Method for smelting antimony by using retired power battery graphite

Abstract

The invention belongs to the technical field of antimony smelting, and particularly relates to a method for smelting antimony by using decommissioned power battery graphite, which comprises the following steps: (1) separating graphite from a decommissioned power battery; (2) the graphite obtained in the step (1) is mixed with one or more of granular carbon, coal and coke, a composite reducing agent is prepared, and the mass ratio of the graphite to the one or more of the granular carbon, the coal and the coke is 1: 10-10: 1; and (3) the composite reducing agent obtained in the step (2) is added into an antimony smelting furnace for antimony smelting operation. According to the method disclosed by the invention, not only can the graphite in the retired power battery be utilized massively, efficiently and greenly, but also the coal consumption of an antimony smelting system can be subjected to energy replacement, the production cost is reduced, and new dangerous solid wastes are not generated, so that the whole technological process has a very good industrial application prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of antimony smelting, and specifically relates to a method for using retired power battery graphite to smelt antimony. Background Art

[0002] The statements in this section are merely intended to provide background information related to the technical solution of the present application to aid understanding, and they do not necessarily constitute prior art for the technical solution of the present application.

[0003] With the global emphasis on environmental protection and sustainable development, the new energy vehicle industry has risen rapidly. As the core component of new energy vehicles, the performance of power batteries is directly related to the vehicle's endurance and cost of use. In recent years, lithium-ion batteries have become the mainstream choice for new energy vehicle power batteries due to their advantages such as high energy density, long cycle life and environmental protection. Generally speaking, the composition of lithium-ion batteries contains 12%-21% graphite. The lithium-ion batteries of electric vehicles only have an effective life of 3-8 years. It is estimated that by 2023, the installed capacity of retired lithium-ion batteries will reach 101 million kWh, or 1.2 million tons, and the peak of lithium-ion battery retirement is coming. Although considerable progress has been made in the recycling of positive electrode materials and other components in lithium-ion batteries, the recycling of retired negative electrode graphite is still in its infancy. The recycling of carbon graphite negative electrode materials in retired power batteries is also worthy of attention because of the following considerations: (1) The waste graphite treated by the discharge-free disassembly technology will be rich in residual lithium. Direct disposal will not only lead to a waste of lithium resources, but also may cause fire risks. (2) Waste graphite contains toxic chemicals such as fluorine and phosphorus from electrolytes, etc. In addition, organic substances such as adhesives and conductive agents also have an important impact on water and soil pollution. (3) Waste graphite will produce dust and cause air pollution. Therefore, recycling waste negative electrode graphite materials is of great significance to alleviate the tight supply of battery negative electrode graphite materials, eliminate safety hazards, and reduce environmental pressure.

[0004] As a traditional fossil fuel, coal has long occupied an important position in the global energy structure. It is widely used in power generation, metal smelting production, cement manufacturing and as industrial energy. However, with the increasingly severe global climate change problem, as well as the challenges of environmental pollution and sustainable development, the control of coal energy has become an important issue in global energy policy. In order to cope with environmental and climate issues, many countries and regions have implemented a series of policies, regulations and measures to strengthen the control of coal energy. These measures include restricting the construction of new coal-fired power plants, raising emission standards, imposing carbon taxes, and providing renewable energy subsidies. Coal is consumed in large quantities every year as a reducing agent for antimony smelting, and coal energy control also has a certain impact on the antimony smelting industry. Summary of the invention

[0005] In order to solve the problems in the prior art that the graphite treatment process of retired power batteries cannot be completely recycled or used in large quantities, and the shortage of coal reducing agents in the antimony smelting industry, the present invention provides a method for using retired power battery graphite for antimony smelting. This application uses the graphite separated from retired power batteries and traditional reducing agents such as coal and coke to make a composite reducing agent for antimony smelting in a reduction furnace, and can adjust important smelting parameters such as the reduction temperature, wind oxygen concentration, primary air dosage, secondary air dosage, and slag-making agent of the antimony smelting furnace to make full use of the advantages of this new composite reducing agent, while ensuring that the smelting effect in the antimony smelting process meets the requirements. By using retired power battery graphite as an antimony smelting reducing agent, the amount of the original reducing agent coal can be reduced, thereby achieving green energy saving and carbon reduction in antimony smelting.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A method for using retired power battery graphite for antimony smelting, the method comprising: (1) separating graphite from retired power batteries; (2) mixing the graphite obtained in step (1) with one or more of granular carbon, coal, and coke to prepare a composite reducing agent, wherein the mass ratio of the graphite to one or more of the granular carbon, coal, and coke is 1:10-10:1; (3) adding the composite reducing agent obtained in step (2) into an antimony smelting furnace to perform antimony smelting operation.

[0008] In one embodiment, separating the graphite from the retired power battery includes separating the graphite by mechanical crushing and screening, acid leaching, purification, expansion, high-temperature thermal decomposition or flotation.

[0009] In one embodiment, the retired power battery includes one or more of a ternary lithium battery, a sodium battery, a solid-state battery, and a lithium iron phosphate battery.

[0010] In one embodiment, graphite separated from retired power batteries is directly used to prepare the composite reducing agent.

[0011] In one embodiment, the composite reducing agent is in the form of powder, granules or blocks.

[0012] In one embodiment, the antimony smelting furnace is any one of a side-blown furnace, a top-blown furnace, a reverberatory furnace, an electric furnace, a rotary kiln, a blast furnace or a bottom-blown furnace.

[0013] In one embodiment, the mass ratio of the graphite to one or more of the particle size carbon, coal, and coke is 1:1-10:1.

[0014] In one embodiment, when the mass ratio of the graphite to one or more of the granular carbon, coal, and coke is 1:1-10:1, in the antimony smelting operation of the antimony smelting furnace, the reduction temperature is set to 910-990°C, the primary air oxygen concentration and the secondary air oxygen concentration are set to 55%-65%, and the primary air consumption during the charging period is set to 1300-1500Nm 3 / h, set the primary air consumption during the reduction period to 2750~2950Nm 3 / h, set the secondary air consumption during the feeding period to 0~500Nm 3 / h, set the secondary air consumption in the reduction period to 1260~1420Nm 3 / h, the slag-forming agent in the antimony smelting furnace is soda ash and lime, wherein the mass proportion of soda ash in the slag-forming agent is 18% to 32%.

[0015] In one embodiment, in step (3), the chemical reaction between the smelting raw material containing antimony oxide and the composite reducing agent in the antimony smelting furnace includes:

[0016] FeS+Cu 2 O=FeO+Cu 2 S;

[0017] 4PbS+4Na 2 CO 3 =4Pb+3NaS+Na 2 SO 4 +4CO 2 ;

[0018] As 2 O 5 +3Na 2 CO 3 =2Na 3 AsO 4 +3CO 2 ;

[0019] Sb 2 O 5 +3Na 2 CO 3 =2Na 3 SbO 4 +3CO 2 ;

[0020] PbS+Fe=Pb+FeS;

[0021] PbO+C=Pb+CO;

[0022] PbO+CO=Pb+CO 2 ;

[0023] ZnO+C=Zn+CO;

[0024] ZnO+CO=Zn+CO 2 .

[0025] Compared with the prior art, the present invention has the following positive and beneficial effects:

[0026] The present invention provides a method for using retired power battery graphite for antimony smelting. Through this method, the present invention can not only utilize the graphite in retired power batteries in a large amount, efficiently and green manner, but also replace the coal consumption of the antimony smelting system with energy (1 ton of retired power battery graphite can replace 0.5-1.5 tons of coal or coke), thereby saving production costs and not generating new hazardous solid waste. Therefore, the entire process of the present invention has a good industrial application prospect. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The embodiments of the present invention are further described below with reference to the accompanying drawings, in which:

[0028] Figure 1 It is a process flow chart of a method for using retired power battery graphite for antimony smelting according to one embodiment. DETAILED DESCRIPTION

[0029] The technical solution of the present invention is further described below in conjunction with the embodiments, but is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention should be included in the protection scope of the present invention.

[0030] Figure 1 The present invention is a process flow chart of a method for using retired power battery graphite for antimony smelting according to an embodiment, which comprises the following steps:

[0031] (1) Separate graphite from retired power batteries.

[0032] The retired power batteries include but are not limited to ternary lithium batteries, sodium batteries, solid-state batteries, lithium iron phosphate batteries, etc. In one embodiment, the method of separating graphite from retired power batteries includes but is not limited to mechanical crushing and screening, acid leaching, purification treatment, expansion treatment, high temperature thermal decomposition, flotation, etc.

[0033] (2) The graphite obtained in step (1) is mixed with one or more of granular carbon, coal, and coke to prepare a composite reducing agent, wherein the mass ratio of the graphite to the one or more of the granular carbon, coal, and coke is 1:10-10:1.

[0034] In the scheme of the present application, before the graphite separated from retired power batteries is mixed with one or more of granular carbon, coal, and coke, the separated graphite may not be pretreated in any way, that is, the graphite separated from retired power batteries may be directly used to prepare the composite reducing agent.

[0035] In one embodiment, the graphite may be crushed before mixing with one or more of the granular carbon, coal, and coke. In one embodiment, the composite reducing agent prepared by mixing the graphite with one or more of the granular carbon, coal, and coke is in the form of powder, granules, or blocks, and its specific form can be determined according to actual needs.

[0036] (3) adding the composite reducing agent obtained in step (2) into an antimony smelting furnace to carry out antimony smelting operation.

[0037] The antimony smelting furnace can be any one of a side-blown furnace, a top-blown furnace, a reverberatory furnace, an electric furnace, a rotary kiln, a blast furnace or a bottom-blown furnace. A smelting raw material containing antimony oxide is added to the antimony smelting furnace, and the chemical reaction between the raw material and the composite reducing agent in the antimony smelting furnace includes:

[0038] FeS+Cu 2 O=FeO+Cu 2 S;

[0039] 4PbS+4Na 2 CO 3 =4Pb+3NaS+Na 2 SO 4 +4CO 2 ;

[0040] As 2 O 5 +3Na 2 CO 3 =2Na 3 AsO 4 +3CO 2 ;

[0041] Sb 2 O 5 +3Na 2 CO 3 =2Na 3 SbO 4 +3CO 2 ;

[0042] PbS+Fe=Pb+FeS;

[0043] PbO+C=Pb+CO;

[0044] PbO+CO=Pb+CO 2 ;

[0045] ZnO+C=Zn+CO;

[0046] ZnO+CO=Zn+CO 2 .

[0047] Compared with traditional reducing agents (such as coke), composite reducing agents containing retired power battery graphite have differences in chemical composition, physical properties, reaction activity, etc. For example, graphite has weaker reducing ability, graphite has high thermal stability and therefore its volatile matter is lower, and graphite has a lower calorific value, which will affect the antimony smelting effect to a certain extent. Therefore, in order to make full use of the advantages of this new composite reducing agent and ensure that the smelting effect in the antimony smelting process is optimal, in one embodiment, the smelting process parameters of the antimony smelting furnace are optimized and adjusted accordingly.

[0048] In one embodiment, when the mass ratio of the graphite to one or more of the granular carbon, coal, and coke is 1:1-10:1, in order to adapt to the composite reducing agent containing retired power battery graphite, multiple smelting parameters of the antimony smelting furnace, such as primary air usage, secondary air usage, oxygen concentration, reduction temperature, and slag-forming agent, can be adjusted and optimized. Specifically, by adjusting the amount of primary air, the airflow distribution in the furnace is optimized to ensure that the composite reducing agent is fully in contact with oxygen and promote the reduction reaction; by adjusting the amount of secondary air, the redox atmosphere in the furnace is balanced to improve the reduction efficiency and reduce unnecessary energy consumption; by accurately controlling the oxygen concentration in the furnace, the oxygen supply required for the composite reducing agent to carry out the reduction reaction is guaranteed, and the energy loss and environmental pollution caused by excessive oxidation are avoided; by adjusting the reduction temperature in the furnace, it is adapted to the calorific value, thermal stability, reaction activity, etc. of the composite reducing agent to promote the efficient reduction reaction in the most optimized temperature range; by selecting a suitable slag-making agent to adapt to the lower volatile matter of the composite reducing agent (which will affect the volatilization effect of the antimony smelting furnace to a certain extent), the volatilization effect is improved, and at the same time, the slag type can be optimized, and the content of arsenic, sulfur and other inclusions in the alloy can be controlled to improve the alloy taste. In addition, the reaction time can be appropriately extended, for example, by 20 to 60 minutes. Prolonging the reaction time can be beneficial to alloy impurity removal and alloy grade to a certain extent, and it can also be beneficial to slag gold separation and improve the recovery rate of antimony in raw materials.

[0049] After a large number of experiments and continuous optimization and adjustment, in one embodiment, when the mass ratio of the graphite to one or more of the granular carbon, coal, and coke is 1:1-10:1, in the antimony smelting operation of the antimony smelting furnace, the reduction temperature is set to 910-990°C, the primary air oxygen concentration and the secondary air oxygen concentration are set to 55%-65%, and the primary air consumption during the charging period is set to 1300-1500Nm 3 / h, set the primary air consumption during the reduction period to 2750~2950Nm 3 / h, set the secondary air consumption during the feeding period to 0~500Nm 3 / h, set the secondary air consumption in the reduction period to 1260~1420Nm 3 / h, the slag-forming agent in the antimony smelting furnace is soda ash and lime, wherein the mass proportion of soda ash in the slag-forming agent is 18% to 32%. The slag-forming agent can optimize the slag shape, control the content of arsenic, sulfur and other inclusions in the alloy, and improve the alloy taste.

[0050] By setting the above-mentioned smelting parameters, the advantages of the composite reducing agent containing retired power battery graphite can be maximized, the production cost can be reduced, and at the same time the smelting effect and efficiency of the antimony smelting furnace can be guaranteed.

[0051] Example 1

[0052] A method for using retired power battery graphite for antimony refining, the specific process flow chart of the method is as follows: Figure 1 As shown, the specific steps include:

[0053] (1) grinding the waste graphite separated from the retired lithium iron phosphate battery to less than 200 mesh, and grinding the particle size carbon to less than 200 mesh, and then mixing the ground graphite and the particle size carbon in a mass ratio of 10:1 to prepare a composite reducing agent;

[0054] (2) The smelting raw material containing antimony oxide is uniformly mixed with the composite reducing agent prepared in step (1) at a mass ratio of 100:5, and soda ash and lime are added as slag-forming agents (the mass proportion of soda ash in the slag-forming agent is 32%). The reduction temperature is set to 990°C, the primary air oxygen concentration and the secondary air oxygen concentration are set to 65%, and the primary air consumption during the feeding period is set to 1500Nm 3 / h, set the primary air consumption during the reduction period to 2950Nm 3 / h, set the secondary air consumption during the feeding period to 500Nm 3 / h, set the secondary air consumption in the reduction period to 1420Nm 3 / h. After reduction, it was found that the material was completely melted and the slag-gold separation effect was obvious, which showed that the reaction was feasible and good. The antimony reduction rate was 86.54%; the chemical reactions occurring in the bottom-blown furnace were as follows:

[0055] FeS+Cu 2 O=FeO+Cu 2 S;

[0056] 4PbS+4Na 2 CO 3 =4Pb+3NaS+Na2 SO 4 +4CO 2 ;

[0057] As 2 O 5 +3Na 2 CO 3 =2Na 3 AsO 4 +3CO 2 ;

[0058] Sb 2 O 5 +3Na 2 CO 3 =2Na 3 SbO 4 +3CO 2 ;

[0059] PbS+Fe=Pb+FeS;

[0060] PbO+C=Pb+CO;

[0061] PbO+CO=Pb+CO 2 ;

[0062] ZnO+C=Zn+CO;

[0063] ZnO+CO=Zn+CO 2 .

[0064] Example 2

[0065] A method for using retired power battery graphite for antimony refining, the specific process flow chart of the method is as follows: Figure 1 As shown, the specific steps include:

[0066] (1) grinding the waste graphite separated from the retired lithium iron phosphate battery to less than 200 mesh, and grinding the particle size carbon to less than 200 mesh, and then mixing the ground graphite and the particle size carbon in a mass ratio of 5:1 to prepare a composite reducing agent;

[0067] (2) The smelting raw material containing antimony oxide is uniformly mixed with the composite reducing agent prepared in step (1) at a mass ratio of 100:5, and soda ash and lime are added as slag-forming agents (the mass proportion of soda ash in the slag-forming agent is 25%). The reduction temperature is set to 950°C, the primary air oxygen concentration and the secondary air oxygen concentration are set to 60%, and the primary air consumption during the feeding period is set to 1400Nm 3 / h, set the primary air consumption during the reduction period to 2850Nm 3 / h, set the secondary air consumption during the feeding period to 200Nm 3 / h, set the secondary air consumption in the reduction period to 1340Nm 3 / h. After reduction, it was found that the material was completely melted and the slag-gold separation effect was obvious, which showed that the reaction was feasible and good. The antimony reduction rate was 85.24%; the chemical reactions occurring in the bottom-blown furnace were as follows:

[0068] FeS+Cu 2 O=FeO+Cu 2 S;

[0069] 4PbS+4Na 2 CO 3 =4Pb+3NaS+Na 2 SO 4 +4CO 2 ;

[0070] As 2 O 5 +3Na 2 CO 3 =2Na 3 AsO 4 +3CO 2 ;

[0071] Sb 2 O 5 +3Na 2 CO 3 =2Na 3 SbO 4 +3CO 2 ;

[0072] PbS+Fe=Pb+FeS;

[0073] PbO+C=Pb+CO;

[0074] PbO+CO=Pb+CO 2 ;

[0075] ZnO+C=Zn+CO;

[0076] ZnO+CO=Zn+CO 2 .

[0077] Example 3

[0078] A method for using retired power battery graphite for antimony refining, the specific process flow chart of the method is as follows: Figure 1 As shown, the specific steps include:

[0079] (1) grinding the waste graphite separated from the retired lithium iron phosphate battery to less than 200 mesh, and grinding the particle size carbon to less than 200 mesh, and then mixing the ground graphite and the particle size carbon in a mass ratio of 1:1 to prepare a composite reducing agent;

[0080] (2) The smelting raw material containing antimony oxide is uniformly mixed with the composite reducing agent prepared in step (1) at a mass ratio of 100:5, and soda ash and lime are added as slag-forming agents (the mass proportion of soda ash in the slag-forming agent is 18%). The reduction temperature is set to 910°C, the primary air oxygen concentration and the secondary air oxygen concentration are set to 55%, and the primary air consumption during the feeding period is set to 1300Nm 3 / h, set the primary air consumption during the reduction period to 2750Nm 3 / h, set the secondary air dosage during the feeding period to 0Nm 3 / h, set the secondary air consumption in the reduction period to 1260Nm 3 / h. After reduction, it was found that the material was completely melted and the slag-gold separation effect was obvious, which showed that the reaction was feasible and good. The antimony reduction rate was 87.57%; the chemical reactions occurring in the bottom-blown furnace were as follows:

[0081] FeS+Cu 2 O=FeO+Cu 2 S;

[0082] 4PbS+4Na 2 CO 3 =4Pb+3NaS+Na 2 SO 4 +4CO 2 ;

[0083] As 2 O 5 +3Na 2 CO 3 =2Na 3 AsO 4 +3CO 2 ;

[0084] Sb 2 O 5 +3Na 2 CO 3 =2Na 3 SbO 4 +3CO 2 ;

[0085] PbS+Fe=Pb+FeS;

[0086] PbO+C=Pb+CO;

[0087] PbO+CO=Pb+CO 2 ;

[0088] ZnO+C=Zn+CO;

[0089] ZnO+CO=Zn+CO 2 .

[0090] References herein to "various embodiments", "some embodiments", "one embodiment" or "an embodiment" etc. refer to that a particular feature, structure or property described in conjunction with the embodiment is included in at least one embodiment. Therefore, the phrases "in various embodiments", "in some embodiments", "in one embodiment" or "in an embodiment" etc. appearing throughout this document do not necessarily refer to the same embodiment. In addition, particular features, structures or properties may be combined in any suitable manner in one or more embodiments. Therefore, the particular features, structures or properties shown or described in conjunction with one embodiment may be combined in whole or in part with features, structures or properties of one or more other embodiments without restriction, as long as the combination is not illogical or inoperable. Expressions similar to "according to A", "based on A", "through A" or "using A" appearing herein are intended to be non-exclusive, that is, "according to A" may cover "according to A only" or "according to A and B", unless it is specifically stated that its meaning is "according to A only". In this application, for the sake of clarity, some exemplary operating steps are described in a certain order, but those skilled in the art will understand that each of these operating steps is not essential, and some of the steps may be omitted or replaced by other steps. These operation steps do not have to be executed sequentially in the manner shown; on the contrary, some of these operation steps can be executed in different orders or in parallel according to actual needs, as long as the new execution manner is not illogical or inoperable.

[0091] Some exemplary embodiments of the present invention are described above. It can be understood that the above embodiments are only used to explain the present invention and do not constitute a limitation on the protection scope of the present invention. The features in these embodiments can be recombined in a suitable manner, and the scheme obtained thereby is still within the protection scope required by the present invention. Based on the above embodiments, all other embodiments obtained by those skilled in the art without making creative work, that is, all modifications, equivalent substitutions and improvements made within the spirit and principles of this application, fall within the protection scope required by the present invention.

Claims

1. A method for using retired power battery graphite for antimony smelting, characterized in that: The method comprises: (1) Separating graphite from retired power batteries; (2) mixing the graphite obtained in step (1) with one or more of granular carbon, coal, and coke to prepare a composite reducing agent, wherein the mass ratio of the graphite to the one or more of the granular carbon, coal, and coke is 1:10-10:1; (3) adding the composite reducing agent obtained in step (2) into an antimony smelting furnace to carry out antimony smelting operation.

2. The method for using retired power battery graphite for antimony smelting according to claim 1, characterized in that: The separation of graphite from retired power batteries includes separating graphite using mechanical crushing and screening, acid leaching, purification, expansion, high-temperature thermal decomposition or flotation.

3. The method for using retired power battery graphite for antimony smelting according to claim 1, characterized in that: The retired power batteries include one or more of ternary lithium batteries, sodium batteries, solid-state batteries, and lithium iron phosphate batteries.

4. The method for using retired power battery graphite for antimony smelting according to claim 1, characterized in that: The graphite separated from retired power batteries is directly used to prepare the composite reducing agent.

5. The method for using retired power battery graphite for antimony smelting according to claim 1, characterized in that: The composite reducing agent is in the form of powder, granules or blocks.

6. The method for using retired power battery graphite for antimony smelting according to claim 1, characterized in that: The antimony smelting furnace is any one of a side-blown furnace, a top-blown furnace, a reverberatory furnace, an electric furnace, a rotary kiln, a blast furnace or a bottom-blown furnace.

7. The method for using retired power battery graphite for antimony smelting according to claim 1, characterized in that: The mass ratio of the graphite to one or more of the granular carbon, coal and coke is 1:1-10:

1.

8. The method for using retired power battery graphite for antimony smelting according to claim 7, characterized in that: In the antimony smelting operation of the antimony smelting furnace, the reduction temperature is set to 910-990°C, the primary air oxygen concentration and the secondary air oxygen concentration are set to 55%-65%, and the primary air consumption during the charging period is set to 1300-1500Nm 3 / h, set the primary air consumption during the reduction period to 2750~2950Nm 3 / h, set the secondary air consumption during the feeding period to 0~500Nm 3 / h, set the secondary air consumption in the reduction period to 1260~1420Nm 3 / h, the slag-forming agent in the antimony smelting furnace is soda ash and lime, wherein the mass proportion of soda ash in the slag-forming agent is 18% to 32%.

9. A method for using retired power battery graphite for antimony smelting according to any one of claims 1 to 8, characterized in that: In the step (3), the smelting raw material containing antimony oxide and the composite reducing agent undergo a chemical reaction in the antimony smelting furnace, and the chemical reaction includes: FeS+Cu2O=FeO+Cu2S; 4PbS+4Na2CO3=4Pb+3NaS+Na2SO4+4CO2; As2O5+3Na2CO3=2Na3AsO4+3CO2; Sb2O5+3Na2CO3=2Na3SbO4+3CO2; PbS+Fe=Pb+FeS; PbO+C=Pb+CO; PbO+CO=Pb+CO2; ZnO+C=Zn+CO; ZnO+CO=Zn+CO2.

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