Method for catalyzing sulfuric acid normal-pressure air selective copper leaching through tellurium-rich bismuth matte silver salt

Abstract

The invention provides a method for catalyzing sulfuric acid normal-pressure air selective copper leaching through tellurium-rich bismuth matte silver salt, and belongs to the field of non-ferrous metal hydrometallurgy. According to the technical scheme, the method comprises the following steps that tellurium-rich bismuth copper matte is subjected to crushing, fine grinding and size mixing with sulfuric acid, then air serves as an oxidizing agent for leaching copper under the normal pressure condition by means of a self-suction stirrer, silver salt is continuously and evenly added in the leaching process, copper in the bismuth copper matte is rapidly and selectively leached, and leaching of tellurium can be greatly inhibited. The obtained leaching residues can be conveniently left in a lead anode slime workshop so as to further recover valuable elements such as tellurium, gold, silver, antimony and bismuth in the leaching residues in a short process, meanwhile, copper disturbing bismuth fire refining is opened, and dispersion loss of tellurium is reduced. According to the method, the technical conditions are mild, the effect of selective copper leaching between copper and tellurium is obvious, the required equipment investment is small, the use amount of sulfuric acid and silver ions is small, the equipment is compact, and operation is easy and convenient.

Description

Technical Field

[0001] The invention belongs to the field of metallurgy and chemical industry, and in particular relates to a method for selectively leaching copper in sulfuric acid and atmospheric pressure air catalyzed by tellurium-rich bismuth matte silver salt. Background Art

[0002] One of the important functions of the lead anode mud smelting workshop of a lead smelter is to recover the elemental bismuth in the lead anode mud and refine it into 99.99% pure bismuth. To this end, it is necessary to separate impurities such as copper, gold, and silver from bismuth. At present, the method of making bismuth matte from crude bismuth is widely used. When the lead smelter produces tellurium-rich lead anode mud, a large amount of tellurium will be transferred to the bismuth matte to form tellurium-rich bismuth matte. The copper content of this bismuth matte is often 15%-30%, while the tellurium content is as high as 2%-4%, and the price of tellurium is stable at 500,000-700,000 yuan / ton all year round. Obviously, reducing the dispersion loss of tellurium in the process of decoppering bismuth matte can significantly improve the recovery rate of tellurium in lead anode mud.

[0003] In the process of open-circuit copper of bismuth matte, there is a traditional method of merging bismuth matte into the smelting and copper removal process of the lead system. Obviously, this method has a great dispersion loss of tellurium, bismuth and antimony in tellurium-rich bismuth matte, and also causes a backlog of gold and silver. Wet processes such as bismuth matte oxygen-pressure sulfuric acid leaching-electrodeposition copper technology provide an effective way to separate copper and bismuth and convert copper products into cathode copper products (a comprehensive recovery method for bismuth matte, CN105543479A), but its initial investment is relatively high; in addition, if it is used to treat tellurium-rich bismuth matte, the strong oxidizing property of the oxygen-pressure sulfuric acid leaching process will cause a large amount of tellurium to be leached together with copper, which not only increases the dispersion loss of tellurium, but also increases the burden of further separation of copper and tellurium in the leachate. In addition, although the chloride solution leaching method performs well in copper leaching (Chen Peihuan. Research on the recovery of silver and other valuable metals from bismuth matte. Comprehensive Utilization of Minerals, 1989, (6), 5), its commercial application is limited by the market acceptance of lead chloride and the corrosion resistance of equipment materials to high concentrations of chloride ions, making the equipment investment cost of this method relatively high. In addition, if it is used to treat tellurium-rich bismuth matte, it will also cause a large amount of tellurium leaching due to the complexation of chloride ions.

[0004] According to the literature research, there are no reports on the research of enhanced process for removing copper from tellurium-rich bismuth matte by wet process and inhibiting tellurium leaching. Summary of the invention

[0005] The object of the present invention is to provide a method for selectively leaching copper in sulfuric acid and atmospheric pressure air catalyzed by tellurium-rich bismuth matte silver salt.

[0006] The object of the present invention is achieved in that the method for selective copper leaching in sulfuric acid and atmospheric pressure air catalyzed by tellurium-rich bismuth matte silver salt comprises pre-treatment, leaching and post-treatment steps, specifically comprising: A. Pretreatment: crushing and fine grinding the tellurium-rich bismuth matte to be treated to obtain material a; B. Leaching: 1) Add sulfuric acid solution to material a for slurry adjustment to obtain material b; 2) Directly introduce 180-220℃ high-temperature steam into material b to heat it and start the self-priming mixer to leaching for 3-10h to obtain material c. During the leaching process, silver salt is continuously and evenly added to material b. At the same time, the steam introduction amount is adjusted to maintain the leaching process temperature constant at 60-85℃ and ensure that the air content in the slurry is 6-9%; C. Post-processing: 1) subjecting material c to liquid-solid separation to obtain leachate d and leach residue e, wherein leachate d is a tellurium-containing copper sulfate solution; 2) The leached residue e is washed to obtain material f, and valuable metals are recovered from material f in the lead anode mud workshop.

[0007] The specific operations are as follows: S1) Crushing and fine grinding of tellurium-rich bismuth matte. The specific conditions are: crushing the tellurium-rich bismuth matte to an average particle size of 1-4 mm, and then grinding the particle size to -200 mesh with a proportion of not less than 85%, to obtain tellurium-rich bismuth matte ore powder.

[0008] S2) Silver salt catalyzed sulfuric acid atmospheric pressure air selective copper leaching - water washing - liquid-solid separation. The specific conditions are: the tellurium-rich bismuth matte powder obtained in step S1 is mixed with sulfuric acid solution to form a slurry with a solid-liquid ratio (kg / L) between 1:5-10. Subsequently, the slurry is heated by directly injecting 200°C high-temperature steam into the slurry, and a self-priming agitator is started at the same time, which can introduce air into the slurry. The air acts as an oxidant in this process to promote the leaching of copper; during the leaching process, silver salt is continuously and evenly added to the leached slurry. During the leaching process, the temperature is maintained at 60-85°C by adjusting the steam input, and the oxygen content of the air in the slurry is maintained at 6%-9%. (Gas content = total volume of air in the leached slurry / total volume of slurry, total volume of slurry = sum of the volumes of gas, liquid and solid phases in the slurry); under the leaching conditions, the leaching experiment can be completed after 3 to 10 hours of continuous leaching. Then liquid-solid separation is carried out, and the obtained liquid is a solution of copper sulfate containing tellurium, which can be used as the original feed liquid for recovering copper and tellurium. The solid residue is stirred and washed at 25°C according to a solid-liquid ratio of 1:3.

[0009] Only a small part of the copper in bismuth matte exists as metallic copper (copper that is easily leached by sulfuric acid at normal pressure), while most of the copper exists in the form of cuprous sulfide (copper that is difficult to leach by sulfuric acid at normal pressure). Silver ions, as catalysts, can accelerate the oxidation of sulfuric acid to leach copper in cuprous sulfide. The leaching of tellurium in bismuth matte is significantly affected by the oxidizing property of the leaching agent and the concentration of sulfuric acid. Reducing the oxidizing property and acidity can inhibit the leaching of tellurium.

[0010] In order to achieve the preferential leaching of copper and less leaching of tellurium in the process of bismuth matte hydroprocess copper removal (tellurium remains in the leaching residue, and tellurium can be further selectively leached by hydroprocess, which is beneficial to reduce the burden of copper and tellurium separation), and reduce the investment cost of wet copper leaching, the present invention proposes a method for selective copper leaching by sulfuric acid atmospheric pressure air catalyzed by tellurium-rich bismuth matte silver salt. In order to achieve the above-mentioned goals, a self-priming stirrer and a catalyst silver salt are particularly used. The specific process and process parameters are as follows: 1. Crushing and fine grinding of tellurium-rich bismuth matte The specific conditions are: the tellurium-rich bismuth matte is crushed to an average particle size of 1-4 mm, and then ground to a particle size of -200 mesh with a proportion of not less than 85%, to obtain tellurium-rich bismuth matte ore powder.

[0011] 2. Silver salt catalyzed sulfuric acid atmospheric pressure air selective copper leaching - water washing - liquid-solid separation The specific conditions are as follows: the tellurium-rich bismuth matte powder obtained in step 1 is mixed with a sulfuric acid solution to form a slurry with a solid-liquid ratio (kg / L) of 1:5-10. Subsequently, the slurry is heated by directly injecting 200°C high-temperature steam into the slurry, and a self-priming agitator is started at the same time, which can introduce air into the slurry, and the air acts as an oxidant in this process to promote the leaching of copper; during the leaching process, silver salt is continuously and evenly added to the leached slurry. During the leaching process, the temperature is maintained at 60-85°C by adjusting the steam input, and the oxygen content of the air in the slurry is maintained at 6%-9%. (Gas content = total volume of air in the leached slurry / total volume of slurry, total volume of slurry = the sum of the volumes of gas, liquid and solid phases in the slurry); under the leaching conditions, the leaching experiment can be completed after 3 to 10 hours of continuous leaching. Then, liquid-solid separation is carried out, and the obtained liquid is a solution of copper sulfate containing tellurium, which can be used as the original feed liquid for recovering copper and tellurium. The solid residue is stirred and washed at 25°C according to a solid-liquid ratio of 1:3. The final slag after washing can be sent to the lead anode mud workshop to continue to recover valuable metals such as tellurium, bismuth, antimony, gold and silver.

[0012] Furthermore, the silver salt described in step 2 is one or a combination of any multiple of silver sulfate, silver nitrate, silver chloride and silver carbonate.

[0013] Furthermore, the amount of silver salt added to the leached slurry in step 2 is to ensure that the silver ion concentration in the sulfuric acid leachate is 5-15 mg / L, preferably 5-8 mg / L.

[0014] Furthermore, the concentration of the sulfuric acid solution in step 2 is preferably 40 to 60 g / L.

[0015] Furthermore, the solid-to-liquid ratio in step 2 is preferably 1:8-10.

[0016] Furthermore, the air content in the slurry as described in step 2 is preferably ensured to be 6%-8%.

[0017] The technology of the present invention uses relatively mild process conditions and a short process to treat tellurium-rich bismuth matte. The technical conditions of the present invention are relatively mild, the effect of selective copper leaching between copper and tellurium is obvious, the required equipment investment is small, the amount of sulfuric acid and silver ions is small, the equipment is compact, and the operation is simple. The obtained leaching slag is convenient to be left in the lead anode mud workshop to further recover the tellurium, gold, silver, antimony, bismuth and other valuable elements therein in a short process, while the copper that interferes with the bismuth fire refining is opened, reducing the dispersion loss of tellurium. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the process flow of the present invention. DETAILED DESCRIPTION

[0019] The present invention is further described below in conjunction with the embodiments, but the present invention is not limited in any way. Any changes or substitutions made based on the teachings of the present invention belong to the protection scope of the present invention.

[0020] The method for selective copper leaching in sulfuric acid and atmospheric pressure air catalyzed by tellurium-rich bismuth matte silver salt of the present invention comprises pre-treatment, leaching and post-treatment steps, specifically comprising: A. Pretreatment: crushing and fine grinding the tellurium-rich bismuth matte to be treated to obtain material a; B. Leaching: 1) Add sulfuric acid solution to material a for slurry adjustment to obtain material b; 2) Directly introduce 180-220℃ high-temperature steam into material b to heat it and start the self-priming mixer to leaching for 3-10h to obtain material c. During the leaching process, silver salt is continuously and evenly added to material b. At the same time, the steam introduction amount is adjusted to maintain the leaching process temperature constant at 60-85℃ and ensure that the air content in the slurry is 6-9%; C. Post-processing: 1) subjecting material c to liquid-solid separation to obtain leachate d and leach residue e, wherein leachate d is a tellurium-containing copper sulfate solution; 2) The leached residue e is washed to obtain material f, and valuable metals are recovered from material f in the lead anode mud workshop.

[0021] The crushing and fine grinding described in step A is to crush the tellurium-rich bismuth matte to an average particle size of 1-4 mm, and then grind it to a particle size of -200 mesh with a proportion of not less than 85%.

[0022] B. The concentration of the sulfuric acid solution in step 1) is 40-60 g / L.

[0023] In step B 1), the solid-liquid ratio of material a to sulfuric acid solution is 1:(8~10) kg / L.

[0024] B. The silver salt in step 2) is one or more of silver sulfate, silver nitrate, silver chloride and silver carbonate.

[0025] B. The amount of silver salt added in the continuous and uniform addition of silver salt in step 2) is to control the silver ion concentration in the leaching solution to be 5-15 mg / L.

[0026] The silver salt is continuously and evenly added in an amount to control the silver ion concentration in the leaching solution to be 5-8 mg / L.

[0027] The air content described in step B 2) is 6~8%.

[0028] The washing described in step C2) is performed by stirring and washing with water having a solid-to-liquid ratio of 1:(2-4).

[0029] The washing temperature is 24-26°C.

[0030] The present invention is further described below with specific implementation cases: Example 1 Tellurium-rich bismuth matte (chemical composition: Cu 19.54%, Te 2.58%, Ag 1.36%, Au 16g / t, Bi5.78%, Sb 2.01%, S 17.45%, Fe 9.00%, Pb 25.35%, As 0.19%) was crushed to an average particle size of 3.2 mm, and then ground to -200 mesh, accounting for 90.24%, to obtain tellurium-rich bismuth matte ore powder.

[0031] In a reactor, bismuth matte powder is slurried with a sulfuric acid solution with a sulfuric acid concentration of 65 g / L according to a leaching solid-liquid ratio (kg / L) of 1:8; then 200°C high-temperature steam is directly introduced into the leaching slurry for heating and a self-priming agitator is turned on at the same time; during the leaching process, silver nitrate is continuously and evenly added to the leaching slurry, and the amount added is to ensure that the silver ion concentration in the sulfuric acid leaching solution is 6 mg / L; during the leaching process, the steam introduction amount is adjusted to maintain the leaching process temperature constant at 70-80°C and to ensure that the air content in the slurry is stable at 7%-9%. Under this condition; the leaching test can be terminated after continuous leaching for 6.5 hours; liquid-solid separation, the leaching solution is a tellurium-containing copper sulfate solution, and the chemical composition is Cu 17.53 g / L, Te 0.58 g / L, Ag 0.003 g / L, Au 0 g / L, Bi 1.17 g / L, Sb 0.019 g / L, Fe 4.04g / L, Pb0.067g / L, As 0.045g / L, the solution can be used as the original feed solution for recovering copper and tellurium; the leached residue is stirred and washed at 25°C according to the washing solid-liquid ratio of 1:3, and the liquid-solid separation after washing is carried out. The final residue can be left in the lead anode mud workshop to recover the tellurium, gold, silver, antimony, bismuth and other valuable elements in the short process. The leaching rates of Cu, Te, Ag, Au, Bi, Sb, Fe, Pb, and As are 85.21%, 21.36%, 0.21%, 0%, 19.23%, 0.90%, 42.64%, 0.25%, and 22.50%, respectively.

[0032] Example 2 Tellurium-rich bismuth matte (chemical composition: Cu 28.99%, Te 4.51%, Ag 3.93%, Au 21g / t, Bi6.32%, Sb 2.06%, S 21.34%, Fe 6.24%, Pb 22.43%, As 0.37%) was crushed to an average particle size of 2.5 mm, and then ground to -200 mesh, accounting for 93.47%, to obtain tellurium-rich bismuth matte ore powder.

[0033] In a reactor, bismuth matte powder is slurried with a sulfuric acid solution with a sulfuric acid concentration of 60 g / L according to a leaching solid-liquid ratio (kg / L) of 1:8; then 200°C high-temperature steam is directly introduced into the leaching slurry for heating and a self-priming agitator is turned on at the same time; during the leaching process, silver carbonate is continuously and evenly added to the leaching slurry, and the amount added is to ensure that the silver ion concentration in the sulfuric acid leaching solution is 5 mg / L; during the leaching process, the steam introduction amount is adjusted to maintain the leaching process temperature constant at 75-85°C and to ensure that the air content in the slurry is stable at 6%-8%. Under this condition; the leaching test can be terminated after continuous leaching for 7.5 hours; liquid-solid separation, the leaching solution is a tellurium-containing copper sulfate solution, and the chemical composition is Cu 25.22g / L, Te 1.08g / L, Ag0.003g / L, Au 0g / L, Bi1.37g / L, Sb 0.018g / L, Fe 5.54g / L, Pb0.039g / L, As 0.18g / L, the solution can be used as the original feed solution for recovering copper and tellurium; the leached residue is stirred and washed at 25°C according to the washing solid-liquid ratio of 1:3, and the liquid-solid separation after washing is carried out. The final residue can be left in the lead anode mud workshop to recover the tellurium, gold, silver, antimony, bismuth and other valuable elements in the short process. The leaching rates of Cu, Te, Ag, Au, Bi, Sb, Fe, Pb, and As are 87.00%, 23.95%, 0.08%, 0%, 21.68%, 0.87%, 88.78%, 0.17%, and 48.65%, respectively.

Claims

1. A method for selective copper leaching in sulfuric acid and atmospheric pressure air catalyzed by tellurium-rich bismuth matte silver salt, characterized in that: The method for selective copper leaching in sulfuric acid and atmospheric pressure air catalyzed by tellurium-rich bismuth matte silver salt comprises pre-treatment, leaching and post-treatment steps, specifically comprising: A. Pretreatment: crushing and fine grinding the tellurium-rich bismuth matte to be treated to obtain material a; B. Leaching: 1) Add sulfuric acid solution to material a for slurry adjustment to obtain material b; 2) Directly introduce 180-220℃ high-temperature steam into material b to heat it and start the self-priming mixer to leach for 3-10h to obtain material c. During the leaching process, silver salt is continuously and evenly added to material b. At the same time, the steam introduction amount is adjusted to maintain the leaching process temperature at 60-85℃ and ensure that the air content in the slurry is 6-9%; C. Post-processing: 1) subjecting material c to liquid-solid separation to obtain leachate d and leach residue e, wherein leachate d is a tellurium-containing copper sulfate solution; 2) The leached residue e is washed to obtain material f, and valuable metals are recovered from material f in the lead anode mud workshop.

2. The method for selective copper leaching in sulfuric acid and atmospheric pressure air catalyzed by tellurium-rich bismuth matte silver salt according to claim 1, characterized in that: The crushing and fine grinding described in step A is to crush the tellurium-rich bismuth matte to an average particle size of 1-4 mm, and then grind it to a particle size of -200 mesh with a proportion of not less than 85%.

3. The method for selective copper leaching in sulfuric acid and atmospheric pressure air catalyzed by tellurium-rich bismuth matte silver salt according to claim 1, characterized in that: B. The concentration of the sulfuric acid solution in step 1) is 40-60 g / L.

4. The method for selective copper leaching in sulfuric acid and atmospheric pressure air catalyzed by tellurium-rich bismuth matte silver salt according to claim 1, characterized in that: In step B 1), the solid-liquid ratio of material a to sulfuric acid solution is 1:(8~10) kg / L.

5. The method for selective copper leaching in sulfuric acid and atmospheric pressure air catalyzed by tellurium-rich bismuth matte silver salt according to claim 1, characterized in that: B. The silver salt in step 2) is one or more of silver sulfate, silver nitrate, silver chloride and silver carbonate.

6. The method for selective copper leaching in sulfuric acid and atmospheric pressure air catalyzed by tellurium-rich bismuth matte silver salt according to claim 1, characterized in that: B. The amount of silver salt added in the continuous and uniform addition of silver salt in step 2) is to control the silver ion concentration in the leaching solution to be 5-15 mg / L.

7. The method for selective copper leaching in sulfuric acid and atmospheric pressure air catalyzed by tellurium-rich bismuth matte silver salt according to claim 1 or 6, characterized in that: The silver salt is continuously and evenly added in an amount to control the silver ion concentration in the leaching solution to be 5-8 mg / L.

8. The method for selective copper leaching in sulfuric acid and atmospheric pressure air catalyzed by tellurium-rich bismuth matte silver salt according to claim 1, characterized in that: The air content in step B2) is 6~8%.

9. The method for selective copper leaching in sulfuric acid and atmospheric pressure air catalyzed by tellurium-rich bismuth matte silver salt according to claim 1, characterized in that: The washing described in step C2) is performed by stirring and washing with water having a solid-to-liquid ratio of 1:(2-4).

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