Liquid-solid separation method for zinc hydrometallurgy pressure leaching ore pulp

Abstract

The invention belongs to the technical field of zinc hydrometallurgy, and particularly discloses a liquid-solid separation method for zinc hydrometallurgy pressure leaching ore pulp, which comprises the following steps: sequentially carrying out first-stage pressure leaching and second-stage pressure leaching on a zinc raw material, respectively adding first-stage pressure leaching supernatant and second-stage pressure leaching supernatant for dilution after the first-stage pressure leaching ore pulp and the second-stage pressure leaching ore pulp are subjected to flash evaporation and regulation cooling and depressurization, and carrying out solid-liquid separation on the first-stage pressure leaching supernatant and the second-stage pressure leaching supernatant; then respectively adding a first-stage flocculating agent and a second-stage flocculating agent for first-stage thickening, second-stage thickening and liquid-solid separation; according to the method, the pressure leaching first-section supernate and the pressure leaching second-section supernate are led into the corresponding pressure leaching first-section ore pulp chute and the corresponding pressure leaching second-section ore pulp chute, the ore pulp in the pressure leaching first-section ore pulp chute and the pressure leaching second-section ore pulp chute is diluted, the polyacrylamide slurry is added into the diluted ore pulp, the liquid-solid separation effect is obviously improved, the separation effect of the pressure leaching first-section thickening pool and the pressure leaching second-section thickening pool is obviously improved, and the separation efficiency is improved. Meanwhile, the dosage of the flocculating agent is reduced by 10-22%.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrometallurgical zinc smelting, and in particular relates to a liquid-solid separation method of pressure leaching slurry in hydrometallurgical zinc smelting. Background Art

[0002] Metallic zinc is an important strategic resource for national economic development and national defense construction. Hydrometallurgy refers to the process of dissolving zinc from zinc roasted ore or other zinc sulfide materials and zinc sulfide concentrate in sulfuric acid solution to extract metallic zinc or zinc compounds. It is the main method of modern zinc smelting. It consists of three major steps: zinc leaching, zinc sulfate solution purification, and zinc electrolytic deposition.

[0003] In the prior art CN110872650A, a zinc concentrate leaching method adopts "two-stage oxygen-enriched pressurized direct leaching". The first and second stage slurries of the pressurized leaching are flashed and adjusted before being depressurized and cooled. The first and second stage slurries of the pressurized leaching after being cooled and depressurized overflow through the chute to the first and second stage thickening tanks for liquid-solid separation. Polyacrylamide slurry is added to the chute to accelerate the liquid-solid separation. After obtaining qualified supernatant and thickened bottom flow, the supernatant and thickened bottom flow are transported to the next process section for operation. However, the solid content of the first and second stage slurries of the pressurized leaching process is large, the liquid-solid separation in the thickening tank is poor, and the unit consumption of polyacrylamide is high.

[0004] Poor liquid-solid separation can cause the following problems:

[0005] 1. The sedimentation effect of the pressurized leaching pulp in the thickening tank is poor, and the supernatant contains a certain amount of solids. When the first-stage supernatant contains solids, the copper precipitation operation is difficult to filter, and the system operation flow is affected; the copper slag grade is reduced, the zinc content of the copper slag increases, and the profit is reduced. When the second-stage supernatant contains solids, the liquid-solid ratio of the first-stage pressurized leaching is reduced, affecting the safe operation of the pressure autoclave.

[0006] 2. The sedimentation effect of the pressurized leaching slurry in the thickening tank is poor, and the thickening bottom flow concentration is low. When the first thickening bottom flow concentration is low, the second stage pressure kettle slurry flow is large, and the steam unit consumption increases; when the second stage thickening bottom flow concentration is low, the slag output is affected.

[0007] Therefore, how to provide a method for improving the liquid-solid separation effect of the hydrometallurgical zinc pressure leaching slurry is a technical problem that technicians in this field urgently need to solve. Summary of the invention

[0008] In view of this, the present invention discloses a liquid-solid separation method for hydrometallurgical zinc pressure leaching slurry. Liquid-solid separation is accelerated, the amount of polyacrylamide used is reduced, the safe operation of the pressure reactor is guaranteed, the copper precipitation filter is significantly improved, and the safe operation of the thickening tank is significantly improved.

[0009] In order to achieve the above object, the present invention adopts the following technical solution:

[0010] A method for liquid-solid separation of hydrometallurgical zinc pressure leaching slurry, wherein the zinc raw material is subjected to first-stage pressure leaching and second-stage pressure leaching in sequence, the first-stage and second-stage pressure leaching slurries are flashed, cooled and pressure-reduced, and then the first-stage and second-stage pressure leaching supernatants are added to dilute them respectively, and then flocculants are added to perform first-stage and second-stage thickening and liquid-solid separation.

[0011] Preferably, the concentration of the first and second stage pressure leaching pulp after flash evaporation, temperature reduction and pressure reduction is 0.09-0.15t / m 3 After adding the first and second stage pressure leaching supernatants for dilution, the concentration decreased by 20% to 35%.

[0012] Preferably, the flocculant is polyacrylamide slurry with a concentration of 1.0 to 2.0 g / L.

[0013] Preferably, the volume ratio of the first stage of pressure leaching slurry to the first stage of densely added flocculant is 100:(0.5-4.5); more preferably, the volume ratio of the first stage of pressure leaching slurry to the first stage of flocculant is 100:(4-4.5).

[0014] Preferably, the volume ratio of the second-stage pressure leaching pulp to the second-stage concentrated flocculant is 100:(0.5-2.0); more preferably, the volume ratio of the second-stage pressure leaching pulp to the second-stage flocculant is 100:(1.5-2.0).

[0015] Preferably, the zinc raw material is subjected to a one-stage pressure leaching together with oxygen, steam and lignin, and iron powder is added to the remaining part of the supernatant of the first stage of leaching to perform a replacement copper precipitation operation, and then pressure filtration is performed to obtain a filtrate and copper slag.

[0016] Preferably, waste electrolyte, oxygen, steam and lignin are added to the underflow of the first stage of pressure leaching for second stage of pressure leaching, the remaining second stage supernatant is returned to the first stage of pressure leaching, and the second stage underflow residue is sent to neutralization.

[0017] It can be seen from the above technical solutions that compared with the prior art, the present invention has the following excellent effects:

[0018] The present invention introduces the supernatant of the first and second stages of pressure leaching into the corresponding first and second stage slurry chutes of pressure leaching, dilutes the slurry in the first and second stage chutes of pressure leaching, and adds polyacrylamide slurry to the diluted slurry, so that the liquid-solid separation effect is significantly improved, the separation effect of the first and second thickening tanks of pressure leaching is significantly improved, and the amount of flocculant used is reduced by 10-22%. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0020] Figure 1 The present invention is a flow chart of liquid-solid separation of pressure leaching slurry in hydrometallurgy of zinc. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] Example 1

[0023] The zinc raw material is subjected to a first-stage pressure leaching together with oxygen, steam and lignin. The first-stage pressure leaching pulp is flashed and adjusted to reduce pressure and temperature. The first-stage pressure leaching pulp after temperature and pressure reduction overflows through the chute to a first-stage thickening tank for liquid-solid separation. Polyacrylamide slurry is simultaneously added to the chute to accelerate liquid-solid separation, and the first-stage pressure leaching supernatant and the first-stage pressure leaching underflow are obtained. The first-stage pressure leaching supernatant is led to the first-stage pressure leaching pulp chute, and the pulp in the first-stage pressure leaching chute is diluted. During the dilution process, a variable frequency pump is used to control the supernatant flow to dilute the first-stage pressure leaching pulp to 0.06-0.10t / m 3 , the concentration of the first-stage pressurized leaching slurry is tested every four hours, and the amount of supernatant is adjusted according to the concentration of the slurry to ensure the concentration of the slurry after dilution. Polyacrylamide slurry is added to the diluted slurry (polyacrylamide is reduced by 10-22% after dilution), and the slurry overflows to the first-stage thickening tank for liquid-solid separation. Iron powder is added to the remaining part of the first-stage leaching supernatant to replace copper precipitation, and then filter press to obtain filtrate and copper slag. After the supernatant of the first stage of pressurized leaching is clarified, the copper precipitation filtration is significantly improved; the bottom flow of the first stage thickening tank rises, and the supernatant output is increased. The following 1#-3# tests are used to verify the effect of liquid-solid separation of the first-stage pressurized leaching slurry with different dilution multiples.

[0024] 1.1# Tester: Take a section of pressurized leaching slurry 300mL (slurry concentration 0.115t / m 3 ), 100 ml of the supernatant from the first stage of pressure leaching was added to the 1# test vessel; the slurry and supernatant from the first stage of pressure leaching in the 1# test vessel were stirred for 30 seconds (slurry concentration 0.0751 t / m 3), gradually add polyacrylamide slurry (concentration of 1g / L), 2ml each time, stir for 30s each time, and settle for 2min each time; polyacrylamide slurry (concentration of 1g / L) is added to 12ml, and after settling for 2min, the pressure leaching slurry of the first stage of the 1# test device has been clarified.

[0025] 2.2# Tester: Take a section of pressurized leaching slurry 300mL (slurry concentration 0.115t / m 3 ), 50 ml of the supernatant from the first stage of pressure leaching was added to the 2# tester; the slurry and supernatant from the first stage of pressure leaching in the 2# tester were stirred for 30 seconds (slurry concentration 0.0962 t / m 3 ), gradually add polyacrylamide slurry (concentration of 1g / L), 2ml each time, stir for 30s each time, and settle for 2min each time; polyacrylamide slurry (concentration of 1g / L) is added to 14, and after settling for 2min, the first stage pressure leaching slurry of 2# test device has been clarified.

[0026] 3.3# Tester: Take a section of pressurized leaching slurry 300mL (slurry concentration 0.115t / m 3 ), polyacrylamide slurry (concentration of 1g / L) was gradually added to the first stage of pressure leaching slurry in the 3# test vessel, 2ml each time, stirred for 30s each time, and settled for 2min each time; polyacrylamide slurry (concentration of 1g / L) was added to 16, and after settling for 2min, the first stage of pressure leaching slurry in the 3# test vessel was clarified.

[0027] Waste electrolyte, oxygen, steam and lignin are added to the first stage of pressurized leaching bottom flow for second stage pressurized leaching. The second stage pressurized leaching pulp is flashed and adjusted to reduce pressure and temperature. The second stage pressurized leaching pulp after temperature and pressure reduction overflows through the chute to the second stage thickening tank for liquid-solid separation. Polyacrylamide slurry is added to the chute to accelerate liquid-solid separation, and the second stage pressurized leaching supernatant and the second stage pressurized leaching bottom flow are obtained. The second stage pressurized leaching supernatant is led to the second stage pressurized leaching pulp chute to dilute the pulp in the second stage pressurized leaching chute. During the dilution process, a variable frequency pump is used to control the supernatant flow to dilute the second stage pressurized leaching pulp to 0.06-0.10t / m 3 , check the concentration of the second stage slurry of the pressure leaching every four hours, adjust the amount of supernatant according to the slurry concentration, and ensure the concentration of the slurry after dilution. Add polyacrylamide slurry to the diluted slurry (polyacrylamide is reduced by 20-35% after dilution), and overflow to the second stage thickening tank for liquid-solid separation. The remaining second stage supernatant returns to the first stage of pressure leaching, and the second stage bottom flow slag is sent for neutralization. The liquid-solid ratio of the second stage of pressure leaching returns to normal, which improves the safe operation of the pressure autoclave; the second stage bottom flow filtration time is significantly shortened, the slag discharge amount is increased, and the safe operation of the thickening tank is improved. The following 1#-3# tests are used to verify the effect of liquid-solid separation of the second stage pressure leaching slurry with different dilution multiples.

[0028] 1.1# Tester: Take 300mL of the second stage slurry under pressure leaching (slurry concentration 0.105t / m 3 ), 100 ml of the supernatant from the second stage of pressure leaching was added to the 1# tester; the slurry from the second stage of pressure leaching and the supernatant from the 1# tester were stirred for 30 seconds (slurry concentration 0.0697 t / m 3 ), gradually add polyacrylamide slurry (concentration of 1g / L), 2ml each time, stir for 30s each time, and settle for 2min each time; polyacrylamide slurry (concentration of 1g / L) is added to 5ml, and after settling for 2min, the second stage slurry of pressure leaching in 1# test device has been clarified.

[0029] 2.2# Tester: Take 300mL of the second stage slurry under pressure leaching (slurry concentration 0.105t / m 3 ), 50 ml of the supernatant from the second stage of pressure leaching was added to the 1# tester; the slurry and supernatant from the second stage of pressure leaching in the 1# tester were stirred for 30 seconds (slurry concentration 0.0875 t / m 3 ), gradually add polyacrylamide slurry (concentration of 1g / L), 2ml each time, stir for 30s each time, and settle for 2min each time; polyacrylamide slurry (concentration of 1g / L) is added to 6ml, and after settling for 2min, the second stage slurry of pressure leaching in 1# test device has been clarified.

[0030] 3.3# Tester: Take 300mL of the second stage slurry under pressure leaching (slurry concentration 0.105t / m 3 ), polyacrylamide slurry (concentration of 1g / L) was gradually added to the second stage ore pulp of 3# test device under pressure leaching, 2ml each time, stirring for 30s each time, and settling for 2min each time; polyacrylamide slurry (concentration of 1g / L) was added to 8ml, and after settling for 2min, the second stage ore pulp of 3# test device under pressure leaching was clarified.

[0031] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for liquid-solid separation of pressure leaching slurry from hydrometallurgy zinc smelting, characterized in that: The zinc raw material is subjected to the first stage pressure leaching and the second stage pressure leaching in sequence. The first and second stage pressure leaching slurries are flashed, cooled and pressure-reduced, and then the first and second stage pressure leaching supernatants are added for dilution. Then, flocculants are added for the first and second stage thickening and liquid-solid separation.

2. The method for liquid-solid separation of pressure leaching slurry from hydrometallurgy zinc according to claim 1, characterized in that: The concentration of the first and second stage pressure leaching pulp after flash evaporation, temperature and pressure adjustment is 0.09-0.15t / m 3 After adding the supernatant of the first and second stage pressure leaching for dilution, the concentration dropped by 20% to 35%.

3. The method for liquid-solid separation of pressure leaching slurry from hydrometallurgy zinc according to claim 1, characterized in that: The flocculant is polyacrylamide slurry with a concentration of 1.0-2.0 g / L.

4. The method for liquid-solid separation of pressure leaching slurry from hydrometallurgy zinc according to claim 1, characterized in that: The volume ratio of the first stage pressure leaching slurry to the first stage densely added flocculant is 100:(0.5-4.5).

5. The method for liquid-solid separation of pressure leaching slurry from hydrometallurgy zinc according to claim 1, characterized in that: The volume ratio of the second-stage pressure leaching pulp to the second-stage thickening added flocculant is 100: (0.5-2).

6. The method for liquid-solid separation of pressure leaching slurry from hydrometallurgy zinc according to claim 1, characterized in that: The remaining part of the supernatant of the first stage leaching is added with iron powder to carry out the copper replacement precipitation operation, and then filtered to obtain the filtrate and copper slag.

7. The method for liquid-solid separation of pressure leaching slurry from hydrometallurgy zinc according to claim 1, characterized in that: The waste electrolyte, oxygen, steam and lignin are added to the first-stage pressure leaching bottom flow for the second-stage pressure leaching, and the remaining second-stage supernatant is returned to the first-stage pressure leaching, and the second-stage bottom flow residue is sent to neutralization.

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