Production method for industrial treatment of nickel pyrometallurgy slag

Abstract

The invention discloses a production method for industrially treating nickel pyrometallurgy furnace slag. The production method comprises the following steps: S1, respectively crushing the nickel pyrometallurgy furnace slag, pyrite, reduction coal and limestone until the particle size is 2-20mm, preparing materials and storing; s2, the crushed slag, pyrite, reducing coal and limestone are added into a side-blown smelting furnace to be subjected to a weak reduction vulcanization reaction; s3, the four materials are rapidly stirred and melted in the side-blown smelting furnace along with a molten pool, the weak reduction vulcanization process is completed, and separation is conducted on the materials and internal grooves of the side-blown smelting furnace by means of the different densities of a nickel-copper sulfide layer and slag; s4, hot slag discharged from the smelting furnace is subjected to side blowing, and the hot slag is discharged through a chute and then enters the depletion settling furnace for continuous reaction; s5, the upper layer is a tailing layer, and the lower layer is an iron layer; s6, high-temperature flue gas produced by the side-blown smelting furnace and the depletion settling furnace is cooled through a waste heat boiler; and S7, the flue gas cooled by the waste heat boiler enters a dust remover for dust removal.

Description

Technical Field

[0001] The present invention relates to the technical field of the metallurgical industry, and particularly relates to a production method for industrially treating nickel pyrometallurgical slag. Background Art

[0002] Nickel pyrometallurgical slag mainly comes from the oxygen-enriched top-blown smelting system and the flash smelting system of nickel smelters. Since the production of the smelting system, a large amount of smelting slag has been generated. As of now, the stockpiled nickel-copper smelting slag is about 40 million tons or more. Currently, about 2.4 million tons of new nickel smelting slag are added every year, among which the annual output of slag from the flash furnace system is 1.15 million tons, and the annual output of slag from the top-blown furnace system is 1.25 million tons. The large amount of stockpiled nickel smelting slag not only occupies land resources, poses a potential threat to the environment, but also causes the permanent loss of valuable metals such as iron, nickel, copper, and cobalt that are mechanically lost or chemically dissolved in the slag, resulting in resource waste. The smelting slag belongs to the FeO-SiO2-MgO ternary slag system. The iron metal element in nickel smelting slag reaches 35-40%. In addition, due to factors such as mechanical inclusion and chemical dissolution, nickel smelting slag also contains a large amount of valuable metals such as nickel, copper, and cobalt, among which the nickel content is 0.55%, the copper content is 0.26%, and the cobalt content is 0.27%. Calculated based on the current stockpiled nickel smelting slag of about 40 million tons and the annual addition of about 2.4 million tons of new nickel smelting slag, the potential utilization value of nickel, copper, cobalt, and iron in nickel slag is more than 35 billion yuan. Summary of the Invention

[0003] In view of the above technical problems, the present invention provides a production method for industrially treating nickel pyrometallurgical slag.

[0004] In order to achieve the above object, the technical solution of the present invention is specifically as follows: A production method for industrially treating nickel pyrometallurgical slag includes the following steps: S1. The nickel pyrometallurgical slag, pyrite, reduction coal, and limestone are respectively crushed to a particle size of 2-20 mm for stockpiling, which is convenient for transportation, batching, and in-furnace reaction through a belt conveyor; S2. The crushed slag, pyrite, reduction coal, and limestone are added to a side-blown smelting furnace for a weak reduction sulfidation reaction in a ratio of slag: reduction coal: pyrite: limestone = 100:20:9:5. The added reducing agent and sulfiding agent induce the conversion of oxidized nickel and copper in the slag into a metallic state or a sulfide state, simplify the dissemination state of valuable minerals, and reduce the distribution rate of valuable metals in the residual state; S3. The process of melting and weakly reducing and sulfidizing the four materials in the side-blown smelting furnace with the rapid agitation of the molten bath. The nickel-copper sulfide layer is separated from the internal channels of the side-blown furnace by the difference in density between the nickel-copper sulfide layer and the slag. The upper layer is the slag layer, and the lower layer is the matte layer. They are discharged from the discharge ports through molten surfaces at different heights. Among them, after the slag in the side-blown smelting furnace accumulates to a certain amount, it is discharged from the top of the side-blown furnace. The nickel-copper sulfide layer in the lower layer of the side-blown smelting furnace is discharged from the discharge port, and the matte is quenched with water and then sold externally; S4. The hot slag discharged from the side-blown smelting furnace, with the nickel and copper content reduced to less than 0.015%, is discharged through a chute and then enters the impoverishment and settling furnace for further reaction. Reducing agents are added again in the impoverishment and settling furnace to reduce the iron in the slag of the side-blown smelting furnace. The dosage of the reducing agent is 3-6% to control the iron content in the slag of the impoverishment and settling furnace to 4-6%, mainly to ensure that the fluidity of the slag can be discharged smoothly. The main reactions in the impoverishment and settling furnace are as follows: FeO + C = Fe + CO; achieving the purpose of carbon reducing ferrous oxide; S5. According to the density difference, it is separated from the channels of the impoverishment and settling furnace by the density difference. The upper layer is the tail slag layer, and the lower layer is the iron layer. They are discharged from the discharge ports at different heights by controlling the height of the molten surface. The tail slag is quenched with water, fished out by a slag skimmer, and transported by belt to the slag yard for stacking and external sales. The molten iron at the lower part of the impoverishment and settling furnace is discharged through a chute to the casting machine to be cast into pig iron for external sales; S6. The high-temperature flue gas produced by the side-blown smelting furnace and the impoverishment and settling furnace is cooled by a waste heat boiler. A wind gun is added to the boiler for the combustion of carbon monoxide in the flue gas, and at the same time, the heat of the boiler is increased; S7. The flue gas cooled by the waste heat boiler enters the dust collector for dust removal, and then is discharged up to standard after desulfurization of the circulating flue gas.

[0005] Among them, in the step S1, the slag of nickel pyrometallurgy, pyrite, reducing coal, and limestone are respectively crushed to a particle size of 2-10 mm for stockpiling.

[0006] Among them, in the step S1, the slag of nickel pyrometallurgy, pyrite, reducing coal, and limestone are respectively crushed to a particle size of 5-20 mm for stockpiling.

[0007] The beneficial effects of the present invention are as follows: The present invention has the advantages of strong raw material applicability, large processing capacity, and low nickel content in the tailings slag, realizing the comprehensive utilization of various metal elements in nickel slag. This production method is green and environmentally friendly, achieving the comprehensive utilization of nickel, copper, iron, and slag resources, maximizing the economic benefits of the enterprise, realizing good economic benefits, and at the same time solving the problems of slag stacking occupying land resources and threatening the environment. The present invention can effectively treat nickel pyrometallurgical slag, effectively separate nickel and copper from iron in nickel slag, recover nickel and copper metals in nickel smelting slag, reduce the nickel and copper content in the slag to less than 0.015%, and the iron recovery rate reaches more than 90%. This process has the advantages of strong raw material applicability, large processing capacity, and low nickel content in the tailings slag, realizing the comprehensive utilization of various metal elements in nickel slag. This production method is green and environmentally friendly, achieving the comprehensive utilization of nickel, copper, iron, and slag resources, and maximizing the economic benefits of the enterprise. The low-grade nickel matte produced by the side-blown smelting furnace of the present invention is a high-quality nickel smelting raw material welcomed by downstream customers; the pig iron produced by the depletion settling furnace is a high-quality raw material for steelmaking; the tailings slag produced by the depletion settling furnace is a high-quality raw material for cement building materials; the steam produced by the waste heat boiler can be used for bathrooms and winter heating, and the excess part is supplied externally. Overall, the comprehensive utilization of nickel smelting slag resources is realized, and due to the production of low-grade nickel matte and high-quality pig iron, the project can achieve good economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 is the process flow chart of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present invention.

[0010] Example 1 As Figure 1 shown, a production method for industrially treating nickel pyrometallurgical slag includes the following steps: S1. The nickel pyrometallurgical slag, pyrite, reduction coal, and limestone are respectively crushed to a particle size of 2 mm for stockpiling, which is convenient for transportation, batching, and furnace reaction through a belt conveyor; S2. The crushed slag, pyrite, reducing coal, and limestone are added to a side-blown smelting furnace in the ratio of slag:reducing coal:pyrite:limestone = 100:20:9:5 for a weak reduction sulfidation reaction. The added reducing agent and sulfiding agent induce the conversion of oxidized nickel and copper in the slag into the metallic state or sulfide state, simplify the dissemination state of valuable minerals, and reduce the distribution rate of valuable metals in the residual state. The main reactions in the side-blown smelting furnace are as follows: Fe3O4 + C = 3FeO + CO; FeO + C = Fe + CO; MSiO4 + CaO = MO + CaSiO4 (M represents Ni, Cu, Co, etc.); 2Cu + FeS = Cu2S + Fe; 3Ni + 2FeS = Ni3S2 + 2Fe; Co + FeS = CoS + Fe; 2Cu + S = Cu2S; 3Ni + 2S = Ni3S2; Co + S = CoS; S + O2 = SO2; achieving the purpose of converting nickel and copper in nickel slag into the metallic state or sulfide state. S3. The four materials are rapidly agitated and melted in the side-blown smelting furnace with the molten pool and complete the process of weak reduction sulfidation. The nickel-copper sulfide layer is separated from the internal cavities of the side-blown furnace by the difference in density from the slag. The upper layer is the slag layer, and the lower layer is the low-grade nickel matte layer, which is discharged from the discharge ports through molten surfaces at different heights. Among them, the slag in the side-blown smelting furnace is discharged from the top of the side-blown furnace after accumulating to a certain amount, and the nickel-copper sulfide layer at the lower layer of the side-blown smelting furnace is discharged from the discharge port. The low-grade nickel matte is sold externally after water quenching. S4. The hot slag discharged from the side-blown smelting furnace, with the nickel and copper content reduced to less than 0.015%, is discharged through a chute and then enters a depleting and settling furnace for further reaction. Reducing agent is replenished in the depleting and settling furnace to reduce the iron in the slag of the side-blown smelting furnace. The dosage of the reducing agent is 3% to control the iron content in the slag of the depleting and settling furnace to 4%, mainly to ensure that the slag fluidity can be smoothly discharged. The main reaction in the depleting and settling furnace is as follows: FeO + C = Fe + CO; achieving the purpose of carbon reducing ferrous oxide. S5. According to the density difference, it is separated from the cavities of the depleting and settling furnace by the density difference. The upper layer is the tail slag layer, and the lower layer is the iron layer, which is discharged from the discharge ports at different heights by controlling the height of the molten surface. The tail slag is water quenched, fished out by a slag skimmer, and transported by belt to the slag yard for stacking and external sales. The molten iron at the lower part of the depleting and settling furnace is discharged through a chute to a casting machine for casting into pig iron for external sales. S6. The high-temperature flue gas produced by the side-blown smelting furnace and the depleting and settling furnace is cooled by a waste heat boiler. Carbon monoxide in the flue gas is burned by adding air guns to the boiler, and at the same time, the heat of the boiler is increased. S7. The flue gas cooled by the waste heat boiler enters a dust collector for dust removal, and then is discharged up to standard after desulfurization of the circulating flue gas.

[0011] Example 2 A production method for industrially treating nickel pyrometallurgical slag includes the following steps: S1. The nickel pyrometallurgical slag, pyrite, reducing coal, and limestone are respectively crushed to a particle size of 5 mm for stockpiling, which is convenient for transportation, batching, and in-furnace reaction through a belt conveyor; S2. The crushed slag, pyrite, reducing coal, and limestone are added to a side-blown smelting furnace according to the ratio of slag:reducing coal:pyrite:limestone = 100:20:9:5 for a weak reduction sulfidation reaction. The added reducing agent and sulfiding agent induce the conversion of oxidized nickel and copper in the slag into metallic or sulfide states, simplify the dissemination state of valuable minerals, and reduce the distribution rate of valuable metals in the residual state; S3. The four materials are quickly agitated and melted in the side-blown smelting furnace with the molten pool to complete the weak reduction sulfidation process. The nickel-copper sulfide layer is separated from the internal channels of the side-blown furnace by the difference in density between the nickel-copper sulfide layer and the slag. The upper layer is the slag layer, and the lower layer is the low-grade nickel matte layer, which is discharged from the discharge port through molten surfaces at different heights. Among them, the slag in the side-blown smelting furnace is discharged from the top of the side-blown furnace after accumulating to a certain amount, and the nickel-copper sulfide layer at the lower layer of the side-blown smelting furnace is discharged from the discharge port. The low-grade nickel matte is water-quenched and then sold externally; S4. The hot slag discharged from the side-blown smelting furnace, with the nickel and copper content reduced to less than 0.015%, is discharged through a chute and then enters a depletion settling furnace for continuous reaction. Reducing agent is replenished in the depletion settling furnace to reduce the iron in the side-blown smelting furnace slag. The dosage of the reducing agent is 6% to control the iron content in the slag of the depletion settling furnace to 6%, mainly to ensure the fluidity of the slag and enable smooth discharge. The main reaction in the depletion settling furnace is as follows: FeO + C = Fe + CO; achieving the purpose of carbon reducing ferrous oxide; S5. According to the density difference, separation is carried out with the channels of the depletion settling furnace. The upper layer is the tail slag layer, and the lower layer is the iron layer, which is discharged from discharge ports at different heights by controlling the height of the molten surface. The tail slag is water-quenched, fished out by a slag skimmer, and transported by belt to the slag yard for stockpiling and external sales. The molten iron at the lower part of the depletion settling furnace is discharged through a chute to a casting machine for casting into pig iron for external sales; S6. The high-temperature flue gas produced by the side-blown smelting furnace and the depletion settling furnace is cooled by a waste heat boiler. A wind gun is added to the boiler for the combustion of carbon monoxide in the flue gas, while increasing the heat of the boiler; S7. The flue gas cooled by the waste heat boiler enters a dust collector for dust removal, and then is desulfurized by circulating flue gas desulfurization and discharged up to standard.

[0012] Example 3 As Figure 1 shown, a production method for industrial treatment of nickel pyrometallurgical slag includes the following steps: S1. The nickel pyrometallurgical slag, pyrite, reducing coal, and limestone are respectively crushed to a particle size of 10 mm for stockpiling, which is convenient for transportation, batching, and in-furnace reaction through a belt conveyor; S2. The crushed slag, pyrite, reducing coal, and limestone are added to a side-blown smelting furnace in the ratio of slag:reducing coal:pyrite:limestone = 100:20:9:5 for a weak reduction and sulfidation reaction. The added reducing agent and sulfiding agent induce the conversion of oxidized nickel and copper in the slag into the metallic state or sulfide state, simplify the dissemination state of valuable minerals, and reduce the distribution rate of valuable metals in the residual state. S3. The four materials are rapidly agitated and melted in the side-blown smelting furnace with the molten pool and complete the process of weak reduction and sulfidation. The nickel-copper sulfide layer is separated from the internal cavities of the side-blown furnace by the difference in density between the nickel-copper sulfide layer and the slag. The upper layer is the slag layer, and the lower layer is the low-grade nickel matte layer, which are discharged from the discharge ports through molten surfaces at different heights. Among them, when the slag in the side-blown smelting furnace accumulates to a certain amount, it is discharged from the top of the side-blown furnace. The nickel-copper sulfide layer at the lower layer of the side-blown smelting furnace is discharged from the discharge port, and the low-grade nickel matte is quenched with water and then sold externally. S4. The hot slag discharged from the side-blown smelting furnace, with the nickel and copper content reduced to less than 0.015%, is discharged through a chute and then enters a depleting and settling furnace for further reaction. Reducing agent is replenished in the depleting and settling furnace to reduce the iron in the slag of the side-blown smelting furnace. The dosage of the reducing agent is 3% to control the iron content in the slag of the depleting and settling furnace to 4%, mainly to ensure the smooth discharge of the slag due to its fluidity. The main reaction in the depleting and settling furnace is as follows: FeO + C = Fe + CO; achieving the purpose of carbon reducing ferrous oxide. S5. According to the density difference, separation is carried out from the cavities of the depleting and settling furnace by the density difference. The upper layer is the tail slag layer, and the lower layer is the iron layer, which are discharged from discharge ports at different heights by controlling the height of the molten surface. The tail slag is quenched with water, fished out by a slag skimmer, and transported by belt to the slag yard for stacking and external sales. The molten iron at the lower part of the depleting and settling furnace is discharged through a chute to a casting machine to be cast into pig iron for external sales. S6. The high-temperature flue gas produced by the side-blown smelting furnace and the depleting and settling furnace is cooled by a waste heat boiler. A wind gun is added to the boiler for the combustion of carbon monoxide in the flue gas, and at the same time, the heat of the boiler is increased. S7. The flue gas cooled by the waste heat boiler enters a dust collector for dust removal, and then is desulfurized by annular flue gas desulfurization and discharged up to the standard.

[0013] Example 4 As Figure 1 shown, a production method for industrially treating nickel pyrometallurgical slag includes the following steps: S1. The nickel pyrometallurgical slag, pyrite, reducing coal, and limestone are respectively crushed to a particle size of 20 mm for stockpiling, which is convenient for transportation, batching, and furnace charging reactions through a belt conveyor. S2. The crushed slag, pyrite, reducing coal, and limestone are added to a side-blown smelting furnace for a weak reduction sulfidation reaction in the ratio of slag:reducing coal:pyrite:limestone = 100:20:9:5. The added reducing agent and sulfiding agent induce the conversion of oxidized nickel and copper in the slag into the metallic state or sulfide state, simplify the dissemination state of valuable minerals, and reduce the distribution rate of valuable metals in the residual state. S3. The four materials are rapidly agitated and melted in the side-blown smelting furnace along with the molten pool to complete the weak reduction sulfidation process. The nickel-copper sulfide layer is separated from the internal channels of the side-blown furnace by using the difference in density between the nickel-copper sulfide layer and the slag. The upper layer is the slag layer, and the lower layer is the low-grade nickel matte layer, which are discharged from the discharge ports at different heights through the molten surface at different heights. Among them, the slag in the side-blown smelting furnace is discharged from the top of the side-blown furnace after accumulating to a certain amount, and the nickel-copper sulfide layer at the lower layer of the side-blown smelting furnace is discharged from the discharge port. The low-grade nickel matte is quenched with water and then sold externally. S4. The hot slag discharged from the side-blown smelting furnace, with the nickel and copper content reduced to less than 0.015%, is discharged through a chute and then enters a depletion settling furnace for further reaction. Reducing agent is replenished in the depletion settling furnace to reduce the iron in the slag of the side-blown smelting furnace. The dosage of the reducing agent is 3% to control the iron content in the slag of the depletion settling furnace to 4%, mainly to ensure the fluidity of the slag so that it can be discharged smoothly. The main reaction in the depletion settling furnace is as follows: FeO + C = Fe + CO; achieving the purpose of carbon reducing ferrous oxide. S5. According to the density difference, separation is carried out from the channels of the depletion settling furnace by using the density difference. The upper layer is the tail slag layer, and the lower layer is the iron layer, which are discharged from the discharge ports at different heights by controlling the height of the molten surface. The tail slag is quenched with water, fished out by a slag skimmer, and transported by belt to the slag yard for stacking and external sales. The molten iron at the lower part of the depletion settling furnace is discharged through a chute to a casting machine for casting into pig iron for external sales. S6. The high-temperature flue gas produced by the side-blown smelting furnace and the depletion settling furnace is cooled by a waste heat boiler. A wind gun is added to the boiler for the combustion of carbon monoxide in the flue gas, and at the same time, the heat of the boiler is increased. S7. The flue gas cooled by the waste heat boiler enters a dust collector for dust removal, and then is discharged up to standard after desulfurization of the circulating flue gas.

[0014] It should be understood that the above specific embodiments of the present invention are only used for exemplary illustration or explanation of the principle of the present invention, and do not constitute a limitation to the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made without departing from the spirit and scope of the present invention shall be included within the protection scope of the present invention. In addition, the appended claims of the present invention are intended to cover all changes and modification examples falling within the scope and boundary of the appended claims, or equivalent forms of such scope and boundary.

Claims

1. A production method for industrially treating nickel pyrometallurgical slag, characterized in that, It includes the following steps: S1. The nickel pyrometallurgical furnace slag, pyrite, reducing coal, and limestone are respectively crushed to a particle size of 2 - 20 mm for stockpiling, which is convenient for transporting, proportioning, and reacting in the furnace through a belt conveyor; S2. The crushed furnace slag, pyrite, reducing coal, and limestone are added to a side - blown smelting furnace for weak reduction and sulfidation reaction according to the ratio of furnace slag:reducing coal:pyrite:limestone = 100:20:9:

5. The added reducing agent and sulfiding agent induce the conversion of oxidized nickel and copper in the slag into metallic or sulfide states, simplify the dissemination state of valuable minerals, and reduce the distribution rate of valuable metals in the residual state; S3. The four materials are rapidly agitated and melted in the side - blown smelting furnace with the molten pool to complete the process of weak reduction and sulfidation. The nickel - copper sulfide layer is separated from the internal channels of the side - blown furnace by the difference in density between the nickel - copper sulfide layer and the slag. The upper layer is the slag layer, and the lower layer is the low - nickel matte layer, which are discharged from the discharge ports at different heights through the molten surface at different heights.

2. Among them, when the furnace slag in the side - blown smelting furnace accumulates to a certain amount, it is discharged from the top of the side - blown furnace. The nickel - copper sulfide layer at the lower layer of the side - blown smelting furnace is discharged from the discharge port, and the low - nickel matte is quenched with water and sold externally; S4. The hot slag discharged from the side - blown smelting furnace, with the nickel and copper content reduced to less than 0.015%, is discharged through a chute and enters the depletion and settling furnace for further reaction. Reducing agent is replenished in the depletion and settling furnace to reduce the iron in the side - blown smelting furnace slag. The dosage of the reducing agent is 3 - 6% to control the iron content in the slag of the depletion and settling furnace to 4 - 6%, mainly to ensure that the slag fluidity can be smoothly discharged. The main reaction in the depletion and settling furnace is as follows: FeO + C = Fe + CO; achieving the purpose of carbon reducing ferrous oxide; S5. According to the density difference, separation is carried out with the channels of the depletion and settling furnace. The upper layer is the tail - slag layer, and the lower layer is the iron layer, which are discharged from the discharge ports at different heights by controlling the height of the molten surface. The tail - slag is quenched with water, fished out by a slag - fishing machine, and transported by belt to the slag yard for stockpiling and external sales. The molten iron at the lower part of the depletion and settling furnace is discharged through a chute to a casting machine for casting into pig iron for external sales; S6. The high - temperature flue gas produced by the side - blown smelting furnace and the depletion and settling furnace is cooled by a waste - heat boiler. A blower gun is added to the boiler for the combustion of carbon monoxide in the flue gas, while increasing the heat of the boiler; S7. The flue gas cooled by the waste - heat boiler enters a dust collector for dust removal, and then is desulfurized by circulating flue gas and discharged up to standard.

3. The production method of an industrial treatment of nickel pyrometallurgical slag according to claim 1, characterized in that, In the step S1, the nickel pyrometallurgical furnace slag, pyrite, reducing coal, and limestone are respectively crushed to a particle size of 2 - 10 mm for stockpiling.

4. A production method for industrially treating nickel pyrometallurgical slag according to claim 1, characterized in that, In the step S1, the nickel pyrometallurgical furnace slag, pyrite, reducing coal, and limestone are respectively crushed to a particle size of 5 - 20 mm for stockpiling.

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