Method for extracting copper and nickel from copper-nickel-sulfur alloy step by step

Abstract

According to the method for extracting the copper and the nickel from the copper-nickel-sulfur alloy step by step, the nickel and the copper are fully dissolved step by step through a first-stage hydrochloric acid leaching process and a second-stage sulfuric acid oxidation leaching process, then the nickel and the copper are extracted step by step with high efficiency and low cost through a method for replacing the copper with the sulfide precipitation nickel and the reduction powder, the separation effect is good, and the method is suitable for industrial production. The problems of energy consumption and environment of a pyrogenic process can be avoided, and the problem that copper and nickel ions cannot be completely leached and cannot be leached step by step in a wet process can be solved.

Description

Technical Field

[0001] The invention belongs to the field of hydrometallurgical resource recovery, and in particular relates to a method for recovering nickel and copper from a copper-nickel-sulfur alloy in steps through a hydrometallurgical process. Background Art

[0002] Traditional copper-nickel ore smelting is divided into two types: pyrometallurgy and hydrometallurgy. Pyrometallurgy is widely used, but it is associated with high energy consumption and severe environmental pollution. For example, the pyrometallurgical process produces large amounts of harmful gases such as sulfur dioxide, which, if not properly handled, can cause serious atmospheric pollution. Hydrometallurgy, to some extent, addresses the energy and environmental challenges associated with pyrometallurgy. Hydrometallurgy typically operates at ambient temperature and pressure, or at relatively low temperatures and pressures. It is relatively safe to operate and requires less equipment, thus reducing production costs and improving efficiency. Hydrometallurgy, to some extent, addresses the energy and environmental challenges associated with pyrometallurgy.

[0003] The treatment of traditional copper-nickel sulfide ores using hydrometallurgy still presents numerous challenges. Copper and nickel ions have similar physicochemical properties (such as reduction potential and complexing ability), making efficient separation difficult using conventional leaching-precipitation methods. For example, in a patented method for copper-nickel leaching and iron separation from copper-nickel sulfide ores (CN112442591A), the oxidant chlorine oxychloride is added to the copper-nickel sulfide ore, preventing complete leaching of copper and nickel ions by step-by-step leaching. The leachate from the currently used pressurized ammonia leaching process for treating copper-nickel sulfide ores can be recycled and poses minimal environmental pollution, but the leaching rate is relatively low. For example, Li Qihou et al. studied the leaching behavior and mechanism of low-grade mixed nickel ore from highly alkaline gangue in the NH-(NH)SO-HO system, achieving a nickel leaching rate of only 70.86%. Bioleaching processes using oxygen and bacterial oxidase as oxidants are relatively inefficient. Zhang Shuilong et al. achieved copper and nickel leaching yields of only 7.32% and 27.08%, respectively, for low-grade, difficult-to-treat, and complex copper-cobalt-nickel polymetallic sulfide ores. Therefore, developing an efficient, environmentally friendly, and low-cost method for the stepwise recovery of nickel and copper from copper-nickel-sulfur alloys is of great practical significance. Summary of the Invention

[0004] In order to address the shortcomings and deficiencies of the prior art, the present invention provides a method for the step-by-step extraction of copper and nickel from a copper-nickel-sulfur alloy. The method uses a one-stage hydrochloric acid leaching and a two-stage sulfuric acid oxidation leaching process to fully dissolve the nickel and copper in steps, and then uses a method of sulfidation precipitation of nickel and replacement of copper with reducing powder to achieve step-by-step recovery of nickel and copper with good separation effect.

[0005] The object of the present invention is achieved by the following technical solution: a method for extracting copper and nickel from a copper-nickel-sulfur alloy in steps, the preparation method comprising the following steps:

[0006] S1) crushing and grinding the copper-nickel-sulfur alloy, and sieving to obtain ore powder with a particle size of 200 mesh or more to increase the surface area of ​​the subsequent leaching reaction and improve the leaching efficiency;

[0007] S2) adding the ore powder obtained in S1) to 4-8M hydrochloric acid to react for 3-5 hours, wherein the liquid-to-solid ratio is 8:1-10:1 and the reaction temperature is 70-90°C. After the reaction is completed, the solid-liquid separation is performed to obtain a nickel-containing solution and a nickel-depleted slag.

[0008] S3) adjusting the pH of the nickel-containing solution obtained in S2) to 2-4, then adding sulfide at a temperature of 40-60° C. to react for 1-2 hours, so that the nickel ions are converted into nickel sulfide precipitate for recovery.

[0009] S4) adding the nickel-removed slag obtained in S2) to 180-250 g / L sulfuric acid for reaction for 2-3 hours, wherein the liquid-to-solid ratio is 8:1-10:1 and the reaction temperature is 70-90° C. During the reaction, an oxidant solution having a liquid-to-solid ratio of 3:1-4:1 is added in 3-5 portions. After completion of the reaction, solid-liquid separation is performed to obtain a copper-containing solution and tailings.

[0010] S5) adding reducing powder to the copper-containing solution obtained in S3) in an amount of 1.1-1.2 times the theoretical amount, reacting at room temperature for 2-3 hours, and separating the solid and liquid to obtain sponge copper after the reaction is completed.

[0011] Furthermore, the copper-nickel-sulfur alloy in said S1) has a copper content of 40%-60%, a nickel content of 10%-30%, and a sulfur content of 10%-20%.

[0012] Furthermore, the sulfide in S3) is one or more of sodium sulfide, sodium hydrosulfide or hydrogen sulfide.

[0013] Furthermore, the oxidant in S4) is one or more of hydrogen peroxide, sodium hypochlorite or potassium permanganate.

[0014] Furthermore, the reducing powder in S5) is one or more of iron powder and zinc powder.

[0015] Furthermore, the nickel concentration of the nickel-containing solution in S2) is 10-30 g / L, and the copper concentration is less than 1 g / L; the nickel content of the denickeling slag is less than 1%, and the copper content is 55%-65%.

[0016] Furthermore, the copper concentration of the copper-containing solution in S4) is 35-45 g / L, and the copper content of the tailings is less than 1%.

[0017] The present invention has the following advantages and beneficial effects:

[0018] (1) The present invention adopts a one-stage hydrochloric acid leaching + two-stage sulfuric acid oxidation leaching process, which can effectively destroy the structure of the copper-nickel-sulfur alloy and fully dissolve the nickel and copper in steps. The leaching rate of nickel in the first stage can reach more than 92%, and the leaching rate of copper in the second stage can reach more than 95%.

[0019] (2) The present invention avoids the emission of harmful gases such as sulfur dioxide in pyrometallurgy, thus reducing environmental pollution. At the same time, the two-stage acid leaching process is carried out at relatively low temperature and pressure, resulting in low energy consumption.

[0020] (3) The reagents used in the present invention are relatively cheap, the equipment requirements are not high, the operation is simple, and the production cost is significantly reduced.

[0021] (4) Through the method of sulfide precipitation and reduction powder replacement, nickel and copper are recovered step by step, with good separation effect. The purity of nickel sulfide can reach over 90%, and the purity of sponge copper can also reach over 90%.

[0022] The present invention mainly relates to the following reaction:

[0023] One stage hydrochloric acid leaching:

[0024] NiS+2H + =Ni 2+ +H2S(g)

[0025] NiO+2H + =Ni 2+ +H2O

[0026] Secondary oxidation sulfuric acid leaching:

[0027] Cu2S+2H2O2+2H2SO4=2CuSO4+S+4H2O BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The present invention is a process flow chart of a method for extracting copper and nickel from a copper-nickel-sulfur alloy in steps.

[0029] Figure 2 The following is the XRD pattern of the copper-nickel-sulfur alloy of the present invention. DETAILED DESCRIPTION

[0030] The present invention will be further described in detail below with reference to examples, but the embodiments of the present invention are not limited thereto.

[0031] Example 1:

[0032] (1) The copper-nickel-sulfur alloy is crushed, ground, and sieved to obtain copper-nickel-sulfur alloy powder with a particle size of more than 300 meshes.

[0033] (2) 20 g of copper-nickel alloy powder (copper content 58.4%, nickel content 20.92%) was added to 200 ml of 6 M hydrochloric acid and reacted at 80° C. for 3 h. After the reaction, solid-liquid separation and rinsing were performed to obtain 250 ml of nickel-containing solution and 14 g of nickel-removed slag.

[0034] (3) The pH of the nickel-containing solution was adjusted to 3, and then sodium sulfide was added at a temperature of 50° C. to react for 1 hour, and solid-liquid separation was performed to obtain nickel sulfide precipitate.

[0035] (4) 14 g of nickel-removed slag was added to 140 ml of 200 g / L sulfuric acid and reacted at 80° C. for 3 h. During the reaction, 50 ml of a 30% hydrogen peroxide solution was added three times. After the reaction was completed, solid-liquid separation and rinsing were performed to obtain 250 ml of a copper-containing solution and 3 g of tailings.

[0036] (5) Add reduced iron powder to the copper-containing solution in an amount of 1.1 times the theoretical amount. React at room temperature for 2 hours. After the reaction is complete, solid-liquid separation is performed to obtain sponge copper.

[0037] Example 2:

[0038] (1) The copper-nickel-sulfur alloy is crushed, ground, and sieved to obtain copper-nickel-sulfur alloy powder with a particle size of more than 300 meshes.

[0039] (2) 20 g of copper-nickel alloy powder (copper content 58.4%, nickel content 20.92%) was added to 190 ml of 8 M hydrochloric acid and reacted at 80° C. for 3 h. After the reaction, solid-liquid separation and rinsing were performed to obtain 250 ml of nickel-containing solution and 14.2 g of nickel-removed slag.

[0040] (3) The pH of the nickel-containing solution was adjusted to 2, and then sodium hydrosulfide was added at a temperature of 40° C. to react for 1 hour, and solid-liquid separation was performed to obtain nickel sulfide precipitate.

[0041] (4) 14.2 g of nickel-removed slag was added to 130 ml of 230 g / L sulfuric acid and reacted at 80° C. for 3 h. During the reaction, 45 ml of a 30% hydrogen peroxide solution was added four times. After the reaction, solid-liquid separation and washing were performed to obtain 250 ml of a copper-containing solution and 2.8 g of tailings.

[0042] (5) Adding reduced iron powder to the copper-containing solution in an amount of 1.15 times the theoretical amount, reacting at room temperature for 2 hours, and separating the solid and liquid to obtain sponge copper.

[0043] Example 3:

[0044] (1) The copper-nickel-sulfur alloy is crushed, ground, and sieved to obtain copper-nickel-sulfur alloy powder with a particle size of more than 300 meshes.

[0045] (2) 100 g of copper-nickel alloy powder (copper content 58.4%, nickel content 20.92%) was added to 900 ml of 8 M hydrochloric acid and reacted at 90° C. for 3 h. After the reaction, solid-liquid separation and rinsing were performed to obtain 1000 ml of nickel-containing solution and 62 g of nickel-removed slag.

[0046] (3) The pH of the nickel-containing solution was adjusted to 3, and then sodium sulfide was added at a temperature of 50° C. to react for 2 hours, and solid-liquid separation was performed to obtain nickel sulfide precipitate.

[0047] (4) 62 g of nickel-removed slag was added to 620 ml of 250 g / L sulfuric acid and reacted at 80° C. for 3 h. During the reaction, 240 ml of 30% hydrogen peroxide solution was added three times. After the reaction was completed, solid-liquid separation and washing were performed to obtain 1000 ml of copper-containing solution and 10 g of tailings.

[0048] (5) Adding reduced zinc powder to the copper-containing solution in an amount of 1.1 times the theoretical amount, reacting at room temperature for 2 h, and separating the solid and liquid to obtain sponge copper.

[0049] Comparative Example 1:

[0050] (1) The copper-nickel-sulfur alloy is crushed, ground, and sieved to obtain copper-nickel-sulfur alloy powder with a particle size of more than 300 meshes.

[0051] (2) 20 g of copper-nickel alloy powder (copper content 58.4%, nickel content 20.92%) was added to 200 ml of 6 M hydrochloric acid and reacted at 80° C. for 3 h. After the reaction, solid-liquid separation and rinsing were performed to obtain 250 ml of nickel-containing solution and 14 g of nickel-removed slag.

[0052] (3) The pH of the nickel-containing solution was adjusted to 3, and then sodium sulfide was added at a temperature of 50° C. to react for 1 hour, and solid-liquid separation was performed to obtain nickel sulfide precipitate.

[0053] (4) 14 g of nickel-removed slag was added to 140 ml of 200 g / L sulfuric acid and reacted at 80° C. for 3 h. After the reaction, solid-liquid separation and washing were performed to obtain 250 ml of copper-containing solution and 8 g of tailings.

[0054] (5) Add reduced iron powder to the copper-containing solution in an amount of 1.1 times the theoretical amount. React at room temperature for 2 hours. After the reaction is complete, solid-liquid separation is performed to obtain sponge copper.

[0055] Comparative Example 2:

[0056] (1) The copper-nickel-sulfur alloy is crushed, ground, and sieved to obtain copper-nickel-sulfur alloy powder with a particle size of more than 300 meshes.

[0057] (2) 20 g of copper-nickel alloy powder (copper content 58.4%, nickel content 20.92%) was added to 200 ml of 200 g / L sulfuric acid and reacted at 80° C. for 3 h. After the reaction, solid-liquid separation and rinsing were performed to obtain 250 ml of nickel-containing solution and 18 g of nickel-removed slag.

[0058] (3) The pH of the nickel-containing solution was adjusted to 3, and then sodium sulfide was added at a temperature of 50° C. to react for 1 hour, and solid-liquid separation was performed to obtain nickel sulfide precipitate.

[0059] (4) 18 g of nickel-removed slag was added to 140 ml of 200 g / L sulfuric acid and reacted at 80° C. for 3 h. During the reaction, 50 ml of a 30% hydrogen peroxide solution was added three times. After the reaction was completed, solid-liquid separation and rinsing were performed to obtain 250 ml of a copper-containing solution and 4 g of tailings.

[0060] (5) Adding reduced zinc powder to the copper-containing solution in an amount of 1.1 times the theoretical amount, reacting at room temperature for 2 h, and separating the solid and liquid to obtain sponge copper.

[0061] The copper and nickel concentrations of the nickel-containing solutions and copper-containing solutions obtained in Examples 1-3 and Comparative Examples 1-2, and the copper and nickel contents of the nickel-removed slag and tailings were measured, and the measurement results are shown in Table 1.

[0062] Table 1

[0063]

[0064] As can be seen from Table 1, the copper concentration of the nickel-containing solutions produced by Examples 1-3 of the present invention is less than 1 g / L, the nickel concentration is 10-30 g / L, and the nickel content of the nickel-removed slag is less than 1%. The copper concentration of the copper-containing solution is between 35-45 g / L, and the copper content of the tailings is less than 1%.

[0065] In Comparative Example 1, since no oxidant was added in step (4) as in Examples 1-3, the copper concentration of the copper-containing solution was lower than 35-45 g / L. In Comparative Example 2, since no hydrochloric acid was used in step (2) as in Examples 1-3, the nickel concentration of the nickel-containing solution was lower than 10-30 g / L, the nickel content of the denickeling slag was much higher than 1%, and the copper content of the tailings was higher than 1%.

[0066] Finally: The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for extracting copper and nickel from a copper-nickel-sulfur alloy in steps, characterized in that: The preparation method comprises the following steps: S1. The copper-nickel-sulfur alloy is crushed, ground, and sieved to obtain a ore powder with a particle size of 200 mesh or more to increase the surface area of ​​the subsequent leaching reaction and improve the leaching efficiency; S2. The ore powder obtained in S1 is added to 4-8M hydrochloric acid and reacted for 3-5h, wherein the liquid-solid ratio is 8:1-10:1, the reaction temperature is 70-90 ° C, and after the reaction, the solid-liquid separation is performed to obtain a nickel-containing solution and a nickel-free slag; S3. The pH of the nickel-containing solution obtained in S2 is adjusted to 2-4, and then a sulfide is added and reacted at a temperature of 40-60 ° C for 1-2 hours to convert the nickel ions into nickel sulfide precipitate for recovery; S4. The nickel-free slag obtained in S2 was added to 180-250 g / L of sulfuric acid for 2-3 h, wherein the liquid-solid ratio was 8: 1-10: 1 and the reaction temperature was 70-90 ° C; an oxidant solution having a liquid-solid ratio of 3: 1-4: 1 was added 3-5 times during the reaction, and after completion of the reaction, solid-liquid separation was performed to obtain a copper-containing solution and tailings; S5. Add reducing powder to the copper-containing solution obtained in S3 in an amount of 1.1-1.2 times the theoretical amount, react at room temperature for 2-3 hours, and separate the solid and liquid after the reaction to obtain sponge copper.

2. The preparation method according to claim 1, characterized in that The copper-nickel-sulfur alloy in S1 has a copper content of 40%-60%, a nickel content of 10%-30%, and a sulfur content of 10%-20%.

3. The preparation method according to claim 1, characterized in that The sulfide in S3 is one or more of sodium sulfide, sodium hydrosulfide or hydrogen sulfide.

4. The preparation method according to claim 1, characterized in that The oxidant in S4 is one or more of hydrogen peroxide, sodium hypochlorite or potassium permanganate.

5. The preparation method according to claim 1, characterized in that The reducing powder in S5 is one or more of iron powder and zinc powder.

6. The preparation method according to claim 1, characterized in that The nickel concentration of the nickel-containing solution in S2 is 10-30 g / L, and the copper concentration is less than 1 g / L; the nickel content of the denickeling slag is less than 1%, and the copper content is 55%-65%.

7. The preparation method according to claim 1, characterized in that The copper concentration of the copper-containing solution in S4 is 35-45 g / L, and the copper content of the tailings is less than 1%.

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