CN117230305A - Method for improving compressive strength of chrome ore powder pellets - Google Patents
Method for improving compressive strength of chrome ore powder pellets Download PDFInfo
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- CN117230305A CN117230305A CN202311128852.4A CN202311128852A CN117230305A CN 117230305 A CN117230305 A CN 117230305A CN 202311128852 A CN202311128852 A CN 202311128852A CN 117230305 A CN117230305 A CN 117230305A
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- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 title claims abstract description 277
- 239000000843 powder Substances 0.000 title claims abstract description 201
- 239000008188 pellet Substances 0.000 title claims abstract description 147
- 238000000034 method Methods 0.000 title claims abstract description 45
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 221
- 239000011651 chromium Substances 0.000 claims abstract description 221
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 claims abstract description 126
- 239000000292 calcium oxide Substances 0.000 claims abstract description 63
- 235000012255 calcium oxide Nutrition 0.000 claims abstract description 63
- 239000000440 bentonite Substances 0.000 claims abstract description 56
- 229910000278 bentonite Inorganic materials 0.000 claims abstract description 56
- SVPXDRXYRYOSEX-UHFFFAOYSA-N bentoquatam Chemical compound O.O=[Si]=O.O=[Al]O[Al]=O SVPXDRXYRYOSEX-UHFFFAOYSA-N 0.000 claims abstract description 56
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 54
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 30
- 238000000227 grinding Methods 0.000 claims abstract description 25
- 238000001816 cooling Methods 0.000 claims abstract description 24
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 21
- 229910052742 iron Inorganic materials 0.000 claims abstract description 9
- 229910052500 inorganic mineral Inorganic materials 0.000 claims description 71
- 235000010755 mineral Nutrition 0.000 claims description 71
- 239000011707 mineral Substances 0.000 claims description 71
- 239000002245 particle Substances 0.000 claims description 69
- 238000005245 sintering Methods 0.000 claims description 54
- 239000000203 mixture Substances 0.000 claims description 22
- 238000002156 mixing Methods 0.000 claims description 12
- 238000005303 weighing Methods 0.000 claims description 10
- 229910018072 Al 2 O 3 Inorganic materials 0.000 claims description 5
- 229910052799 carbon Inorganic materials 0.000 claims description 3
- 229910004298 SiO 2 Inorganic materials 0.000 claims description 2
- 238000004519 manufacturing process Methods 0.000 abstract description 12
- 229910000831 Steel Chemical group 0.000 abstract description 7
- 238000010304 firing Methods 0.000 abstract description 7
- 239000010959 steel Chemical group 0.000 abstract description 7
- 230000000052 comparative effect Effects 0.000 description 18
- 238000012360 testing method Methods 0.000 description 11
- 238000005453 pelletization Methods 0.000 description 4
- 230000006835 compression Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000011819 refractory material Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Classifications
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
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Abstract
The invention discloses a method for improving compressive strength of chrome ore powder pellets, which comprises the following steps: the invention prepares chrome ore pellets by adding quicklime and coke powder into chrome ore powder, firstly firing the chrome ore powder into sinter, then crushing the sinter, finely grinding the sinter, adding bentonite and water into the sinter to prepare raw pellets with the grain diameter of 9-16 mm, and then entering a belt type roasting machine to prepare the chrome ore pellets according to the specified procedures of preheating, roasting and cooling. Compared with the prior art, the method for improving the compressive strength of the chromium ore powder pellets can improve the compressive strength of the chromium ore powder pellets by at least 370N/ball on the premise of not improving the roasting temperature of the belt conveyor during roasting, thereby avoiding burning out iron and steel parts, reducing the probability of accidents and improving the equipment operation rate and the production efficiency of the chromium ore pellet belt conveyor production line by reducing the roasting temperature of the chromium ore powder during roasting of the belt conveyor.
Description
Technical Field
The invention belongs to the technical field of production of chromium ore powder pellets, and particularly relates to a method for improving compressive strength of chromium ore powder pellets.
Background
In the prior art, when a belt type machine is adopted to produce chrome ore powder pellets, even if the temperature of a high-temperature roasting section is increased to 1320-1350 ℃, the compressive strength of the finished chrome ore pellets is still at a level of about 2000N/pellet, and even most of the compressive strength of the finished chrome ore pellets cannot reach 2000N/pellet. In order to improve the compressive strength of the chromium ore pellets, the traditional method is to further improve the roasting temperature of a high-temperature section of the belt conveyor so as to improve the compressive strength of the chromium ore pellets, but the high-temperature roasting requires steel and iron parts and refractory materials which are more resistant to high temperature, so that the production and operation costs are increased, the steel and iron parts are easy to burn out, accidents can occur, and the equipment operation rate is influenced by the fact that the equipment is not periodically stopped for maintenance.
Therefore, it is necessary to develop a method for improving the compressive strength of the chrome ore powder pellets without improving the roasting temperature of the belt conveyor during the roasting, so that the steel iron piece is prevented from being burnt out, the accident occurrence probability is reduced, and the equipment operation rate and the production efficiency of the chrome ore pellet belt conveyor production line are improved by reducing the roasting temperature of the chrome ore powder during the belt conveyor roasting.
Disclosure of Invention
In order to solve the technical problems in the prior art, the invention provides a method for improving compressive strength of chrome ore powder pellets, which comprises the following steps:
step one, chromium ore powder batching and sintering
The chromium mineral powder, the quicklime and the coke powder are weighed and proportioned according to the following parts by weight:
770-830 parts of chromium ore powder
70-130 parts of quicklime
100 parts of coke powder
Then mixing evenly, adding water, and sintering on a sintering machine after distributing to obtain chromium sinter with binary alkalinity of 0.7-1.5;
step two, finely grinding the chromium sinter
Cooling, crushing and finely grinding the chromium sinter into chromium sinter powder, wherein the proportion of particles with the particle size smaller than 200 meshes in the chromium sinter powder is controlled to be more than 75 percent;
step three, preparing raw pellets
Weighing and proportioning chromium sinter powder and bentonite according to the following parts by weight:
985-990 parts of chromium sintered ore powder
10 to 15 portions of bentonite
Then adding water, and preparing into raw pellets with the particle size of 9-16 mm in a disc pelletizer;
step four, preparing chrome ore pellets
The raw pellets are distributed and roasted on a belt type machine roasting device, the roasting temperature of a high temperature section is controlled to be 1320-1340 ℃, and finished chrome pellets are obtained after the high temperature roasting and on-machine cooling.
As an embodiment, in the above method for improving compressive strength of chrome ore powder pellets:
in the first step, the mixture ratio of the chromium mineral powder, the quicklime and the coke powder is as follows:
829 parts of chromium mineral powder
71 parts of quicklime
100 parts of coke powder
The binary alkalinity of the chromium sinter is 0.8;
in the second step, the proportion of particles with the particle size smaller than 200 meshes in the chromium sintering mineral powder is 77.5 percent;
in the third step, the mixture ratio of the chromium sintering mineral powder and bentonite is as follows:
985 parts of chromium sinter powder
15 parts of bentonite;
in the fourth step, the high temperature section roasting temperature is 1320 ℃, and the high temperature section roasting time is 27min.
As an embodiment, in the above method for improving compressive strength of chrome ore powder pellets:
in the first step, the mixture ratio of the chromium mineral powder, the quicklime and the coke powder is as follows:
810 parts of chromium mineral powder
Quicklime 90 parts
100 parts of coke powder
The binary alkalinity of the chromium sinter is 1.0;
in the second step, the proportion of particles with the particle size smaller than 200 meshes in the chromium sintering mineral powder is 77.5 percent;
in the third step, the mixture ratio of the chromium sintering mineral powder and bentonite is as follows:
987 parts of chromium sinter powder
13 parts of bentonite;
in the fourth step, the high temperature section roasting temperature is 1320 ℃, and the high temperature section roasting time is 27min. As an embodiment, in the above method for improving compressive strength of chrome ore powder pellets: in the first step, the mixture ratio of the chromium mineral powder, the quicklime and the coke powder is as follows:
793 parts of chromium mineral powder
Quicklime 107 parts
100 parts of coke powder
The binary alkalinity of the chromium sinter is 1.2;
in the second step, the proportion of particles with the particle size smaller than 200 meshes in the chromium sintering mineral powder is 77.5 percent;
in the third step, the mixture ratio of the chromium sintering mineral powder and bentonite is as follows:
988 parts of chromium sinter powder
12 parts of bentonite;
in the fourth step, the high temperature section roasting temperature is 1320 ℃, and the high temperature section roasting time is 27min. As an embodiment, in the above method for improving compressive strength of chrome ore powder pellets: in the first step, the mixture ratio of the chromium mineral powder, the quicklime and the coke powder is as follows:
776 parts of chromium mineral powder
Quicklime 124 parts
100 parts of coke powder
The binary alkalinity of the chromium sinter is 1.4;
in the second step, the proportion of particles with the particle size smaller than 200 meshes in the chromium sintering mineral powder is 77.5 percent;
in the third step, the mixture ratio of the chromium sintering mineral powder and bentonite is as follows:
990 parts of chromium sinter powder
10 parts of bentonite;
in the fourth step, the high temperature section roasting temperature is 1320 ℃, and the high temperature section roasting time is 27min. As an embodiment, in the above method for improving compressive strength of chrome ore powder pellets: in the first step, the mixture ratio of the chromium mineral powder, the quicklime and the coke powder is as follows:
810 parts of chromium mineral powder
Quicklime 90 parts
100 parts of coke powder
The binary alkalinity of the chromium sinter is 1.0;
in the second step, the proportion of particles with the particle size smaller than 200 meshes in the chromium sintering mineral powder is 77.5 percent;
in the third step, the mixture ratio of the chromium sintering mineral powder and bentonite is as follows:
987 parts of chromium sinter powder
13 parts of bentonite;
in the fourth step, the high temperature section roasting temperature is 1340 ℃ and the high temperature section roasting time is 27min.
Further, in the method for improving the compressive strength of the chromium ore powder pellet, the chromium ore powder is turkey chromium ore powder, the original chromium grade is 26.37%, the iron grade is 14.1%, and the chromium ore powder comprises SiO in percentage by weight 2 8.75%, 0.6% CaO and Al 2 O 3 The content is 9.54 percent, the MgO content is 20.6 percent, and the proportion of particles with the particle size smaller than 200 meshes in the chromium ore powder is 28.3 percent; the quicklime contains 83 weight percent of CaO and 83 weight percent of SiO 2 The content is 2.1 percent; the fixed carbon content of the coke powder is 83.2%, the ash content is 12.2%, and the proportion of particles with the particle size smaller than 3mm in the coke powder is 78%.
The method for improving the compressive strength of the chromium ore powder pellets has the following advantages and beneficial effects: the chromium ore powder is added with quicklime and coke powder, sintered into sintered ore on a sintering machine, crushed and finely ground, added with bentonite and water to prepare raw pellets with the particle size of 9-16 mm, and then fed into a belt type roasting machine to prepare the chromium ore pellets according to the specified procedures of preheating, roasting and cooling. Compared with the prior art, the method for improving the compressive strength of the chromium ore powder pellets can improve the compressive strength of the chromium ore powder pellets by at least 370N/ball on the premise of not improving the roasting temperature of the belt conveyor during roasting, thereby avoiding burning out iron and steel parts, reducing the probability of accidents and improving the equipment operation rate and the production efficiency of the chromium ore pellet belt conveyor production line by reducing the roasting temperature of the chromium ore powder during roasting of the belt conveyor.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below in connection with specific embodiments of the present invention. It will be apparent that the described embodiments are only some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The method for improving the compressive strength of the chrome ore powder pellet generally comprises the following steps: adding quicklime and coke powder into chromium ore powder, firing the mixture on a sintering machine to prepare sintered ore, crushing and finely grinding the sintered ore, adding bentonite and water to prepare raw pellets with the particle size of 9-16 mm, and then entering a belt type roasting machine to prepare chromium ore pellets according to the specified preheating, roasting and cooling procedures. The method for improving the compressive strength of the chrome ore powder pellets can improve the compressive strength of the chrome ore powder pellets on the premise of not improving the roasting temperature of the belt conveyor during roasting, so that the steel and iron parts are prevented from being burnt out by reducing the roasting temperature of the chrome ore powder during the belt conveyor during roasting, the accident occurrence probability is reduced, and the equipment operation rate and the production efficiency of the chrome ore pellet belt conveyor production line are improved.
Specifically, the method for improving the compressive strength of the chromium ore powder pellets comprises the following steps:
step one, chromium ore powder batching and sintering
The chromium mineral powder, the quicklime and the coke powder are weighed and proportioned according to the following parts by weight:
770-830 parts of chromium ore powder
70-130 parts of quicklime
100 parts of coke powder
Then mixing evenly, adding water, and sintering into binary alkalinity (CaO/SiO) on a sintering machine after distributing 2 ) 0.7 to 1.5 of chromium sinter;
step two, finely grinding the chromium sinter
Cooling, crushing and finely grinding the chromium sinter into chromium sinter powder, wherein the proportion of particles with the particle size smaller than 200 meshes (0.074 mm) in the chromium sinter powder is controlled to be more than 75 percent;
step three, preparing raw pellets
Weighing and proportioning the chromium sintering mineral powder and bentonite according to the following parts by weight:
985-990 parts of chromium sintered ore powder
10 to 15 portions of bentonite
Then adding water, and preparing into raw pellets with the particle size of 9-16 mm in a disc pelletizer;
step four, preparing chrome ore pellets
And (3) distributing and roasting the raw pellets on a belt type machine roasting device, controlling the roasting temperature of a high-temperature section to be 1320-1340 ℃, and cooling the raw pellets on a machine after high-temperature roasting to obtain finished chromium ore pellets.
As a specific embodiment, in the method for improving the compressive strength of the chromium ore powder pellets, the chromium ore powder is turkey chromium ore powder, the original chromium grade is 26.37 percent, the iron grade is 14.1 percent, and the chromium ore powder comprises SiO by weight percent 2 8.75%, 0.6% CaO and Al 2 O 3 The content is 9.54 percent, the MgO content is 20.6 percent, and the proportion of particles with the particle size smaller than 200 meshes (0.074 mm) in the chromium ore powder is 28.3 percent; the quicklime contains 83% CaO and 83% SiO by weight 2 The content is 2.1 percent; the coke powder has a fixed carbon content of 83.2% and ash content of 12.2%, wherein the proportion of particles with a particle size of less than 3mm is 78%.
Specific embodiments of the method for improving the compressive strength of chromium ore powder pellets according to the present invention will be further described below with reference to comparative examples and examples.
Comparative example 1
The conventional method for producing chrome ore pellets using a belt conveyor as comparative example 1 includes the steps of:
(1) Fine grinding of chromium ore powder
Finely grinding chromium ore, wherein the proportion of particles with the particle size smaller than 200 meshes (0.074 mm) is 78.8 percent after the fine grinding. Wherein the chromium ore powder is turkish chromium ore powder, the original chromium grade is 26.37 percent, the iron grade is 14.1 percent, and the chromium ore powder comprises SiO by weight percent 2 8.75%, 0.6% CaO and Al 2 O 3 The content of the chromium ore powder was 9.54%, the MgO content was 20.6%, and the proportion of particles having a particle size of less than 200 meshes (0.074 mm) in the chromium ore powder was 28.3%.
(2) Proportioning materials
Weighing and proportioning finely ground chromium mineral powder and bentonite according to the following parts by weight:
987 parts of chromium mineral powder
Bentonite 13 parts
Among them, bentonite is a conventional bentonite commercially available.
(3) Mixing and pelletizing
Uniformly mixing the chromium mineral powder and bentonite by a mixer, adding water into a disc pelletizer, pelletizing to produce pellets, wherein the water content of the pellets is 9.7% by weight, and the average particle size of the pellets is 9-16 mm;
(4) Preheating, roasting and cooling of belt conveyor
And (3) distributing and roasting on a belt type machine roasting device, and then cooling on the belt type machine to obtain finished chrome ore pellets, wherein the roasting temperature of a high-temperature section is 1320 ℃, and the roasting time of the high-temperature section is 27min.
The finished chrome ore pellets prepared as described above were subjected to experimental tests and had a compressive strength of 1867N/pellet.
As shown in the above comparative example 1, after the chromium ore powder was finely ground and pelletized, the compressive strength thereof after being calcined at a high temperature of 1320℃by a belt conveyor was only 1867N/pellet.
Comparative example 2
The conventional method for producing chrome ore pellets using a belt conveyor as comparative example 2 includes the steps of:
(1) Fine grinding of chromium ore powder
Finely grinding chromium ore, wherein the proportion of particles with the particle size smaller than 200 meshes (0.074 mm) is 78.8 percent after the fine grinding. Wherein the chromium ore powder is turkish chromium ore powder, the original chromium grade is 26.37 percent, the iron grade is 14.1 percent, and the chromium ore powder comprises SiO by weight percent 2 8.75%, 0.6% CaO and Al 2 O 3 The content of the chromium ore powder was 9.54%, the MgO content was 20.6%, and the proportion of particles having a particle size of less than 200 meshes (0.074 mm) in the chromium ore powder was 28.3%.
(2) Proportioning materials
Weighing and proportioning finely ground chromium mineral powder and bentonite according to the following parts by weight:
987 parts of chromium mineral powder
Bentonite 13 parts
Among them, bentonite is a conventional bentonite commercially available.
(3) Mixing and pelletizing
Uniformly mixing the chromium mineral powder and bentonite by a mixer, adding water into a disc pelletizer, pelletizing to produce pellets, wherein the water content of the pellets is 9.7% by weight, and the average particle size of the pellets is 9-16 mm;
(4) Preheating, roasting and cooling of belt conveyor
And (3) distributing and roasting on a belt type machine roasting device, and then cooling on the belt type machine to obtain finished chrome ore pellets, wherein the roasting temperature of a high-temperature section is 1340 ℃, and the roasting time of the high-temperature section is 27min.
The finished chrome ore pellets prepared as described above were tested experimentally for compressive strength of 2113N/pellet.
As shown in the above comparative example 2, after the chromium ore powder was finely ground and pelletized, the compressive strength was 2113N/pellets after being calcined at a high temperature of 1340℃of the belt conveyor, and only 246N/pellets were improved as compared with the case where the belt conveyor of comparative example 1 was calcined at a high temperature of 1320 ℃.
Example 1
In the embodiment 1 of the invention, the chromium ore powder is firstly added with quicklime powder and coke powder, sintered into sintered ore with binary alkalinity of 0.8, then finely ground into ore powder, added with bentonite and water to prepare green pellets, and then baked on a belt conveyor to obtain the chromium ore pellets. Embodiment 1 specifically includes the following steps:
step one, chromium ore powder batching and sintering
The chromium mineral powder, the quicklime and the coke powder are weighed and proportioned according to the following parts by weight:
829 parts of chromium mineral powder
71 parts of quicklime
100 parts of coke powder
Then mixing evenly, adding water, and sintering into binary alkalinity (CaO/SiO) on a sintering machine after distributing 2 ) 0.8 chromium sinter;
step two, finely grinding the chromium sinter
Cooling, crushing and finely grinding the chromium sinter into chromium sinter powder, wherein the proportion of particles with the particle size smaller than 200 meshes (0.074 mm) in the chromium sinter powder is controlled to be 77.5 percent;
step three, preparing raw pellets
Weighing and proportioning the chromium sintering mineral powder and bentonite according to the following parts by weight:
985 parts of chromium sinter powder
Bentonite 15 parts
Then adding water, and preparing into raw pellets with the particle size of 9-16 mm in a disc pelletizer;
step four, preparing chrome ore pellets
And (3) distributing and roasting the raw pellets on a belt type machine roasting device, wherein the roasting temperature of a high-temperature section is controlled to be 1320 ℃, the roasting time of the high-temperature section is controlled to be 27min, and the finished product chromium ore pellets are obtained through on-machine cooling after the high-temperature roasting.
Experimental tests were carried out on the finished chrome ore pellets prepared by using example 1, and the compressive strength of the finished chrome ore pellets was 2237N/ball.
The test result of example 1 shows that chromium mineral powder is firstly added with quicklime powder and coke powder, sintered into sintered ore with binary alkalinity of 0.8, then finely ground into mineral powder, then added with bentonite and water to prepare green pellets, and then baked on a belt conveyor, and compared with comparative example 1, the compressive strength of the finished pellets of example 1 reaches 2237N/pellet at the same baking temperature of 1320 ℃, and the compressive strength of the finished pellets is improved by 370N/pellet compared with comparative example 1; the finished ball of example 1 had 124N/ball improved compressive strength even compared to control 2, which had a higher firing temperature of 1340 ℃.
Example 2
In the embodiment 2 of the invention, the binary alkalinity of the sinter is improved to 1.0, and the method specifically comprises the following steps:
step one, chromium ore powder batching and sintering
The chromium mineral powder, the quicklime and the coke powder are weighed and proportioned according to the following parts by weight:
810 parts of chromium mineral powder
Quicklime 90 parts
100 parts of coke powder
Then mixing evenly, adding water, and sintering into binary alkalinity (CaO/SiO) on a sintering machine after distributing 2 ) Chromium sinter of 1.0;
step two, finely grinding the chromium sinter
Cooling, crushing and finely grinding the chromium sinter into chromium sinter powder, wherein the proportion of particles with the particle size smaller than 200 meshes (0.074 mm) in the chromium sinter powder is controlled to be 77.5 percent;
step three, preparing raw pellets
Weighing and proportioning the chromium sintering mineral powder and bentonite according to the following parts by weight:
987 parts of chromium sinter powder
Bentonite 13 parts
Then adding water, and preparing into raw pellets with the particle size of 9-16 mm in a disc pelletizer;
step four, preparing chrome ore pellets
And (3) distributing and roasting the raw pellets on a belt type machine roasting device, wherein the roasting temperature of a high-temperature section is controlled to be 1320 ℃, the roasting time of the high-temperature section is controlled to be 27min, and the finished product chromium ore pellets are obtained through on-machine cooling after the high-temperature roasting.
Experimental tests were carried out on the finished chrome ore pellets prepared by using example 2, the compressive strength of the finished chrome ore pellets being 2388N/ball.
The test result of example 2 shows that chromium mineral powder is firstly added with quicklime powder and coke powder, sintered into sintered ore with binary alkalinity of 1.0, then finely ground into mineral powder, then added with bentonite and water to prepare green pellets, and then baked on a belt conveyor, and compared with comparative example 1, the compressive strength of the finished pellets of example 2 reaches 2388N/pellets at the same baking temperature of 1320 ℃, and 521N/pellets are improved compared with comparative example 1; the finished ball of example 2 had an increase in compressive strength of 275N/ball, even compared to control 2, which had a higher firing temperature of 1340 ℃.
Example 3
In the embodiment 3 of the invention, the binary alkalinity of the sinter is improved to 1.2, and the method specifically comprises the following steps:
step one, chromium ore powder batching and sintering
The chromium mineral powder, the quicklime and the coke powder are weighed and proportioned according to the following parts by weight:
793 parts of chromium mineral powder
Quicklime 107 parts
100 parts of coke powder
Then mixing evenly, adding water, and sintering into binary alkalinity (CaO/SiO) on a sintering machine after distributing 2 ) 1.2 of chromium sinter;
step two, finely grinding the chromium sinter
Cooling, crushing and finely grinding the chromium sinter into chromium sinter powder, wherein the proportion of particles with the particle size smaller than 200 meshes (0.074 mm) in the chromium sinter powder is controlled to be 77.5 percent;
step three, preparing raw pellets
Weighing and proportioning the chromium sintering mineral powder and bentonite according to the following parts by weight:
988 parts of chromium sinter powder
Bentonite 12 parts
Then adding water, and preparing into raw pellets with the particle size of 9-16 mm in a disc pelletizer;
step four, preparing chrome ore pellets
And (3) distributing and roasting the raw pellets on a belt type machine roasting device, wherein the roasting temperature of a high-temperature section is controlled to be 1320 ℃, the roasting time of the high-temperature section is controlled to be 27min, and the finished product chromium ore pellets are obtained through on-machine cooling after the high-temperature roasting.
Experimental tests were carried out on the finished chrome ore pellets prepared by using example 3, the compressive strength of the finished chrome ore pellets being 2501N/ball.
The test result of example 3 shows that chromium mineral powder is firstly added with quicklime powder and coke powder, sintered into sintered ore with binary alkalinity of 1.2, then finely ground into mineral powder, then added with bentonite and water to prepare green pellets, and then baked on a belt conveyor, and compared with comparative example 1, the compressive strength of the finished pellets of example 3 reaches 2501N/pellets at the same baking temperature of 1320 ℃, and the compressive strength of the finished pellets is improved by 634N/pellets compared with comparative example 1; the finished ball compressive strength of example 3 was increased by 388N/ball even compared to control example 2, which had a higher firing temperature of 1340 ℃.
Example 4
In the embodiment 4 of the invention, the binary alkalinity of the sinter is improved to 1.4, and the method specifically comprises the following steps:
step one, chromium ore powder batching and sintering
The chromium mineral powder, the quicklime and the coke powder are weighed and proportioned according to the following parts by weight:
776 parts of chromium mineral powder
Quicklime 124 parts
100 parts of coke powder
Then mixing evenly, adding water, and sintering into binary alkalinity (CaO/SiO) on a sintering machine after distributing 2 ) 1.4 of chromium sinter;
step two, finely grinding the chromium sinter
Cooling, crushing and finely grinding the chromium sinter into chromium sinter powder, wherein the proportion of particles with the particle size smaller than 200 meshes (0.074 mm) in the chromium sinter powder is controlled to be 77.5 percent;
step three, preparing raw pellets
Weighing and proportioning the chromium sintering mineral powder and bentonite according to the following parts by weight:
990 parts of chromium sinter powder
Bentonite 10 parts
Then adding water, and preparing into raw pellets with the particle size of 9-16 mm in a disc pelletizer;
step four, preparing chrome ore pellets
And (3) distributing and roasting the raw pellets on a belt type machine roasting device, wherein the roasting temperature of a high-temperature section is controlled to be 1320 ℃, the roasting time of the high-temperature section is controlled to be 27min, and the finished product chromium ore pellets are obtained through on-machine cooling after the high-temperature roasting.
Experimental tests were carried out on the finished chrome ore pellets prepared by using example 4, the compressive strength of the finished chrome ore pellets being 2533N/ball.
The test result of example 4 shows that chromium ore powder is firstly added with quicklime powder and coke powder, sintered into sintered ore with binary alkalinity of 1.4, then finely ground into ore powder, then added with bentonite and water to prepare green pellets, and then baked on a belt conveyor, and compared with comparative example 1, the compressive strength of the finished pellets of example 4 reaches 2533N/pellets at the same baking temperature of 1320 ℃, and 666N/pellets are improved compared with comparative example 1; the finished ball of example 4 had an increase in compressive strength of 420N/ball even compared to control 2, which had a higher firing temperature of 1340 ℃.
Example 5
The method in example 5 is similar to the method in example 2, the binary alkalinity of the sinter is 1.0, but the roasting temperature of the high-temperature section of the belt conveyor is increased from 1320 ℃ to 1340 ℃, and the method specifically comprises the following steps:
step one, chromium ore powder batching and sintering
The chromium mineral powder, the quicklime and the coke powder are weighed and proportioned according to the following parts by weight:
810 parts of chromium mineral powder
Quicklime 90 parts
100 parts of coke powder
Then mixing evenly, adding water, and sintering into binary alkalinity (CaO/SiO) on a sintering machine after distributing 2 ) Chromium sinter of 1.0;
step two, finely grinding the chromium sinter
Cooling, crushing and finely grinding the chromium sinter into chromium sinter powder, wherein the proportion of particles with the particle size smaller than 200 meshes (0.074 mm) in the chromium sinter powder is controlled to be 77.5 percent;
step three, preparing raw pellets
Weighing and proportioning the chromium sintering mineral powder and bentonite according to the following parts by weight:
987 parts of chromium sinter powder
Bentonite 13 parts
Then adding water, and preparing into raw pellets with the particle size of 9-16 mm in a disc pelletizer;
step four, preparing chrome ore pellets
And (3) distributing and roasting the raw pellets on a belt type machine roasting device, wherein the roasting temperature of a high-temperature section is controlled to be 1340 ℃, the roasting time of the high-temperature section is controlled to be 27min, and the finished product chromium ore pellets are obtained through on-machine cooling after the high-temperature roasting.
Experimental tests were carried out on the finished chrome ore pellets prepared by using example 5, and the compressive strength of the finished chrome ore pellets was 2611N/ball.
The test result of example 5 shows that the chromium ore powder is firstly added with quicklime powder and coke powder, sintered into sintered ore with binary alkalinity of 1.0, then finely ground into ore powder, then added with bentonite and water to prepare green pellets, then baked on a belt conveyor, and the high-temperature section baking temperature is 1340 ℃, compared with comparative example 2, the compression strength of the finished pellets of example 5 reaches 2611N/pellets at the same baking temperature of 1340 ℃, and 498N/pellets are improved compared with comparative example 2; compared with the embodiment 2 of the invention, in which the binary basicity of the sintering ore is 1.0 and the high-temperature section roasting temperature is 1320 ℃, the compression strength of the finished ball of the embodiment 5 is also improved by 223N/ball.
In summary, compared with the prior art, the method for improving the compressive strength of the chromium ore powder pellets comprises the steps of adding quicklime and coke powder into the chromium ore powder, firstly firing the mixture into sintered ore on a sintering machine, crushing and finely grinding the sintered ore, adding bentonite and water into the crushed sintered ore to prepare raw pellets with the particle size of 9-16 mm, and then entering a belt type roasting machine to prepare the chromium ore pellets according to the specified procedures of preheating, roasting and cooling. Compared with the prior art, the method for improving the compressive strength of the chromium ore powder pellets can improve the compressive strength of the chromium ore powder pellets by at least 370N/ball on the premise of not improving the roasting temperature of the belt conveyor during roasting, thereby avoiding burning out iron and steel parts, reducing the probability of accidents and improving the equipment operation rate and the production efficiency of the chromium ore pellet belt conveyor production line by reducing the roasting temperature of the chromium ore powder during roasting of the belt conveyor.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and are not limiting thereof; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims (7)
1. The method for improving the compressive strength of the chrome ore powder pellets is characterized by comprising the following steps of:
step one, chromium ore powder batching and sintering
The chromium mineral powder, the quicklime and the coke powder are weighed and proportioned according to the following parts by weight:
770-830 parts of chromium ore powder
70-130 parts of quicklime
100 parts of coke powder
Then mixing evenly, adding water, and sintering on a sintering machine after distributing to obtain chromium sinter with binary alkalinity of 0.7-1.5;
step two, finely grinding the chromium sinter
Cooling, crushing and finely grinding the chromium sinter into chromium sinter powder, wherein the proportion of particles with the particle size smaller than 200 meshes in the chromium sinter powder is controlled to be more than 75 percent;
step three, preparing raw pellets
Weighing and proportioning chromium sinter powder and bentonite according to the following parts by weight:
985-990 parts of chromium sintered ore powder
10 to 15 portions of bentonite
Then adding water, and preparing into raw pellets with the particle size of 9-16 mm in a disc pelletizer;
step four, preparing chrome ore pellets
The raw pellets are distributed and roasted on a belt type machine roasting device, the roasting temperature of a high temperature section is controlled to be 1320-1340 ℃, and finished chrome pellets are obtained after the high temperature roasting and on-machine cooling.
2. The method for improving the compressive strength of the chrome ore powder pellets according to claim 1, wherein the method comprises the following steps:
in the first step, the mixture ratio of the chromium mineral powder, the quicklime and the coke powder is as follows:
829 parts of chromium mineral powder
71 parts of quicklime
100 parts of coke powder
The binary alkalinity of the chromium sinter is 0.8;
in the second step, the proportion of particles with the particle size smaller than 200 meshes in the chromium sintering mineral powder is 77.5 percent;
in the third step, the mixture ratio of the chromium sintering mineral powder and bentonite is as follows:
985 parts of chromium sinter powder
15 parts of bentonite;
in the fourth step, the high temperature section roasting temperature is 1320 ℃, and the high temperature section roasting time is 27min.
3. The method for improving the compressive strength of the chrome ore powder pellets according to claim 1, wherein the method comprises the following steps: in the first step, the mixture ratio of the chromium mineral powder, the quicklime and the coke powder is as follows:
810 parts of chromium mineral powder
Quicklime 90 parts
100 parts of coke powder
The binary alkalinity of the chromium sinter is 1.0;
in the second step, the proportion of particles with the particle size smaller than 200 meshes in the chromium sintering mineral powder is 77.5 percent;
in the third step, the mixture ratio of the chromium sintering mineral powder and bentonite is as follows:
987 parts of chromium sinter powder
13 parts of bentonite;
in the fourth step, the high temperature section roasting temperature is 1320 ℃, and the high temperature section roasting time is 27min.
4. The method for improving the compressive strength of the chrome ore powder pellets according to claim 1, wherein the method comprises the following steps: in the first step, the mixture ratio of the chromium mineral powder, the quicklime and the coke powder is as follows:
793 parts of chromium mineral powder
Quicklime 107 parts
100 parts of coke powder
The binary alkalinity of the chromium sinter is 1.2;
in the second step, the proportion of particles with the particle size smaller than 200 meshes in the chromium sintering mineral powder is 77.5 percent;
in the third step, the mixture ratio of the chromium sintering mineral powder and bentonite is as follows:
988 parts of chromium sinter powder
12 parts of bentonite;
in the fourth step, the high temperature section roasting temperature is 1320 ℃, and the high temperature section roasting time is 27min.
5. The method for improving the compressive strength of the chrome ore powder pellets according to claim 1, wherein the method comprises the following steps: in the first step, the mixture ratio of the chromium mineral powder, the quicklime and the coke powder is as follows:
776 parts of chromium mineral powder
Quicklime 124 parts
100 parts of coke powder
The binary alkalinity of the chromium sinter is 1.4;
in the second step, the proportion of particles with the particle size smaller than 200 meshes in the chromium sintering mineral powder is 77.5 percent;
in the third step, the mixture ratio of the chromium sintering mineral powder and bentonite is as follows:
990 parts of chromium sinter powder
10 parts of bentonite;
in the fourth step, the high temperature section roasting temperature is 1320 ℃, and the high temperature section roasting time is 27min.
6. The method for improving the compressive strength of the chrome ore powder pellets according to claim 1, wherein the method comprises the following steps:
in the first step, the mixture ratio of the chromium mineral powder, the quicklime and the coke powder is as follows:
810 parts of chromium mineral powder
Quicklime 90 parts
100 parts of coke powder
The binary alkalinity of the chromium sinter is 1.0;
in the second step, the proportion of particles with the particle size smaller than 200 meshes in the chromium sintering mineral powder is 77.5 percent;
in the third step, the mixture ratio of the chromium sintering mineral powder and bentonite is as follows:
987 parts of chromium sinter powder
13 parts of bentonite;
in the fourth step, the high temperature section roasting temperature is 1340 ℃ and the high temperature section roasting time is 27min.
7. The method for improving the compressive strength of pellets of chromium ore powder according to any one of claims 1 to 6, wherein the chromium ore powder is turkey chromium ore powder, the original chromium grade is 26.37%, the iron grade is 14.1%, and the weight percentage of SiO in the chromium ore powder is as follows 2 8.75%, 0.6% CaO and Al 2 O 3 The content is 9.54 percent, the MgO content is 20.6 percent, and the proportion of particles with the particle size smaller than 200 meshes in the chromium ore powder is 28.3 percent; the quicklime contains 83 weight percent of CaO and 83 weight percent of SiO 2 The content is 2.1 percent; the fixed carbon content of the coke powder is 83.2%, the ash content is 12.2%, and the proportion of particles with the particle size smaller than 3mm in the coke powder is 78%.
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