A pressure leaching method for highly reducible zinc oxide ore

Abstract

The invention belongs to the technical field of zinc smelting, and specifically discloses a pressure leaching method for highly reducing zinc oxide ore, comprising the following steps: (1) preparing, slurrying and grinding the highly reducing zinc oxide ore; (2) first-stage pressure leaching: continuously pumping the highly reducing zinc oxide slurry and the second-stage supernatant into a first-stage pressure autoclave, and leaching the slurry under a pressure of 0.4-0.6MPa, a temperature of 90-110°C and an oxygen amount of 100-300Nm 3 / h, stirring rate 100-120r / min, continuous one-stage pressure leaching; (3) copper precipitation, iron removal; (4) two-stage pressure leaching: the first-stage leaching bottom flow, zinc waste electrolyte, and lignin sulfonate calcium slurry are continuously pumped into the second-stage pressure autoclave at a pressure of 0.8-1.2MPa, a temperature of 120-150℃, and an oxygen volume of 500-1200Nm 3 / h, stirring rate 100-120r / min, two-stage pressure leaching is continuously carried out. After the present invention adopts the "high-reducibility zinc oxide ore pressure leaching" process technology, the leaching rate of high-reducibility zinc oxide ore is significantly improved, there is no risk of precipitation of H2S, AsH3, and H2 during the leaching process, and valuable metals are safely recovered.

Description

Technical Field

[0001] The invention belongs to the technical field of zinc smelting, and in particular relates to a pressure leaching method for highly reducing zinc oxide ore. Background Art

[0002] Steel mills, copper smelters, lead smelters, etc. produce a variety of smoke and dust, which are processed into zinc oxide ores of different components. This type of zinc oxide ore is characterized by high reducibility and high impurities, and cannot be processed by conventional atmospheric pressure hot acid leaching processes. The atmospheric pressure and hot acid leaching of this part of zinc oxide ore has the following problems:

[0003] 1. This type of zinc oxide ore contains high levels of reducing substances such as infusible sulfur and metallic zinc, but low leaching rates of zinc, iron, indium, copper, cadmium, etc.

[0004] 2. This type of zinc oxide ore contains high levels of reducing substances such as infusible sulfur and metallic zinc. During the leaching process of the zinc oxide ore, metal sulfides are prone to precipitate H2S with the smell of rotten eggs when they encounter free acids in the solution. Zinc oxide ore contains metallic zinc and arsenic, which are prone to precipitate H2 and AsH3 when they encounter free acids in the solution.

[0005] Therefore, how to provide a highly reductive zinc oxide ore leaching method with high leaching rate and reduced dangerous gas precipitation is a technical problem that technicians in this field urgently need to solve. Summary of the invention

[0006] In view of this, the present invention adopts the "high-reducibility zinc oxide ore pressure leaching" process technology. Pressure leaching uses oxygen as an oxidant, dilute sulfuric acid as a leaching agent, and calcium lignin sulfonate as a dispersant. The leaching operation is continuously performed under pressure, heating, and strong stirring to increase the leaching rate while reducing the risk of H2S, AsH3, and H2 precipitation.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] A pressure leaching method for highly reducible zinc oxide ore comprises the following steps:

[0009] (1) Preparation, slurry preparation and grinding of highly reducible zinc oxide ore;

[0010] (2) One-stage pressure leaching: The highly reducing zinc oxide slurry obtained in step (1) and the second-stage supernatant are continuously pumped into a first-stage pressure autoclave at a pressure of 0.4-0.6 MPa, a temperature of 90-110°C, and an oxygen content of 100-300 Nm 3 / h, and continuously perform a period of pressure leaching at a stirring rate of 100-120r / min, and the period of pressure leaching time is 45-120min;

[0011] (3) Copper deposition and iron removal;

[0012] (4) Two-stage pressure leaching: The first-stage leaching bottom flow, zinc waste electrolyte, steam, and calcium lignin sulfonate slurry are continuously pumped into the second-stage pressure autoclave at a pressure of 0.8-1.2MPa, a temperature of 120-150℃, and an oxygen volume of 500-1200Nm 3 / h, stirring rate 100-120r / min, two-stage pressure leaching is continuously carried out, the second-stage pressure leaching time is 90-150min, and the supernatant of the second stage is returned to the first stage pressure leaching.

[0013] Preferably, the metal zinc content of the highly reducible zinc oxide ore after configuration is less than 10%, and the insoluble sulfur content is less than 15%.

[0014] Preferably, neutral wash water is used to slurry the highly reducing zinc oxide ore, and the slurry concentration is controlled at 0.7-1.0 t / m 3 .

[0015] Preferably, the slurry particle size of the high-reducibility zinc oxide ore after grinding is controlled to have a pass rate of -320 mesh of more than 95%.

[0016] Preferably, the highly reducing zinc oxide ore includes any one or more of lead system smoke, steel system high-zinc smoke, and copper system smoke.

[0017] Preferably, the free acid in the first stage pressurized leaching solution is controlled at 5-15 g / L, and the solution iron is controlled at 1-5 g / L.

[0018] Preferably, the free acid content of the second-stage pressure leaching solution is controlled at 50-90 g / L, and the insoluble zinc content of the second-stage slag is 1-3%.

[0019] Preferably, a flocculant is added to the first-stage pressurized leaching pulp for a first-stage thickening, and then solid-liquid separation is performed to obtain a first-stage supernatant and a first-stage pressurized leaching underflow, and waste electrolyte, oxygen, steam, and calcium lignin sulfonate are added to the first-stage pressurized leaching underflow to perform a second-stage pressurized leaching, and a flocculant is added to the second-stage pressurized leaching pulp for a second-stage thickening, and then solid-liquid separation is performed to obtain a second-stage supernatant and a second-stage underflow slag, and the second-stage underflow slag is sent to the next operation.

[0020] Preferably, iron powder is added to the first-stage supernatant to carry out copper precipitation replacement operation, copper slag and copper precipitation supernatant are obtained by filter pressing, neutralizer and oxidant are added to the copper precipitation supernatant to carry out iron removal operation, solid-liquid separation is carried out to obtain iron removal supernatant and neutralized iron removal and oxidized low-zinc material, and the neutralized iron removal and oxidized low-zinc material is subjected to second-stage pressure leaching together with the first-stage pressurized leaching underflow.

[0021] Preferably, the flocculant is, the neutralizer is zinc slurry, and the oxidant is oxygen.

[0022] It can be seen from the above technical solutions that compared with the prior art, the present invention has the following excellent effects:

[0023] After the present invention adopts the "high-reducibility zinc oxide ore pressure leaching" process technology, the leaching rate of the high-reducibility zinc oxide ore is significantly improved. During the leaching process, H2S, AsH3, and H2 are leached in the oxygen autoclave (in a closed container) without the risk of precipitation. After all reactions, they are precipitated into the bottom slag, and the valuable metals are safely recovered. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] 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.

[0025] Figure 1 The figure is a flow chart of pressure leaching of highly reducing zinc oxide ore according to the present invention. DETAILED DESCRIPTION

[0026] 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.

[0027] Example 1

[0028] A pressure leaching method for highly reducible zinc oxide ore comprises the following steps:

[0029] 1. Preparation, slurry preparation and grinding of highly reducible zinc oxide ore

[0030] 1. Ore blending: The purchased highly reducing zinc oxide ore is stockpiled and analyzed, and an ore blending plan is made based on the element analysis results (as shown in Table 1). The ore blending plan is to ensure stable and continuous operation of pressurized leaching.

[0031] 2. Slurry preparation: The prepared mixed high-reducing zinc oxide ore is taken to the intermediate bin, transported by belt, iron removed by iron remover, sieved by vibrating screen, and then put into the slurry preparation tank together with the slurry preparation liquid (neutral washing water in the system) for slurry preparation. The slurry concentration is 0.8t / m 3 .

[0032] 3. Grinding: After the slurry is adjusted, it is pumped to the grinding equipment through a pressure pump for grinding. The slurry particle size is controlled to have a pass rate of more than 95% at -320 mesh. The qualified slurry is pumped into the slurry storage tank.

[0033] Raw materials 1-10 are mixed in different proportions. The element analysis results of the highly reducing zinc oxide ore and the mixed ore are shown in Table 1.

[0034] Table 1 Highly Reducible Zinc Oxide Ore and Mixed Ore Column

[0035]

[0036] 2. Highly Reducible Zinc Oxide Slurry Pressure Leaching

[0037] 1. One-stage pressure leaching

[0038] After grinding, high-reducing zinc oxide slurry, second-stage leaching solution, steam, and calcium lignin sulfonate are continuously pumped into a first-stage autoclave. The liquid-to-solid ratio of high-reducing zinc oxide slurry and second-stage leaching solution is controlled at 5-8:1; the steam volume is 2.5t / h, and the amount of calcium lignin sulfonate is 0.7m 3 / h, under pressure (0.45MPa), temperature (105℃), strong oxidation (oxygen volume 260Nm 3 / h), continuous one-stage pressure leaching under strong stirring (120r / min), the free acid in the one-stage pressure leaching solution is controlled at 11g / L, and the solution iron is controlled at 5g / L.

[0039] The supernatant of the first-stage pressure leaching is added with iron for pre-copper precipitation, and the liquid after copper precipitation is neutralized to remove iron. Oxygen is used as the oxidant, and zinc roasted sand is used as the neutralizer. The slurry after neutralization and iron removal is separated into liquid and solid, and the bottom flow is filtered. The filter press residue is slurried with waste electrolyte, and the neutralized residue is transported to the second-stage pressure leaching kettle for further recovery.

[0040] 2. Two-stage pressure leaching

[0041] The first stage leaching underflow (including neutralization slag), zinc waste electrolyte, steam, and calcium lignin sulfonate slurry are continuously pumped into the second stage autoclave. The liquid-to-solid ratio of the underflow and zinc waste electrolyte is 0.5, the steam volume is 14t / h, and the calcium lignin sulfonate flow rate is 0.7m 3 / h, under pressure (1.1MPa), temperature (145℃), strong oxidation (oxygen volume 1100Nm 3 / h), strong stirring (120r / min) for continuous two-stage pressure leaching. The free acid of the second-stage pressure leaching liquid is controlled at 65g / L, and the insoluble zinc in the second-stage slag is 1.3%. The second-stage pressure leaching pulp is added with flocculants for two-stage thickening, and then the solid-liquid separation is obtained to obtain the second-stage supernatant and the second-stage underflow slag, and the second-stage underflow slag is sent to the next stage operation. The first-stage leaching rate is 60%, and the second-stage leaching rate is 40%.

[0042] Example 2

[0043] A pressure leaching method for highly reducible zinc oxide ore comprises the following steps:

[0044] 1. Preparation, slurry preparation and grinding of highly reducible zinc oxide ore

[0045] 1. Ore blending: The purchased highly reducing zinc oxide ore is stockpiled and analyzed, and an ore blending plan is prepared based on the elemental analysis results (as shown in Table 2). The elemental composition of the mixed ore is shown in Table 2 to ensure stable and continuous operation of pressurized leaching.

[0046] 2. Slurry preparation: The prepared mixed high-reducing zinc oxide ore is taken to the intermediate bin, transported by belt, iron removed by iron remover, sieved by vibrating screen, and then put into the slurry preparation tank together with the slurry preparation liquid (neutral washing water in the system) for slurry preparation. The slurry concentration is controlled at 0.85t / m 3 .

[0047] 3. Grinding: After the slurry is adjusted, it is pumped to the grinding equipment through a pressure pump for grinding. The slurry particle size is controlled to have a pass rate of more than 95% at -320 mesh. The qualified slurry is pumped into the slurry storage tank.

[0048] Raw materials 1-10 were mixed in different proportions. The element analysis results of the highly reducing zinc oxide ore and the mixed ore are shown in Table 2.

[0049] Table 2 Highly Reducible Zinc Oxide Ore and Mixed Ore Column

[0050]

[0051] 2. Highly Reducible Zinc Oxide Slurry Pressure Leaching

[0052] One stage pressure leaching

[0053] After grinding, high-reducing zinc oxide slurry, second-stage leaching solution, steam, and calcium lignin sulfonate are continuously pumped into a first-stage autoclave. The liquid-to-solid ratio of high-reducing zinc oxide slurry and second-stage leaching solution is controlled at 5-8:1; the steam volume is 2.5t / h, and the amount of calcium lignin sulfonate is 0.7m 3 / h, under pressure (0.42MPa), temperature (103℃), strong oxidation (oxygen volume 240Nm 3 / h), continuous one-stage pressurized leaching under strong stirring (120r / min), the free acid in the one-stage pressurized leaching solution was controlled at 9.0g / L, and the solution iron was controlled at 4.5g / L.

[0054] The supernatant of the first-stage pressure leaching is added with iron for pre-copper precipitation, and the liquid after copper precipitation is neutralized to remove iron. Oxygen is used as the oxidant, and zinc roasted sand is used as the neutralizer. The slurry after neutralization and iron removal is separated into liquid and solid, and the bottom flow is filtered. The filter press residue is slurried with waste electrolyte, and the neutralized residue is transported to the second-stage pressure leaching kettle for further recovery.

[0055] Two-stage pressure leaching

[0056] The first stage leaching underflow (including neutralization slag), zinc waste electrolyte, and calcium lignin sulfonate slurry are continuously pumped into the second stage autoclave. The liquid-to-solid ratio of the underflow and zinc waste electrolyte is 0.5, the steam volume is 14t / h, and the flow rate of calcium lignin sulfonate is 0.7m3 / h, under pressure (1.05MPa), temperature (142℃), strong oxidation (oxygen volume 980Nm 3 / h), strong stirring (120r / min) for continuous two-stage pressure leaching. The free acid of the second-stage pressure leaching liquid is controlled at 57g / L, and the insoluble zinc in the second-stage slag is 1.6%. The second-stage pressure leaching pulp is added with flocculants for two-stage thickening, and then the solid-liquid separation is obtained to obtain the second-stage supernatant and the second-stage underflow slag, and the second-stage underflow slag is sent to the next stage operation. The first-stage leaching rate is 55%, and the second-stage leaching rate is 45%.

[0057] 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 pressure leaching method for highly reducing zinc oxide ore, characterized in that: The following steps are involved: (1) Preparation, slurry preparation and grinding of highly reducible zinc oxide ore; (2) One-stage pressure leaching: The highly reducing zinc oxide slurry obtained in step (1) and the second-stage supernatant are continuously pumped into a first-stage pressure autoclave at a pressure of 0.4-0.6 MPa, a temperature of 90-110°C, and an oxygen content of 100-300 Nm 3 / h, and continuously perform a period of pressure leaching at a stirring rate of 100-120r / min, and the period of pressure leaching time is 45-120min; (3) Copper deposition and iron removal; (4) Two-stage pressure leaching: The first-stage leaching bottom flow, zinc waste electrolyte, steam, and calcium lignin sulfonate slurry are continuously pumped into the second-stage pressure autoclave at a pressure of 0.8-1.2MPa, a temperature of 120-150℃, and an oxygen volume of 500-1200Nm 3 / h, stirring rate 100-120r / min, two-stage pressure leaching is continuously carried out, the second-stage pressure leaching time is 90-150min, and the supernatant of the second stage is returned to the first stage pressure leaching.

2. The pressure leaching method of a highly reducing zinc oxide ore according to claim 1, characterized in that: After the high-reducibility zinc oxide ore is prepared, the metallic zinc content is required to be less than 10%, and the insoluble sulfur content is less than 15%.

3. The pressure leaching method of a highly reducible zinc oxide ore according to claim 1, characterized in that: Use neutral washing water to adjust the slurry of highly reducing zinc oxide ore, and control the slurry concentration at 0.7-1.0t / m 3 .

4. The pressure leaching method of a highly reducing zinc oxide ore according to claim 1, characterized in that: The slurry particle size of the high-reducibility zinc oxide ore after grinding is controlled at -320 mesh with a pass rate of more than 95%.

5. The pressure leaching method of a highly reducible zinc oxide ore according to claim 1, characterized in that: The highly reducible zinc oxide ore includes any one or more of the smoke from the lead system, the high-zinc smoke from the steel system, and the smoke from the copper system.

6. The pressure leaching method of a highly reducible zinc oxide ore according to claim 1, characterized in that: The free acid content of the first-stage pressurized leaching solution is controlled at 5-15 g / L, and the solution iron content is controlled at 1-5 g / L.

7. The pressure leaching method of a highly reducible zinc oxide ore according to claim 1, characterized in that: The free acid content of the second-stage pressure leaching solution is controlled at 50-90 g / L, and the insoluble zinc content of the second-stage slag is 1-3%.

8. The pressure leaching method of a highly reducible zinc oxide ore according to claim 1, characterized in that: The first-stage pressurized leaching pulp is added with flocculants for the first-stage thickening, and then the solid-liquid separation is performed to obtain a first-stage supernatant and a first-stage pressurized leaching underflow. The first-stage pressurized leaching underflow is added with waste electrolyte, oxygen, steam, and calcium lignin sulfonate for the second-stage pressurized leaching. The second-stage pressurized leaching pulp is added with flocculants for the second-stage thickening, and then the solid-liquid separation is performed to obtain a second-stage supernatant and a second-stage underflow slag, and the second-stage underflow slag is sent to the next operation.

9. The pressure leaching method of a highly reducing zinc oxide ore according to claim 8, characterized in that: The first-stage supernatant is added with iron powder to carry out copper replacement precipitation operation, and copper slag and copper precipitation supernatant are obtained by filter pressing. A neutralizer and an oxidant are added to the copper precipitation supernatant to carry out iron removal operation. Solid-liquid separation is carried out to obtain an iron removal supernatant and a neutralized iron removal and oxidized low-zinc material. The neutralized iron removal and oxidized low-zinc material are subjected to second-stage pressure leaching together with the first-stage pressure leaching underflow.

10. The pressure leaching method of a highly reducing zinc oxide ore according to claim 9, characterized in that: The neutralizer is zinc slurry and the oxidant is oxygen.

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