A copper removal refining agent and a production process for recycled refined lead

Abstract

The present invention discloses a copper-removing refining agent and a production process for regenerated refined lead. The preparation method of the copper-removing refining agent comprises the following steps: mixing iron oxide / silica composite powder and thiourea in an aqueous solution of polyvinyl alcohol, drying, and annealing to obtain iron sulfide composite powder; ultrasonically mixing the iron sulfide composite powder and lead sulfide powder in an aqueous solution of polyvinyl alcohol, pressing into a mold, annealing, pulverizing and sieving, and centrifuging to obtain the copper-removing refining agent; the present invention composes mesoporous silica with iron sulfide and lead sulfide, and coats it with a carbon layer, which prolongs the contact time between the copper-removing refining agent and lead liquid. Iron sulfide is formed with a porous structure, having a high surface area and a large contact area with lead liquid, and has good copper-removing efficiency. The composite degree of lead sulfide and iron sulfide is uniform, and mesoporous silica is used as a carrier. The dross formed after copper removal forms slag under the promotion of the drossing agent mesoporous silica, which is convenient for fishing and slag removal, and reduces the lead content in the dross, with high economic benefits.

Description

Technical Field

[0001] The present invention belongs to the technical field of recycled lead, and particularly relates to a copper removal refining agent and a production process of recycled refined lead. Background Art

[0002] There are usually two methods for removing copper from crude lead by pyrometallurgical refining: liquation and sulfur addition. The liquation method is used for preliminary copper removal, and the sulfur addition method is used for deep copper removal. In the copper removal process of the pyrometallurgical refining method for crude lead, the method of adding a copper removal agent to the crude lead liquid is widely used. The copper removal agent is mainly sulfur, pyrite, red phosphorus or high-grade lead concentrate (the main component is PbS). The main principle is that during the heating process, copper reacts chemically with sulfur elements to form copper sulfide. Since copper sulfide is insoluble in the lead liquid, it will naturally settle to the bottom of the container or float to the surface to form dross. After fishing out and removing the dross, a relatively pure lead product can be obtained.

[0003] The Chinese patent application with the publication number CN105063369A discloses a copper removal composition for recycled lead refining and its application, which is composed of 30-45wt% of Fe, 40-55wt% of S, 3-15wt% of SiO2 and 0.002wt% of lead powder. It prolongs the reaction and treatment time, which is beneficial to the fishing of copper dross and improves the copper removal efficiency. However, sulfur and iron are easily oxidized in the air, not easy to store, and have poor stability. After sulfur contacts the lead liquid, it is easy to react with oxygen to form sulfur dioxide, reducing the sulfur content while generating harmful gases.

[0004] The Chinese patent application with the publication number CN112695206A discloses a copper removal agent for pyrometallurgical refining of crude lead, a preparation method and an application, which is composed of 50-70% of pyrite, 10-30% of sulfur, 1-20% of portland cement and 5-20% of iron powder. The synergistic reaction of pyrite and sulfur, the use of portland cement to form slag and the use of iron powder to displace can fully reduce the lead content in the slag and fully remove the impurity copper in the crude lead liquid, reducing the lead liquid loss. However, in this scheme, only the formula components are stirred and mixed, so that the synergistic effect of pyrite and sulfur is small, the improvement of the slag removal efficiency is not high, and there is still the problem that sulfur and iron powder are not easy to store and the stability is low. Summary of the Invention

[0005] The purpose of the present invention is to solve the problem of how to improve the stability and copper removal efficiency of the copper removal refining agent, and provide a copper removal refining agent and a production process of recycled refined lead.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] A copper removal refining agent, the preparation method of which comprises the following steps:

[0008] Step 1: Ultrasonically mix iron oxide / silica composite powder and thiourea in an aqueous solution of polyvinyl alcohol with a concentration of 5 - 8 wt%, filter to obtain a precipitate, vacuum dry the precipitate, place it in a tube furnace, and under nitrogen protection, heat it to 500 - 550 °C at a rate of 5 °C / min for annealing treatment for 3 - 4 h. After cooling, crush it and pass it through a 100 - mesh sieve to obtain iron sulfide composite powder.

[0009] Step 2: Ultrasonically mix iron sulfide composite powder and lead sulfide powder in an aqueous solution of polyvinyl alcohol with a concentration of 5 - 8 wt%, filter to obtain a precipitate, press the precipitate into a mold, vacuum dry it, place it in a tube furnace, and under nitrogen protection, heat it to 250 - 350 °C at a rate of 5 °C / min for annealing treatment for 80 - 100 min. After cooling, obtain carbonized composite powder. Crush the carbonized composite powder and pass it through a 100 - mesh sieve to obtain carbon / refining agent composite powder. Centrifuge to remove pure carbon particles in the carbon / refining agent composite powder, and after vacuum drying, obtain a copper - removing refining agent.

[0010] Further, the mass ratio of iron oxide / silica composite powder to thiourea in Step 1 is 6 - 10 g:5 - 10 g.

[0011] Further, the preparation steps of the iron oxide / silica composite powder are as follows:

[0012] In a tube furnace, heat the iron / silica composite powder to 400 - 450 °C at a rate of 5 °C / min for annealing treatment in air for 3 - 4 h to obtain iron oxide / silica composite powder.

[0013] Further, the iron / silica composite powder is prepared by the following steps:

[0014] In a reaction kettle, stir and dissolve mesoporous silica, 2 - aminoterephthalic acid, and ferric chloride hexahydrate in DMF and mix them by stirring for 30 - 40 min. Heat to 120 - 130 °C and react for 20 - 24 h. After cooling, filter the precipitate, wash the precipitate, and vacuum dry it to obtain iron / silica composite powder.

[0015] Further, the dosage ratio of mesoporous silica, 2 - aminoterephthalic acid, ferric chloride hexahydrate, and DMF is 4 - 8 g:4 - 6 g:6 - 8 g:200 - 300 mL.

[0016] Further, the mesoporous silica is prepared by the following steps:

[0017] The PEG-PPG-PEG copolymer was stirred and dissolved in an aqueous hydrochloric acid solution of 35-40 wt% in a reaction kettle. n-Butanol was added, and after stirring and mixing, tetraethyl orthosilicate was added dropwise. The mixture was stirred and reacted for 2-4 h, then heated to 90-100 °C and stirred and reacted for 20-24 h. The precipitate was obtained by filtration, and the precipitate was calcined in air at 500-550 °C for 7-8 h to obtain mesoporous silica.

[0018] Further, the dosage ratio of the PEG-PPG-PEG copolymer, the aqueous hydrochloric acid solution, n-butanol, and tetraethyl orthosilicate is 6-10 g: 300-400 mL: 20-25 mL: 30-35 mL.

[0019] Further, the mass ratio of the iron sulfide composite powder and the lead sulfide powder is 6-10 g: 25-30 g.

[0020] A production process for regenerated refined lead includes the following steps:

[0021] S01. The crude lead smelted in an oxygen-enriched side-blown furnace enters the impurity removal pot through a lead chute to obtain lead liquid. When the lead liquid cools down to 600-650 °C, caustic soda accounting for 0.01-0.015 wt% of the total mass of the lead liquid is added, and it is stirred for 2-3 h. Sampling and testing are carried out. After the contents of elements such as antimony and tin meet the requirements, stirring is stopped, and the alkali slag is fished out.

[0022] S02. When the lead liquid cools down to 280-320 °C, the copper content is sampled and tested. A copper removal refining agent with a weight 1.5-2 times that of the copper content is added, and it is stirred for 60-80 min. Sampling and testing are carried out. After the contents of elements such as copper meet the requirements, stirring is stopped, and the copper slag is fished out.

[0023] S03. The lead liquid is transferred to the finished product pot, heated to 450-480 °C, and caustic soda accounting for 0.01-0.015 wt% of the total mass of the lead liquid is added. The mixer is started for lead washing operation. After the scum in the lead liquid is completely washed out, after 1-2 times of lead washing and slag fishing, after sampling and testing to meet the standards, stirring is stopped, the scum is fished out, heat is kept, and ingots are cast to obtain regenerated refined lead.

[0024] The beneficial effects of the present invention:

[0025] (1) The copper removal refining agent prepared in the present invention is a composite of iron sulfide and lead sulfide with mesoporous silica and is coated with a carbon layer, which prolongs the contact time between the copper removal refining agent and the lead liquid. Iron sulfide is formed with a porous structure, has a high surface area, and has a large contact area with the lead liquid, so the copper removal efficiency is good. The composite degree of lead sulfide and iron sulfide is uniform, and it uses mesoporous silica as a carrier for the drossing agent. The scum formed after copper removal forms slag under the promotion of the mesoporous silica of the drossing agent, which is convenient for fishing and slag removal, and reduces the lead content in the scum, with high economic benefits.

[0026] (2) The copper-removing refining agent prepared by the present invention utilizes the bonding ability of polyvinyl alcohol to uniformly compound iron oxide / silica composite powder and thiourea. At high temperature, thiourea reacts with iron oxide to form iron sulfide. The iron sulfide is combined on the surface of mesoporous silica by the carbon structure formed by the carbonization of polyvinyl alcohol. The bonding strength is high, and thiourea also makes the formed carbon structure have the effect of sulfur doping, obtaining an iron sulfide composite powder with iron sulfide and sulfur-doped carbon loaded on the surface.

[0027] (3) The copper-removing refining agent prepared by the present invention combines the iron sulfide composite powder and lead sulfide powder together under the bonding action of polyvinyl alcohol, and is pressed into a mold. The iron sulfide composite powder and lead sulfide powder are uniformly combined, and polyvinyl alcohol is rapidly carbonized under nitrogen protection. The uniformly combined iron sulfide composite powder / lead sulfide powder is coated by the carbonization of polyvinyl alcohol. The carbon layer on the surface prolongs the contact time between the iron sulfide composite powder / lead sulfide powder and the lead liquid, reduces the contact of sulfur elements with air, and improves the copper-removing efficiency. As the carbon layer decomposes at high temperature, lead sulfide and the iron sulfide composite powder come into contact with the lead liquid and react with the copper element in the lead liquid. The iron sulfide with a porous structure has a large contact area with the lead liquid and a high copper-removing efficiency. Specific embodiments

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

[0029] Example 1: A copper-removing refining agent is prepared by the following steps:

[0030] S1. Stir and dissolve 6 g of PEG-PPG-PEG copolymer in 300 mL of 35 wt% hydrochloric acid aqueous solution in a reaction kettle, add 20 mL of n-butanol, stir and mix, then dropwise add 30 mL of tetraethyl orthosilicate at a rate of 1 mL / s, stir and react for 2 h, raise the temperature to 90 °C and stir and react for 20 h, filter to obtain a precipitate, and calcine the precipitate in air at 500 °C for 7 h to obtain mesoporous silica.

[0031] S2. Stir and dissolve 4 g of mesoporous silica, 4 g of 2-aminoterephthalic acid, and 6 g of ferric chloride hexahydrate in 200 mL of DMF in a reaction kettle, stir and mix for 30 min, raise the temperature to 120 °C and react for 20 h, cool and filter the precipitate, wash the precipitate with DMF and ethanol, and vacuum dry at 80 °C for 20 h to obtain an iron / silica composite powder.

[0032] S3. Heat the iron / silica composite powder in a tube furnace from room temperature to 400 °C at a rate of 5 °C / min and anneal it in air for 3 h to obtain an iron oxide / silica composite powder. Ultrasonically mix 6 g of the iron oxide / silica composite powder and 5 g of thiourea in an aqueous solution of 5 wt% polyvinyl alcohol, filter to obtain a precipitate, vacuum dry the precipitate at 60 °C for 4 h, then place it in a tube furnace, heat it to 500 °C at a rate of 5 °C / min under nitrogen protection and anneal it for 3 h, cool it and crush it through a 100-mesh sieve to obtain a ferrous sulfide composite powder.

[0033] S4. Ultrasonically mix 6 g of the ferrous sulfide composite powder and 25 g of lead sulfide powder in an aqueous solution of 5 wt% polyvinyl alcohol, filter to obtain a precipitate, press the precipitate into a mold under a pressure of 80 Mpa, vacuum dry it at 60 °C for 10 h, then place it in a tube furnace, heat it to 250 °C at a rate of 5 °C / min under nitrogen protection and anneal it for 80 min, cool it to obtain a carbonized composite powder, crush the carbonized composite powder through a 100-mesh sieve to obtain a carbon / refining agent composite powder, disperse the carbon / refining agent composite powder in deionized water, remove the pure carbon particles in the carbon / refining agent composite powder by centrifugation, vacuum dry the remaining carbon / refining agent composite powder at 60 °C for 10 h to obtain a copper-removing refining agent.

[0034] A production process for recycled refined lead includes the following steps:

[0035] S01. The crude lead smelted in an oxygen-enriched side-blown furnace enters a decontamination pot through a lead chute to obtain lead liquid. When the lead liquid cools to 600 °C, add 0.01 wt% of caustic soda based on the total mass of the lead liquid, stir for 2 h, take samples for testing. After the contents of elements such as antimony and tin meet the requirements, stop stirring and remove the alkali slag.

[0036] S02. When the lead liquid cools to 280 °C, take samples to detect the copper content, add a copper-removing refining agent with a weight 1.5 times that of the copper content, stir for 60 min, take samples for testing. After the contents of elements such as copper meet the requirements, stop stirring and remove the copper slag.

[0037] S03. Transfer the lead liquid to a finished product pot, heat it to 450 °C, add 0.01 wt% of caustic soda based on the total mass of the lead liquid, start the stirrer for lead washing operation. When the scum in the lead liquid is completely washed out, after 1 time of lead washing and slag removal, stop stirring after the samples pass the test, remove the scum, and keep warm for ingot casting preparation.

[0038] S04. The qualified refined lead liquid enters the fully automated ingot casting machine system through the lead discharge pipe at the bottom of the finished product pot. After completing operations such as mold filling, robot surface opening, immersion water cooling and solidification, surface finishing, palletizing, packing, metering, and labeling on the automated ingot casting, transfer the qualified refined lead product to the product area for placement to obtain recycled refined lead.

[0039] Example 2: A copper-removing refining agent is prepared by the following steps:

[0040] S1. Stir and dissolve 8 g of PEG-PPG-PEG copolymer in 350 mL of 37.5 wt% hydrochloric acid aqueous solution in a reaction kettle, add 22.5 mL of n-butanol, stir and mix, then dropwise add 32.5 mL of tetraethyl orthosilicate at a rate of 1 mL / s, stir and react for 3 h, raise the temperature to 95 °C and stir and react for 22 h, filter to obtain a precipitate, and calcine the precipitate in air at 525 °C for 7.5 h to obtain mesoporous silica.

[0041] S2. Stir and dissolve 6 g of mesoporous silica, 5 g of 2-aminoterephthalic acid and 7 g of ferric chloride hexahydrate in 250 mL of DMF in a reaction kettle, stir and mix for 35 min, raise the temperature to 125 °C and react for 22 h, cool and then filter the precipitate, wash the precipitate with DMF and ethanol, and vacuum dry at 85 °C for 22 h to obtain iron / silica composite powder.

[0042] S3. Heat the iron / silica composite powder in a tube furnace to 425 °C at a rate of 5 °C / min and anneal in air for 3.5 h to obtain iron oxide / silica composite powder. Ultrasonically mix 8 g of iron oxide / silica composite powder and 7.5 g of thiourea in 6.5 wt% aqueous solution of polyvinyl alcohol, filter to obtain a precipitate, vacuum dry the precipitate at 65 °C for 5 h and then place it in a tube furnace, heat it to 525 °C at a rate of 5 °C / min under nitrogen protection and anneal for 3.5 h, cool and then crush and screen through a 100-mesh sieve to obtain iron sulfide composite powder.

[0043] S4. Ultrasonically mix 8 g of iron sulfide composite powder and 27.5 g of lead sulfide powder in 6.5 wt% aqueous solution of polyvinyl alcohol, filter to obtain a precipitate, press and mold the precipitate in a mold under a pressure of 85 Mpa, vacuum dry at 65 °C for 11 h, then place it in a tube furnace, heat it to 300 °C at a rate of 5 °C / min under nitrogen protection and anneal for 90 min, cool to obtain carbonized composite powder, crush and screen the carbonized composite powder through a 100-mesh sieve to obtain carbon / refining agent composite powder, disperse the carbon / refining agent composite powder in deionized water, remove the pure carbon particles in the carbon / refining agent composite powder by centrifugation, and vacuum dry the remaining carbon / refining agent composite powder at 65 °C for 11 h to obtain the copper-removing refining agent.

[0044] A production process of recycled refined lead includes the following steps:

[0045] S01. The crude lead smelted in an oxygen-enriched side-blown furnace enters a decontamination pot through a lead chute to obtain lead liquid. When the lead liquid cools to 625 °C, add 0.0125 wt% of flake caustic soda based on the total mass of the lead liquid, stir for 2.5 h, take samples for testing, and stop stirring and remove the alkali slag after the contents of elements such as antimony and tin meet the requirements.

[0046] S02. When the lead liquid is cooled to 300 °C, take a sample to detect the copper content, add a copper removal refining agent with a weight 1.75 times that of the copper content, stir for 70 min, take a sample for detection, and stop stirring after the contents of elements such as copper meet the requirements, then fish out the copper slag.

[0047] S03. Transfer the lead liquid to the finished product pot, heat it up to 465 °C, add 0.0125 wt% of flake caustic soda based on the total mass of the lead liquid, start the mixer for lead washing operation, and stop stirring and fish out the floating slag after the floating slag in the lead liquid is completely washed out and after 1.5 times of lead washing and slag fishing, and sample for detection to meet the standard, then keep it warm and prepare for ingot casting.

[0048] S04. The qualified refined lead liquid enters the fully automated ingot casting machine system through the lead discharge pipe at the lower part of the finished product pot. After entering the mold, the robot opens the surface, submersible water condensation solidification, surface repair, stacking, packing, metering, and labeling are completed on the automated ingot casting, and then the qualified refined lead products are transferred to the product area for placement to obtain recycled refined lead.

[0049] Example 3: A copper removal refining agent is prepared by the following steps:

[0050] S1. Stir and dissolve 10 g of PEG-PPG-PEG copolymer in 400 mL of 40 wt% hydrochloric acid aqueous solution in a reaction kettle, add 25 mL of n-butanol, stir and mix, then dropwise add 35 mL of tetraethyl orthosilicate at a rate of 1 mL / s, stir and react for 4 h, heat up to 100 °C and stir and react for 24 h, filter to obtain a precipitate, and calcine the precipitate in air at 550 °C for 8 h to obtain mesoporous silica.

[0051] S2. Stir and dissolve 8 g of mesoporous silica, 6 g of 2-aminoterephthalic acid, and 8 g of ferric chloride hexahydrate in 300 mL of DMF in a reaction kettle, stir and mix for 40 min, heat up to 130 °C and react for 24 h, cool and then filter the precipitate, wash the precipitate with DMF and ethanol, and vacuum dry at 90 °C for 24 h to obtain iron / silica composite powder.

[0052] S3. Heat the iron / silica composite powder in a tube furnace to 450 °C at a rate of 5 °C / min and anneal in air for 4 h to obtain iron oxide / silica composite powder. Ultrasonically mix 10 g of iron oxide / silica composite powder and 10 g of thiourea in 8 wt% polyvinyl alcohol aqueous solution, filter to obtain a precipitate, vacuum dry the precipitate at 70 °C for 6 h and then place it in a tube furnace, heat it up to 550 °C at a rate of 5 °C / min under nitrogen protection and anneal for 4 h, cool and then crush and pass through a 100-mesh sieve to obtain iron sulfide composite powder.

[0053] S4. Mix 10 g of iron sulfide composite powder and 30 g of lead sulfide powder ultrasonically in an 8 wt% aqueous solution of polyvinyl alcohol, filter to obtain a precipitate, press the precipitate into a mold under a pressure of 90 Mpa, dry it in vacuum at 70 °C for 12 h, then place it in a tube furnace and heat it up to 350 °C at a rate of 5 °C / min under nitrogen protection for annealing treatment for 100 min. After cooling, obtain carbonized composite powder, crush the carbonized composite powder through a 100-mesh sieve to obtain carbon / refining agent composite powder. Disperse the carbon / refining agent composite powder in deionized water, and remove the pure carbon particles in the carbon / refining agent composite powder by centrifugation. Vacuum-dry the remaining carbon / refining agent composite powder at 70 °C for 12 h to obtain a copper-removing refining agent.

[0054] Principle of the invention:

[0055] By synthesizing mesoporous silica, the adsorption capacity of mesoporous silica for dross is improved, the separation effect of copper slag and lead liquid is enhanced, and the slag-cleaning effect of mesoporous silica is improved; using mesoporous dioxide as a carrier, porous Fe-MOF is hydrothermally generated on the surface of mesoporous silica, and Fe-MOF is oxidized to form iron oxide through annealing treatment. Utilizing the bonding ability of polyvinyl alcohol, the iron oxide / silica composite powder and thiourea are uniformly compounded. At high temperature, thiourea reacts with iron oxide to form iron sulfide. The iron sulfide is combined on the surface of mesoporous silica by the carbon structure formed by the carbonization of polyvinyl alcohol, with high bonding strength, and thiourea also makes the formed carbon structure have the effect of sulfur doping, obtaining iron sulfide composite powder with iron sulfide and sulfur-doped carbon loaded on the surface; then the iron sulfide composite powder and lead sulfide powder are combined together under the bonding action of polyvinyl alcohol and pressed into a mold, so that the iron sulfide composite powder and lead sulfide powder are uniformly combined, and polyvinyl alcohol is rapidly carbonized under nitrogen protection. Utilizing the carbonization of polyvinyl alcohol to coat the uniformly combined iron sulfide composite powder / lead sulfide powder to obtain carbonized composite powder. Remove the pure carbon particles generated during the crushing process by crushing and centrifugation to obtain a copper-removing refining agent. The copper-removing refining agent uses the carbon layer on the surface to extend the contact time between the iron sulfide composite powder / lead sulfide powder and the lead liquid, reduce the contact between sulfur elements and air, and improve the copper-removing efficiency. As the carbon layer decomposes at high temperature, lead sulfide and iron sulfide composite powder come into contact with the lead liquid and react with the copper element in the lead liquid. The iron sulfide with a porous structure has a large contact area with the lead liquid and high copper-removing efficiency. Copper displaces the lead element and iron element in lead sulfide and iron sulfide to obtain insoluble copper sulfide, and the copper sulfide floats up to form dross. Under the promotion of the drossing agent mesoporous silica, dross with less lead content is formed, improving the copper-removing efficiency and reducing lead liquid loss.

[0056] The PEG-PPG-PEG copolymer is a polyethylene glycol-polypropylene glycol-polyethylene glycol block, CAS No.: 9003-11-6.

[0057] A production process for recycled refined lead includes the following steps:

[0058] S01. The crude lead smelted in the oxygen-enriched side-blown furnace enters the impurity removal pot through a lead chute to obtain lead liquid. When the lead liquid cools down to 650 °C, caustic soda accounting for 0.015 wt% of the total mass of the lead liquid is added, and it is stirred for 3 h. After sampling and testing, when the contents of elements such as antimony and tin meet the requirements, the stirring is stopped, and the alkali slag is fished out.

[0059] S02. When the lead liquid cools down to 320 °C, the copper content is sampled and tested. A copper removal refining agent with a weight twice that of the copper content is added, and it is stirred for 80 min. After sampling and testing, when the contents of elements such as copper meet the requirements, the stirring is stopped, and the copper slag is fished out.

[0060] S03. The lead liquid is transferred to the finished product pot, heated to 480 °C, and caustic soda accounting for 0.015 wt% of the total mass of the lead liquid is added. The mixer is started for lead washing operation. When the scum in the lead liquid is completely washed out, after 2 times of lead washing and slag fishing, after sampling and testing to meet the standards, the stirring is stopped, the scum is fished out, and it is kept warm for ingot casting preparation.

[0061] S04. The qualified refined lead liquid enters the fully automated ingot casting machine system through the lead discharging pipe at the lower part of the finished product pot. After entering the mold, the robot opens the surface, the immersion water cooling and solidification, surface finishing, palletizing, packing, metering, and marking are completed on the automated ingot casting, and then the qualified refined lead products are transferred to the product area for placement to obtain recycled refined lead.

[0062] Comparative Example 1: The difference from Example 1 is that in S2, silica powder (particle size 5 - 10 μm) is used to replace mesoporous silica to prepare the copper removal refining agent, and recycled refined lead is prepared with this copper removal refining agent.

[0063] Comparative Example 2: The difference from Example 1 is that in S3, deionized water is used to replace the polyvinyl alcohol aqueous solution to prepare the copper removal refining agent, and recycled refined lead is prepared with this copper removal refining agent.

[0064] Comparative Example 3: The difference from Example 1 is that in S4, 6 g of iron sulfide composite powder and 25 g of lead sulfide powder are ultrasonically mixed in deionized water, the precipitate is filtered out, the precipitate is pressed into shape in a mold under a pressure of 80 Mpa, vacuum dried at 60 °C for 10 h, and pulverized through a 100-mesh sieve to obtain the copper removal refining agent, and recycled refined lead is prepared with this copper removal refining agent.

[0065] Comparative Example 4: The difference from Example 1 is that sulfur is used as the copper removal refining agent, and recycled refined lead is prepared with this copper removal refining agent.

[0066] The performance of the copper removal refining agents prepared in Examples 1 - 3 and Comparative Examples 1 - 4 was tested. The amount of recycled refined lead processed was 10 tons, and the copper element content in the recycled refined lead was 0.055 wt% for all. The produced recycled refined lead was tested according to the standard of GB / T 469. The copper element content in the recycled refined lead before and after copper removal, as well as the lead content in the slag, were detected. The results are shown in Table 1:

[0067] Table 1

[0068]

[0069] As can be seen from Table 1, the copper removal refining agent prepared by the present invention can reduce the copper element content in the recycled lead to 0.0006%, and has a small amount of slag, a low lead content in the slag, less lead loss, and high economic benefits.

[0070] In Comparative Example 1, due to the use of the traditional drossing agent, silica powder, its function of promoting dross formation is less than that in Example 1, and its adsorption ability is weak, resulting in more dispersed dross, an increase in the total amount of dross, and an increase in the lead content in the slag.

[0071] In Comparative Example 2, since the carbonization effect of polyvinyl alcohol was not used to fix the iron oxide powder during sulfidation, the binding force between the generated iron sulfide and mesoporous silica was weak, resulting in partial agglomeration of iron sulfide and mesoporous silica, weakening the drossing effect, increasing the lead content in the slag, and leading to a lower copper removal efficiency than that in Example 1.

[0072] In Comparative Example 3, since only the iron sulfide composite powder and lead sulfide powder were pressed into shape and compounded by physical action, the compounded iron sulfide composite powder and lead sulfide powder were likely to fall off during the crushing process, and without the protection of the carbon layer, the reaction time of the copper removal refining agent in the lead liquid could not be extended. The total amount of slag decreased, but the lead content in the slag increased, indicating incomplete dross removal and a lower copper removal efficiency than that in Example 1.

[0073] In Comparative Example 4, sulfur was directly added. When sulfur contacted the high-temperature lead liquid, it would burn and cause losses, resulting in an increase in the copper element content in Comparative Example 4. To further reduce the copper element content, the amount of sulfur used needed to be increased, leading to a significant increase in the amount of sulfur used, and a high lead content in the slag in the total amount of slag, with large lead losses.

[0074] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A copper removal refining agent, characterized in that, The preparation method of the copper removal refining agent comprises the following steps: Step 1: Ultrasonically mix the iron oxide / silicon dioxide composite powder and thiourea in a 5-8 wt% aqueous solution of polyvinyl alcohol, filter to obtain a precipitate, vacuum dry the precipitate, place it in a tubular furnace, and anneal it at 500-550 °C for 3-4 h at a rate of 5 °C / min under nitrogen protection. After cooling, crush it through a 100-mesh sieve to obtain the iron sulfide composite powder; Step 2: Ultrasonically mix the iron sulfide composite powder and lead sulfide powder in a 5-8 wt% aqueous solution of polyvinyl alcohol, filter to obtain a precipitate, press and mold the precipitate, vacuum dry it, place it in a tubular furnace, and anneal it at 250-350 °C for 80-100 min at a rate of 5 °C / min under nitrogen protection. After cooling, obtain the carbonized composite powder, crush the carbonized composite powder through a 100-mesh sieve to obtain the carbon / refining agent composite powder, remove the pure carbon particles in the carbon / refining agent composite powder by centrifugal separation, and obtain the copper removal refining agent after vacuum drying; The preparation steps of the iron oxide / silicon dioxide composite powder are as follows: In a tubular furnace, heat the iron / silicon dioxide composite powder to 400-450 °C at a rate of 5 °C / min and anneal it in air for 3-4 h to obtain the iron oxide / silicon dioxide composite powder; The iron / silicon dioxide composite powder is prepared by the following steps: In a reaction kettle, stir and dissolve mesoporous silica, 2-aminoterephthalic acid, and ferric chloride hexahydrate in DMF, stir and mix for 30-40 min, heat to 120-130 °C and react for 20-24 h. After cooling, filter the precipitate, wash the precipitate, and obtain the iron / silicon dioxide composite powder after vacuum drying.

2. The copper removal refining agent according to claim 1, characterized in that, In Step 1, the mass ratio of the iron oxide / silicon dioxide composite powder to thiourea is 6-10 g: 5-10 g.

3. The copper removal refining agent according to claim 1, characterized in that, The dosage ratio of the mesoporous silica, 2-aminoterephthalic acid, ferric chloride hexahydrate, and DMF is 4-8 g: 4-6 g: 6-8 g: 200-300 mL.

4. The copper removal refining agent according to claim 3, characterized in that, The mesoporous silica is prepared by the following steps: In a reaction kettle, stir and dissolve the PEG-PPG-PEG copolymer in a 35-40 wt% hydrochloric acid aqueous solution, add n-butanol, stir and mix, then dropwise add tetraethyl orthosilicate, stir and react for 2-4 h, heat to 90-100 °C and stir and react for 20-24 h. Filter to obtain a precipitate, and calcine the precipitate in air at 500-550 °C for 7-8 h to obtain the mesoporous silica.

5. The copper removal refining agent according to claim 4, wherein The dosage ratio of the PEG-PPG-PEG copolymer, hydrochloric acid aqueous solution, n-butanol, and tetraethyl orthosilicate is 6-10 g: 300-400 mL: 20-25 mL: 30-35 mL.

6. The copper removal refining agent according to claim 1, wherein, In Step 2, the mass ratio of the iron sulfide composite powder to the lead sulfide powder is 6-10 g: 25-30 g.

7. A production process for regenerated refined lead, characterized in that, It includes the copper removal refining agent described in any one of claims 1-6; The production process is as follows: S01. The crude lead smelted in the oxygen-enriched side-blown furnace enters the impurity removal pot through a lead chute to obtain lead liquid. When the lead liquid cools down to 600 - 650 °C, caustic soda accounting for 0.01 - 0.015 wt% of the total mass of the lead liquid is added, and it is stirred for 2 - 3 h. After sampling and testing, when the contents of antimony and tin elements meet the requirements, the stirring is stopped, and the alkali slag is fished out. S02. When the lead liquid cools down to 280 - 320 °C, the copper content is sampled and tested. A copper removal refining agent with a weight 1.5 - 2 times that of the copper content is added, and it is stirred for 60 - 80 min. After sampling and testing, when the copper element content meets the requirements, the stirring is stopped, and the copper slag is fished out. S03. The lead liquid is transferred to the finished product pot, heated to 450 - 480 °C, and caustic soda accounting for 0.01 - 0.015 wt% of the total mass of the lead liquid is added. The lead washing operation is carried out by starting the stirrer. After the dross in the lead liquid is completely washed out, after 1 - 2 times of lead washing and dross fishing, after sampling and testing and meeting the standards, the stirring is stopped, the dross is fished out, heat is kept, and ingots are cast to obtain recycled refined lead.

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