U.S. patent application number 12/088245 was filed with the patent office on 2008-10-23 for coated slag.
This patent application is currently assigned to BASF SE. Invention is credited to Andrea Eisenhardt, Marcus Leberfinger, Johann Leitner, Hans-Jurgen Reese, Hans Ulrich Schmidt.
Application Number | 20080257108 12/088245 |
Document ID | / |
Family ID | 37453107 |
Filed Date | 2008-10-23 |
United States Patent
Application |
20080257108 |
Kind Code |
A1 |
Leberfinger; Marcus ; et
al. |
October 23, 2008 |
Coated Slag
Abstract
The invention relates to coated slag, which is coated with a
layer of a hydrophobic polyurethane.
Inventors: |
Leberfinger; Marcus;
(Georgsmarienhutte, DE) ; Schmidt; Hans Ulrich;
(Osnabruck, DE) ; Reese; Hans-Jurgen; (Damme,
DE) ; Leitner; Johann; (Olching, DE) ;
Eisenhardt; Andrea; (Vechta, DE) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
BASF SE
Ludwigshafen
DE
|
Family ID: |
37453107 |
Appl. No.: |
12/088245 |
Filed: |
October 5, 2006 |
PCT Filed: |
October 5, 2006 |
PCT NO: |
PCT/EP2006/067066 |
371 Date: |
March 27, 2008 |
Current U.S.
Class: |
75/303 ;
75/330 |
Current CPC
Class: |
C04B 26/16 20130101;
Y02W 30/91 20150501; C04B 41/4884 20130101; C09D 175/04 20130101;
C08G 18/36 20130101; Y02W 30/50 20150501; C04B 41/009 20130101;
C08G 18/542 20130101; C04B 2111/00767 20130101; Y02W 30/94
20150501; Y02W 30/542 20150501; C21B 3/04 20130101; C04B 41/63
20130101; C04B 26/16 20130101; C04B 18/141 20130101; C04B 38/0038
20130101; C04B 41/009 20130101; C04B 28/08 20130101 |
Class at
Publication: |
75/303 ;
75/330 |
International
Class: |
C22B 7/04 20060101
C22B007/04 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 10, 2005 |
DE |
10 2005 048 808.0 |
Claims
1. A coated slag, which is coated with a layer of a hydrophobic
polyurethane.
2. The coated slag according to claim 1, wherein the layer of the
polyurethane is not more than 5 mm thick.
3. The coated slag according to claim 1, wherein the layer of the
polyurethane is from 0.1 to 5 mm thick.
4. The coated slag according to claim 1, wherein the particles of
the slag are bound by the polyurethane to give a molding.
5. The coated slag according to claim 1, wherein the preparation of
the polyurethanes is effected by reacting polyisocyanates with
compounds having at least two active hydrogen atoms.
6. The coated slag according to claim 5, wherein the compounds
having at least two active hydrogen atoms comprise at least one
hydroxy-functional component known from fat chemistry.
7. The coated slag according to claim 5, wherein the compounds
having at least two active hydrogen atoms comprise at least one
phenol-modified indene/cumarone resin.
8. A process for the production of coated slag, wherein the slag is
wetted with the liquid starting components of a hydrophobic
polyurethane which cure on the surface of the slag.
9. The process according to claim 8, wherein the wetting of the
slag with the liquid starting components of the hydrophobic
polyurethane is effected by spraying.
10. The process according to claim 8, wherein the wetting of the
slag with the liquid starting components of the hydrophobic
polyurethane is effected by pouring.
11. The process according to claim 8, wherein the wetting of the
slag with the liquid starting components of the hydrophobic
polyurethane is effected in a mixer.
Description
[0001] The invention relates to slag coated with a hydrophobic
polyurethane.
[0002] Slags are obtained in many processes, in particular in
metallurgy. Depending on the production process, a distinction is
made in the case of slags between blast furnace, smelting and steel
mill slag. Depending on the process, these are produced from metal
ores, coke, limestone and dolomite as byproducts in the actual
production process. Blast furnace slag is generally used as cement
raw material and in road construction and in isolated case also as
fertilizer. The steel furnace slag obtained in a slightly smaller
amount is predominantly used in the building material sector and to
lesser extents as fertilizer. A small part, generally about 10%, is
disposed of in landfills.
[0003] A part of the steel furnace slag is also used in hydraulic
engineering in addition to road construction. The substantial
requirements with regard to hydraulic engineering stones are
specified in "Technische Lieferbedingungem fur Wasserbausteine" and
include requirements with regard to the rock density, the
classification by dimensions and weight, the stone shape, the
compressor strength, the frost resistance and the constancy of
volume. Slag used in hydraulic engineering now often replaces
constructions which were previously produced from lattice work. In
general, the slag stones are no longer set in a complicated manner
but are randomly dumped.
[0004] A disadvantage of the use of slag is firstly insufficient
mechanical stability. Thus, it has been found that, for example,
10-20% of the slag disintegrates to a very fine particle size on
use in hydraulic engineering. This comminution process leads in the
course of time to cementing which is virtually water-impermeable
and thus constitutes potential rupture points of the top
layers.
[0005] Furthermore, it is necessary to avoid the release of toxic
substances from the slag into the environment or, in the case of
hydraulic engineering, into the water. An adverse effect on the
biocoenosis and at the same time on the self-purifying capacity of
the body of water are feared as a result.
[0006] The prior art discloses the use of slag in combination with
a plastic for civil engineering and hydraulic engineering.
[0007] Thus, DE 1 946 469 describes a sealing layer for inclined
surfaces, in particular in hydraulic engineering, which layer
consists of stones, slag and a binder. Binders used are in
particular asphalt and a thermoplastic. By the addition of the
plastic to the binder, the sealing layer is prevented from flowing
away.
[0008] U.S. patent application--please insert the number--and KR
2002008805 describe the use of slag and a polymer resin as material
in road construction. This is said to increase the strength of the
material.
[0009] JP 2001163649 describes a mixture comprising an inorganic
material, for example, industrial wastes which are coated with a
sulfur-containing melt. This gives a construction material of
<44 mm which can be used in road construction but also in the
coastal region. The elution of toxic material is prevented by the
coating so that the mixture can also be used as construction
material.
[0010] JP 53137222 describes the provision of porous material, for
example slag, with a photocurable coating. Hardness, heat
resistance and chemical stability of the material are improved as a
result.
[0011] KR 2002001916 describes a water-curable coating for
surrounding silica, glass or slag. The coating consists of
sodium-polyacrylate. The composite has good resistance to sea
water.
[0012] JP 2004236546 describes the coating of slag with calcium
carbonate. The slag provided with the coating is applied to the
coast or to the bottom of the water and is said to regulate the pH
of the sea water and to reduce the construction costs.
[0013] JP 7048187 describes the recycling of waste slag in the
construction sector by coating with a liquid resin, in particular
an epoxy resin or a fiber-reinforced resin.
[0014] A disadvantage of the solutions mentioned is in particular
that they generally have insufficient resistance to environmental
influences. This may result in the coating being destroyed and its
advantages no longer being effective.
[0015] It was an object to treat slag stones so that they have high
mechanical stability and are environmentally compatible. The
process for the treatment of the slag stones should be simple and
reliable.
[0016] The object could surprisingly be achieved by coating the
slag with a layer of a hydrophobic polyurethane.
[0017] The invention accordingly relates to slag coated with a
layer of a hydrophobic polyurethane.
[0018] The invention furthermore relates to a process for the
production of coated slag, wherein the slag is coated with the
liquid starting components of a hydrophobic polyurethane which cure
on the surface of the slag.
[0019] Slag used may be all types known in industry. In particular,
it may be blast furnace, smelting and steel mill slag. The slag is
generally present in the form of pieces having a diameter in the
range of from 0.5 to 50 cm, preferably from 0.5 to 20 cm,
particularly preferably from 2 to 15 cm, in particular from 2.5 to
6.5 cm. A small proportion of smaller pieces down to fine dust can
be tolerated since this can be incorporated into the coating.
However, the amount of dust should not exceed 10% by weight, based
on the slag, since otherwise disturbances in the polyurethane may
occur.
[0020] The layer of the polyurethane on the stone is generally only
a few millimeters, preferably not more than 5 mm, in particular
from 0.1 to 5 mm, thick. The slag is substantially completely
coated.
[0021] The coating of the slag is effected, as mentioned above, by
applying the liquid starting components of the polyurethanes to the
slag, where they cure. The slag stones can be laid out and wetted
with the liquid starting components of the polyurethanes. The
wetting can be effected, for example, by pouring or spraying, but
also by simple mechanical mixing, but preferably by spraying.
[0022] The process can be designed so that the coated slag is
present in the form of individual pieces.
[0023] Preferably, the coated slag is present in the form of a
composite body, i.e. the individual pieces are bonded to one
another by the polyurethane. The individual pieces of the slag are
firmly bonded by the polyurethane, the bonding taking place only at
the points of contact. As a result, cavities form in the interior
of the molding.
[0024] The composite bodies can be produced by introducing the slag
into a mold and adding the liquid starting components of the
polyurethanes thereto, preferably by pouring or spraying as stated
above. The size of the mold is not critical but should only be so
large that the liquid starting components of the polyurethane can
wet the entire slag before they cure. Preferably, the moldings have
a size of 100+50.times.100+50.times.15+10 cm.
[0025] In a further embodiment of the process according to the
invention, the slag is applied where it is to be used, for example
on embankments, dams, dykes or traffic routes, and wetted on site
with the liquid starting components of the polyurethanes, where
they cure.
[0026] In a further embodiment of the invention, the slag is mixed
with the liquid starting components of the polyurethane in a mixer.
The mixture is then discharged from the mixer and the polyurethane
cures.
[0027] The mixers used for mixing the slag with the starting
components of the plastic can in principle be all types of mixers
with which substantially complete wetting of the slag with the
starting components of the plastic is possible. Mixers which
consist of an open container, for example a drum, which is
preferably provided with internals, have proven particularly
suitable. For the mixing, either the drum can be rotated or the
internals can be moved.
[0028] Such mixers are known and are used, for example, in the
construction industry for the production of concrete mixes.
[0029] If the mixture is applied directly to the surface to be
consolidated, it may be advantageous to mount the mixer on a
vehicle, for example a tractor, a front loader or a truck. In this
embodiment of the process according to the invention, the mixture
can be trans-ported in each case to the place where it is to be
applied. After the mixer has been emptied, the mixture can be
distributed manually, for example by means of raking.
[0030] In an embodiment of the process according to the invention,
the mixing of the slag with the liquid starting components of the
polyurethane is effected continuously. For this purpose, the slag
and the liquid starting components of the polyurethane are
introduced continuously into the mixer and the wetted stones are
discharged continuously. In this procedure, it must be ensured that
the starting materials remain in the mixer until sufficient wetting
of the slag can take place. Expediently, such a mixing apparatus
can be moved along the sections to be consolidated at a speed such
that the slag wetted with the liquid starting components of the
plastic are discharged from the mixer in an amount required for
consolidation. It is also possible to operate the continuous mixing
apparatus while stationary and to transport the wetted slag
discharged from the mixture to the desired location.
[0031] In a further embodiment of the continuous design of the
process according to the invention, the mixer may be a rotating
drum into which slag is introduced continuously. This drum is
equipped with nozzles which continuously distribute the starting
components of the plastic over the stones. Here, the rotation of
the drum ensures thorough mixing of plastic and stones.
Plastic/slag composites are then discharged continuously through
the opening at the end of the drum. The rotating drum may be
horizontal but may also be inclined at various angles in order to
promote the discharge.
[0032] In a further embodiment of the continuous process, the slag
is transported continuously onto a conveyer belt which is moved
through a tunnel. This has openings via which the starting
materials of the plastic are discharged continuously onto the slag.
At the end of the conveyer belt, the slag then falls into an open
mixing drum which discharges the composite at a conveying speed
which can be set.
[0033] The following may be stated with regard to the hydrophobic
polyurethanes.
[0034] In the context of the present invention, components of the
polyurethanes are understood very generally as meaning compounds
having free isocyanate groups and compounds having groups which are
reactive with isocyanate groups. Groups which are reactive with
isocyanate groups are generally hydroxyl groups or amino groups.
Hydroxyl groups are preferred since the amino groups are very
reactive and the reaction mixture therefore has to be processed
rapidly. The products formed by reaction of these components are
generally referred to below as polyurethanes.
[0035] Polyurethanes used may be the conventional and known
compounds of this type. The polyurethanes are prepared by reacting
polyisocyanates with compounds having at least two active hydrogen
atoms. Polyisocyanates used can in principle be all
polyisocyanates, mixtures and prepolymers which are liquid at room
temperature and have at least two isocyanate groups.
[0036] Aromatic polyisocyanates are preferably used, particularly
preferably isomers of toluoylene diisocyanate (TDI) and of
diphenylmethane diisocyanate (MDI), in particular mixtures of MDI
and polyphenylenepolymethylene polyisocyanates (crude MDI). The
polyisocyanates may also be modified, for example, by the
incorporation of isocyanurate groups and in particular by the
incorporation of urethane groups. The last-mentioned compounds are
prepared by reacting polyisocyanates with less stoichiometric
amount of compounds having at least two active hydrogen atoms and
are usually referred to as NCO prepolymers. Their NCO content is in
general in the range from 2 to 29% by weight.
[0037] In general, polyfunctional alcohols, so-called polyols, or
less preferably, polyfunctional amines are generally used as
compounds having at least two hydrogen atoms reactive with
isocyanate groups.
[0038] In a preferred embodiment of the process according to the
invention, compact polyurethanes used are those which have been
rendered hydrophobic. The hydrophobicity can be produced in
particular by addition of hydroxyl-functional components known in
fat chemistry to at least one of the starting components of the
polyurethane system, preferably to the polylol component.
[0039] A number of hydroxyl-functional components are known in fat
chemistry and may be used. Examples are castor oil, oils modified
with hydroxyl groups, such as grapeseed oil, black cumin oil,
pumpkin seed oil, borage seed oil, soybean oil, wheatgerm oil,
rapeseed oil, sunflower oil, peanut oil, apricot kernel oil,
pistachio kernel oil, almond oil, olive oil, macadamia nut oil,
avocado oil, sea buckthorn oil, sesame oil, hazelnut oil, evening
primrose oil, wild rose oil, hemp oil, safflower oil, walnut oil,
fatty acid esters modified with hydroxyl groups and based on
myristoleic acid, palmitoleic acid, oleic acid, vaccenic acid,
petroselinic acid, gadoleic acid, erucic acid, nervonic acid,
linoleic acid, linolenic acid, stearidonic acid, arachidonic acid,
timnodonic acid, clupanodonic acid and cervonic acid. Castor oil
and its reaction products with alkylene oxides or
ketone-formaldehyde resins are preferably used here. The
last-mentioned compounds are sold, for example, by Bayer AG under
the name Desmophen.RTM. 1150.
[0040] A further preferably used group of polyols known in fat
chemistry can be obtained by ring opening of epoxidized fatty acid
esters with simultaneous reaction with alcohols and, if
appropriate, subsequent further transesterification reactions. The
incorporation of hydroxyl groups into oils and fats is effected in
the main by epoxidation of the olefinic double bonds present in
these products, followed by the reaction of the epoxide groups
formed with a monohyrdric or polyhydric alcohol. A hydroxyl group
or, in the case of polyfunctional alcohols, a structure having a
larger number of OH groups is obtained from the epoxide ring. Since
oils and fats are generally glyceryl esters, parallel
trans-esterification reactions also take place in the case of the
abovementioned reactions. The compounds thus obtained preferably
have a molecular weight in the range from 500 to 1500 g/mol. Such
products are available, for example, from Henkel.
[0041] In a particularly preferred embodiment of the process
according to the invention, the compact polyurethane used is one
which can be prepared by reacting polyisocyanates with compounds
having at least two hydrogen atoms reactive with isocyanate groups,
wherein the compounds having at least two reactive hydrogen atoms
comprise at least one polylol known in fat chemistry and at least
one phenol-modified aromatic hydrocarbon resin in particular an
indene/cumarone resin. These polyurethanes and their components
have such a high hydrophobicity that they can in principle cure
even under water.
[0042] Preferably used phenol-modified aromatic hydrocarbon resins
having a terminal phenol group are phenol-modified indene/cumarone
resins, particularly preferably industrial mixtures of aromatic
hydrocarbon resins, in particular those which comprise, as a
substantial constituent, compounds of the general formula (I)
##STR00001##
where n is from 2 to 28. Such products are commercially available
and are offered, for example, by Rutgers VTF AG under the trade
name NOVARES.RTM..
[0043] The phenol-modified aromatic hydrocarbon resins, in
particular the phenol-modified indene/cumarone resins, generally
have an OH content of from 0.5 to 5.0% by weight.
[0044] The polylol known in fat chemistry and the phenol-modified
aromatic hydrocarbon resin, in particular the indene/cumarone
resin, are preferably used in a weight ratio from 100:1 to
100:50.
[0045] Together with said compounds further compounds having at
least two active hydrogen atoms may be used. Because of their high
stability to hydrolysis, polyether alcohols are preferred. They are
prepared by conventional and known processes, generally by an
addition reaction of alkylene oxides with H-functional starter
substances. The concomitantly used polyether alcohols preferably
have a functionality of at least 3 and a hydroxyl number of at
least 400 mg KOH/g, preferably at least 600 mg KOH/g, in particular
in the range from 400 to 1000 mg KOH/g. They are prepared in a
conventional manner by reacting at least trifunctional starter
substances with alkylene oxides. Starter substances which may be
used are preferably alcohols having at least three hydroxyl groups
in the molecule, for example glycerol, trimethylolpropane,
pentaerythritol, sorbitol or sucrose. A preferably used alkylene
oxide is propylene oxide.
[0046] Further conventional constituents, for example catalysts and
conventional assistants and additives, may be added to the reaction
mixture. In particular, drying agents, for example zeolites, should
be added to the reaction mixture in order to avoid accumulation of
water in the components and hence foaming of the polyurethanes. The
addition of these substances is preferably effected to the
compounds having at least two hydrogen atoms reactive with
isocyanate groups. This mixture is frequently referred to in
industry as polyol component. For improving the long-term stability
of the composites, it is furthermore advantageous to add agents for
preventing attack by microorganisms. Moreover, the addition of UV
stabilizers is advantageous for avoiding embrittlement of the
moldings.
[0047] The polyurethanes used can in principle be prepared without
the presence of catalysts. For improving the curing, catalysts may
be concomitantly used. Catalysts chosen should preferably be those
which result in as long a reaction time as possible. As a result,
it is possible for the reaction mixture to remain liquid for a long
time. As described, it is also possible in principle to work
entirely without a catalyst.
[0048] The combination of the polyisocyanates with the compounds
having at least two hydrogen atoms reactive with isocyanate groups
should be effected in a ratio such that a stoichiometric excess of
isocyanate groups, preferably of at least 5%, in particular in the
range from 5 to 60%, is present.
[0049] The preferably used hydrophobic polyurethanes are
distinguished by particularly good processability. Thus, these
polyurethanes exhibit particularly good adhesion, in particular to
moist substrates, such as wet rock, in particular granite rubble.
The curing of the polyurethanes takes place in virtually compact
form in spite of the presence of water. The compact polyurethanes
used exhibit completely compact curing even in the case of thin
layers.
[0050] The preferably used polyurethanes are therefore
outstandingly suitable for the consolidation of embankments, in
particular dams and dykes. The bond between rock and polyurethane
is very strong. Furthermore, particularly with the use of very
hydrophobic polyurethanes, there is virtually no hydrolytic
degradation of the polyurethanes and hence very long durability of
the embankments consolidated by the process according to the
invention.
[0051] For carrying out the process according to the invention, the
polyisocyanates are preferably mixed with the compounds having at
least two active hydrogen atoms and this mixture is mixed with the
stones. In principle, it would also be possible for both starting
components of the polyurethane to be added separately to the stones
and mixed together with them. In this case, however, nonuniform
mixing and hence inadequate mechanical properties of the
polyurethane may occur.
[0052] The mixing of the starting components of the polyurethane
can be effected in a known manner. In the simplest case, the
components can be introduced in the desired ratio into a vessel,
for example a bucket, mixed by simple stirring and then mixed with
the stones in the mixing apparatus. It is also possible to mix the
starting components of the polyurethane in a mixing member
customary in polyurethane chemistry, for example a mixing head, and
to bring this mixture into contact with the stones.
[0053] By means of the hydrophobic treatment of the polyurethanes,
their hydrolytic decomposition can be suppressed. The coating thus
has a virtually unlimited life.
[0054] As a result of the coating with the hydrophobic
polyurethanes, there is no emission of soluble metal compounds from
the slag. The coated slag can therefore be used for all
applications, in particular for hydraulic engineering.
[0055] The coated slag according to the invention has high strength
and can be widely used. It can be used both in the form of
individual stones and in the form of composite bodies.
[0056] The advantage of the composite bodies in hydraulic
engineering is in particular their high strength. Furthermore,
owing to the cavities in their interior and the resulting water
permeability, they can absorb the energy of the waves and therefore
provide effective protection of the banks.
* * * * *