Method for reducing and depleting silver furnace copper slag and reducing copper content in slag

Abstract

The invention relates to the technical field of pyrometallurgy, in particular to a silver furnace copper slag reduction dilution and slag copper content reduction method which comprises the following steps: weighing original copper slag, melting the original copper slag, and forming molten copper slag after precipitation separation; the molten copper slag is adjusted, so that the ratio of Fe to SiO2 in the molten copper slag is 0.9%-1.2%, and standard copper slag is formed; a layer of standard copper slag is laid at the bottom of an electric furnace, power is supplied to the electric furnace, and coke is used for arc striking; and adding materials into the electric furnace again, namely adding the separated standard copper slag, and sequentially adding a slag former, a vulcanizing agent and a reducing agent. According to the method, the Fe / SiO2 ratio in the copper slag is adjusted, the vulcanizing agent, the reducing agent and the slag former are added into the copper slag for high-temperature melting, and the melting temperature and time are controlled in the melting process, so that the purposes of reducing magnetic iron, reducing the slag viscosity, reducing the interface surface tension and reducing the slag copper content are achieved, and the slag copper content in the silver furnace copper slag is reduced to 0.20% or below.

Description

Technical Field

[0001] The invention relates to the technical field of pyrometallurgy, and in particular to a method for reducing and depleting copper slag in a silver furnace and reducing the copper content in the slag. Background Art

[0002] The Baiyin furnace is the only oxygen-enriched molten pool smelting furnace in my country with completely independent intellectual property rights. Its smelting process is advanced, unique in the world's copper smelting process, and occupies an important position. The Baiyin furnace copper smelting slag is characterized by a variety of slag types and complex forms, a high content of artificial secondary copper minerals in useful minerals, fine particle size of useful minerals, and a high degree of dispersion of useful minerals. It is a typical complex and difficult to select copper smelting slag in China. At present, the Baiyin furnace slag stored in the slag yard mainly includes depleted slag after depletion, which contains about 0.70% copper; old Baiyin furnace slag, which contains 0.80%~0.90% copper, and new slag produced by the new Baiyin furnace, which contains 0.90%~1.00% copper, and the value of copper is very considerable. Most of these smelting slags are treated by water quenching and then stockpiling, which not only wastes the high-temperature heat energy of about 1300℃ in the slag and consumes a lot of water resources, but also occupies a lot of land for slag storage, which brings serious potential pollution to the local environment.

[0003] At present, there are two main methods for copper smelting slag dilution, namely pyrometallurgical dilution and mineral processing dilution. The pyrometallurgical smelting method can reduce the copper content of the slag to the slag-matte equilibrium level, while the mineral processing method can only recover most of the included matte.

[0004] Chinese invention patent CN202410240287.9 ​​discloses a method for recovering copper matte by injecting fly ash into depleted copper smelting slag. Copper smelting slag (slag-matte mixture) is added into a depleted electric furnace and heated to 1100-1300°C, so that the copper smelting slag is heated to a molten state to obtain a copper smelting slag melt; fly ash is used as a reducing agent and a slag-forming agent, and copper matte and waste slag are obtained after natural sedimentation and separation, completing the depletion process of the copper smelting slag. This depletion process has a long flow and complex production equipment.

[0005] Chinese invention patent CN202210013252.2 discloses a method for reduction and depletion of copper slag in a furnace, in which a reducing agent is sprayed onto the high-temperature molten copper slag in the sedimentation zone through a spray gun, and the molten copper slag in the sedimentation zone is subjected to reduction and depletion treatment in the furnace by the reducing agent, thereby improving the efficiency of reduction and depletion of copper slag, eliminating the electric furnace depletion process, shortening the smelting process, and improving the smelting efficiency. However, this reduction method is prone to excessive reduction of divalent and trivalent iron, resulting in the formation of copper-iron alloys in the copper matte, which is difficult to separate in the later stage, thereby improving the depletion efficiency and reducing production costs. Summary of the invention

[0006] The present invention provides a method for reducing and depleting copper slag in a silver furnace and reducing the copper content in the slag, which overcomes the shortcomings of the above-mentioned prior art and can effectively solve the problem that the existing method for reducing copper slag in a silver furnace cannot reduce the viscosity of the slag and the copper content in the slag.

[0007] In order to solve the above problems, the present invention provides a method for reducing and depleting copper slag in a silver furnace and reducing the copper content in the slag, comprising: Weighing original copper slag, melting the original copper slag, and forming molten copper slag after precipitation and separation; Adjust the molten copper slag so that the Fe / SiO2 ratio in the molten copper slag is 0.9% to 1.2% to form a standard copper slag; First, lay a layer of standard copper slag on the bottom of the electric furnace, supply power to the furnace, and use coke to start the arc; Adding materials again to the electric furnace, that is, adding the separated standard copper slag, and adding slagging agent, sulfiding agent and reducing agent in sequence; The electric furnace heats up for smelting, and the sulfiding agent sulfides the Cu2O in the copper slag to form copper matte and slag.

[0008] The above-mentioned adjustment of the molten copper slag so that the Fe / SiO2 ratio in the molten copper slag is 0.9% to 1.2% includes adding a slag-forming agent to the molten copper slag, wherein the acidic material of the slag-forming agent contains SiO2, and the alkaline material of the slag-forming agent contains FeO, and the Fe / SiO2 ratio is adjusted by the reaction of the slag-forming agent with the molten copper slag.

[0009] The above-mentioned sulfiding agent is pyrite. Under high temperature conditions, pyrite and standard copper slag undergo redox reaction as follows: FeS+3Fe3O4+5SiO2=5(2FeO·SiO2)+SO2 The equilibrium reaction between pyrite and standard copper slag is as follows: Cu2O+FeS=FeO+Cu2S Among them, the usage of pyrite is 4%~6%.

[0010] The above-mentioned slag-forming agent is a mixture of CaF2, Al2O3 and SiO2, and the amount of the slag-forming agent is 0.5%~1.5%.

[0011] The above-mentioned reducing agent is anthracite, and its components include: ash content: 20%~20.5%; volatile matter: 9.5%~10%; moisture content: 0~0.3%; sulfur content: 0.5%~0.7%; carbon content: 70%~75%; and the amount of reducing agent used is 0.4%~0.5%.

[0012] The above-mentioned electric furnace heating smelting includes a smelting temperature of 1050°C to 1150°C and a smelting time of 1 to 1.5 hours.

[0013] The invention adjusts the Fe / SiO2 ratio in the copper slag, adds a sulfiding agent, a reducing agent and a slag-forming agent into the copper slag for high-temperature melting, and controls the smelting temperature and time during the melting process, so as to achieve the purpose of reducing magnetic iron, reducing slag viscosity, reducing interfacial surface tension and reducing the copper content in the slag, so that the copper content in the silver furnace copper slag is reduced to below 0.20%. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The specific implementation modes of the present invention are further described in detail below in conjunction with the accompanying drawings.

[0015] Figure 1 This is a process flow chart of Example 1 of the present invention. DETAILED DESCRIPTION

[0016] The present invention is not limited by the following embodiments, and specific implementation methods can be determined based on the technical solution of the present invention and actual conditions.

[0017] Example 1: Figure 1 As shown, the embodiment of the present invention discloses a method for reducing and depleting copper slag in a silver furnace and reducing the copper content in the slag, comprising: The first step: weighing the original copper slag, melting the original copper slag, and forming molten copper slag after precipitation and separation; Step 2: Adjust the molten copper slag so that the Fe / SiO2 ratio in the molten copper slag is 0.9% to 1.2% to form a standard copper slag; Step 3: First, lay a layer of standard copper slag on the bottom of the electric furnace, supply power to the furnace, and use coke to start the arc; Step 4: Add materials to the electric furnace again, that is, add the separated standard copper slag, and add slag-making agent, sulfiding agent and reducing agent in sequence; Step 5: The electric furnace is heated up for smelting, and the sulfiding agent sulfides the Cu2O in the copper slag to generate copper matte and slag.

[0018] In the second step, the molten copper slag is adjusted so that the Fe / SiO2 ratio in the molten copper slag is 0.9% to 1.2%, including adding a slag-forming agent to the molten copper slag, wherein the acidic material of the slag-forming agent contains SiO2, and the alkaline material of the slag-forming agent contains FeO, and the Fe / SiO2 ratio is adjusted by the reaction of the slag-forming agent with the molten copper slag. When the Fe / SiO2 ratio is within the range of 0.9% to 1.2%, the reduction and depletion effect of the copper slag is better, and the density of the copper slag is relatively small, 3.11g / cm 3 ~3.38g / cm 3 The viscosity of copper slag is controllable, which is beneficial to the separation of slag and matte.

[0019] In the present invention, when the appropriate Fe / SiO2 ratio is 1.0, the density of the slag is: 3.11g / cm 3 , the viscosity of slag and slag is 1.32 poise, at this time, the slag-matte separation effect is best.

[0020] In the third step, the consumption amount of coke for arc initiation can be selected according to actual needs, and the voltage and current during arc initiation can be set. Among them, the electric furnace can also be a reverberatory furnace.

[0021] Among them, in the fourth step, the sulfiding agent is pyrite, and under high temperature conditions, the pyrite and the standard copper slag undergo an oxidation-reduction reaction as follows: FeS+3Fe3O4+5SiO2=5(2FeO·SiO2)+SO2, Thus, the viscosity and density of copper slag are reduced, and the Fe / SiO2 of copper slag is increased. In addition, pyrite is widely available and inexpensive, so pyrite is selected as the sulfiding agent in the experiment.

[0022] The equilibrium reaction between pyrite and standard copper slag is as follows: Cu2O+FeS=FeO+Cu2S Among them, the amount of pyrite is 4%~6%; it can be seen that the addition of pyrite is more conducive to the sulfidation of Cu2O in copper slag and the formation and polymerization of copper matte.

[0023] The slag-forming agent is a mixture of CaF2, Al2O3 and SiO2, and the amount of slag-forming agent is 0.5%~1.5%. The purpose of adding slag-forming agent is to reduce the melting point of copper slag from 1300℃ to about 1100℃, thus reducing energy consumption.

[0024] The reducing agent is anthracite, and its components include: ash content: 20%~20.5%; volatile matter: 9.5%~10%; moisture: 0~0.3%; sulfur content: 0.5%~0.7%; carbon content: 70%~75%; the amount of reducing agent is 0.4%~0.5%. By adding reducing agent to reduce magnetic iron, specifically: reducing the Fe3O4 content in copper slag can improve the conditions for matte droplets to settle in the slag, such as viscosity, density, and slag-matte interfacial tension; reducing the Fe3O4 content in the slag will reduce the oxidation loss of copper, thereby reducing the copper content in the slag.

[0025] However, it should be noted that when the magnetic iron content of the slag itself is low and the amount of sulfiding agent added can fully meet the reduction of magnetic iron, adding excessive reducing agent will lead to a large amount of reduction of slag FeO and a decrease in Fe / SiO2, thereby causing a decrease in slag basicity. The increase in SiO2 content will lead to an increase in viscosity and a decrease in interfacial tension, which is not conducive to the aggregation and sedimentation of copper matte, resulting in difficulty in slag-matte separation.

[0026] Among them, in the fifth step, the electric furnace is heated for smelting, including a smelting temperature of 1050℃~1150℃ and a smelting time of 1~1.5h. Therefore, in the whole smelting process, the melting temperature and time are controlled, and the temperature rise can accelerate the reduction of Fe3O4 and the reduction of slag viscosity, accelerate the aggregation and sedimentation of copper-sulfur phases, and is conducive to the separation of slag and sulfur and shortening the smelting time.

[0027] It should be noted that if the smelting temperature is too high, not only will the energy consumption increase and the erosion of the furnace lining by the molten slag increase, but it will also increase the solubility of the copper-sulfur phase in the slag, which is not conducive to reducing the copper content in the slag.

[0028] Embodiment 2: The embodiment of the present invention discloses a method for reducing and depleting copper slag in a silver furnace and reducing the copper content in the slag, comprising: Take 12kg of copper slag from a silver furnace. The specific composition of the copper slag is: CaO: 4.30; MgO: 1.90; SiO2: 30.7; Al2O3: 6.10; Cu: 0.29; Fe: 26.55; S: 0.74. Add 60g of anthracite (ash content: 21%; volatile matter: 9.5%; moisture: 0.3%; sulfur content: 0.7%; carbon content: 72%), and the dosage is 0.5%. Take 0.48kg of FeS (4%). A layer of copper slag is first laid on the bottom of the furnace, and then power is supplied, and an arc is struck with coke. 10g of coke is consumed for arc striking, the voltage is 50V, and the current is 260A during arc striking, the voltage is 80V, and the current is 320A during charging, the voltage is 70V, and the current is 180A during insulation, the charging time is 30min, the insulation time is 1h, the furnace temperature is 1100℃, and the slag weight is 8.45kg. Before taking out of the furnace, an iron rod is inserted into the molten pool to take an upper slag sample for analysis, and the result is: Cu 0.20%.

[0029] Embodiment 3: The embodiment of the present invention discloses a method for reducing and depleting copper slag in a silver furnace and reducing the copper content in the slag, comprising: Take 12kg of copper slag from a silver furnace. The specific composition of the copper slag is: CaO: 4.78; MgO: 1.87; SiO2: 30.93; Al2O3: 7.05; Cu: 0.30; Fe: 29.44; S: 1.14. Add 60g of anthracite (ash content: 21.5%; volatile matter: 9.5%; moisture: 0.3%; sulfur content: 0.7%; carbon content: 75%), and the dosage is 0.5%. Take 0.48kg of FeS (5%). A layer of copper slag is first laid on the bottom of the furnace, and then power is supplied, and an arc is struck with coke. 50g of coke is consumed for arc striking, the voltage is 55V, and the current is 300A during arc striking, the voltage is 90V, and the current is 300A during charging, the voltage is 70V, and the current is 120-180A during insulation, the charging time is 20min, the insulation time is 1h, the furnace temperature is 1080℃, the slag weighs 10.25kg, and an iron rod is inserted into the molten pool before taking out of the furnace to take an upper slag sample for analysis. The copper content in the slag is 0.18%.

[0030] Embodiment 4: The embodiment of the present invention discloses a method for reducing and depleting copper slag in a silver furnace and reducing the copper content in the slag, comprising: Take 12kg of copper slag from a silver furnace. The specific composition of the copper slag is: CaO: 4.51; MgO: 1.92; SiO2: 30.00; Al2O3: 6.62; Cu: 0.80; Fe: 28.32; S: 1.51. Add 60g of anthracite (ash content: 21.5%; volatile matter: 9.5%; moisture: 0.3%; sulfur content: 0.7%; carbon content: 75%), and the dosage is 0.5%. Take 0.48kg of FeS (5%). A layer of copper slag is first laid on the bottom of the furnace, and then power is supplied, and an arc is struck with coke. 50g of coke is consumed for arc striking, the voltage is 50V, and the current is 300A during arc striking, the voltage is 80V, and the current is 300A during charging, the voltage is 50V, and the current is 150A during insulation, the charging time is 18min, the insulation time is 1h, the furnace temperature is 1115℃, and the slag weighs 9.55kg. Before taking out of the furnace, an iron rod is inserted into the molten pool to take the upper slag sample for analysis. The analysis results show that the slag contains 0.20% copper.

[0031] In summary, the embodiment of the present invention adjusts the Fe / SiO2 ratio in the copper slag, adds a sulfiding agent, a reducing agent and a slag-forming agent to the copper slag for high-temperature melting, and controls the smelting temperature and time during the melting process to achieve the purpose of reducing magnetic iron, reducing slag viscosity, reducing interfacial surface tension and reducing slag copper content, so that the copper content in the silver furnace copper slag is reduced to below 0.20%.

Claims

1. A method for reducing and depleting copper slag in a silver furnace and reducing the copper content in the slag, characterized in that: include: Weighing original copper slag, melting the original copper slag, and forming molten copper slag after precipitation and separation; Adjust the molten copper slag so that the Fe / SiO2 ratio in the molten copper slag is 0.9% to 1.2% to form a standard copper slag; First, lay a layer of standard copper slag on the bottom of the electric furnace, supply power to the furnace, and use coke to start the arc; Adding materials again to the electric furnace, that is, adding the separated standard copper slag, and adding slagging agent, sulfiding agent and reducing agent in sequence; The electric furnace heats up for smelting, and the sulfiding agent sulfides the Cu2O in the copper slag to form copper matte and slag.

2. The method for reducing and depleting copper slag in a silver furnace and reducing the copper content in the slag according to claim 1, characterized in that: The method of adjusting the molten copper slag so that the Fe / SiO2 ratio in the molten copper slag is 0.9% to 1.2% comprises adding a slag-forming agent to the molten copper slag, wherein the acidic material of the slag-forming agent contains SiO2, and the alkaline material of the slag-forming agent contains FeO, and adjusting the Fe / SiO2 ratio by reacting the slag-forming agent with the molten copper slag.

3. The method for reducing and depleting copper slag in a silver furnace and reducing the copper content in the slag according to claim 1, characterized in that: The sulfiding agent is pyrite. Under high temperature conditions, pyrite and standard copper slag undergo an oxidation-reduction reaction as follows: FeS+3Fe3O4+5SiO2=5(2FeO·SiO2)+SO2 The equilibrium reaction between pyrite and standard copper slag is as follows: Cu2O+FeS=FeO+Cu2S, Among them, the usage of pyrite is 4%~6%.

4. The method for reducing and depleting copper slag in a silver furnace and reducing the copper content in the slag according to claim 1, characterized in that: The slag-forming agent is a mixture of CaF2, Al2O3 and SiO2, and the amount of the slag-forming agent is 0.5% to 1.5%.

5. The method for reducing and depleting copper slag in a silver furnace and reducing the copper content in the slag according to claim 1, characterized in that: The reducing agent is anthracite, and its components include: ash content: 20%~20.5%; volatile matter: 9.5%~10%; moisture: 0~0.3%; sulfur content: 0.5%~0.7%; carbon content: 70%~75%; and the amount of the reducing agent is 0.4%~0.5%.

6. The method for reducing and depleting copper slag in a silver furnace and reducing the copper content in the slag according to claim 1, characterized in that: The electric furnace heating smelting includes a smelting temperature of 1050° C. to 1150° C. and a smelting time of 1 to 1.5 hours.

Images