4.53 80.76 200 6 120 4.86 13.35 30.61
92.72 0.59 3.46 81.39 200 6 300 4.57 13.47 31.72 90.14 0.36 3.45
76.81 200 12 120 4.67 13.09 29.98 92.48 0.36 3.47 80.94 200 12 300
4.58 13.51 32.04 89.55 0.17 2.92 76.46 200 24 120 4.76 12.70 28.85
91.81 0.29 3.15 80.16 200 24 300 4.58 13.44 32.41 89.53 0.19 2.69
76.72
[0092] As can be seen from the results in Table 5, the diatomite
samples coated with the zinc oxide coating exhibited unexpected and
desirable reduction in yellowness (b value). In general, yellowness
is not found to be desirable for many filler applications. The
heat-treatment at 300.degree. C. was also found to further reduce
yellowness. Decreases in brightness (L value) were acceptable given
the decrease in yellowness, as were decreases in blue light
brightness, as overall the dried as well as the heat treated
samples still exhibited improved coloration.
[0093] Other embodiments of this invention will be apparent to
those skilled in the art from consideration of the specification
and practice of the invention disclosed herein. It is intended that
the specification and examples be considered as exemplary only,
with a true scope and spirit of the invention being indicated by
the following claims.
* * * * *