Method for preparing sulfur-containing nickel button in sulfate solution

Abstract

The invention provides a method for preparing a sulfur-containing nickel button in a sulfate solution, belongs to the technical field of hydrometallurgy and electrochemistry, and solves the problems that hydrogen is separated out and the product quality is poor in the existing sulfur-containing nickel button production. The additive is prepared from the following components: 0.1 to 0.3 g / L of hydrogen peroxide, 0.5 to 1.0 g / L of thiourea, 1.0 to 2.0 g / L of saccharin sodium salt, 1.5 to 2.0 g / L of boric acid, 0.025 to 0.15 g / L of 2-ethylhexyl sodium sulfate and 0.025 to 0.2 g / L of sodium p-styrenesulfonate; the electrolyte comprises a sulfate solution, a refined nickel sulfate solution and a pore inhibitor; loading a nickel block into a titanium material dissolving basket as an anode, taking a sulfur-containing nickel buckle polar plate as a cathode, and carrying out electrolytic reaction on the nickel block and the titanium material dissolving basket in an electrolytic tank; and after the electrolytic reaction is completed, taking out the sulfur-containing nickel button polar plate, and vibrating, so that the sulfur-containing nickel button is separated from the template. The prepared sulfur-containing nickel button product is stable in quality, short in production period, large in single particle weight and easy to release, and has a good application prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrometallurgy and electrochemistry, and particularly relates to a method for preparing sulfur-containing nickel buttons in a sulfate solution. Background Art

[0002] my country's electroplating nickel process mainly uses electrolytic nickel as anode material. International Nickel Company INCO has developed active sulfur-containing nickel buckles, which have gradually monopolized the world market. Sulfur-containing nickel buckles have many advantages, such as good electrochemical properties, good solubility, and relatively low dissolution potential. They can effectively solve the problem of anode passivation in electroplating nickel production, thereby avoiding problems such as fluctuations in nickel ion concentration and pH value of the plating solution caused by passivation. Secondly, sulfur-containing nickel buckles have good solubility, dissolve evenly during use, and will not dissolve in a pinhole-like manner. They have less residue and high utilization rate. The maximum available anode current density is more than 10 times higher than that of ordinary nickel plates, and the cell voltage is lower than that of nickel plates and nickel blocks, which can save electricity consumption.

[0003] In recent years, my country has also begun to study the production of active sulfur-containing nickel buttons, but its low production efficiency has seriously restricted the large-scale production of sulfur-containing nickel buttons. To improve production efficiency, the current density must be increased, but high current density often leads to hydrogen precipitation during nickel deposition, causing pinholes to appear on the surface of the cathode nickel product. The present invention adds a high current additive to the sulfate electrolyte to increase the current density applicable to the electrolyte, and cooperates with a non-permanent conductive substrate to produce sulfur-containing nickel buttons with high current density. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing sulfur-containing nickel buttons in a sulfate solution, so as to solve the problems of hydrogen precipitation and poor product quality in the existing production of sulfur-containing nickel buttons.

[0005] The technical solution of the present invention is: a method for preparing sulfur-containing nickel buttons in a sulfate solution, comprising the following steps: Step 1: Pass the purified electrolyte into the electrolytic cell, add additives into the electrolytic cell, mix the additives and the electrolyte evenly, and keep the mixed and purified electrolyte and the additives in a circulating state; The additive comprises hydrogen peroxide 0.1-0.3 g / L, thiourea 0.5-1.0 g / L, saccharin sodium 1.0-2.0 g / L, boric acid 1.5-2.0 g / L, 2-ethylhexyl sodium sulfate 0.025-0.15 g / L, and sodium styrene sulfonate 0.025-0.2 g / L; The electrolyte comprises sulfate solution, refined nickel sulfate solution and pore inhibitor; Step 2: Put the nickel block into the titanium dissolving basket as the anode, and use the sulfur-containing nickel buckle plate as the cathode, and the two are electrolyzed in the electrolytic cell; Step 3: After the electrolysis reaction is completed, take out the sulfur-containing nickel button plate and vibrate it to separate the sulfur-containing nickel button from the template.

[0006] As a further improvement of the present invention, in step 1, a vinyl resin tank is used as an electrolytic cell.

[0007] As a further improvement of the present invention, in step 1, the electrolyte temperature is 55-65° C., the pH value is 7.5-7.8, and the nickel content in the refined nickel sulfate solution is 80-90 g / L.

[0008] As a further improvement of the present invention, in step 2, the content of Ni+Co in the nickel block is ≥99.50%.

[0009] As a further improvement of the present invention, in step 2, the initial current density of each cathode cycle in the electrolysis reaction is controlled to be 200-300A / m 2 , time is 4-4.5h; then the current density is increased to 600-900A / m 2 , until the sulfur-containing nickel buckle plate is out of the slot, the electrolysis reaction time is 144-240h.

[0010] As a further improvement of the present invention, in step 2, the voltage of the electrolytic cell is 2.0-3.0V, and the inter-electrode distance is 190-195mm.

[0011] The beneficial effects of the present invention are as follows: the electrolyte of the present invention is composed of a sulfate solution, a refined nickel sulfate solution and a pore inhibitor, and an additive prepared by compounding hydrogen peroxide, thiourea, sodium saccharin, boric acid, sodium 2-ethylhexyl sulfate and sodium styrene sulfonate is added to the electrolyte. Through the action of the chemical substances of each component, a balance can be achieved between the surface roughness of the sulfur-containing nickel buckle plate, the internal stress of the growth of the sulfur-containing nickel buckle, and the tension of the solution. At the same time, the sulfur-containing nickel buckle plate can be made to produce no hydrogen while increasing the production current density, thereby improving the production efficiency and quality of the sulfur-containing nickel buckle. After adding the additive, at a current density of 600-900A / m 2 Sulfur-containing nickel buttons are produced by electrolytic reaction under conditions. The sulfur-containing nickel buttons have stable quality, short production cycle, large single grain weight, and are easy to strip, and have good application prospects.

[0012] Hydrogen peroxide is an oxidant. Adding appropriate hydrogen peroxide in a certain solution pH environment can improve the dispersion ability of the electrolyte, improve the current efficiency, and prevent hydrogen evolution from the sulfur-containing nickel buckle plate under high current density conditions. Thiourea and sodium 2-ethylhexyl sulfate are surfactants that are not easy to generate foam and can act as wetting agents in the system. The two work synergistically with metal ions to promote the overflow of bubbles on the surface of the sulfur-containing nickel buckle plate and prevent the growth of pores on the surface of the sulfur-containing nickel buckle. Sodium styrene sulfonate has unsaturated groups such as double bonds, which makes the potential of the sulfur-containing nickel buckle plate significantly negatively shifted, can adjust the surface tension of the solution, and play the role of a surfactant. Sodium saccharin is a main brightener, which breaks the CS bond on the surface of the sulfur-containing nickel buckle plate, and the detached sulfur compound forms nickel sulfide with nickel through electrochemical reduction and enters the nickel layer, and is reduced to nickel sulfide to regulate the external light gloss of the sulfur-containing nickel buckle.

[0013] The additives in the present invention have the following synergistic effects: 1. Synergistic coordination of the main brightener: saccharin sodium cooperates with thiourea and 2-ethylhexyl sodium sulfate to refine the grains of the nickel deposit layer, and the cathode potential shifts negatively. Saccharin sodium itself does not have the ability to adjust the current density range, but after being compounded with thiourea and 2-ethylhexyl sodium sulfate in a certain proportion, the presence of unsaturated groups narrows the current density range during nickel deposition and reduces the tensile stress of the nickel deposit layer; 2. Regeneration reaction of sulfur-containing additives: The sulfur-containing additive contains S4-, which reacts with nickel ions at the cathode: S4-+xNi2+→NixS, and is deposited together with nickel to the cathode, thereby increasing the sulfur content in the sulfur-containing nickel button product; 3. Additive balance: A standard curve for additive component consumption is established through the consumption rate difference between different component additives.

[0014] The current density in the sulfur-containing nickel button production method of the present invention is 600-900A / m 2 By controlling the current density parameters, the electrochemical activity of the sulfur-containing nickel buttons is enhanced, and they can work stably at a higher current density, reducing the edge effect. Sulfur-containing nickel buttons with a bright appearance and regular shape can be prepared, while the production efficiency is improved, which is 2-4 times higher than in the past. The sulfur-containing nickel buttons produced have high purity and good electrochemical dissolution activity. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is an appearance diagram of the sulfur-containing nickel button product produced in Example 1 of the present invention; Figure 2 This is an appearance diagram of the sulfur-containing nickel buckle product produced in Example 2 of the present invention. DETAILED DESCRIPTION

[0016] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0017] A method for preparing sulfur-containing nickel buttons in a sulfate solution comprises the following steps: Step 1: Pass the purified electrolyte into the electrolytic cell, add additives into the electrolytic cell, mix the additives and the electrolyte evenly, and keep the mixed and purified electrolyte and the additives in a circulating state; The electrolytic cell is equipped with a circulation component, which mixes the additive and the electrolyte evenly through a peristaltic pump. The circulation component keeps the mixed and purified electrolyte in a circulating state. The circulating state of the electrolyte can make the additive evenly distributed in the electrolyte, thereby ensuring the uniformity and stability of the electrolysis process.

[0018] The additive comprises hydrogen peroxide 0.1-0.3 g / L, thiourea 0.5-1.0 g / L, saccharin sodium 1.0-2.0 g / L, boric acid 1.5-2.0 g / L, 2-ethylhexyl sodium sulfate 0.025-0.15 g / L, and sodium styrene sulfonate 0.025-0.2 g / L; The electrolyte comprises sulfate solution, refined nickel sulfate solution and pore inhibitor; The electrolyte consists of refined nickel sulfate solution and pore inhibitor. The refined nickel sulfate solution provides nickel ions in the electrolyte, while the pore inhibitor can reduce the pores generated during the electrolysis process, thereby increasing the electrolyte volume, stability and safety.

[0019] Step 2: Put the nickel block into the titanium dissolving basket as the anode, and use the sulfur-containing nickel buckle plate as the cathode, and the two are electrolyzed in the electrolytic cell; The use of a titanium dissolving basket for electrolytic reaction can effectively control the ratio of nickel blocks to sulfur-containing nickel buckle plates. The nickel blocks have good solubility, produce less anode mud, are easy to load or replenish, and use the nickel block materials completely, reducing waste, lowering costs, and saving energy consumption. The titanium dissolving basket has the characteristics of acid resistance, alkali resistance, corrosion resistance, high temperature resistance, and high strength. It can remain stable during the electrolytic reaction, reduce the problem of uneven current distribution, improve the load capacity of the nickel blocks, and reduce nickel block passivation.

[0020] Step 3: After the electrolysis reaction is completed, take out the sulfur-containing nickel button plate and vibrate it to separate the sulfur-containing nickel button from the template.

[0021] In step 1, a vinyl resin tank is used as an electrolytic cell; the electrolyte temperature is 55-65° C., the pH value is 7.5-7.8, and the nickel content in the refined nickel sulfate solution is 80-90 g / L.

[0022] As an electrolytic cell, the vinyl resin tank can resist the corrosion of chemical media such as acid, alkali, and salt in the electrolyte, thereby extending its service life; the vinyl resin tank adopts an integral casting structure, which not only improves the strength and corrosion resistance of the electrolytic cell, but also reduces stress shrinkage and linear expansion problems; the integral casting structure of the vinyl resin tank reduces the maintenance requirements of the electrolytic cell, reduces production interruptions caused by frequent maintenance, and improves production efficiency.

[0023] In step 2, the content of Ni+Co in the nickel block is ≥99.50%, and the size of the nickel block is 50±10×50±10mm; the initial current density of each cathode cycle in the electrolysis reaction is controlled to be 200-300A / m 2 , time is 4-4.5h; then the current density is increased to 600-900A / m 2 , until the sulfur-containing nickel buckle plate is out of the slot, the electrolysis reaction time is 144-240h; the electrolytic cell voltage is 2.0-3.0V, and the inter-electrode distance is 190-195mm.

[0024] The sulfur-containing nickel buckle plate is made of a conductive template of stainless steel foil bonded to a PET film. The stainless steel foil conductive template has good electrical conductivity and can withstand large currents, thereby maintaining electrical conductivity for a long time. At the same time, the surface of the stainless steel foil conductive template is high in hardness and wear-resistant, and is not easy to scratch or rust, thereby extending the service life of the sulfur-containing nickel buckle plate; the PET film can prevent material adhesion, prevent chemical materials from corroding and damaging containers and equipment, extend its service life, reduce wear and corrosion on the equipment surface, thereby reducing maintenance costs and improving production efficiency; coating the surface of the sulfur-containing nickel buckle plate with conductive coating can improve conductivity. The conductive coating significantly improves the electrical conductivity of the plate by forming a layer of conductive film on the surface of the plate. At the same time, it can reduce the use of adhesives and reduce production costs. The conductive coating can also significantly improve the adhesion between the material and the current collector and reduce delamination. ‌‌ By rationally adjusting and controlling the voltage and inter-electrode spacing parameters of the electrolytic cell, the electrolysis process can be further optimized, the electrolysis efficiency can be increased, and the electrode performance can be improved.

[0025] Embodiment 1, Step 1: Use a vinyl resin tank as an electrolytic cell, and pass the purified sulfate solution, refined nickel sulfate solution and pore inhibitor into the electrolytic cell. The electrolyte temperature is 55°C, the pH value is 7.5, and the nickel content in the refined nickel sulfate solution is 80g / L.

[0026] Add additives to a special configuration box, stir, and then pass into the electrolytic cell. Use deionized water to fully stir and dissolve before adding. The components of the additives are 0.1g / L hydrogen peroxide, 0.5g / L thiourea, 1.0g / L saccharin sodium, 1.5g / L boric acid, 0.025g / L sodium 2-ethylhexyl sulfate, and 0.025g / L sodium styrene sulfonate.

[0027] The additive is mixed evenly with the electrolyte, so that the mixed and purified electrolyte and the additive are in a circulating state.

[0028] Step 2: The voltage of the electrolytic cell is 2.0V, and the inter-electrode distance is 190mm; a nickel block is placed in a titanium dissolution basket as an anode, the Ni+Co content in the nickel block is 99.50%, and the size is 40×40mm. A sulfur-containing nickel buckle plate is used as a cathode, and the cathode size is 980×860mm. The cathode and anode area ratio is 0.65. The sulfur-containing nickel buckle plate is made of a conductive template of stainless steel foil bonded to a PET film, and the surface is coated with a conductive coating; the titanium basket is opened by a titanium lock to replace half of the anode material, and at the same time, 4 sets of copper ears are used to increase the contact area with the titanium basket body, so as to achieve the effect of regulating the anode dissolution process and ensuring good conductivity.

[0029] The two undergo electrolytic reaction in the electrolytic cell; during the electrolytic reaction, the initial current density of each cathode cycle is controlled to be 200A / m 2 , time is 4h; then the current density is increased to 600A / m 2 , until the sulfur-containing nickel buckle plate is out of the slot, the electrolysis reaction time is 144h.

[0030] Step 3: After the electrolytic reaction is completed, the sulfur-containing nickel button plate is taken out and vibrated to separate the sulfur-containing nickel button from the template to obtain a finished product.

[0031] Embodiment 2, Step 1: Use a vinyl resin tank as an electrolytic cell, and pass the purified sulfate solution, refined nickel sulfate solution and pore inhibitor into the electrolytic cell. The electrolyte temperature is 60°C, the pH value is 7.6, and the nickel content in the refined nickel sulfate solution is 85g / L.

[0032] Add additives to a special configuration box, stir, and then pass into the electrolytic cell. Use deionized water to fully stir and dissolve before adding. The components of the additives are 0.2g / L hydrogen peroxide, 0.7g / L thiourea, 1.5g / L saccharin sodium, 1.7g / L boric acid, 0.085g / L sodium 2-ethylhexyl sulfate, and 0.1g / L sodium styrene sulfonate.

[0033] The additive is mixed evenly with the electrolyte, so that the mixed and purified electrolyte and the additive are in a circulating state.

[0034] Step 2: The voltage of the electrolytic cell is 2.5V, and the inter-electrode distance is 193mm. The nickel block is loaded into the titanium dissolution basket as the anode. The Ni+Co content in the nickel block is 99.60%, and the size is 50×50mm. The sulfur-containing nickel buckle plate is used as the cathode. The cathode size is 980×860mm, and the cathode-anode area ratio is 0.65. The sulfur-containing nickel buckle plate is made of a conductive template of stainless steel foil bonded to a PET film, and the surface is coated with a conductive coating; the titanium basket is opened by a titanium lock to replace half of the anode material, and at the same time, 4 sets of copper ears are used to increase the contact area with the titanium basket body, so as to achieve the effect of regulating the anode dissolution process and ensuring good conductivity.

[0035] The two undergo electrolytic reaction in the electrolytic cell; during the electrolytic reaction, the initial current density of each cathode cycle is controlled to be 250A / m 2 , time is 4.3h; then the current density is increased to 750A / m 2 , until the sulfur-containing nickel buckle plate is out of the slot, the electrolysis reaction time is 190h.

[0036] Step 3: After the electrolytic reaction is completed, the sulfur-containing nickel button plate is taken out and vibrated to separate the sulfur-containing nickel button from the template to obtain a finished product.

[0037] Embodiment 3, Step 1: Use a vinyl resin tank as an electrolytic cell, and pass the purified sulfate solution, refined nickel sulfate solution and pore inhibitor into the electrolytic cell. The electrolyte temperature is 65°C, the pH value is 7.8, and the nickel content in the refined nickel sulfate solution is 90g / L.

[0038] Add additives into a special configuration box, stir, and then pass into the electrolytic cell. Use deionized water to fully stir and dissolve before adding. The components of the additives are 0.3 g / L hydrogen peroxide, 1.0 g / L thiourea, 2.0 g / L saccharin sodium, 2.0 g / L boric acid, 0.15 g / L sodium 2-ethylhexyl sulfate, and 0.2 g / L sodium styrene sulfonate.

[0039] The additive is mixed evenly with the electrolyte, so that the mixed and purified electrolyte and the additive are in a circulating state.

[0040] Step 2: The voltage of the electrolytic cell is 3.0V, and the inter-electrode distance is 195mm. The nickel block is loaded into the titanium dissolution basket as the anode. The Ni+Co content in the nickel block is 99.70%, and the size is 60×60mm. The sulfur-containing nickel buckle plate is used as the cathode. The cathode size is 980×860mm, and the cathode-anode area ratio is 0.65. The sulfur-containing nickel buckle plate is made of a conductive template of stainless steel foil bonded to a PET film, and the surface is coated with a conductive coating; the titanium basket is opened by a titanium lock to replace half of the anode material, and at the same time, 4 sets of copper ears are used to increase the contact area with the titanium basket body, so as to achieve the effect of regulating the anode dissolution process and ensuring good conductivity.

[0041] The two undergo electrolytic reaction in the electrolytic cell; during the electrolytic reaction, the initial current density of each cathode cycle is controlled to be 300A / m 2 , time is 4.5h; then the current density is increased to 900A / m 2 , until the sulfur-containing nickel buckle plate is out of the slot, the electrolysis reaction time is 240h.

[0042] Step 3: After the electrolytic reaction is completed, the sulfur-containing nickel button electrode plate is taken out and vibrated to separate the sulfur-containing nickel button from the template to obtain a finished sulfur-containing nickel button.

[0043] The chemical composition analysis of the sulfur-containing nickel buckle products obtained by this method in Example 1-3 is shown in Table 1. The percentage content of Ni+Co in the obtained finished products meets the Ni9997 product standard, and the chemical impurity content of the obtained finished products is less than the Ni9997 product standard requirement.

[0044] The appearance of the sulfur-containing nickel buckle products produced by the present method in Examples 1-2 are as follows: Figure 1 , Figure 2 As shown, the sulfur-containing nickel buckle product is uniform in thickness, has no obvious nodules on the surface, has good metallic luster and is well formed.

Claims

1. A method for preparing sulfur-containing nickel buttons in a sulfate solution, characterized in that: The following steps are involved: Step 1: Pass the purified electrolyte into the electrolytic cell, add additives into the electrolytic cell, mix the additives and the electrolyte evenly, and keep the mixed and purified electrolyte and the additives in a circulating state; The additive comprises 0.1-0.3 g / L hydrogen peroxide, 0.5-1.0 g / L thiourea, 1.0-2.0 g / L saccharin sodium, 1.5-2.0 g / L boric acid, 0.025-0.15 g / L sodium 2-ethylhexyl sulfate, and 0.025-0.2 g / L sodium styrene sulfonate; The electrolyte comprises sulfate solution, refined nickel sulfate solution and pore inhibitor; Step 2: Put the nickel block into the titanium dissolving basket as the anode, and use the sulfur-containing nickel buckle plate as the cathode, and the two are electrolyzed in the electrolytic cell; Step 3: After the electrolysis reaction is completed, take out the sulfur-containing nickel button plate and vibrate it to separate the sulfur-containing nickel button from the template.

2. The method for preparing sulfur-containing nickel buttons in a sulfate solution according to claim 1, characterized in that: In step 1, a vinyl resin tank is used as an electrolytic cell.

3. The method for preparing sulfur-containing nickel buttons in a sulfate solution according to claim 1, characterized in that: In step 1, the electrolyte temperature is 55-65° C., the pH value is 7.5-7.8, and the nickel content in the refined nickel sulfate solution is 80-90 g / L.

4. The method for preparing sulfur-containing nickel buttons in a sulfate solution according to claim 1, characterized in that: In step 2, the content of Ni+Co in the nickel block is ≥99.50%.

5. The method for preparing sulfur-containing nickel buttons in a sulfate solution according to claim 1, characterized in that: In step 2, the initial current density of each cathode cycle in the electrolysis reaction is controlled to be 200-300A / m 2 , time is 4-4.5h; then the current density is increased to 600-900A / m 2 , until the sulfur-containing nickel buckle plate is out of the slot, the electrolysis reaction time is 144-240h.

6. The method for preparing sulfur-containing nickel buttons in a sulfate solution according to claim 1, characterized in that: In step 2, the voltage of the electrolytic cell is 2.0-3.0V, and the inter-electrode distance is 190-195mm.

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