WO2020062145A1 - Oxygen pressure leaching method for copper sulfide concentrate and copper smelting method - Google Patents

Abstract

An oxygen pressure leaching method for a copper sulfide concentrate and a copper smelting method. The oxygen pressure leaching method comprises: first, adding water to the copper sulfide concentrate and grinding same into pulp; adding a first dispersant, a first vanadium precipitation agent, two sections of supernatant liquid, and the pulp to an autoclave for performing one section of oxygen pressure leaching to obtain one section of underflow and one section of supernatant liquid; and then adding the one section of underflow, the waste electrodeposited liquid, a second dispersant, and a second vanadium precipitation agent to the autoclave for performing two sections of oxygen pressure leaching to obtain the two sections of supernatant liquid and two sections of leaching residues; and adding a neutralizing agent to the one section of supernatant liquid to obtain the neutral supernatant liquid and the neutral drag, and using an electrodeposited copper of the neutral supernatant liquid. The method controls the content of iron and sulfuric acid in the leaching solution while ensuring the high leaching rate of copper.

Description

Oxygen pressure leaching method of copper sulfide concentrate and copper smelting method Technical field

The invention relates to an oxygen pressure leaching method of copper sulfide concentrate and a copper smelting method, and belongs to the technical field of non-ferrous metal wet smelting.

Background technique

At present, copper sulfide concentrate is basically smelted by fire. First, copper in the copper sulfide concentrate is smelted into crude copper, and then the crude copper is electrolyzed to obtain cathode copper. The sulfur-containing flue gas is sent to produce acid to produce sulfuric acid. And low-grade copper sulfide ore uses hydrometallurgy, that is, leaching-extraction-electrodeposition process to produce electrodeposited copper, because the raw material contains low sulfur and does not produce sulfuric acid. In some areas where copper sulfide concentrates are produced, due to the weak industrial base in the surroundings, sulfuric acid cannot be transported, stored, and sold, and the method of smelting copper sulfide concentrates by fire cannot be implemented. Therefore, it is of great practical significance to study the method of producing sulfur by oxygen pressure leaching similar to zinc sulfide concentrate and apply it to the hydrometallurgical method of copper sulfide concentrate. Although the oxygen leaching process of zinc sulfide concentrate has been used in industrial production for more than 30 years of practical experience, the oxygen leaching process of copper sulfide concentrate is still in the experimental stage. There is still a large gap in production. The biggest difficulty of the oxygen pressure leaching process of copper sulfide concentrate is that copper leaching requires high temperature, the temperature rises, and the copper leaching rate is high. However, the iron and sulfuric acid content in the leaching solution increases. The neutralizing agent such as limestone is used to reduce the acid and iron in the subsequent steps. It will produce a large amount of neutralization slag and cause copper loss. Because iron in the leaching solution is Fe ³⁺ , the filtering performance of iron slag is also poor. In 2007, a 66,000 t / a copper-oxygen leaching plant was completed in Arizona, USA. The plant uses a section of high-temperature and high-pressure oxygen leaching process. The resulting leaching solution is desiliconized for copper electrodeposition, and most of the generated electrode liquid is sent. The acid is leached to the copper oxide ore heap, and the heap leaching solution is extracted and purified and then returned to the oxygen pressure leaching, that is, the mixed electrolyzed fluid entering the autoclave has a low acidity. Therefore, the plant uses the excess sulfuric acid produced by the oxygen pressure leaching of copper sulfide concentrate for copper oxide ore heap leaching.

However, in areas where there is not enough copper oxide to consume excess sulfuric acid, it is also very difficult to control the iron and sulfuric acid content in the leaching solution to meet the working conditions of the subsequent electrodeposition copper process while ensuring the copper leaching rate. .

Summary of the Invention

In view of the shortcomings of the prior art, the present invention is based on the operability of industrial production, and provides an oxygen pressure leaching method of copper sulfide concentrate to control the iron and sulfuric acid content in the leaching solution while ensuring a high leaching rate of copper. Make it meet the requirements of subsequent electrowinning; in addition, the invention also provides a copper smelting method.

In order to solve the above technical problems, the technical solution of the present invention is as follows:

The oxygen pressure leaching method of copper sulfide concentrate includes the following steps:

S1. Grind copper sulfide concentrate with water to make pulp;

S2. The first dispersant, the first alum agent, the second stage supernatant and the slurry obtained in S1 are added to an autoclave to obtain a first acid concentration (that is, the concentration of H ₂ SO ₄ ) of 50 to 70 g / L. A slurry is passed into the autoclave, and oxygen is leached at a temperature of 135 to 145 ° C and a pressure of 1.3 to 1.5 MPa. After the reaction is completed, the temperature and pressure are reduced, and the solid-liquid separation is obtained. A bottom stream and a supernatant;

Among them, in general, the first dispersant is added in an amount of 3 to 5 kg / t-concentrate (that is, after 3 to 5 kg of the first dispersant is added to the corresponding pulp after grinding into a pulp per ton of copper sulfide concentrate), the first The addition amount of the alum agent is 25-30 kg / t-concentrate, preferably, the addition amount of the first dispersant is 3.5-4.5 kg / t-concentrate, and the addition amount of the first alum agent is 26-28 kg / t-concentrate; the concentration of H ₂ SO ₄ in a section of the supernatant is 25 to 35 g / L, the concentration of Cu ²⁺ is 90 to 100 g / L, and the concentration of Fe ³⁺ is 8 to 14 g / L;

S3. Add a piece of underflow, waste electricity effusion, second dispersant, and second alum agent to the autoclave to obtain a second slurry with an initial acid concentration of 100-130 g / L, and then pass into the autoclave. Oxygen was subjected to two-stage oxygen pressure leaching at a temperature of 165 to 175 ° C and a pressure of 1.4 to 1.6 MPa. After the reaction was completed, the temperature and pressure were reduced, and solid-liquid separation was performed to obtain two-stage supernatant and two-stage leaching residue;

Among them, the concentration of H ₂ SO ₄ in the waste electricity effluent is 160 to 180 g / L, preferably 165 to 175 g / L; generally, the amount of the second dispersant is 5 to 7 kg / t-concentrate, and the second The amount of alum added is 30-35kg / t-concentrate; preferably, the amount of second dispersant is 5.5-6.5kg / t-concentrate and the amount of second alum is 32-34kg / t -Concentrate;

A neutralizing agent is added to a section of the supernatant, and reacted to obtain a neutralizing slurry having a pH value of 2.5-3.5, and then solid-liquid separation is performed to obtain a neutralizing supernatant and a neutralizing residue.

In the present invention, the concentration of Cu ²⁺ in the neutralization supernatant is 90 to 100 g / L, the concentration of Fe ^{3+ is} less than or equal to 2 g / L, and the pH value is 2.5 to 3.5, which can satisfy the composition of the new electrolyte solution in the copper electrodeposition process. Claim.

In the present invention, two stages of countercurrent oxygen pressure leaching are used, one stage is at intermediate temperature and medium pressure to drop acid, and the second stage is high temperature and high pressure leaching of copper. Among them, the second stage supernatant is returned to a stage of oxygen pressure leaching to provide acid for a stage of oxygen pressure leaching reaction and participate in a stage of oxygen. Under pressure leaching, the acid is consumed in the reaction system. The copper leached in the second stage of oxygen pressure leaching is accumulated in the leaching solution and enters the first stage of the supernatant. The temperature and pressure used in the first stage of oxygen pressure leaching are relatively low, and the iron leaching rate is low. At the same time, during the two-stage oxygen pressure leaching process, alum agents are added to suppress the leaching of iron. In this way, it can not only ensure the high leaching rate of copper, but also effectively control the iron and sulfuric acid content in the leaching solution. In addition, during the two-stage oxygen pressure leaching reaction, the required acid is mainly provided by the waste electricity effusion.

In S1, the solid content of the pulp is 60-70 wt%, preferably 63-68 wt%.

Further, in S1, the ore is pulverized by a sand mill. The agitating disc of the sand mill can fully contact the grinding medium with the material. Further, the grinding medium is 0.8 to 1 mm zirconium beads, and the specific surface area is large, which can sufficiently grind the material. fine.

In S1, the ore particles having a particle size of less than 15 μm in the pulp account for more than 90% by weight of the total minerals, and preferably, more than 90% by weight of the total minerals. Ensure certain particle size conditions, improve reaction efficiency, and further increase the leaching rate. Generally speaking, minerals can be understood as copper sulfide concentrates. When neutralizing slag is added, minerals can be understood as a mixture of neutralizing slag and copper sulfide concentrates.

In S2, the reaction time for a period of oxygen pressure leaching is 1.5-2.5h, preferably 1.8-2.3h.

In S2, during the one-stage oxygen pressure leaching reaction, the oxygen partial pressure in the autoclave is 0.9-1.1 MPa, and preferably 0.95-1.05 MPa.

In S3, the reaction time of the two-stage oxygen pressure leaching is 2.5-3.5 h, preferably 2.8-3.3 h.

In S3, during the two-stage oxygen pressure leaching reaction, the oxygen partial pressure in the autoclave is 0.8-1.0 MPa, and preferably 0.85-0.95 MPa.

Through reasonable control of the reaction time, the high completion of the leaching reaction can be ensured, and the leaching time can be shortened, thereby avoiding time wastage. Through the control of the oxygen partial pressure, the requirements for the reaction conditions of the oxygen pressure leaching reaction can be guaranteed, and the oxygen pressure leaching reaction can be performed efficiently.

In S3, the neutralizing agent is limestone and / or copper roasting sand. Preferably, the neutralizing agent is copper roasting sand. The neutralization slag obtained by the neutralization reaction is sent to S1 for grinding and pulping, and further The mass ratio of neutralization slag and copper sulfide concentrate can be set as required. Generally speaking, the neutralization slag and copper sulfide concentrate can be mixed at any ratio. Further, in the copper baking sand, the copper content is 18-25 wt%, the iron content is 25-35% by weight, the sulfur content is 4-6 wt%, and the remaining components are gangue.

The neutralizing agent is limestone, and the underflow generated can be neutralized slag by pressure filtration, and can be processed by storage and the like.

In S3, the waste electricity accumulation liquid is a copper electricity accumulation waste liquid, wherein the Cu ²⁺ concentration is not higher than 40 g / L, and the Fe ³⁺ concentration is not higher than 2 g / L.

In the present invention, both the dispersant and the alum agent can be selected from the dispersants and alum agents commonly used in the non-ferrous metal wet smelting and leaching process. Further, the dispersant may be a lignin sulfonate, and the alum agent may be It is an ammonium salt or a base.

In the present invention, the solid-liquid separation process can be performed by a thickener.

In the present invention, the concentration of oxygen introduced into the autoclave is not less than 99%.

The oxygen pressure leaching method of the present invention can be applied to leaching treatment of copper sulfide concentrates of different grades.

Based on the same inventive concept, the present invention also provides a copper smelting method. First, the copper sulfide concentrate is subjected to leaching treatment according to the oxygen pressure leaching method described above to obtain a neutralized supernatant; and then, the neutralized supernatant is used. It is used to collect electric liquid, and to obtain electrolytic copper and copper electrolytic waste liquid.

Further, in the process of the electric product, the control current density is 160 to 180 A / m ² , and the cycle of the electric product is 7 days.

The main reactions involved in the present invention are as follows:

CuFeS ₂ + O ₂ + 2H ₂ SO ₄ → CuSO ₄ + FeSO ₄ + 2S ⁰ + 2H ₂ O (1)

2FeSO ₄ + 0.5O ₂ + H ₂ SO ₄ → Fe ₂ (SO ₄ ) ₃ + H ₂ O (2)

Fe ₂ (SO ₄ ) ₃ + 3H ₂ O → Fe ₂ O ₃ + 3H ₂ SO ₄ (3)

3Fe ₂ (SO ₄ ) ₃ +2 (A) OH + 10H ₂ O → 2 (A) Fe ₃ (SO ₄ ) ₂ (OH) ₆ + 5H ₂ SO ₄ (4)

Among them, A is selected from Na ⁺ , K ⁺ , NH ₄ ⁺ ; reactions (1), (2), (3), and (4) mainly occur during the oxygen pressure leaching process.

Compared with the prior art, the beneficial effects of the present invention are as follows:

(1) Fully grind copper sulfide concentrate and other materials into ore slurry to improve leaching efficiency and leaching rate.

(2) Two-stage countercurrent oxygen pressure leaching, two-stage oxygen pressure leaching using waste electricity effluent to directly leaching a section of underflow, and the two-stage supernatant leaching to reduce acidity with one stage of oxygen pressure to produce one-stage supernatant components (H ₂ SO ₄ The concentration is 25 ～ 35g / L, the concentration of Cu ²⁺ is 90 ～ 100g / L, and the concentration of Fe ³⁺ is 8 ～ 14g / L). The composition requirements of traditional copper electrodeposition new liquid (Cu ²⁺ concentration is 90 ～ 100g / L, Fe ³⁺ concentration is 2g / L, pH is 2.5 ～ 3.5).

(3) The iron is removed under the condition of high temperature and high acid, and the iron is directly deposited in the autoclave in the form of alum slag, which solves the problem of high iron content in the supernatant liquid of copper oxygen pressure leaching.

(4) Use a neutralizer to neutralize a section of the supernatant. In addition to neutralizing sulfuric acid, some impurities such as iron and arsenic can be removed from the solution. No solvent extraction is required to further reduce the impurity content, which can meet the electrodeposition copper industry. Requirements, simplifying process flow and equipment configuration.

(5) Two-stage countercurrent oxygen pressure leaching can increase the leaching rate of copper. The total leaching rate of copper in two-stage oxygen pressure leaching can reach more than 90%, and the supernatant of one stage is low in acid and iron, and the neutralizing dose used is small. , Less slag, less copper loss. For the copper that has not been leached in the second-stage leaching slag, flotation can be sent to recover copper and sulfur.

(6) The smelting waste electricity effluent can be effectively used, which can reduce production costs and realize the reuse of resources.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flowchart of a copper smelting method according to the present invention.

detailed description

Hereinafter, the present invention will be described in detail with reference to the embodiments.

Example 1

Take 100 g of copper sulfide concentrate (containing Cu 22.81 wt%, Fe 27.22 wt%), grind it to 90%, and the particle size of the concentrate is less than 15 μm to obtain a slurry. Add the two-stage supernatant, 0.4g of dispersant, 2.5g of alum agent and ore slurry into the autoclave, control the liquid-solid ratio to 4: 1, and pass in oxygen, control the temperature to 135 ° C, pressure 1.3MPa, and perform one-stage oxygen pressure Leaching and reacting for 2h, a section of supernatant 370mL and a section of underflow were obtained. The section of supernatant contained Cu 90.78g / L, Fe10.81g / L, and H ₂ SO ₄ 28g / L. The generated one-stage underflow was sent to a two-stage autoclave. Waste electric effusion, 0.6g of dispersant, and 3g of alum were added. The liquid-solid ratio was controlled to 4: 1, oxygen was passed in, the temperature was controlled to 165 ° C, and the pressure was 1.4MPa. A two-stage oxygen pressure leaching was performed, and the reaction was performed for 2.5 hours to produce 70 g of two-stage leaching slag (containing Cu3.1wt%, Fe33.7wt%), the total copper leaching rate of two stages was 90.49%, and the total iron leaching rate was 13.34%.

Example 2

Take 100 g of copper sulfide concentrate (containing Cu 22.81 wt%, Fe 27.22 wt%), grind it to 90%, and the particle size of the concentrate is less than 15 μm to obtain a slurry. Add the two-stage supernatant, 0.5g of dispersant and 3g of alum agent and ore slurry to the autoclave, control the liquid-solid ratio to 4: 1, pass in oxygen, control the temperature of 140 ° C, and pressure of 1.4MPa, and perform a one-stage oxygen pressure leaching. At 2.5 h, a section of supernatant 367 mL and a section of underflow were generated. The section of the supernatant contained 92.34 g / L of Cu, 13.84 g / L of Fe, and 30 g / L of H ₂ SO ₄ . The generated one-stage underflow was sent to a two-stage autoclave, and waste electric effusion, 0.7g of dispersant and 3.5g of alum were added, the liquid-solid ratio was controlled to 4: 1, oxygen was passed in, the temperature was controlled at 170 ° C, and the pressure was 1.5MPa With a reaction time of 3 h, two-stage oxygen pressure leaching was performed to produce 68 g of two-stage leaching slag (containing Cu2.6wt%, Fe33.1wt%), the total copper leaching rate of two stages was 92.25%, and the total iron leaching rate was 17.31%.

Comparative Example 1

Take 100 g of copper sulfide concentrate (containing Cu 22.81 wt%, Fe 27.22 wt%), grind it to 90%, and the particle size of the concentrate is less than 15 μm to obtain a slurry. Mix the pulp with the leaching agent (sulfuric acid concentration is 160g / L, copper content is 40g / L, iron content is 2g / L), add an appropriate amount of dispersant, and divide into two groups for a period of oxygen pressure leaching. Table 1 shows.

Table 1 Comparative Example 1 Parametric Oxygen Leaching Parameters and Results

It can be known from Table 1 that the leaching solution of a stage of oxygen pressure leaching contains acid and iron, and the higher the temperature, the higher the acid and iron content in the leaching solution. By comparison, it can be seen that the leaching rate of iron in the comparative example is far beyond that of iron in this application .

Comparative Example 2

Take 100 g of copper sulfide concentrate (containing Cu 22.81 wt%, Fe 27.22 wt%), grind it to 90%, and the particle size of the concentrate is less than 15 μm to obtain a slurry. Mix the pulp with the leaching agent (sulfuric acid concentration is 40g / L, copper content is 70g / L, iron content is 35g / L), add appropriate amount of dispersant and alum agent, divide into two groups, and perform a period of oxygen pressure leaching. Specific test The conditions and results are shown in Table 2.

Table 2 Comparative Example 2 Parametric Oxygen Pressure Leaching Parameters and Results

It can be known from Table 2 that the addition of alum agent can effectively reduce the iron content in the leaching solution, but the leaching rate of copper is also reduced, which is not conducive to obtaining a high copper leaching rate. By adjusting the two-stage oxygen pressure leaching-related process parameters, the present application can reduce the iron leaching rate and obtain a high copper leaching rate, effectively solving this contradiction.

The content explained in the above embodiments should be understood as these embodiments are only used to more clearly illustrate the present invention, but not to limit the scope of the present invention. After reading the present invention, those skilled in the art will appreciate various equivalent forms of the present invention. The modifications fall within the scope defined by the claims appended to this application.

Claims (10)

1. The oxygen pressure leaching method of copper sulfide concentrate includes the following steps:

   S1. Grind copper sulfide concentrate with water to make pulp;

   S2. The first dispersant, the first alum agent, the second stage supernatant and the slurry obtained in S1 are added to an autoclave to obtain a first slurry having an initial acid concentration of 50 to 70 g / L, and then fed to the autoclave. Pass in oxygen and carry out a period of oxygen pressure leaching at a temperature of 135-145 ° C and a pressure of 1.3-1.5 MPa. After the reaction is completed, reduce the temperature and pressure, and separate the solid and liquid to obtain a bottom stream and a supernatant.

   Among them, the concentration of H ₂ SO ₄ in a section of the supernatant is 25 to 35 g / L, the concentration of Cu ²⁺ is 90 to 100 g / L, and the concentration of Fe ³⁺ is 8 to 14 g / L;

   S3. Add a piece of underflow, waste electricity effusion, second dispersant, and second alum agent to the autoclave to obtain a second slurry with an initial acid concentration of 100-130 g / L, and then pass into the autoclave. Oxygen was subjected to two-stage oxygen pressure leaching at a temperature of 165 to 175 ° C and a pressure of 1.4 to 1.6 MPa. After the reaction was completed, the temperature and pressure were reduced, and solid-liquid separation was performed to obtain a two-stage supernatant and a two-stage leaching residue;

   Among them, the concentration of H ₂ SO ₄ in the waste electricity effluent is 160-180 g / L;

   A neutralizing agent is added to a section of the supernatant, and reacted to obtain a neutralizing slurry having a pH value of 2.5-3.5, and then solid-liquid separation is performed to obtain a neutralizing supernatant and a neutralizing residue.
2. The oxygen pressure leaching method for copper sulfide concentrate according to claim 1, wherein, in S1, the solid content of the pulp is 60-70 wt%; preferably, in S1, the ore particles with a particle size of less than 15 μm account for the mineral 90% by weight or more of the total amount.
3. The oxygen pressure leaching method for copper sulfide concentrate according to claim 1, characterized in that, in S2, a period of oxygen pressure leaching reaction time is 1.5-2.5h.
4. The oxygen pressure leaching method for copper sulfide concentrate according to claim 1, wherein in S2, the oxygen partial pressure in the autoclave during the one-stage oxygen pressure leaching reaction is 0.9-1.1 MPa.
5. The oxygen pressure leaching method for copper sulfide concentrate according to claim 1, wherein the first dispersant is added in an amount of 3 to 5 kg / t-concentrate, and the first alum agent is added in an amount of 25 to 30 kg. The added amount of the second dispersant is 5 to 7 kg / t-concentrate, and the added amount of the second alum agent is 30 to 35 kg / t-concentrate.
6. The oxygen pressure leaching method of copper sulfide concentrate according to claim 1, wherein the reaction time of the two-stage oxygen pressure leaching in S3 is 2.5-3.5h.
7. The oxygen pressure leaching method for copper sulfide concentrate according to claim 1, wherein in S3, during the two-stage oxygen pressure leaching reaction, the oxygen partial pressure in the autoclave is 0.8-1.0 MPa.
8. The oxygen pressure leaching method of copper sulfide concentrate according to claim 1, wherein in S3, the neutralizing agent is limestone and / or copper sintering sand, and preferably, the neutralizing agent is copper sintering sand , The neutralization slag obtained by the neutralization reaction is sent to S1 in a mill for pulping.
9. The oxygen pressure leaching method for copper sulfide concentrate according to claim 1, characterized in that, in S3, the waste electricity accumulation liquid is copper electricity accumulation waste liquid, wherein the concentration of Cu ²⁺ is not higher than 40 g / L, Fe ³⁺ concentration is not higher than 2g / L.
10. A copper smelting method, characterized in that the copper sulfide concentrate is subjected to leaching treatment according to the oxygen pressure leaching method according to any one of claims 1 to 9 to obtain a neutralized supernatant; and then the neutralized supernatant is used. Electrolyte is electrolyzed, and electrolyzed to obtain electrolyzed copper and copper electrolyzed waste liquid.

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