Method for leaching nickel concentrate and removing copper

Abstract

The invention discloses a nickel concentrate leaching and copper removal method, relates to the technical field of nickel wet smelting, and aims to solve the problems of long purification and copper removal process flow, high copper removal cost, poor quality of produced copper sponge and the like in the existing nickel electrolysis production process. The method comprises the following steps of chlorine leaching, replacement copper deposition and electrodeposition copper removal. The produced nickel-rich low-copper solution is sent to a nickel electrolysis process to produce electric nickel, and copper powder with the copper content larger than 95% is produced and can be sold as a copper product. The method is short in technological process, low in copper removal cost and high in quality of produced copper products.

Description

Technical Field

[0001] The invention relates to the technical field of leaching and purifying nickel-containing materials and wet refining, and in particular to a method for leaching nickel concentrate and removing copper. Background Art

[0002] A factory uses chlorine leaching to leach nickel, copper, cobalt, iron and other valuable metals from the material into the solution. The nickel-rich and high-copper leaching solution enters the nickel electrolysis process, is mixed with the electrolytic anode liquid, and is purified and impurities removed to produce electrolytic nickel. The current method of removing copper in the purification process is: the solution is added with nickel concentrate and anode mud to replace copper, the high-nickel copper slag is then leached with chlorine, the leachate enters the liquid making process for electrolysis, and the cathode produces sponge copper, making the copper open. This method has a long process flow, high copper removal costs, and poor quality sponge copper, which can only be sold as a copper-containing intermediate product. Summary of the invention

[0003] The purpose of the present invention is to provide a method for leaching and removing copper from nickel concentrate, using nickel concentrate as raw material, providing a method for leaching with chlorine gas, replacing copper precipitation, and removing copper by electrowinning, producing a nickel-rich and low-copper solution for nickel electrolysis, reducing the burden of copper removal in the nickel electrolysis production process, and producing copper powder containing more than 95% copper, which can be sold as a copper product. The method has a short process flow, low copper removal cost, and high-quality copper products.

[0004] In order to achieve the above purpose, the present invention specifically adopts the following technical solutions: A method for leaching and removing copper from nickel concentrate comprises the following steps: (1) Replacement copper precipitation: nickel concentrate is slurried with new water and return liquid (electrolytic copper removal liquid) and then replaced by leaching. Chlorine leaching slag is added during leaching. The leaching potential is controlled at 0~50mV, the leaching temperature is 70~80℃, and the leaching time is 2~4h. Replacement leaching liquid and replacement leaching slag are obtained. Part of the nickel is leached, and the copper and most of the unleached nickel concentrate enter the replacement leaching slag. The replacement leaching liquid is sent to the nickel electrolysis production process, and the replacement leaching slag is sent to the chlorine leaching process.

[0005] Among them, the main components of the electrolytic copper removal solution are: Ni 180~185g / L, Cu 15~20g / L; the main components of the chlorine leaching slag are S90~95%, Ni 2~4%.

[0006] The slurry liquid-solid ratio is 3: 1. In the early stage of production, when there is no return of electrolytic copper removal liquid, the nickel concentrate is directly leached with chlorine gas without displacement leaching.

[0007] (2) Chlorine leaching: The displacement leaching slag is slurried with electrolytic copper removal liquid and then leached with chlorine. The leaching potential is controlled at 450-500 mV, the leaching temperature is 105-110 °C, and the leaching time is 3-5 hours to obtain chlorine leaching solution and chlorine leaching slag. Chlorine leaching causes base metals such as nickel to be leached out, and sulfur and precious metals enter the chlorine leaching slag. The chlorine leaching solution is sent to the electrolytic copper removal process, and part of the chlorine leaching slag is used for displacement leaching, and the rest is exported.

[0008] The slurry liquid-solid ratio is 3:1; in the initial stage of production, the chlorine leaching raw material is nickel concentrate, which is slurried with the prepared copper-containing solution, and the slurry contains 15-20g / L copper.

[0009] (3) Electrolytic copper removal: The chlorine leaching solution (cathodic solution) enters the electrolytic copper removal tank for electrolytic removal, with a current density of 300-330A / m 2 , the electrolyte temperature is 60-65℃, the electrolyte flow rate is 0.08-0.12L / Ah, part of the copper is generated into copper powder at the cathode and the circuit is open, so that the copper in the system is kept balanced. The copper powder is exported, and the electrolytic copper removal liquid is sent to the replacement copper precipitation and chlorine leaching processes for slurrying, replenishing copper ions, so that the replacement leaching reaction and chlorine leaching reaction can proceed.

[0010] In summary, the present invention designs a cycle of three steps of displacement leaching-chlorine leaching-electrowinning for treating nickel concentrate. First, the nickel concentrate is subjected to displacement leaching to obtain a nickel-rich, low-copper nickel chloride solution and a displacement leaching slag, and the nickel chloride solution is sent to a nickel electrolysis step to produce electro-nickel; by leaching the displacement leaching slag with chlorine, almost all of the valuable base metals in the nickel concentrate are leached out, and the precious metals and sulfur are suppressed in the slag; by electrowinning copper removal of the chlorine leaching solution, relatively pure copper powder is obtained, and part of the copper in the chlorine leaching solution is opened to maintain the copper balance in the system; the liquid (anolyte) after copper removal by electrowinning is returned to the displacement leaching and chlorine leaching to provide copper ions for the two steps, so that the redox reactions of the displacement leaching and the chlorine leaching can be carried out.

[0011] The beneficial effects of the present invention are as follows: (1) Compared with the chemical precipitation copper removal method, the method of the present invention does not produce nickel-containing copper slag, and the output copper powder with higher purity can be directly sold as copper material.

[0012] (2) The method of the present invention reasonably controls the copper content in the system. Electrolytic decoppering only removes the copper brought into the raw materials, maintains the copper balance of the system, and ensures the copper ion concentration required for displacement leaching and chlorine leaching.

[0013] (3) The method of the present invention does not introduce other chemical reagents and the process flow is short. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0015] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0016] The main components of the nickel concentrate selected in our experiment are shown in Table 1: Example 1 Method for leaching nickel concentrate and removing copper (in the early stage of production, without return liquid) (1) Chlorine leaching: Dissolve solid copper sulfate pentahydrate with fresh water to prepare a solution containing 20g / L copper. After the nickel concentrate is slurried with the prepared copper-containing solution, it enters the chlorine leaching tank. Chlorine is introduced into the tank for chlorine leaching. After leaching, the slurry is separated into liquid and solid to obtain chlorine leaching liquid and chlorine leaching slag. The slurry liquid-solid ratio is 3:1, the leaching potential is 450-480mV, the leaching temperature is 110℃, and the leaching time is 4h.

[0017] The main components of chlorine leaching solution are: Ni 182.55g / L, Cu 32.88g / L, Fe 9.72g / L, Co 1.63g / L, Pb 0.095g / L, Zn 0.0033g / L, As 0.0045g / L, Mn 0.16g / L. The main components of chlorine leaching solution are Ni 3.67%, S 92.06%.

[0018] (2) Electrolytic copper removal: The chlorine leaching solution (cathode solution) enters the electrolytic copper removal tank for electrolytic copper removal. The cathode is a copper starting plate and the anode is a titanium-coated ruthenium anode. The cathode is lifted and the copper powder is scraped off every 2 hours. The current density is 300A / m 2 , electrolyte temperature 60℃, electrolyte flow rate 0.08L / Ah. The main components of the copper removal solution (anolyte): Ni182.53g / L, Cu16.02g / L, and the main components of the copper powder: Cu95.23%.

[0019] (3) Displacement leaching: The nickel concentrate is slurried with copper electrowinning decoppering liquid, and the slurried slurry enters the displacement leaching tank for displacement leaching. Chlorine leaching slag is added to control the leaching potential. After leaching, the slurry is separated into liquid and solid. The slurry liquid-solid ratio is 3:1, the leaching potential is 0-25mV, the leaching temperature is 70℃, and the leaching time is 3h. The main components of the leaching solution are: Ni184.33g / L, Cu0.013g / L.

[0020] Example 2 (1) Displacement leaching: Nickel concentrate is mixed with electrolytic copper removal liquid and fresh water to make pulp, and the pulped slurry enters the displacement leaching tank for displacement leaching. Chlorine leaching slag is added to control the leaching potential. After leaching, the slurry is liquid-solid separated to obtain displacement leaching liquid and displacement leaching slag. The slurry liquid-solid ratio is 3:1, the leaching potential is 25-50mV, the leaching temperature is 80℃, and the leaching time is 3h. The main components of the displacement leaching liquid are: Ni185.28g / L, Cu0.018g / L.

[0021] (2) Chlorine leaching: Use new water and electrolytic copper removal liquid to slurry and replace the leaching residue. The slurry enters the chlorine leaching tank, and chlorine is introduced into the tank for chlorine leaching. After leaching, the slurry is separated into liquid and solid to obtain chlorine leaching liquid and chlorine leaching residue. The slurry liquid-solid ratio is 3:1, the leaching potential is 480-500mV, the leaching temperature is 108℃, and the leaching time is 4h. The main components of the chlorine leaching liquid are: Ni181.78g / L, Cu33.42g / L, Fe9.94g / L, Co1.58g / L, Pb0.09g / L, Zn0.0034g / L, As0.0043g / L, Mn0.14g / L, and the main components of the chlorine leaching residue are Ni 4.35%, S91.58%.

[0022] (3) Electrolytic copper removal: The chlorine leaching solution (cathode solution) enters the electrolytic copper removal tank for electrolytic copper removal. The cathode is a copper starting plate and the anode is a titanium-coated ruthenium anode. The cathode is lifted and the copper powder is scraped off every 2 hours. The current density is 330A / m 2 , electrolyte temperature 65℃, electrolyte flow rate 0.12L / Ah. The main components of the electrolytic copper removal solution (anolyte): Ni181.35g / L, Cu16.54g / L. The electrolytic copper removal solution is sent to the displacement leaching and chlorine leaching processes for slurrying. The main components of the copper powder: Cu95.65%.

[0023] Example 3 (1) Displacement leaching: Nickel concentrate is mixed with electrolytic copper removal liquid and fresh water to make pulp, and the pulped slurry enters the displacement leaching tank for displacement leaching. Chlorine leaching residue is added to control the leaching potential. After leaching, the slurry is liquid-solid separated to obtain displacement leaching liquid and displacement leaching residue. The slurry liquid-solid ratio is 3:1, the leaching potential is 0-25mV, the leaching temperature is 75℃, and the leaching time is 3h. The main components of the displacement leaching solution are: Ni184.69g / L, Cu0.0095g / L.

[0024] (2) Chlorine leaching: Use new water and electrolytic copper removal liquid to slurry and replace the leaching residue. The slurry enters the chlorine leaching tank, and chlorine is introduced into the tank for chlorine leaching. After leaching, the slurry is separated into liquid and solid to obtain chlorine leaching liquid and chlorine leaching residue. The slurry liquid-solid ratio is 3:1, the leaching potential is 480-500mV, the leaching temperature is 105℃, and the leaching time is 4h. The main components of the chlorine leaching liquid are: Ni181.78g / L, Cu34.21g / L, Fe8.56g / L, Co1.55g / L, Pb0.11g / L, Zn0.0065g / L, As0.0037g / L, Mn0.12g / L, and the main components of the chlorine leaching residue are Ni4.06%, S91.85%.

[0025] (3) Electrolytic copper removal: The chlorine leaching solution (cathode solution) enters the electrolytic copper removal tank for electrolytic copper removal. The cathode is a copper starting plate and the anode is a titanium-coated ruthenium anode. The cathode is lifted and the copper powder is scraped off every 2 hours. The current density is 315A / m 2 , electrolyte temperature 63℃, electrolyte flow rate 0.1L / Ah. The main components of the electrolytic copper removal solution (anolyte): Ni182.23g / L, Cu17.08g / L. The electrolytic copper removal solution is sent to the displacement leaching and chlorine leaching processes for slurrying. The main components of the copper powder: Cu95.47%.

Claims

1. A method for leaching nickel concentrate and removing copper, characterized in that: The following steps are involved: (1) Displacement leaching: The nickel concentrate is slurried with new water and electrolytic copper removal liquid and then subjected to displacement leaching. Chlorine leaching residue is added during leaching. The leaching potential is controlled at 0-50 mV, the leaching temperature is 70-80 °C, and the leaching time is 2-4 h to obtain displacement leaching solution and displacement leaching residue. (2) Chlorine leaching: The displacement leaching slag is slurried with an electrolytic copper removal solution and then subjected to chlorine leaching. The leaching potential is controlled at 450-500 mV, the leaching temperature is 105-110°C, and the leaching time is 3-5 hours to obtain a chlorine leaching solution and a chlorine leaching slag. The chlorine leaching solution is sent to the electrolytic copper removal process, and part of the chlorine leaching slag is used for displacement leaching. (3) Copper removal: The copper removal is carried out by electrolytic copper removal. The chlorine leaching solution is used as the cathode liquid to enter the electrolytic copper removal tank for electrolytic copper removal. The current density is 300-330A / m 2 , the electrolyte temperature is 60-65°C, the electrolyte flow rate is 0.08-0.12L / Ah, and copper powder and electrolytic decoppering solution are obtained. The electrolytic decoppering solution is sent to displacement leaching and chlorine leaching processes for slurrying.

2. A method for leaching and removing copper from nickel concentrate according to claim 1, characterized in that: In the displacement leaching step, the slurry liquid-to-solid ratio is 3:1; in the early stage of production when there is no return of the electrolytic copper removal solution, the nickel concentrate is directly leached with chlorine gas without displacement leaching.

3. A method for leaching and removing copper from nickel concentrate according to claim 1, characterized in that: In the displacement leaching step, the main components of the electrolytic copper removal solution are: Ni 180~185g / L, Cu 15~20g / L; the main components of the chlorine leaching slag are S 90~95%, Ni2~4%.

4. A method for leaching and removing copper from nickel concentrate according to claim 1, characterized in that: In the chlorine leaching step, the slurry liquid-solid ratio is 3:1; in the initial production stage, the chlorine leaching raw material is nickel concentrate, which is slurried with a prepared copper-containing solution, and the slurry contains 15-20 g / L copper.

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