Medium-temperature iron precipitation separation method for one-section low-temperature two-section high-temperature high-zinc high-iron solution oxygen pressure kettle

Abstract

The invention discloses a one-stage low-temperature two-stage high-temperature high-zinc high-iron solution oxygen pressure kettle medium-temperature iron precipitation separation method, which belongs to the technical field of lead-zinc smelting, and comprises the following steps: one-stage and two-stage oxygen pressure leaching, replacement copper precipitation, pre-neutralization, indium precipitation, mineralization iron precipitation and neutralization iron removal. According to the method, first-stage low-temperature countercurrent oxygen pressure leaching and second-stage high-temperature countercurrent oxygen pressure leaching are adopted, efficient leaching of various valuable metals such as zinc, copper and indium is achieved, valuable elements such as silver, lead and elemental sulfur are enriched in the second-stage oxygen pressure leaching residues, the sulfur content and the lead-silver enrichment ratio in the second-stage oxygen pressure leaching residues are increased, and the yield is increased. And the second-stage oxygen pressure leaching residues are conveyed to sulfur flotation to produce qualified sulfur concentrate and sulfur tailings rich in lead and silver, the sulfur concentrate is conveyed to a sulfur melting system to produce sulfur, and the sulfur tailings are conveyed to a lead system to be subjected to pyrogenic treatment. According to the method, the copper slag, the pre-neutralization slag and the indium precipitation slag can be respectively produced; hematite is produced after indium precipitation liquid is treated, zinc and iron are efficiently separated, and the slag amount is reduced; and treating the mineralized iron-precipitated solution to generate a neutralized iron-removed solution, and purifying and electrodepositing the neutralized iron-removed solution to produce metal zinc.

Description

Technical Field

[0001] This invention relates to the field of lead-zinc smelting technology, and more specifically to a method for separating iron precipitation in an oxygen pressure vessel containing a high-zinc and high-iron solution, using a first-stage low-temperature and second-stage high-temperature process. Background Technology

[0002] Currently, zinc sulfide concentrate undergoes a two-stage countercurrent leaching process: a first-stage high-temperature leaching (120–155℃) and a second-stage high-temperature leaching (120–165℃). This process achieves efficient leaching of various valuable metals such as zinc, copper, and indium. Valuable elements such as silver, lead, and elemental sulfur are enriched in the second-stage oxygen pressure leaching residue, increasing the sulfur content and lead-silver enrichment ratio. The residue is then sent to a sulfur flotation system to produce a sulfur concentrate with a sulfur content of 65–80%, as well as lead-rich sulfur tailings. The sulfur concentrate is then sent to a thermal filtration and elemental sulfur recovery system, while the sulfur tailings are sent to a lead system for pyrometallurgical treatment. The first-stage oxygen pressure leaching solution undergoes iron powder replacement to precipitate copper. The copper-precipitated liquid is then neutralized with zinc oxide fumes to precipitate indium. The supernatant from the indium-precipitated solution is oxidized and neutralized with oxygen and limestone powder, producing copper slag, indium-precipitated slag (sent for indium recovery), and iron slag (slag dump).

[0003] With the increasing awareness of environmental protection, energy conservation, cost, and efficiency, some problems existing in the oxygen pressure leaching system of zinc smelting have become important factors restricting the company's sustainable development. These problems are mainly manifested in the following ways:

[0004] 1. Low direct recovery rate of zinc via wet process

[0005] Statistics from recent years show that the direct recovery rate of zinc by wet process is only 93-94%, which is lower than that of similar enterprises, leading to higher smelting costs.

[0006] 2. Copper and indium recovery rates are low.

[0007] Recent operational data shows that the wet recovery rate of copper is only 60-65%, and the recovery rate of indium is only 20-30%. The overall recovery rate of copper and indium is low, failing to fully realize the advantages of the oxygen pressure leaching method, indicating significant potential for improving copper and indium recovery rates.

[0008] 3. Large volume of leaching residue and high residue treatment costs.

[0009] Iron, lead, and other minerals enter the leaching residue in the form of alum and other compounds, resulting in a high leaching residue rate (around 100-120% for the first stage of oxygen pressure leaching and 60-70% for the second stage) and a large amount of residue production. This affects the normal operation of the sulfur flotation and sulfur melting systems. In recent years, with the rise in fuel prices, the cost of pyrometallurgical treatment has increased, with the cost of treating one ton of residue reaching over 900 yuan, which seriously affects the economic benefits of enterprises.

[0010] 4. Poor flotation performance

[0011] The sulfur concentrate has a fine particle size and contains red substances, indicating that the second-stage leaching pulp produced by oxygen pressure leaching does not have enough time for the sulfur crystal growth process during the flash-conditioning process, and that there is a mixture of sulfur and slag materials, which cannot be effectively separated during the flotation process.

[0012] 5. Sulfuric acid deficiency

[0013] Due to the impact of the local market, Hulunbuir Chihong Sulfuric Acid is operating at a loss, with a loss of more than 300 yuan per ton of sulfuric acid.

[0014] Therefore, improving the overall recovery rate of copper, indium, silver, and elemental sulfur through the optimization of the overall oxygen pressure leaching system and parameter control, reducing slag production at the source, and improving the overall technical and economic indicators of the zinc sulfide concentrate oxygen pressure leaching system are technical problems that urgently need to be solved by those skilled in the art. Summary of the Invention

[0015] In view of this, the present invention provides a method for separating iron precipitation in an oxygen autoclave of a first-stage low-temperature and second-stage high-temperature high-zinc and high-iron solution.

[0016] To achieve the above objectives, the present invention adopts the following technical solution:

[0017] A method for separating iron precipitation in a low-temperature, high-temperature, high-zinc, and high-iron solution in an oxygen pressure vessel includes the following steps: (1) Low-temperature oxygen pressure leaching: Zinc sulfide concentrate slurry, pre-leaching liquid, oxygen, and lignin are continuously fed into an oxygen pressure vessel. The reaction is carried out under low temperature, low pressure, weak oxidation, and stirring. After flash evaporation, the slurry in the vessel is adjusted to atmospheric pressure and thickened to obtain a supernatant and a bottom stream (slag rate 75-85%).

[0018] (2) Displacement copper precipitation: Iron powder is used to displace copper in the supernatant of the first stage. After pressure filtration, copper precipitation liquid and copper slag are obtained. The copper slag is washed with water and sold or recycled for copper treatment.

[0019] (3) Pre-neutralization: The copper-precipitated liquid is pre-neutralized using the iron-removing underflow or zinc roasted sand. The slurry is then thickened to obtain the pre-neutralized supernatant (H). + Neutralized to 2-5 g / L) and pre-neutralized underflow, the pre-neutralized underflow is sent to the second stage oxygen pressure leaching for further leaching;

[0020] (4) Indium precipitation: The pH of the pre-neutralized supernatant was adjusted to 4.0-4.5 using zinc oxide dust, and then the pH of the solution was adjusted to 4.5-4.8 using limestone powder for indium precipitation. After pressure filtration, indium precipitation liquid (containing ≤5mg / L indium) and indium precipitation residue were obtained. The indium precipitation residue was sent to the indium recovery system.

[0021] (5) Iron mineralization: After indium precipitation, the solution is acidified to pH 2.0-3.5 and preheated to 120-150℃ before being continuously fed into an oxygen pressure vessel for iron mineralization. Iron mineralization is carried out under medium temperature, medium pressure, and oxidative stirring. Pure zinc oxide powder is added simultaneously for neutralization. The acidity of the solution is controlled at 10-20 g / L. The slurry is flash-evaporated, adjusted to atmospheric pressure, and thickened to obtain a supernatant and underflow (hematite with iron content >55%).

[0022] (6) Neutralization and iron removal: The supernatant of iron precipitation is neutralized with zinc calcined sand as a neutralizing agent, while maintaining the pH at 4.8-5.2. Oxygen or air is introduced for oxidation to remove iron. After thickening, the neutralized iron removal underflow and neutralized iron removal supernatant are obtained. The neutralized iron removal underflow is sent to the pre-neutralization and neutralization process or after pressure filtration and pulping, it is sent to the second stage oxygen pressure leaching process. The neutralized iron removal supernatant (Fe≤20mg / L) is sent to the purification system.

[0023] Furthermore, the underflow treatment method described in step (1) is as follows:

[0024] 1) Two-stage high-temperature oxygen pressure leaching: The underflow from the first stage, the pre-leaching liquid from the second stage, oxygen, and lignin are continuously pumped into the first-stage oxygen pressure vessel. The process is carried out at a high temperature of 135–160℃, a medium pressure of 1.0–1.2 MPa, and an oxygen consumption of 80–120 Nm³. 3 / t·dry ore is stirred and reacted under strong oxidation. The slurry in the kettle is flashed at 100~450KPa and 120~135℃, then adjusted to normal pressure and thickened to obtain two-stage supernatant and two-stage underflow.

[0025] 2) Two-stage underflow pressure filtration: The two-stage underflow is pressure filtered to obtain two-stage filtrate and two-stage filtrate residue; the two-stage filtrate, the two-stage supernatant and the zinc electrowinning waste electrolyte are mixed to form a first-stage pre-leaching solution for first-stage oxygen pressure leaching;

[0026] 3) The second-stage filter press residue is slurried and stirred with clean water or low-zinc washing water, and then subjected to sulfur flotation to obtain sulfur concentrate and sulfur tailings. The sulfur tailings are sent to the pyrometallurgical treatment system.

[0027] 4) The sulfur concentrate is melted to obtain sulfur and hot filter residue, which is then sent to the pyrometallurgical processing system.

[0028] Furthermore, in step (1), the low temperature is 100–110°C, the low pressure is 0.40–0.70 MPa, the oxygen partial pressure is 0.15–0.25 MPa, and the weak oxidation is an oxygen consumption of 40–55 Nm³. 3 / t·Dry ore;

[0029] The flash evaporation pressure is 100–350 kPa and the temperature is 95–105 °C.

[0030] The endpoint is free acid of 10-20 g / L, TFe below 14 g / L, and Fe...3+ The content is less than 0.5 g / L.

[0031] In step (1) of this invention, the oxygen pressure operation process employs low temperature, low oxygen partial pressure, and controlled low endpoint acid for leaching, utilizing oxygen and the first-stage leaching pre-liquid (second-stage supernatant + 30% waste electrolyte) Fe 3+ To disrupt the mineral structure of zinc sulfide concentrate, thereby maximizing zinc leaching while controlling the iron ions in the final leaching solution to be predominantly Fe, the method aims to improve zinc leaching efficiency. 2+ This process avoids the re-precipitation of copper, indium, and iron ions into the slag, thereby improving the leaching rate of zinc, copper, indium, iron, and other multimetals. The two-stage oxygen pressure leaching process employs high temperature, high pressure, and high final acid leaching to achieve complete leaching of zinc sulfide, indium, and copper, while maintaining a strong oxidizing atmosphere and acidity conditions.

[0032] Furthermore, in step (2), the TFe content in the copper-precipitated solution is below 16 g / L, and the copper content in the copper-precipitated solution is 100–300 mg / L.

[0033] In step (2) of this invention, the supernatant is subjected to iron powder replacement and copper precipitation in a copper precipitation tank. The resulting copper slurry overflows into an intermediate copper precipitation tank and is pumped to a copper precipitation filter press for filtration via a transfer pump from the intermediate tank. The copper precipitation filter liquid is then transported to a pre-neutralization tank. The resulting filter residue is pulped and washed with clean water and then filtered through a copper slag washing diaphragm filter press, producing copper slag. During the replacement process, copper and arsenic co-precipitates are formed, accompanied by the formation of cuprous chloride. The copper slag can facilitate the removal of impurities such as arsenic and chlorine.

[0034] Furthermore, the pre-neutralization of the undercurrent treatment method described in step (3) is as follows:

[0035] The pre-neutralized underflow is pressure filtered to obtain pre-neutralized underflow filtrate and pre-neutralized underflow filtrate residue. The pre-neutralized underflow filtrate is fed into the pre-neutralized supernatant. The pre-neutralized underflow filtrate is mixed with the neutralized iron-removing underflow and then slurryed, and then mixed with a first-stage underflow.

[0036] Furthermore, in step (3), the endpoint free acid in the pre-neutralization supernatant is 2-5 g / L, and TFe is below 16 g / L.

[0037] In step (3) of this invention, the copper precipitation solution is pre-neutralized in a pre-neutralization tank using neutralized iron removal underflow / zinc roasted sand. The pre-neutralized ore overflows into a thickening tank, where flocculants can be added to accelerate liquid-solid separation. The pre-neutralization supernatant is then transported to the indium precipitation tank. The pre-neutralization underflow is filtered and slurry-adjusted using a filter press before being transported to the second-stage oxygen pressure leaching, where it is combined with the first-stage underflow as the raw material for the second-stage oxygen pressure leaching. The pre-neutralization underflow filtrate is returned to the pre-neutralization supernatant storage tank.

[0038] Furthermore, in step (4), the final free acid in the indium precipitation solution is 4.5–4.8 g / L, and the TFe is below 16 g / L.

[0039] In step (4) of this invention, the pre-neutralized supernatant undergoes indium precipitation in an indium precipitation tank. Zinc oxide dust and limestone powder produced by the lead system fuming furnace are used as neutralizing agents to precipitate indium, thereby removing In from the solution. 3+ Reduce to below 5 mg / L. The produced indium precipitate slurry overflows into the indium precipitation intermediate tank, and the slurry is filtered through the indium precipitation filter press. The indium precipitation filter liquid is transported to the iron precipitation reactor. The indium precipitation slag is transported to the indium recovery system after being slurryed with waste electrolyte.

[0040] Furthermore, the treatment steps for the mineralized iron sludge underflow mentioned in step (5) are as follows:

[0041] ① The underflow of precipitated iron is filtered to obtain mineralized underflow filtrate and hematite. The underflow filtrate is then fed into the supernatant of precipitated iron.

[0042] ② After washing and pulping, hematite was centrifuged to obtain slurry and iron oxide (Fe2O3);

[0043] ③ After the slurry is filtered, iron oxide (Fe2O3) and filtrate are obtained. The filtrate is washed with water and then sent to the second stage of the integrated washing tank for leaching and slurry production.

[0044] Furthermore, in step (5), the intermediate temperature is 135–160°C, the intermediate pressure is 0.70–0.90 MPa, and the oxygen consumption for oxidation is 1.5–3.5 Nm³. 3 / m 3 Solution;

[0045] The flash evaporation pressure is 100–350 kPa and the temperature is 95–105 °C.

[0046] High-purity zinc oxide powder is added to the iron precipitator to neutralize the free acid in the supernatant of the precipitated iron to 10-20 g / L and TFe to below 2 g / L.

[0047] In step (5) of this invention, the oxygen pressure autoclave iron precipitation process employs medium-temperature oxidation and neutralization. After indium precipitation, the liquid is acidified and preheated before entering the oxygen pressure autoclave for iron precipitation. The temperature is further increased by medium-pressure steam from the autoclave head (reaching 135–160°C). Oxygen is used as the oxidant, and oxygen is introduced into chambers 1, 3, and 5 of the autoclave (75–80% oxygen in chamber 1 and 20–25% oxygen in the other chambers). High-purity zinc oxide powder is used as the neutralizing agent, added to chambers 2, 4, and 6 of the autoclave after slurry preparation (75–80% neutralizing agent in chamber 2 and 20–25% neutralizing agent in the other chambers) to neutralize the free acid in the precipitated liquid to 10–20 g / L. The high-temperature, high-pressure slurry produced by the autoclave is flash-evaporated, depressurized, and cooled before being sent to a thickening tank, where flocculants are added to accelerate liquid-solid separation. The supernatant is neutralized and iron removed in the neutralization and iron removal tank. The mineralized iron underflow is filtered, slurried, washed, and centrifuged to produce hematite (Fe2O3>50%), which is sold as a by-product. The filtrate produced by centrifugation is filtered again and transported to the integrated washing tank for use in the secondary leaching residue slurry.

[0048] Furthermore, the pH value of the neutralized iron-removing supernatant in step (6) is 4.8 to 5.2, and the TFe content is below 20 mg / L.

[0049] In step (6) of this invention, the supernatant of the mineralized iron precipitate undergoes iron removal in the neutralization and iron removal tank. Zinc calcined sand is used as a neutralizing agent for neutralization, and air or oxygen is introduced for oxidation and iron removal. The neutralized iron removal slurry overflows into the thickening tank, where flocculants can be added to accelerate liquid-solid separation. The qualified supernatant is sent to the purification section. Part of the neutralized iron removal underflow is sent to the pre-neutralization tank for neutralization and use, while the other part is filtered, slurried, and transported to the second-stage oxygen pressure leaching for further treatment.

[0050] The beneficial effects of this invention are as follows:

[0051] 1. This invention employs a two-stage oxygen pressure leaching method, comprising a first-stage low-temperature (<110℃) and a second-stage high-temperature (135~155℃) countercurrent oxygen pressure leaching process. This achieves efficient leaching of various valuable metals such as zinc, copper, and indium, enriching valuable elements such as silver, lead, and elemental sulfur in the second-stage oxygen pressure leaching residue. This increases the sulfur content and lead-silver enrichment ratio in the residue. The residue is then sent to a sulfur flotation system to produce sulfur concentrate containing 75-85% sulfur, as well as lead- and silver-rich sulfur tailings. The sulfur concentrate is sent to a sulfur melting system to produce sulfur, and the sulfur tailings are sent to a lead system for pyrometallurgical treatment.

[0052] 2. The method for copper replacement, pre-neutralization, and indium precipitation in the first-stage oxygen pressure leaching solution of the present invention is as follows: the first-stage oxygen pressure leaching solution is replaced with iron powder for copper precipitation → the liquid after copper precipitation is pre-neutralized using the neutralized iron removal underflow or zinc roasted sand → the pre-neutralized supernatant is neutralized and indium precipitated using zinc oxide dust and limestone powder, respectively producing copper slag, pre-neutralized slag (returned to the second-stage oxygen pressure leaching), and indium precipitated slag (sent to the indium recovery system).

[0053] 3. The oxygen pressure autoclave medium-temperature iron precipitation method of this invention: After indium precipitation, the liquid is acidified and preheated, and then subjected to medium-temperature (135-160℃) oxidation (oxygen) and neutralization (high-purity zinc oxide powder) in an oxygen pressure autoclave for iron precipitation, producing hematite with an iron content >50%, achieving efficient separation of zinc and iron and reducing slag volume. The liquid after iron precipitation is neutralized with zinc roasted sand and oxidized with air or oxygen. The qualified neutralized and iron-removed liquid is sent for purification and electrowinning to produce metallic zinc. Attached Figure Description

[0054] Figure 1 The process flow diagram provided for this invention. Detailed Implementation

[0055] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are merely embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0056] Example 1

[0057] A method for medium-temperature iron precipitation separation in an oxygen autoclave of a high-zinc, high-iron solution with a first-stage low-temperature and second-stage high-temperature process:

[0058] (1) First-stage low-temperature oxygen pressure leaching: Qualified zinc sulfide concentrate slurry, first-stage pre-leaching liquid (second-stage supernatant + waste electrolyte), oxygen, lignin, etc., are continuously fed into the first-stage oxygen pressure vessel. The leaching is carried out at low temperature (105℃), low pressure (0.60MPa, oxygen partial pressure 0.15MPa), and weak oxidation (oxygen consumption 52Nm³ / h). 3 The reaction was carried out under strong stirring (120 r / min) with dry ore. The slurry in the reactor was flash evaporated (pressure 120 kPa, temperature 97 ℃), adjusted (atmospheric pressure, temperature 95 ℃), and thickened to obtain a supernatant (H). + 15g / L, TFe10g / L) and a first-stage underflow (600 tons of input in the first stage, 510 tons of leaching residue in the second stage, with a residue rate of 85%).

[0059] (2) Displacement copper precipitation: Iron powder is used to displace copper in the supernatant of the first stage. After pressure filtration, copper precipitation liquid and copper slag are obtained. The copper slag is washed with water and then sold or recycled for copper treatment.

[0060] (3) Pre-neutralization: The copper-precipitated liquid is pre-neutralized using the iron-removing underflow or zinc roasted sand. The slurry is then thickened to obtain the pre-neutralized supernatant (H). + Neutralized to 3 g / L) and pre-neutralized underflow, the pre-neutralized underflow is sent to the second stage oxygen pressure leaching for further leaching.

[0061] (4) Indium precipitation: The pH of the pre-neutralized supernatant was adjusted to 4.0 using zinc oxide dust, and then the pH of the solution was adjusted to 4.6 using limestone powder for indium precipitation. After pressure filtration, the indium precipitation liquid (containing 4 mg / L of indium) and indium precipitation residue were obtained. The indium precipitation residue was sent to the indium recovery system.

[0062] (5) Iron Mineralization: After indium precipitation, the solution is acidified (pH controlled at 2.0) and preheated (125℃) before being continuously fed into an oxygen autoclave for iron mineralization. The process is carried out at medium temperature (142℃), medium pressure (0.70MPa), and oxidation (oxygen consumption 1.5Nm³ / h). 3 / m 3 • The iron removal process was carried out under strong stirring (120 r / min) in solution, with high-purity zinc oxide powder added simultaneously for neutralization. The acidity of the solution was controlled at 15 g / L (to improve iron removal efficiency). The slurry was then subjected to flash evaporation (pressure 120 kPa, temperature 95 ℃), adjustment (atmospheric pressure, temperature 95 ℃), and thickening to obtain the supernatant (H). + 14 g / L, TFe 1.9 g / L) and bottom flow (hematite with 50% iron content).

[0063] (6) Neutralization and iron removal: The supernatant of the iron precipitation is neutralized with a neutralizing agent (zinc calcined sand) (pH value controlled at 4.8), and oxygen or air is introduced for oxidation to remove iron. After thickening, the neutralized iron removal underflow and neutralized iron removal supernatant are obtained. The neutralized iron removal underflow is sent to the pre-neutralization and neutralization process or after pressure filtration and pulping, it is sent to the second stage oxygen pressure leaching process. The neutralized iron removal supernatant (Fe is 15mg / L) is sent to the purification system.

[0064] The bottom flow treatment method described in step (1) is as follows:

[0065] 1) Two-stage high-temperature oxygen pressure leaching: The underflow from the first stage, the pre-leaching liquid from the second stage (waste electrolyte), oxygen, lignin, etc., are continuously pumped into the first-stage oxygen pressure vessel. The leaching is carried out at high temperature (135–153°C), medium pressure (1.0 MPa), and strong oxidation (oxygen consumption 80 Nm³ / h). 3 The reaction is carried out under strong stirring (120 r / min) with dry ore. The slurry in the reactor is flashed (pressure 120 kPa, temperature 120 °C), adjusted (atmospheric pressure, temperature 95 °C), and thickened to obtain two-stage supernatant and two-stage underflow.

[0066] 2) Two-stage underflow pressure filtration: The two-stage underflow is pressure filtered to obtain two-stage filtrate and two-stage filtrate residue; the two-stage filtrate, the two-stage supernatant and the zinc electrowinning waste electrolyte are mixed to form a first-stage pre-leaching solution for first-stage oxygen pressure leaching.

[0067] 3) The second-stage filter press residue is slurried and stirred with clean water or low-zinc washing water, and then subjected to sulfur flotation to obtain sulfur concentrate and sulfur tailings. The sulfur tailings are sent to the pyrometallurgical treatment system.

[0068] 4) The sulfur concentrate is melted to obtain sulfur and hot filter residue, which is then sent to the pyrometallurgical processing system.

[0069] Example 2

[0070] A method for medium-temperature iron precipitation separation in an oxygen autoclave of a high-zinc, high-iron solution with a first-stage low-temperature and second-stage high-temperature process:

[0071] (1) First-stage low-temperature oxygen pressure leaching: Qualified zinc sulfide concentrate slurry, first-stage pre-leaching liquid (second-stage supernatant + waste electrolyte), oxygen, lignin, etc., are continuously fed into the first-stage oxygen pressure vessel. The leaching is carried out at low temperature (108℃), low pressure (0.65MPa, oxygen partial pressure 0.25MPa), and weak oxidation (oxygen consumption 53Nm³ / h). 3 The reaction was carried out under strong stirring (120 r / min) with dry ore. The slurry in the reactor was flash evaporated (pressure 125 kPa, temperature 103 ℃), adjusted (atmospheric pressure, temperature 98 ℃), and thickened to obtain a supernatant (H). + 14g / L, TFe12g / L) and a first-stage underflow (600 tons of input in the first stage, 480 tons of leaching residue in the second stage, with a residue rate of 80%).

[0072] (2) Displacement copper precipitation: Iron powder is used to displace copper in the supernatant of the first stage. After pressure filtration, copper precipitation liquid and copper slag are obtained. The copper slag is washed with water and then sold or recycled for copper treatment.

[0073] (3) Pre-neutralization: The copper-precipitated liquid is pre-neutralized using the iron-removing underflow or zinc roasted sand. The slurry is then thickened to obtain the pre-neutralized supernatant (H). + Neutralized to 4 g / L) and pre-neutralized underflow, the pre-neutralized underflow is sent to the second stage oxygen pressure leaching for further leaching.

[0074] (4) Indium precipitation: The pH of the pre-neutralized supernatant was adjusted to 4.5 using zinc oxide dust, and then the pH of the solution was adjusted to 4.8 using limestone powder for indium precipitation. After pressure filtration, the indium precipitation liquid (containing 4 mg / L of indium) and indium precipitation residue were obtained. The indium precipitation residue was sent to the indium recovery system.

[0075] (5) Iron Mineralization: After indium precipitation, the solution is acidified (pH controlled at 3.0) and preheated (125℃) before being continuously fed into an oxygen autoclave for iron mineralization. The process is carried out at medium temperature (150℃), medium pressure (0.80MPa), and oxidation (oxygen consumption 1.8Nm³ / min). 3 / m 3 • The iron removal process was carried out under strong stirring (120 r / min) in solution, with high-purity zinc oxide powder added simultaneously for neutralization. The acidity of the solution was controlled at 15 g / L (to improve iron removal efficiency). The slurry was then subjected to flash evaporation (pressure 150 kPa, temperature 101 °C), adjustment (atmospheric pressure, temperature 98 °C), and thickening to obtain the supernatant (H). + 12 g / L, TFe 1.5 g / L) and bottom flow (hematite with 54% iron content).

[0076] (6) Neutralization and iron removal: The supernatant of the iron precipitation is neutralized with a neutralizing agent (zinc calcined sand) (pH value controlled at 4.8), and oxygen or air is introduced for oxidation to remove iron. After thickening, the neutralized iron removal underflow and neutralized iron removal supernatant are obtained. The neutralized iron removal underflow is sent to the pre-neutralization and neutralization process or after pressure filtration and pulping, it is sent to the second stage oxygen pressure leaching process. The neutralized iron removal supernatant (Fe is 12mg / L) is sent to the purification system.

[0077] The bottom flow treatment method described in step (1) is as follows:

[0078] 1) Two-stage high-temperature oxygen pressure leaching: The underflow from the first stage, the pre-leaching liquid from the second stage (waste electrolyte), oxygen, lignin, etc., are continuously pumped into the first-stage oxygen pressure vessel. The leaching is carried out at high temperature (135℃), medium pressure (1.0MPa), and strong oxidation (oxygen consumption 80Nm³ / h). 3 The reaction is carried out under strong stirring (120 r / min) with dry ore. The slurry in the reactor is flashed (pressure 120 kPa, temperature 120 °C), adjusted (atmospheric pressure, temperature 102 °C), and thickened to obtain two-stage supernatant and two-stage underflow.

[0079] 2) Two-stage underflow pressure filtration: The two-stage underflow is pressure filtered to obtain two-stage filtrate and two-stage filtrate residue; the two-stage filtrate, the two-stage supernatant and the zinc electrowinning waste electrolyte are mixed to form a first-stage pre-leaching solution for first-stage oxygen pressure leaching.

[0080] 3) The second-stage filter press residue is slurried and stirred with clean water or low-zinc washing water, and then subjected to sulfur flotation to obtain sulfur concentrate and sulfur tailings. The sulfur tailings are sent to the pyrometallurgical treatment system.

[0081] 4) The sulfur concentrate is melted to obtain sulfur and hot filter residue, which is then sent to the pyrometallurgical processing system.

[0082] Example 3

[0083] A method for medium-temperature iron precipitation separation in an oxygen autoclave of a high-zinc, high-iron solution with a first-stage low-temperature and second-stage high-temperature process:

[0084] (1) First-stage low-temperature oxygen pressure leaching: Qualified zinc sulfide concentrate slurry, first-stage pre-leaching liquid (second-stage supernatant + waste electrolyte), oxygen, lignin, etc., are continuously fed into the first-stage oxygen pressure vessel. The reaction is carried out under low temperature (temperature 108℃), low pressure (pressure 0.60MPa, oxygen partial pressure 0.25MPa), weak oxidation (oxygen consumption 54Nm3 / t·dry ore), and strong stirring (120r / min). The slurry in the vessel is flashed (pressure 125KPa, temperature 103℃), adjusted (atmospheric pressure, temperature 98℃), and thickened to obtain the first-stage supernatant (H). + 17g / L, TFe14g / L) and a first-stage underflow (600 tons of input in the first stage, 492 tons of leaching residue in the second stage, with a residue rate of 82%).

[0085] (2) Displacement copper precipitation: Iron powder is used to displace copper in the supernatant of the first stage. After pressure filtration, copper precipitation liquid and copper slag are obtained. The copper slag is washed with water and then sold or recycled for copper treatment.

[0086] (3) Pre-neutralization: The copper-precipitated liquid is pre-neutralized using the iron-removing underflow or zinc roasted sand. The slurry is then thickened to obtain the pre-neutralized supernatant (H). + Neutralized to 4 g / L) and pre-neutralized underflow, the pre-neutralized underflow is sent to the second stage oxygen pressure leaching for further leaching.

[0087] (4) Indium precipitation: The pH of the pre-neutralized supernatant was adjusted to 4.5 using zinc oxide dust, and then the pH of the solution was adjusted to 4.8 using limestone powder for indium precipitation. After pressure filtration, the indium precipitation liquid (containing 5 mg / L of indium) and indium precipitation residue were obtained. The indium precipitation residue was sent to the indium recovery system.

[0088] (5) Iron Mineralization: After indium precipitation, the solution is acidified (pH controlled at 3.0) and preheated (145℃) before being continuously fed into an oxygen autoclave for iron mineralization. The process is carried out at medium temperature (160℃), medium pressure (0.80MPa), and oxidation (oxygen consumption 2.5Nm³ / h). 3 / m 3 • The iron removal process was carried out under strong stirring (120 r / min) in solution, with high-purity zinc oxide powder added simultaneously for neutralization. The acidity of the solution was controlled at 20 g / L (to improve iron removal efficiency). The slurry was then subjected to flash evaporation (pressure 120 kPa, temperature 101 °C), adjustment (atmospheric pressure, temperature 98 °C), and thickening to obtain the supernatant (H). + 19 g / L, TFe 1.7 g / L) and bottom flow (hematite with 56% iron content).

[0089] (6) Neutralization and iron removal: The supernatant of the iron precipitation is neutralized with a neutralizing agent (zinc calcined sand) (pH value controlled at 5.2), and oxygen or air is introduced for oxidation to remove iron. After thickening, the neutralized iron removal underflow and neutralized iron removal supernatant are obtained. The neutralized iron removal underflow is sent to the pre-neutralization and neutralization process or after pressure filtration and pulping, it is sent to the second stage oxygen pressure leaching process. The neutralized iron removal supernatant (Fe is 10mg / L) is sent to the purification system.

[0090] The bottom flow treatment method described in step (1) is as follows:

[0091] 1) Two-stage high-temperature oxygen pressure leaching: The underflow from the first stage, the pre-leaching liquid from the second stage (waste electrolyte), oxygen, lignin, etc., are continuously pumped into the first-stage oxygen pressure vessel, and subjected to high temperature (135℃), medium pressure (1.2MPa), and strong oxidation (oxygen consumption 105Nm³ / h). 3 The reaction is carried out under strong stirring (120 r / min) with dry ore. The slurry in the reactor is flashed (pressure 120 kPa, temperature 120 °C), adjusted (atmospheric pressure, temperature 102 °C), and thickened to obtain two-stage supernatant and two-stage underflow.

[0092] 2) Two-stage underflow pressure filtration: The two-stage underflow is pressure filtered to obtain two-stage filtrate and two-stage filtrate residue; the two-stage filtrate, the two-stage supernatant and the zinc electrowinning waste electrolyte are mixed to form a first-stage pre-leaching solution for first-stage oxygen pressure leaching.

[0093] 3) The second-stage filter press residue is slurried and stirred with clean water or low-zinc washing water, and then subjected to sulfur flotation to obtain sulfur concentrate and sulfur tailings. The sulfur tailings are sent to the pyrometallurgical treatment system.

[0094] 4) The sulfur concentrate is melted to obtain sulfur and hot filter residue, which is then sent to the pyrometallurgical processing system.

[0095] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for medium-temperature iron precipitation separation in an oxygen autoclave of a high-zinc, high-iron solution with a first-stage low-temperature and second-stage high-temperature process, characterized in that, Includes the following steps: (1) Low-temperature oxygen pressure leaching: Zinc sulfide concentrate slurry, first-stage leaching pre-liquid, oxygen and lignin are continuously fed into the first-stage oxygen pressure vessel. The reaction is carried out under low temperature, low pressure, weak oxidation and stirring. After flash evaporation, the slurry in the vessel is adjusted to normal pressure and thickened to obtain first-stage supernatant and first-stage underflow. (2) Displacement copper precipitation: Iron powder is used to displace copper in the supernatant of the first stage. After pressure filtration, copper precipitation liquid and copper slag are obtained. The copper slag is washed with water and sold or recycled for copper treatment. (3) Pre-neutralization: The liquid after copper precipitation is pre-neutralized using the neutralized iron removal underflow or zinc roasted sand. The slurry is thickened to obtain the pre-neutralized supernatant and the pre-neutralized underflow. The pre-neutralized underflow is sent to the second stage oxygen pressure leaching for further leaching. (4) Indium precipitation: The pH of the pre-neutralized supernatant was adjusted to 4.0-4.5 using zinc oxide dust, and then the pH of the solution was adjusted to 4.5-4.8 using limestone powder for indium precipitation. After pressure filtration, indium precipitation liquid and indium precipitation residue were obtained. The indium precipitation residue was sent to the indium recovery system. (5) Mineralization and iron precipitation: After indium precipitation, the solution is acidified to pH 2.0-3.5 and preheated to 120-150℃ before being continuously fed into an oxygen pressure vessel for mineralization and iron precipitation; the mineralization and iron precipitation are carried out under medium temperature, medium pressure and oxidative stirring; pure zinc oxide powder is added simultaneously for neutralization, and the acidity of the solution is controlled at 10-20 g / L. The slurry is flashed, adjusted to atmospheric pressure, and thickened to obtain a supernatant and underflow. (6) Neutralization and iron removal: The supernatant of the iron precipitation is neutralized with zinc calcined sand as a neutralizing agent, while maintaining the pH at 4.8-5.

2. Oxygen or air is introduced for oxidation to remove iron. After thickening, the neutralized iron removal underflow and neutralized iron removal supernatant are obtained. The neutralized iron removal underflow is sent to the pre-neutralization and neutralization process or after pressure filtration and pulping, it is sent to the second stage oxygen pressure leaching process. The neutralized iron removal supernatant is sent to the purification system.

2. The method for separating iron precipitation in an oxygen autoclave of a first-stage low-temperature and second-stage high-temperature high-zinc and high-iron solution according to claim 1, characterized in that, The bottom current treatment method described in step (1) is as follows: 1) Two-stage high-temperature oxygen pressure leaching: The underflow from the first stage, the pre-leaching liquid from the second stage, oxygen, and lignin are continuously pumped into the first-stage oxygen pressure vessel. The process is carried out at a high temperature of 135–160℃, a medium pressure of 1.0–1.2 MPa, and an oxygen consumption of 80–120 Nm³. 3 / t·dry ore is stirred and reacted under strong oxidation. The slurry in the kettle is flashed at 100~450KPa and 120~135℃, then adjusted to normal pressure and thickened to obtain two-stage supernatant and two-stage underflow. 2) Two-stage underflow pressure filtration: The two-stage underflow is pressure filtered to obtain two-stage filtrate and two-stage filtrate residue; the two-stage filtrate, the two-stage supernatant and the zinc electrowinning waste electrolyte are mixed to form a first-stage pre-leaching solution for first-stage oxygen pressure leaching; 3) The residue from the second-stage filter press is slurried and stirred with clean water or low-zinc washing water, and then subjected to sulfur flotation to obtain sulfur concentrate and sulfur tailings. The sulfur tailings are sent to the pyrometallurgical treatment system. 4) The sulfur concentrate is melted to obtain sulfur and hot filter residue, which is then sent to the pyrometallurgical processing system.

3. The method for separating iron precipitation in an oxygen autoclave of a first-stage low-temperature and second-stage high-temperature high-zinc and high-iron solution according to claim 1, characterized in that, In step (1), the low temperature is 100–110°C, the low pressure is 0.40–0.70 MPa, the oxygen partial pressure is 0.15–0.25 MPa, and the weak oxidation is an oxygen consumption of 40–55 Nm³. 3 / t·Dry ore; The flash evaporation pressure is 100–350 kPa and the temperature is 95–105 °C. The endpoint free acid is 10-20 g / L, and TFe is below 14 g / L.

4. The method for separating iron precipitation in an oxygen autoclave of a first-stage low-temperature and second-stage high-temperature high-zinc and high-iron solution according to claim 1, characterized in that, The copper content in the copper-precipitated solution in step (2) is 100-300 mg / L.

5. The method for separating iron precipitation in an oxygen autoclave of a first-stage low-temperature and second-stage high-temperature high-zinc and high-iron solution according to claim 1, characterized in that, The pre-neutralization and undercurrent treatment method described in step (3) is as follows: The pre-neutralized underflow is pressure filtered to obtain pre-neutralized underflow filtrate and pre-neutralized underflow filtrate residue. The pre-neutralized underflow filtrate is fed into the pre-neutralized supernatant. The pre-neutralized underflow filtrate is mixed with the neutralized iron-removing underflow and then slurryed, and then mixed with a first-stage underflow.

6. The method for separating iron precipitation in an oxygen autoclave of a first-stage low-temperature and second-stage high-temperature high-zinc and high-iron solution according to claim 1, characterized in that, The endpoint free acid in the pre-neutralization supernatant described in step (3) is 2-5 g / L.

7. The method for separating iron precipitation in an oxygen autoclave of a first-stage low-temperature and second-stage high-temperature high-zinc and high-ferric solution according to claim 1, characterized in that, The final free acid concentration in the indium precipitation solution in step (4) is 4.5–4.8 g / L.

8. The method for separating iron precipitation in an oxygen autoclave of a first-stage low-temperature and second-stage high-temperature high-zinc and high-iron solution according to claim 1, characterized in that, The treatment steps for the mineralized iron sludge underflow mentioned in step (5) are as follows: ① The mineralized iron underflow is filtered to obtain mineralized iron underflow filtrate and hematite. The mineralized iron underflow filtrate is fed into the mineralized iron supernatant. ②Hematite is pulped, washed, and then centrifuged to obtain slurry and iron oxide; ③ After the slurry is filtered, iron oxide and filtrate are obtained. The filtrate is washed with water and then sent to the integrated washing tank (used for secondary slurry processing).

9. The method for separating iron precipitation in an oxygen autoclave of a first-stage low-temperature and second-stage high-temperature high-zinc and high-iron solution according to claim 1, characterized in that, The intermediate temperature in step (5) is 135–160℃, the intermediate pressure is 0.70–0.90 MPa, and the oxygen consumption for oxidation is 1.5–3.5 Nm³. 3 / m 3 Solution; The flash evaporation pressure is 100–350 kPa and the temperature is 95–105 °C. The mineralized iron oxide was neutralized using pure zinc oxide powder, with the final free acid level controlled at 10–20 g / L and TFe level below 2 g / L.

10. The method for separating iron precipitation in an oxygen autoclave of a first-stage low-temperature and second-stage high-temperature high-zinc and high-iron solution according to claim 1, characterized in that, The pH value of the neutralized iron-removing underflow in step (6) is 4.8 to 5.2, and the TFe is below 20 mg / L.

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