Method for improving appearance quality of electrodeposited cobalt plate surface

Abstract

The invention discloses a method for improving the appearance quality of an electrodeposited cobalt plate surface, which comprises the following steps: 1) preparing an additive, the concentration of which is related to the current density; (2) adding the additive prepared in the step (1) into a liquid preparation tank, and uniformly mixing with the cobalt chloride solution, wherein the flow of the additive is related to the circulation volume of the cobalt chloride solution; and 3) conveying the new liquid prepared in the step 2) to each electrodeposition cell, electrifying for electrodeposition, preparing an electrodeposited cobalt plate, scalding, shearing, packaging and warehousing, wherein the flow of the new liquid is related to the current density.According to the process, the appearance quality of the electrodeposited cobalt plate surface is improved by introducing the additive, the number of unqualified products is reduced, and the economic benefit is increased.

Description

Technical Field

[0001] The invention belongs to the field of nonferrous metallurgy and provides a method for improving the appearance quality of an electrolytic cobalt plate. Background Art

[0002] Cobalt is a metal with high hardness, high tensile strength, good mechanical processing performance, corrosion resistance and magnetism. It is one of the important raw materials for manufacturing high-temperature alloys, cemented carbides and magnetic alloys. At present, the production systems for electrolytic cobalt include hydrochloric acid system and sulfuric acid system. Among them, the electrolytic cobalt in the hydrochloric acid system has low solution viscosity, strong ion activity, fine crystal particles and high current efficiency, while the electrolytic cobalt in the sulfuric acid system has coarse grains and a rough surface. Therefore, electrolytic cobalt in the hydrochloric acid system is often used in the high-end market, and electrolytic cobalt in the sulfuric acid system is often used in the mid-to-high-end market.

[0003] When electrowinning cobalt in the hydrochloric acid system, the cobalt chloride solution that has been deeply purified is used to produce electrowinning cobalt through the electrowinning process, which is cut into cobalt blocks for sale; the chlorine gas precipitated at the anode is collected and properly disposed of in the dechlorination treatment system. The appearance quality requirements of the electrowinning cobalt plate surface are as follows: (1) The surface of the cobalt plate should be clean and free of sponge, sludge, oil, and liquid and inclusions in the interlayer; (2) The thickness of the edge of the cobalt plate should not be less than 2mm, and there should be no dendritic grains and pores with a diameter greater than 2mm; (3) The surface of the cobalt plate should be flat, and there should be no grains higher than 5mm on the surface and edge of the cobalt plate. The total area of ​​dense grains higher than 2mm on the plate surface should not exceed 10% of the single surface area of ​​the cobalt plate. Due to the fluctuations in the local pH value and metal ion concentration of the plate surface during the electrowinning process, there is a problem of more grains on the plate surface. Cobalt plates with more grains on the plate surface are unqualified products, and their sales price is lower than that of genuine cobalt, which reduces economic benefits. Summary of the invention

[0004] The present invention aims to provide a method for improving the appearance quality of an electrolytic cobalt plate surface, so as to improve the surface quality of the cobalt plate and reduce the output of defective products.

[0005] To achieve the above object, the present invention adopts the following technical solution: A method for improving the appearance quality of an electrolytic cobalt plate surface, characterized by comprising the following steps: Step 1, preparing additives, the concentration of the additives is related to the current density; Step 2, adding the additive prepared in step 1 into the liquid preparation tank and mixing it evenly with the cobalt chloride solution, and the flow rate of the additive is related to the circulation volume of the cobalt chloride solution; Step 3: transport the new solution prepared in step 2 to each electrowinning cell, apply power for electrowinning, prepare electrowinning cobalt plates, wash and shear them, and then pack and store them. The flow rate of the new solution is related to the current density.

[0006] The additive in step 1 is one or more of sodium chloride, magnesium chloride, calcium chloride, manganese chloride, and potassium chloride, and the concentration of the additive is 6×10-7 ~8×10 -7 mol / (A·m -2 ·L).

[0007] The flow rate of the additive in step 2 is 0.026~0.032m 3 / h, the circulation volume of cobalt chloride solution is 2.6~3.2m 3 / h.

[0008] In step 3, the new liquid flow rate is 10-15 L / (A·m -2 ·h·slot).

[0009] Compared with the prior art, the present invention has the following beneficial effects: This process regulates the composition of the electrolytic solution by introducing additives, stabilizes the local pH value and metal ion concentration of the board surface, avoids the growth of cobalt ion clusters and the formation of grains, thereby improving the quality of the board surface, reducing the output of defective products, and increasing economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a process flow chart of the present invention.

[0011] Figure 2 This is a photo of the cobalt plate before the process of the present invention is implemented.

[0012] Figure 3 This is a photo of the cobalt plate after the process of the present invention is implemented. DETAILED DESCRIPTION

[0013] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0014] Embodiment 1 A method for improving the appearance quality of an electrolytic cobalt plate surface is specifically implemented according to the following steps: Experimental process: Step 1: Mix sodium chloride, magnesium chloride and manganese chloride with water to prepare additives. The concentration of additives is 6.5*10 - 7 mol / (A·m -2 ·L); Step 2: Add the additive solution into the liquid preparation tank and mix it evenly with the 70g / L cobalt chloride solution. The additive flow rate is 0.029m 3 / h, the circulation volume of cobalt chloride solution is 2.9m 3 / h; Step 3: Deliver the prepared new solution to each electrolytic cell at a flow rate of 11L / (A·m -2 ·h· tank), power on for electrowinning, prepare electrowinning cobalt plates, wash and cut them, and then pack them for storage.

[0015] Experimental results: See attached Figure 2 After implementation, the surface of the cobalt plate is bright and free of grains.

[0016] The experimental results of Example 1 show that the surface appearance quality of the electrolytic cobalt plate prepared by Example 1 is good and free of grains.

[0017] Embodiment 2 A method for improving the appearance quality of an electrolytic cobalt plate surface is specifically implemented according to the following steps: Experimental process: Step 1: Prepare additives with magnesium chloride, manganese chloride and potassium chloride and water, with the concentration of additives being 7.0*10 -7 mol / (A·m -2 ·L); Step 2: Add the additive solution to the liquid preparation tank and mix it evenly with the 85g / L cobalt chloride solution. The additive flow rate is 0.031m 3 / h, the circulation volume of cobalt chloride solution is 3.1m 3 / h; Step 3: Deliver the prepared new solution to each electrolytic cell at a flow rate of 13L / (A·m -2 ·h· tank), power on for electrowinning, prepare electrowinning cobalt plates, wash and cut them, and then pack them for storage.

[0018] Experimental results: See attached Figure 2 After implementation, the surface of the cobalt plate is bright and free of grains.

[0019] The experimental results of Example 2 show that the surface appearance quality of the electrolytic cobalt plate prepared by Example 2 is good and free of grains.

[0020] Embodiment 3 A method for improving the appearance quality of an electrolytic cobalt plate surface is specifically implemented according to the following steps: Experimental process: Step 1: Prepare additives using magnesium chloride, manganese chloride and calcium chloride, with an additive concentration of 7.5*10 -7 mol / (A·m -2 ·L); Step 2: Add the additive solution to the liquid preparation tank and mix it evenly with the 65g / L cobalt chloride solution. The additive flow rate is 0.027m 3 / h, the circulation volume of cobalt chloride solution is 2.7m 3 / h; Step 3: Deliver the prepared new solution to each electrolytic cell at a flow rate of 12L / (A·m -2 ·h· tank), power on for electrowinning, prepare electrowinning cobalt plates, wash and cut them, and then pack them for storage.

[0021] Experimental results: See attached Figure 2 After implementation, the surface of the cobalt plate is bright and free of grains.

[0022] The experimental results of Example 3 show that the surface appearance quality of the electrolytic cobalt plate prepared by Example 1 is good and free of grains.

Claims

1. A method for improving the appearance quality of an electrolytic cobalt plate, characterized in that: The following steps are involved: Step 1, preparing additives, the concentration of the additives is related to the current density; Step 2, adding the additive prepared in step 1 into a liquid preparation tank and mixing evenly with a 60-100 g / L cobalt chloride solution, wherein the flow rate of the additive is related to the circulation volume of the cobalt chloride solution; Step 3: transport the new solution prepared in step 2 to each electrowinning cell, apply power for electrowinning, prepare electrowinning cobalt plates, wash and shear them, and then pack and store them. The flow rate of the new solution is related to the current density.

2. A method for improving the appearance quality of an electrolytic cobalt plate according to claim 1, characterized in that: The additive in step 1 is one or more of sodium chloride, magnesium chloride, calcium chloride, manganese chloride, and potassium chloride, and the concentration of the additive is 6×10 -7 ~8×10 -7 mol / (A·m -2 ·L).

3. A method for improving the appearance quality of an electrolytic cobalt plate according to claim 1, characterized in that: The flow rate of the additive in step 2 is 0.026~0.032m 3 / h, the circulation volume of cobalt chloride solution is 2.6~3.2m 3 / h.

4. A method for improving the appearance quality of an electrolytic cobalt plate according to claim 1, characterized in that: In step 3, the new liquid flow rate is 10-15 L / (A·m -2 ·h·slot).

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