A method for enriching and recovering silver and selenium from low-nickel and high-nickel copper anode mud

Abstract

The invention discloses a method for enriching and recovering silver and selenium from low-nickel and high-nickel copper anode muds. The method comprises the following steps: slurrying copper anode mud and dilute sulfuric acid solution in a slurrying tank, pumping the pulp into a reactor through a pump, introducing oxygen to carry out low-pressure oxygen leaching under acidic and constant temperature conditions, stopping the introduction of oxygen to carry out anaerobic leaching, filtering and washing the pulp to obtain filtrate and filter residue, and repeatedly washing the filter residue to obtain a pressurized copper-removing material. The method can effectively remove impurities such as copper and tellurium from the copper anode mud, reduce the leaching of silver and selenium, and almost all of the silver and selenium can be enriched in the residue, which is convenient for subsequent alloy treatment to recover silver and selenium. After the silver and selenium content in the pressurized liquid is greatly reduced, subsequent tellurium recovery and extraction are also convenient. The treatment process is simple and easy to operate. The leaching rate of copper can reach more than 98%, and the leaching rate of tellurium can reach more than 55%.

Description

Technical Field

[0001] The invention relates to the technical field of metallurgy, and in particular to a method for enriching and recovering silver and selenium from low-nickel and high-nickel copper anode muds. Background Art

[0002] In the rare metal metallurgical industry, the pressure leaching process is often used to remove copper, nickel, and tellurium from high-nickel and low-nickel copper anode muds, and to enrich and recover silver and selenium. It mainly uses medium-pressure steam to heat the system to 150-160°C in a pressure autoclave, and then introduces oxygen for oxygen pressure leaching. This method can effectively remove impurity metals such as copper, tellurium, and nickel, but due to the high temperature and high pressure leaching conditions, a large amount of selenium in the copper anode mud is leached into the solution. After pressure leaching, the selenium concentration in the pressurized liquid can reach 15-20g / L, which is not conducive to subsequent normal pressure treatment and has an adverse effect on the separation and recovery of tellurium. Due to the incomplete separation of selenium in the selenium precipitation process, the selenium content in the tellurium precipitation slag during the tellurium precipitation process exceeds 20%, which is almost the same as the tellurium content, which is extremely unfavorable for the subsequent separation and extraction of tellurium. Summary of the invention

[0003] The purpose of the present invention is to provide a method for fully separating copper, nickel and tellurium from low-nickel and high-nickel copper anode muds and fully enriching and recovering silver and selenium in order to address the shortcomings of the above-mentioned methods of removing copper, nickel and tellurium from copper anode mud by pressure leaching process and enriching and recovering silver and selenium, in which a large amount of selenium is leached out, resulting in incomplete separation of selenium and silver, and the selenium content is too high during the tellurium precipitation process, which affects the separation and extraction of tellurium.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is:

[0005] Step 1, slurrying: add copper anode mud and dilute sulfuric acid solution with a mass ratio of 1:3-4 to 90-150g / L in a slurrying tank, heat the system to 80-85°C, keep the temperature constant for 2-3h under stirring, pre-impregnate soluble copper sulfate, nickel sulfate and other salts in the material, and fully mix the low-nickel mud with the high-nickel mud to obtain slurry; the mass ratio of low-nickel mud to high-nickel mud in the copper anode mud is 3-6:1;

[0006] Step 2, low-pressure oxygen leaching: the slurry prepared in step 1 is pumped into the autoclave through the slurry pump, the pressure regulating valve control parameter is adjusted to 0.4MPa, oxygen is directly introduced for oxygen pressure leaching, the oxygen flow rate is controlled to 70-75Nm3 / h, and the oxygen leaching lasts for 4.5-5.5h; copper and tellurium impurities are leached under the conditions of low temperature and high oxygen partial pressure of the reaction system. Due to the use of low acidity and low temperature, selenium and silver are not oxidized and are all enriched in the slag, which plays a role in enriching silver and selenium and removing copper and tellurium impurities;

[0007] Step 3, anaerobic leaching: close the oxygen valve, stop aerobic leaching, ensure that the pressure in the system is maintained at 0.4MPa, heat to 120-140°C, and then anaerobic leaching is performed on the copper oxide and nickel oxide contained in the slurry prepared in step 2. After reacting for 0.5-1h, the pressure is released and the material is discharged, and finally the copper, nickel, and tellurium impurities are separated from the silver and selenium;

[0008] Step 4, filter pressing and washing: filter the slurry prepared in step 3 to obtain a filtrate and a filter residue, wherein the filtrate is a pressurized liquid, and the filter residue is washed with 50-60°C warm water to obtain a pressurized copper-removing material;

[0009] The filtrate is analyzed by ICP spectral determination method, and the copper content is about 50-70g / L, the silver content is less than 0.0005g / L, the selenium content is less than 0.15g / L, and the tellurium content is about 1-3g / L; the copper leaching rate is more than 98%, and the tellurium leaching rate is 55-60%; the pressurized decopperized material is analyzed by ICP spectral determination method, and the copper content is ≯1.2%, the nickel content is ≯1.8%, the tellurium content is ≯1.0%, the silver content is 10%-12%, and the selenium content is 12%-14%.

[0010] Compared with the prior art, the present invention has the following advantages:

[0011] (1) The present invention adopts low-temperature pressurized leaching to solve the problem that silver and selenium dissolve into the pressurized liquid caused by traditional high-temperature pressurized leaching, so that the silver and selenium contents in the pressurized liquid are respectively lower than 0.0005 g / L and 0.15 g / L, so that all silver and selenium are enriched in the slag, reducing the dispersion loss of silver and selenium.

[0012] (2) The present invention adopts a low-temperature self-heating pressurized leaching process, which for the first time reduces the pressurized liquid treatment process from the original three steps of silver precipitation, selenium precipitation, and tellurium precipitation to one step of tellurium precipitation, eliminates the use of sulfur dioxide in the pressurized liquid treatment process, improves production safety, and reduces reagent costs.

[0013] (3) The present invention reduces the selenium concentration in the leaching solution from the original 15-20 g / L to below 0.15 g / L by lowering the leaching temperature and acidity of the pressurized leaching, thereby solving the problem of high selenium content and low tellurium content in the tellurium recovery process of the leaching solution, and reduces the selenium content in the tellurium precipitation tail material from more than 15% to less than 3%, providing favorable conditions for the production of tellurium refining.

[0014] (4) The present invention utilizes the principle of heat release from oxidation of impurities such as nickel, copper, and tellurium in copper anode mud, and adopts aerobic leaching at a relatively low temperature. The heat required for the leaching reaction is maintained by the self-heat release of the oxidation reaction, thereby eliminating the use of pressurized steam in the pressurized leaching process and greatly saving energy consumption.

[0015] (5) The present invention adopts a low-temperature autothermal pressure leaching process, which can shorten the production cycle of the autoclave from the original 10 to 11 hours to 6.5 to 7.5 hours, and realizes an increase in the production frequency of the autoclave from 3 to 4 autoclaves / day to 5 to 6 autoclaves / day, thereby significantly improving the production efficiency of the autoclave. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0017] The present invention is further described in detail below with reference to specific embodiments.

[0018] Example 1

[0019] A method for enriching and recovering silver and selenium from low-nickel and high-nickel copper anode muds comprises the following steps:

[0020] Step 1: slurrying: add 7 tons of copper anode mud and 21 tons of dilute sulfuric acid solution with a concentration of 130 g / L into the slurrying tank, heat the system to 80°C, keep the temperature constant for 2 hours under stirring, pre-impregnate the soluble copper sulfate, nickel sulfate and other salts in the material, and fully mix the low-nickel mud with the high-nickel mud to obtain ore slurry; the mass of the low-nickel mud in the copper anode mud is 5.25 tons, and the mass of the high-nickel mud is 1.75 tons;

[0021] Step 2: Low-pressure oxygen leaching: The slurry prepared in step 1 is pumped into the autoclave through a slurry pump, the pressure regulating valve control parameter is adjusted to 0.4 MPa, and oxygen is directly introduced for oxygen pressure leaching. The oxygen flow rate is controlled to 70 Nm 3 / h, oxygen leaching lasts for 5.5h; copper and tellurium impurities are leached out under the conditions of low temperature and high oxygen partial pressure in the reaction system. Due to the low acidity and low temperature, selenium and silver are not oxidized and are all enriched in the slag, which plays a role in enriching silver and selenium and removing copper and tellurium impurities;

[0022] Step 3, anaerobic leaching: close the oxygen valve, stop aerobic leaching, ensure that the pressure in the system is maintained at 0.4MPa, heat to 120°C, and perform anaerobic leaching on the copper oxide and nickel oxide contained in the slurry prepared in step 2. After reacting for 1h, release the pressure and discharge the material, and finally separate the copper, nickel, and tellurium impurities from silver and selenium;

[0023] Step 4, filter pressing and washing: the slurry prepared in step 3 is filter pressed, the filtrate is a pressurized liquid, and the filter residue is washed with 50°C warm water to obtain a pressurized copper-removing material;

[0024] The concentrations of copper, silver, selenium and tellurium in the filtrate are 60.77 g / L, 0.0005 g / L, 0.11 g / L and 2.02 g / L respectively, and the leaching rates of copper and tellurium are 98% and 60% respectively; the contents of copper, nickel and tellurium in the pressurized decoppering material are 1.1%, 1.51% and 0.60% respectively, the content of silver is 11.68% and the content of selenium is 13.54%, which meet the requirements of alloy production of silver anode plates.

[0025] Example 2

[0026] A method for enriching and recovering silver and selenium from low-nickel and high-nickel copper anode muds comprises the following steps:

[0027] Step 1: slurrying: add 7 tons of copper anode mud and 28 tons of dilute sulfuric acid solution with a concentration of 130 g / L into the slurrying tank, heat the system to 85°C, keep the temperature constant for 3 hours under stirring, pre-impregnate the soluble copper sulfate, nickel sulfate and other salts in the material, and fully mix the low-nickel mud with the high-nickel mud to obtain ore slurry; the mass of the low-nickel mud in the copper anode mud is 6 tons, and the mass of the high-nickel mud is 1 t;

[0028] Step 2, low-pressure oxygen leaching: the slurry prepared in step 1 is pumped into the autoclave through the slurry pump, the pressure regulating valve control parameter is adjusted to 0.4MPa, oxygen is directly introduced for oxygen pressure leaching, the oxygen flow rate is controlled to 73Nm3 / h, and the oxygen leaching lasts for 4.5h; copper and tellurium impurities are leached under the conditions of low temperature and high oxygen partial pressure of the reaction system. Due to the low acidity and low temperature, selenium and silver are not oxidized and are all enriched in the slag, which plays a role in enriching silver and selenium and removing copper and tellurium impurities;

[0029] Step 3, anaerobic leaching: close the oxygen valve, stop aerobic leaching, ensure that the pressure in the system is maintained at 0.4MPa, heat to 130°C, and then anaerobic leaching is performed on the copper oxide and nickel oxide contained in the slurry prepared in step 2. After reacting for 0.5h, the pressure is released and the material is discharged, and finally the copper, nickel, and tellurium impurities are separated from the silver and selenium;

[0030] Step 4, filter pressing and washing: the slurry prepared in step 3 is filter pressed, the filtrate is a pressurized liquid, and the filter residue is washed with 60°C warm water to obtain a pressurized copper-removing material;

[0031] The concentrations of copper, silver, selenium and tellurium in the filtrate are 54.02 g / L, 0.0002 g / L, 0.099 g / L and 1.51 g / L respectively, and the leaching rates of copper and tellurium are 98.5% and 57% respectively; the contents of copper, nickel and tellurium in the pressurized decoppering material are 1.04%, 1.49% and 0.63% respectively, the content of silver is 10.26% and the content of selenium is 12.91%, which meet the requirements of alloy production of silver anode plates.

[0032] Example 3

[0033] A method for enriching and recovering silver and selenium from low-nickel and high-nickel copper anode muds comprises the following steps:

[0034] Step 1: slurrying: add 7 tons of copper anode mud and 28 tons of dilute sulfuric acid solution with a concentration of 120 g / L into the slurrying tank, heat the system to 85°C, keep the temperature constant for 3 hours under stirring, pre-impregnate the soluble copper sulfate, nickel sulfate and other salts in the material, and fully mix the low-nickel mud with the high-nickel mud to obtain ore slurry; the mass of the low-nickel mud in the copper anode mud is 5.6 tons, and the mass of the high-nickel mud is 1.4 tons;

[0035] Step 2, low-pressure oxygen leaching: the slurry prepared in step 1 is pumped into the autoclave through the slurry pump, the pressure regulating valve control parameter is adjusted to 0.4MPa, oxygen is directly introduced for oxygen pressure leaching, the oxygen flow rate is controlled to 75Nm3 / h, and the oxygen leaching lasts for 4.5h; copper and tellurium impurities are leached under the conditions of low temperature and high oxygen partial pressure of the reaction system. Due to the low acidity and low temperature, selenium and silver are not oxidized and are all enriched in the slag, which plays a role in enriching silver and selenium and removing copper and tellurium impurities;

[0036] Step 3, anaerobic leaching: close the oxygen valve, stop aerobic leaching, ensure that the pressure in the system is maintained at 0.4MPa, heat to 140°C, and perform anaerobic leaching on the copper oxide and nickel oxide contained in the slurry prepared in step 2. After reacting for 0.5h, release the pressure and discharge the material, and finally separate the copper, nickel, and tellurium impurities from silver and selenium;

[0037] Step 4, filter pressing and washing: the slurry prepared in step 3 is filter pressed, the filtrate is a pressurized liquid, and the filter residue is washed with 55°C warm water to obtain a pressurized copper-removing material;

[0038] The concentrations of copper, silver, selenium and tellurium in the filtrate are 64.02 g / L, 0.0005 g / L, 0.1 g / L and 1.67 g / L respectively, and the leaching rates of copper and tellurium are 98.1% and 55% respectively; the contents of copper, nickel and tellurium in the pressurized decoppering material are 1.12%, 1.67% and 0.83% respectively, the content of silver is 11.37% and the content of selenium is 13.14%, which meet the requirements of alloy production of silver anode plates.

[0039] The chemical composition analysis results of the products are shown in Tables 1, 2 and 3.

[0040] Table 1 Chemical composition of filtrate

[0041]

[0042] Table 2 Chemical composition of pressure decoppering material

[0043]

[0044] Table 3 Summary of Cu and Te leaching rates in filtrate

[0045]

[0046] It can be concluded from the data in Tables 1-3 that Examples 1-3 use the method for enriching and recovering silver and selenium from low-nickel and high-nickel copper anode muds provided by the present invention, which can effectively remove copper and tellurium impurities in the copper anode mud, and effectively reduce the dissolution of silver and selenium, and reduce dispersion losses.

Claims

1. A method for enriching and recovering silver and selenium from low-nickel and high-nickel copper anode muds, characterized in that: The following steps are involved: Step 1, slurrying: add copper anode mud and dilute sulfuric acid solution with a mass ratio of 1:3-4 to 90-150g / L in a slurrying tank, heat the system to 80-85°C, keep the temperature constant for 2-3h under stirring, pre-impregnate soluble copper sulfate, nickel sulfate and other salts in the material, and fully mix the low-nickel mud with the high-nickel mud to obtain slurry; the mass ratio of low-nickel mud to high-nickel mud in the copper anode mud is 3-6:1; Step 2: Low-pressure oxygen leaching: The slurry prepared in step 1 is pumped into the autoclave through a slurry pump, the pressure regulating valve control parameter is adjusted to 0.4 MPa, and oxygen is directly introduced for oxygen pressure leaching. The oxygen flow rate is controlled to 70-75 Nm 3 / h, oxygen leaching lasts for 4.5-5.5h; copper and tellurium impurities are leached out under the conditions of low temperature and high oxygen partial pressure of the reaction system. Due to the low acidity and low temperature, selenium and silver are not oxidized and are all enriched in the slag, which plays a role in enriching silver and selenium and removing copper and tellurium impurities; Step 3, anaerobic leaching: close the oxygen valve, stop aerobic leaching, ensure that the pressure in the system is maintained at 0.4MPa, heat to 120-140°C, and then anaerobic leaching is performed on the copper oxide and nickel oxide contained in the slurry prepared in step 2. After reacting for 0.5-1h, the pressure is released and the material is discharged, and finally the copper, nickel, and tellurium impurities are separated from the silver and selenium; Step 4, filter pressing and washing: the slurry prepared in step 3 is filter pressed to obtain a filtrate and a filter residue, the filtrate is a pressurized liquid, and the filter residue is washed with warm water at 50-60°C to obtain a pressurized copper-removing material; The filtrate is analyzed by ICP spectral determination method, wherein the copper content is 50-70 g / L, the silver content is less than 0.0005 g / L, the selenium content is less than 0.15 g / L, and the tellurium content is 1-3 g / L; the copper leaching rate is more than 98%, and the tellurium leaching rate is 55-60%; the pressurized decopper material is analyzed by ICP spectral determination method, wherein the copper content is ≯1.2%, the nickel content is ≯1.8%, the tellurium content is ≯1.0%, the silver content is 10%-12%, and the selenium content is 12%-14%.

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