U.S. patent application number 13/509793 was filed with the patent office on 2013-09-05 for process for controlling a crystal form of alite in portland cement clinker.
This patent application is currently assigned to Nanjing University of Technology. The applicant listed for this patent is Lin Chen, Song Deng, Xuerun Li, Suhua Ma, Xiaodong Shen, Weiqiang Zhou. Invention is credited to Lin Chen, Song Deng, Xuerun Li, Suhua Ma, Xiaodong Shen, Weiqiang Zhou.
Application Number | 20130228102 13/509793 |
Document ID | / |
Family ID | 42431857 |
Filed Date | 2013-09-05 |
United States Patent
Application |
20130228102 |
Kind Code |
A1 |
Shen; Xiaodong ; et
al. |
September 5, 2013 |
PROCESS FOR CONTROLLING A CRYSTAL FORM OF ALITE IN PORTLAND CEMENT
CLINKER
Abstract
The present invention relates to a process of controlling
crystal form of Alite in Portland cement clinker, wherein the said
Portland cement clinker is thermally treated in order to change the
crystal form of Alite in Portland cement clinker, so as to improve
performance of resulting Portland cement clinker. The said process
of present invention is easy and feasible.
Inventors: |
Shen; Xiaodong; (Nanjing,
CN) ; Ma; Suhua; (Nanjing, CN) ; Li;
Xuerun; (Nanjing, CN) ; Chen; Lin; (Nanjing,
CN) ; Zhou; Weiqiang; (Nanjing, CN) ; Deng;
Song; (Nanjing, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Shen; Xiaodong
Ma; Suhua
Li; Xuerun
Chen; Lin
Zhou; Weiqiang
Deng; Song |
Nanjing
Nanjing
Nanjing
Nanjing
Nanjing
Nanjing |
|
CN
CN
CN
CN
CN
CN |
|
|
Assignee: |
Nanjing University of
Technology
Nanjing, Jiangsu
CN
|
Family ID: |
42431857 |
Appl. No.: |
13/509793 |
Filed: |
July 15, 2010 |
PCT Filed: |
July 15, 2010 |
PCT NO: |
PCT/CN10/75183 |
371 Date: |
March 28, 2013 |
Current U.S.
Class: |
106/749 |
Current CPC
Class: |
C04B 7/43 20130101; Y02P
40/121 20151101; C04B 7/02 20130101; C04B 7/48 20130101 |
Class at
Publication: |
106/749 |
International
Class: |
C04B 7/02 20060101
C04B007/02 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 13, 2009 |
CN |
200910212646.5 |
Claims
1. A process for controlling a crystal form of Alite in Portland
cement clinker, wherein the method comprises: (1) the calcining
prepared Portland cement raw meal to form a cement clinker, the
calcining comprising; (2) increasing the temperature of the
Portland cement raw meal at a rate of 1-35.degree. C. per min to a
first temperature of 1400-1600.degree. C.; holding the temperature
at the first temperature; and naturally cooling the formed cement
clinker; heat treating cement clinker after the temperature of the
cement clinker is reduced from the first temperature to
600-800.degree. C., the heat treatment comprising: heating the
cement clinker at a rate of 1-35.degree. C. per minute until the
cement clinker reaches a second temperature of 700-1300.degree. C.;
holding the temperature of the cement clinker at the second
temperature; and naturally cooling the cement clinker; and grinding
the cement clinker after cooling from the second temperature.
2. The process according to claim 1, wherein the holding times of
the calcining and heat treatment operations are each 5-120 minutes,
respectively.
3. The process according to claim 1, wherein the specific surface
area of the grounded clinker powder is 340-360 m.sup.2/kg.
4. The process according to claim 1, wherein the cooled clinker is
grounded to a powder using a ball mill.
5. A process for controlling crystal form of Alite in Portland
cement clinker, wherein the method comprises: calcining a Portland
cement raw meal to form a cement clinker, the calcining comprising:
heating the Portland cement raw meal to a first temperature between
1400-1600.degree. C. at a rate of 1-35.degree. C. per min; holding
the temperature at the first temperature; cooling at a rate of
40-80.degree. C. per min to a temperature of 700-1300.degree. C.;
holding the temperature at 700.about.1300.degree. C.; and naturally
cooling the formed cement clinker; and grinding the cooled clinker
to a powder.
6. The process according to claim 5, wherein the holding times of
the calcining and heat treatment operations are each 5-120 minutes,
respectively.
7. The process according to claim 5, wherein the specific surface
area of powder of the grounded clinker is 340-360 m.sup.2/kg.
8. The process according to claim 5, wherein the cooled clinker is
grounded to a powder using a ball mill.
9. The process according to claim 5, wherein cooling at a rate of
40-80.degree. C. is performed using a cooling device.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a process for controlling
crystal form of Alite in Portland cement clinker, and particularly
relates to a method for improving the performance of Portland
cement clinker.
BACKGROUND OF THE INVENTION
[0002] Cement industry is growing rapidly in China. The output of
cement in China in 2008 was around 1.45 billion tons, which took up
around 50% of global cement total output and had been No. 1 cement
producing country for 24 consecutive years all over the world. Due
to the fact that Chinese economy is in the phase of rapid
development, it is predicted that China's cement output will
continuously increase at a rate of 10%. Although lots of cement is
produced in China, the overall cement quality is relatively low,
thus the lifetime of concrete work is influenced, therefore, the
performance of cement has to be improved. Portland cement mainly
consists of Portland cement clinker, plaster and composite
material. In order to improve the performance of Portland cement,
the performance of Portland cement clinker has to be improved.
Portland cement clinker mainly consists of Alite, Belite,
C.sub.3A(3CaOAl.sub.2O.sub.3) and C.sub.4AF
(4CaO3Al.sub.2O.sub.3Fe.sub.2O.sub.3). Alite is the main supplier
to provide gelling property of Portland cement clinker, while it is
also the main energy consumer. Therefore, the content of C.sub.3S
in clinker or its activity has to be improved in order to improve
gelling property of Portland cement clinker, however, the increase
of the content of C.sub.3S in clinker will lead to increase of
energy consumption, therefore, under the national demand of energy
saving and emission reduction, one of the effective measures to
improve the performance of cement clinker is to improve the
activity of Alite in Portland cement clinker. At present, doping is
the most commonly used method to improve the activity of Alite,
wherein high-activity Alite is obtained via modification of its
crystal form.
SUMMARY OF THE INVENTION
[0003] The object of present invention is to improve the
performance of Portland cement clinker, providing a process for
controlling crystal form of Alite in Portland cement clinker, as a
result, the crystal form of Alite in Portland cement clinker is
changed and therefore the performance of Portland cement clinker is
improved.
[0004] In order to realize said object, the technical scheme of
present invention is: a process for controlling crystal form of
Alite in Portland cement clinker, wherein it includes the following
steps: [0005] (1) The prepared Portland cement raw meal is
calcined; [0006] (2) Portland cement raw meal is heated to
1400.about.1600.degree. C. at a rate of 1.about.35.degree. C. per
min, and kept at said temperature and then naturally cooled; [0007]
(3) When its temperature is at 600.about.800.degree. C., the said
cooled clinker is heated at a rate of 1-35.degree. C. per minute
until it reaches 700.about.1300.degree. C., the said clinker is
kept at said temperature, and then it is naturally cooled; [0008]
(4) The said cooled clinker is ground to powder with the aid of
ball mill;
[0009] Or it consists of the following steps: [0010] (1B) The
prepared Portland cement raw meal is calcined; [0011] (2B) Portland
cement raw meal is heated to 1400.about.1600.degree. C. at a rate
of 1.about.35.degree. C. per minute, kept at said temperature and
then it is transferred to a cooler, being cooled at a rate of
40.about.80.degree. C. per minute; [0012] (3B) When the temperature
reaches 700.about.1300.degree. C., it is kept at said temperature;
[0013] (4B) The said clinker is naturally cooled; the cooled
clinker is ground to powder with the aid of ball mill.
[0014] The holding time of step (2), (3), (2B) and (3B) is
preferred to be 5.about.120 min, respectively. The specific surface
area of ground powder of step (4) and (4B) is preferred to be
340.about.360 m.sup.2/kg.
[0015] In step (1) and (1B), the prepared cement raw meal is
calcined to form clinker according to regular processing
parameters. Besides, calcined clinker could also be directly used
in the following thermal treatment.
BENEFICIAL EFFECTS OF PRESENT INVENTION
[0016] The present invention relates to a process for controlling
crystal from of Alite in Portland cement clinker, wherein Portland
cement clinker is thermally treated so that the crystal form of
Alite in Portland cement clinker is changed and the performance of
Portland cement clinker is improved. The present process is easy
and feasible.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is XRD spectrum of Alite in cement clinker at
different 2.theta. (the said clinker is produced by Huaihai Cement
Factory), wherein FIG. 1-1 is XRD spectrum
(2.theta.=32.about.33.degree.) of Alite in cement clinker without
thermal treatment, FIG. 1-2 is XRD spectrum
(2.theta.=51.5.about.52.7.degree.) of Alite in cement clinker
without thermal treatment;
[0018] FIG. 2 is XRD spectrum of Alite in cement clinker at
different 2.theta. (the said clinker is produced by Huaihai Cement
Factory and is thermally treated); wherein FIG. 2-1 is XRD spectrum
(2.theta.=32.about.33.degree.) of Alite in cement clinker after
thermal treatment, FIG. 2-2 is XRD spectrum
(2.theta.=51.0.about.52.5.degree.) of Alite in cement clinker after
thermal treatment.
EMBODIMENT
[0019] The present invention is further illustrated with reference
to the following examples, but the present invention is not limited
to the following examples.
Example 1
[0020] (1) The prepared Portland cement raw meal is heated to
1450.degree. C. and calcined for 1 h; and then cooled; [0021] (2)
The temperature of Portland cement raw meal is increased at a rate
of 5.degree. C./min until it reaches 1450.degree. C., and kept at
said temperature for 30 min, and then naturally cooled; [0022] (3)
The said cooled clinker is heated at a temperature below
800.degree. C., the temperature is increased at a rate of
10.degree. C. per minute until it reaches 1100.degree. C.,
subsequently, the clinker is kept at said temperature for 60 min
and then naturally cooled; [0023] (4) The said cooled clinker was
ground to powder with the aid of ball mill, the specific surface
area of said powder is 340 m.sup.2/kg; the XRD spectrum of Alite in
said clinker and the XRD spectrum of Alite in clinker of Xuchou
Huaihai Cement Factory without thermal treatment are shown in FIG.
1 and FIG. 2; it can be seen that after calcination at 1100.degree.
C. for 60 min, the crystal form of Alite in Portland cement clinker
of Huaihai Cement Factory is changed from M3 to M1.
[0024] (5) 4 g plaster was added to 96 g finally obtained cement
clinker, the said mixture is stirred uniformly, subsequently, 29 mL
water (ratio between water and cement w/c=0.29) was added, the said
mixture was stirred and molded to form 20.times.20.times.20 mm
samples, and the 3d and 28d compressive strength of the samples are
determined. Samples are first cured in a curing box for 24 h,
wherein the relative humidity is 90% and the temperature is
20.+-.2.degree. C., and then knockout sample is cured in a water
curing case at 20.+-.1.degree. C. The comparison of resulting
strength is shown in Table 1.
TABLE-US-00001 TABLE 1 Plaster strength of Portland cement clinker
(MPa) Examples 3 d 28 d Xuzhou Huaihai Cement Factory 55.6 88.6
(Portland cement clinker) Example 1 57.3 92.9
Example 2
[0025] (1) The prepared Portland cement raw meal is heated to
1480.degree. C. and calcined for 0.5 h; and then cooled; [0026] (2)
The temperature of said Portland cement raw meal is increased at a
rate of 10.degree. C./min until it reaches 1500.degree. C., and
kept at said temperature for 60 min, and then it was naturally
cooled; [0027] (3) The said cooled clinker is heated at a
temperature below 700.degree. C., the temperature is increased at a
rate of 15.degree. C./min until it reaches 1000.degree. C.,
subsequently, the said clinker and kept at said temperature for 90
min, and then naturally cooled; the said clinker is ground to
powder with the aid of ball mill, the resulting specific surface
area of said powder is 350 m.sup.2/kg; [0028] (4) 4 g plaster is
added to 96 g finally obtained cement clinker, the said mixture is
stirred uniformly, subsequently, 29 mL water (ratio between water
and cement w/c=0.29) is added, the said mixture was stirred and
molded to form 20.times.20.times.20 mm samples, and the 3d and 28d
compressive strength of the samples are determined. Samples are
first cured in a curing box for 24 h, wherein the relative humidity
is 90% and the temperature is 20.+-.2.degree. C., and then knockout
sample is cured in a water curing box at 20.+-.1.degree. C. The
comparison of resulting strength is shown in Table 2.
TABLE-US-00002 [0028] TABLE 2 Plaster strength of Portland cement
clinker (MPa) Examples 3 d 28 d Xuzhou Huaihai Cement Factory 55.6
88.6 (Portland cement clinker) Example 2 58.0 95.6
Example 3
[0029] (1) The prepared Portland cement raw meal is heated to
1450.degree. C. and calcined for 1 h; and then cooled; [0030] (2)
The temperature of said Portland cement raw meal is increased at a
rate of 5.degree. C./min until it reaches 1450.degree. C., and kept
at said temperature for 60 minutes, and then the said mixture
enters a cooling machine, and the temperature of said mixture is
decreased at a rate of 55.degree. C./minute; [0031] (3) The
temperature is cooled to 1000.degree. C., and the mixture is kept
at said temperature for 60 minutes; [0032] (4) And then it was
naturally cooled; the cooled clinker is ground to powder with the
aid of ball mill, wherein the specific surface area of said powder
was 360 m.sup.2/kg; [0033] (5) 4 g plaster was added to 96 g
finally obtained cement clinker, the said mixture was stirred
uniformly, subsequently, 29 mL water (ratio between water and
cement w/c=0.29) is added, the said mixture is stirred and molded
to form 20.times.20.times.20 mm samples, and the 3d and 28d
compressive strength of samples are determined. Samples are first
cured in a curing box for 24 h, wherein the relative humidity is
90% and the temperature is 20.+-.2.degree. C., and then knockout
sample is cured in a water curing box at 20.+-.1.degree. C. The
comparison of resulting strength is shown in Table 3.
TABLE-US-00003 [0033] TABLE 3 Plaster strength of Portland cement
clinker (MPa) Examples 3 d 28 d Xuzhou Huaihai Cement Factory 55.6
88.6 (Portland cement clinker) Example 3 58.5 105.0
Example 4
[0034] (1) The prepared Portland cement raw meal is heated to
1450.degree. C. and calcined for 1 h; and then cooled; [0035] (2)
The temperature of said Portland cement raw meal is increased at a
rate of 15.degree. C./min until it reaches 1500.degree. C., and
kept at said temperature for 30 minutes, and then the said mixture
enters a cooling machine, and the temperature of said mixture was
decreased at a rate of 50.degree. C. per minute; [0036] (3) The
temperature is cooled to 1100.degree. C., and then the mixture is
kept at said temperature for 30 minutes; [0037] (4) And then it was
naturally cooled; the cooled clinker was ground to powder with the
aid of ball mill, wherein the specific surface area of said powder
was 350 m.sup.2/kg; [0038] (5) 4 g plaster is added to 96 g finally
obtained cement clinker, the said mixture was stirred,
subsequently, 29 mL water (ratio between water and cement w/c=0.29)
is added, the said mixture is stirred and molded to form
20.times.20.times.20 mm samples, and the 3d and 28d compressive
strength of samples are determined. Samples are first cured in a
curing box for 24 h, wherein the relative humidity is 90% and the
temperature is 20.+-.2.degree. C., and then knockout sample is
cured in a water curing case at 20.+-.1.degree. C. The comparison
of resulting strength is shown in Table 4.
TABLE-US-00004 [0038] TABLE 4 Plaster strength of Portland cement
clinker (MPa) Examples 3 d 28 d Xuzhou Huaihai Cement Factory 55.6
88.6 (Portland cement clinker) Example 4 56.8 91.5
* * * * *