Method for improving blast furnace high-aluminum smelting slagging

Abstract

The invention discloses a method for improving blast furnace high-aluminum smelting slagging, relates to a metallurgical technology, and provides a scheme aiming at the problem that the amount of magnesian flux added into sintered ore in the prior art is limited. And adding a certain proportion of light-burned dolomite powder and injection coal powder, mixing, feeding into a mill for milling, and injecting into a blast furnace from a tuyere through a coal gun, wherein the powder with the granularity of-200 is 80-82%. The method has the advantage that the continuous high MgO requirement of the slag is easily realized by adjusting the injection mass ratio of the light-burned dolomite powder to 2-3%. The grade of the sintered ore is improved; slagging at the upper part of a blast furnace is improved; the bosh slag amount is reduced; and the air permeability of a material column is improved. And thirdly, the acid slag in the tuyere convolute area is quickly adjusted and balanced, the slag desulfurization effect in the continuous high-aluminum smelting process is met, and the molten iron components are favorably improved and stabilized.

Description

Technical Field

[0001] The invention relates to metallurgical technology, in particular to a method for improving slag making in blast furnace high-aluminum smelting. Background Art

[0002] The existing technology for high-aluminum smelting mainly stabilizes the slag system by increasing the MgO content in the slag, and increasing the MgO in the slag is mainly achieved by adjusting the MgO in the sintered ore. Limited by the control of the physical and chemical properties of the sintered ore and the grade of the sintered ore, the amount of magnesium flux added to the sintered ore is limited. And with the gradual increase of the Al2O3 content in the slag, the MgO content in the sintered ore cannot meet the demand for continuous high MgO in the blast furnace slag, limiting the expansion of the amount of high-aluminum ore in the blast furnace.

[0003] The industry achieves high-aluminum smelting in blast furnaces basically by controlling the slag composition to stabilize the slag properties, mainly by adding magnesia flux to increase the MgO content in the slag, thereby increasing the slag magnesium-aluminum ratio to improve slag properties. The Al2O3 content in the slag mostly does not exceed 17%, the proportion of high-aluminum ore used is limited, and the cost of ore blending is difficult to further reduce. Summary of the invention

[0004] The object of the present invention is to provide a method for improving slag making in blast furnace high aluminum smelting to solve the problems existing in the above-mentioned prior art.

[0005] The method for improving slag making in high-aluminum smelting in a blast furnace described in the present invention comprises adding a certain proportion of lightly burned dolomite powder and pulverized coal to mix the powder into a mill, wherein the particle size after pulverizing reaches 80%-82% of -200, and the powder is sprayed into the blast furnace from the tuyere through a coal gun. After the lightly burned dolomite powder enters the tuyere cyclotron area, it mixes with the ash produced by the combustion of pulverized coal in the tuyere area of ​​the blast furnace to generate tuyere slag with high basicity, effectively reducing and neutralizing the high SiO2 and high Al2O3 in the pulverized coal ash to form high-viscosity, high-melting-point acidic slag on the edge surface of the cyclotron area, improving the air permeability and liquid permeability of the tuyere area, optimizing the slag making system in the lower part of the blast furnace, and effectively improving the adverse effects of high-melting-point, high-viscosity acidic slag in the high-aluminum smelting process. After the pulverized coal is mixed and sprayed and lightly burned, it is beneficial to expand the use of high-aluminum ore in blast furnaces.

[0006] Lightly burned dolomite powder is the product of high-temperature calcination of dolomite, and its main components include calcium oxide (CaO) and magnesium oxide (MgO). During the calcination process, the main components of dolomite are calcium and magnesium carbonate, which will lose carbon dioxide to form a mixture of calcium oxide and magnesium oxide.

[0007] The method for improving slag making in high-aluminum smelting in blast furnaces described in the present invention has the advantage that by adjusting the injection mass ratio of light-burned dolomite powder by 2%-3%, it is easy to achieve continuous high MgO demand in slag. The amount of magnesia flux used in sintered ore is reduced, the grade of sintered ore is improved, the slag making in the upper part of the blast furnace is improved, the amount of slag in the furnace belly is reduced, and the permeability of the material column is improved. Third, the acidic slag in the tuyere whirlpool zone is quickly adjusted and balanced to meet the desulfurization effect of the slag in the continuous high-aluminum smelting process, which is conducive to improving and stabilizing the composition of molten iron.

[0008] Improve the slag making system in the lower part of the blast furnace and improve the permeability of the material column, which is conducive to expanding the use of high-aluminum ore in the blast furnace. Reduce the introduction of magnesium flux into the sintered ore, which is conducive to improving the quality of the sintered ore, increasing the grade of the sintered ore, and reducing the amount of slag in the blast furnace smelting process. The lower part of the magnesium flux injection has a short cycle and fast reaction, which can achieve the effect of quickly adjusting the slag composition and reduce the impact of production fluctuations. DETAILED DESCRIPTION

[0009] 1. Operations on feeding and inventory management:

[0010] 1. When the storage capacity of light-burned dolomite powder bin is less than 10 tons, notify the dispatching room that the coal-injected light-burned dolomite powder bin needs to be deashed.

[0011] 2. After receiving the notification that light-burned dolomite powder is entering the factory, the on-duty personnel will arrive at the site for confirmation and notify the quality inspection department to take samples before the ash-laying operation can be carried out.

[0012] 3. Before gas ash conveying, open the bag filter on the top of the silo to remove dust. After it is normal, start the ash cleaning operation to avoid dust spillage. During the ash cleaning process, confirm that the automatic sampling is working normally.

[0013] 4. The belt system stops feeding during the plastering process.

[0014] 5. During the ash pumping process, the staff on duty shall monitor the weight of the silo. When the weight of the silo exceeds 50 tons, the ash pumping must be stopped. If there is still residual amount in the pump truck when the ash pumping is stopped, the staff on duty shall report to the workshop.

[0015] 6. The night shift shall fill in the daily report of the amount of light-burned dolomite powder entering the factory and the amount consumed, and the workshop shall track the comparison between the amount entering the factory and the amount consumed in a timely manner.

[0016] 2. About the operation of feeding:

[0017] 1. Before loading the belt, open the bag on the top of the bin to remove dust to avoid dust spillage.

[0018] 2. After setting the weight of the dolomite powder adding belt scale as required, start the dolomite powder adding belt and 1# and 2# dragging belts at the same time. If any of the belts breaks, all three belts must stop feeding. Feeding can only be resumed after the cause is found and dealt with.

[0019] 3. During the feeding process, timely track the cumulative amount of dolomite powder loaded by the belt scale and compare it with the weight of the light-burned dolomite powder discharged from the powder bin. The weight deviation must be less than 5%.

[0020] 4. Lightly burned dolomite powder and pulverized coal are mixed into a mill for pulverization, the ratio is 2%-3%, and the particle size -200 accounts for 80%-82%. In this embodiment, the ratio is selected to be 2.5%, and the particle size -200 accounts for 80.5%.

[0021] 5. After mixing the light-burned coal with the raw coal in the above set proportion and pulverizing them, transport and inject them according to the set coal injection amount of the blast furnace.

[0022] 3. Comparison of the effects after mixed spraying:

[0023] After mixed injection and light burning, the coal injection pays close attention to the changes in the particle size and injection performance of the mixed coal powder. Through the comparison of the data of 6 months before and after mixed injection and light burning, the number of coal guns blocking the blast furnace tuyere remained at 8-10 / month, with no significant changes; the proportion of mixed coal injection particle size -200 mesh remained at 80.5% without significant changes. The blast furnace pays attention to the theoretical combustion temperature, gas flow distribution, slag and iron composition changes, etc., and the operation focuses on stabilizing the thermal system to ensure the stability of blast furnace production. The viscosity of high-aluminum slag after mixed injection and light burning is 260-340mpa.s and averages 298mpa.s, which is slightly higher than the average of 283mpa.s before mixed injection, and is lower than 350mpa.s. The viscosity experimental data is fully controllable, and the blast furnace production is not affected. The average S stability rate of molten iron after mixed injection and light burning is 91.8%, slightly higher than 90.9% before injection. The desulfurization effect of high-aluminum slag after mixed injection and light burning is normal.

[0024] For those skilled in the art, various other corresponding changes and deformations can be made according to the technical solutions and concepts described above, and all of these changes and deformations should fall within the protection scope of the claims of the present invention.

Claims

1. A method for improving slag making in high-aluminum smelting in a blast furnace, comprising the steps of preparing a mixed powder and spraying the mixed powder in a blast furnace; It is characterized in that In the mixed powder, the mass ratio of light-burned dolomite powder to coal powder is 2%-3%, and the particle size -200 accounts for 80%-82%.

2. A method for improving slag making in blast furnace high aluminum smelting according to claim 1, characterized in that: In the mixed powder, the mass ratio of light-burned dolomite powder to coal powder is 2.5%.

3. A method for improving slag making in blast furnace high aluminum smelting according to claim 1, characterized in that: In the mixed powder, the particle size -200 accounts for 80.5%.

4. A method for improving slag making in blast furnace high aluminum smelting according to claim 1, characterized in that: The mixed powder is obtained by mixing light-burned dolomite powder and pulverized coal into a mill.

5. A method for improving slag making in blast furnace high aluminum smelting according to claim 1, characterized in that: The step of spraying the mixed powder in the blast furnace is specifically: spraying the mixed powder into the blast furnace from the tuyere through the coal gun.