High-purity sulfur-containing active nickel particles and preparation method thereof

Abstract

The preparation method comprises the following steps: adding a nickel-sulfur / nickel compound into a nickel melt, refining under electromagnetic stirring to obtain a nickel-sulfur melt, casting the nickel-sulfur melt in a mold to obtain a high-purity nickel-sulfur cast ingot, carrying out hot isostatic pressing treatment to obtain a billet with a compact structure, and carrying out high-temperature sintering to obtain the high-purity active nickel particles. Cutting the billet according to the size of a finished product to obtain high-purity sulfur-containing active nickel particles; the nickel-sulfur / nickel compound is selected from one of a nickel block coated with a nickel-sulfur compound, a nickel foil coated with the nickel-sulfur compound and a nickel sintered body containing the nickel-sulfur compound. According to the method, vacuum induction melting is adopted, the sulfur element is added into nickel in a specific mode, whole-process electromagnetic stirring is combined, preparation of the nickel-sulfur cast ingot which is high in component purity, stable in sulfur content and free of segregation is achieved, and batch production of the high-purity sulfur-containing active nickel particles is completed by adopting a targeted processing technology according to the characteristic that nickel-sulfur brittleness is large subsequently. The preparation method disclosed by the invention is low in comprehensive cost, small in environmental pollution and suitable for industrial production.

Description

Technical Field

[0001] The invention belongs to the field of electroplating, and in particular relates to high-purity sulfur-containing active nickel particles and a preparation method thereof. Background Art

[0002] my country's nickel electroplating industry mainly uses electrolytic nickel as anode material, while foreign countries have been using sulfur-containing active nickel since the 1960s. Sulfur-containing active nickel has attracted widespread attention in the nickel electroplating industry due to its high activity, ability to be used at higher current density, and low residue.

[0003] The main component of sulfur-containing active nickel is nickel, and the sulfur content is usually not more than 300ppm. Excessive addition will cause severe embrittlement of nickel and deterioration of activity. Compared with electrolytic nickel, sulfur-containing active nickel has the following advantages: (1) It can be used at a higher current density without passivation, with high anode efficiency and good coating quality; (2) It has high dissolution activity; (3) It has high activity, and the anode can start to dissolve at a relatively negative potential, and the starting voltage of the electroplating tank is low, saving electricity; (4) It reduces copper pollution. The residue after electroplating of sulfur-containing active nickel is nickel sulfide, which can react with copper ions in the electroplating solution to form copper sulfide precipitation; (5) There is less residue, which saves metal nickel and reduces plating solution pollution; (6) It does not produce a sponge-like structure during dissolution, ensuring the continuity of the electroplating process. As an important electroplating industrial material, sulfur-containing active nickel is mainly used as a basket electroplating anode during the electroplating process, that is, the sulfur-containing active nickel anode is placed in the electroplating basket for electroplating. Therefore, the product form is mostly a block form that is convenient for filling, such as cake, crown, bead, etc. The purity and sulfur content of the sulfur-containing active nickel anode will affect the peak current density of the anode dissolution, the amount of residue generated and the anode utilization efficiency. Generally, the higher the purity of the sulfur-containing active nickel anode in the electroplating basket and the smaller the fluctuation of the sulfur content, the more stable the electroplating process, the less residue generated and the higher the anode utilization rate.

[0004] At present, the main forms of sulfur-containing active nickel products are nickel cakes (also known as nickel buckles), nickel crowns, and nickel beads. The main preparation method is electrolysis. The product purity is low, and it is difficult to accurately control the sulfur content, size specifications, etc. With the continuous improvement and development of nickel electroplating technology, the quality requirements for nickel plating are constantly increasing. Sulfur-containing nickel beads, nickel cakes, nickel crowns, etc. with low purity, unstable sulfur content, irregular shape, and rough surface are gradually unable to meet the needs of the nickel electroplating industry. Compared with ordinary sulfur-containing nickel cakes, nickel crowns, and nickel beads, high-purity sulfur-containing nickel particles have higher purity, more stable sulfur content, more uniform size and shape, and are not easy to form bridges and gaps in the basket during the electroplating process. The anode sedimentation is more stable and uniform, which can significantly improve the quality of nickel plating.

[0005] As a new sub-series of sulfur-containing active nickel products, high-purity sulfur-containing active nickel particles can be used in multiple fields such as batteries, electroplating, stainless steel and alloys. At present, the market demand for high-purity sulfur-containing active nickel particles is extremely high. Taking a domestic new energy company as an example, the company's annual demand for high-purity sulfur-containing active nickel particles is about 10 tons, and the demand is increasing year by year. However, there are very few companies that have the ability to prepare high-purity sulfur-containing active nickel particles, and the overall market is in a state of supply exceeding demand. Patents and literature on sulfur-containing active nickel products are also mainly based on the preparation of sulfur-containing nickel cakes, nickel crowns, and nickel beads. No patents for the preparation of high-purity sulfur-containing active nickel particles have been found.

[0006] The patent with publication number CN 101209494A discloses a method for preparing sulfur-containing nickel beads, which comprises introducing a mixed gas consisting of carbonyl nickel vapor, carbon monoxide, and hydrogen sulfide (or carbonyl sulfide) into a decomposer, heating the nickel beads and then placing them into the decomposer, so that the mixed gas forms a countercurrent contact with the nickel beads, and controlling the heating temperature and the decomposer pressure. The metal nickel and sulfur generated by the decomposition of the carbonyl nickel and hydrogen sulfide (or carbonyl sulfide) in the mixed gas are deposited on the surface of the nickel beads, and finally nickel beads having a certain amount of sulfur on the surface are obtained.

[0007] The document "Preparation of Sulfur-Containing Active Nickel Buttons for Special Electroplating Industry" introduces a method for preparing nickel buttons. The specific process is as follows: in a mixed system of nickel sulfate and nickel chloride, the purified nickel solution is used as the electrolyte, and an appropriate amount of sulfur doping agent TS and additive SB are added as new solution. The nickel sulfide anode is used as the soluble anode, and the stainless steel plate is used as the cathode. A specific electrolysis system is used for diaphragm electrolysis. During the electrolysis process, nickel is precipitated on the conductive surface of the cathode plate, and the sulfur doping agent is precipitated at the cathode in the form of physical adsorption and electrodialysis, so as to achieve the purpose of sulfur doping of the nickel button. After the production cycle is reached, the cathode is removed from the tank to peel off the nickel button, and the nickel button is surface treated with a special rinsing agent to obtain a sulfur-containing active nickel button.

[0008] Patent CN 101063210 B introduces a process for producing high-activity nickel cakes using nickel-containing waste as raw materials. First, the nickel and soluble substances in the regenerated nickel are dissolved, and the insoluble precipitate is filtered. Next, a precipitant is added to remove impurity elements such as Fe, Cu, and Zn in the solution. Subsequently, the solution is subjected to deep impurity removal and extraction, and a soda solution is added to adjust the pH. The precipitate is filtered and washed to prepare nickel carbonate. Finally, the above substances are used to prepare an electrolyte, and a nickel cake electrode plate and a nickel plate containing 0.02% copper are used as the cathode and anode, respectively. The current is increased multiple times within a production cycle of 3-15 days to finally produce a high-activity nickel cake for electroplating.

[0009] The document "Preparing Sulfur-Containing Active Nickel Crowns with a New Process" introduces a process for preparing nickel crowns, which uses a high-sulfur nickel plate as an anode and a special stainless steel plate as a cathode to prepare sulfur-containing active nickel crowns by electrolysis. The specific process is: adding a qualified purified electrolyte containing a certain amount of additives to the cathode diaphragm belt. As the electrolysis process proceeds, crown-shaped sulfur-containing active nickel gradually precipitates on the cathode. After peeling, rinsing and surface treatment are performed to obtain the sulfur-containing active nickel crown.

[0010] The patent application publication number CN 110078137 A introduces a method for preparing a nickel sulfide electrode material, the main steps of which include powder preparation, sintering, and grinding. In the powder preparation step, a mixed solution containing nickel salt and sulfur-containing raw materials is first prepared, and then the mixed solution is heated, cooled, filtered and washed to obtain a black cake-like material, and finally ultrasonically etched to obtain a black powder material. The sintering process refers to sintering the black nickel sulfide material at a high temperature, and finally grinding it to obtain a nickel sulfide electrode material.

[0011] In summary, the preparation of sulfur-containing active nickel products disclosed in the prior art is mainly based on electrolysis, which has the potential risk of polluting the environment and high energy consumption. On the other hand, the sulfur-containing active nickel products prepared by electrolysis have low purity, large fluctuations in sulfur content, rough surface and irregular shape. Therefore, the active nickel products prepared by the prior art are far from meeting market demand. Summary of the invention

[0012] In view of the deficiencies in the prior art, the first object of the present invention is to provide a method for preparing high-purity sulfur-containing active nickel particles. The present invention adopts vacuum induction melting, adds sulfur to nickel in a specific manner, and combines electromagnetic stirring throughout the process to achieve the preparation of nickel-sulfur ingots with high purity, stable sulfur content and no segregation. Subsequently, based on the characteristics of high brittleness of nickel-sulfur, hot isostatic pressing and cutting processing are combined to complete the batch production of high-purity sulfur-containing active nickel particles. The preparation method of the present invention has low comprehensive cost, low environmental pollution, and is suitable for industrial production.

[0013] The second object of the present invention is to provide a high-purity sulfur-containing active nickel particle prepared by the above-mentioned preparation method. The high-purity sulfur-containing active nickel particle prepared by the preparation method of the present invention has high purity, the purity can reach 4N or above, the sulfur content fluctuates little (taking the product with a sulfur content of 200ppm as an example, the sulfur element content fluctuation can be controlled within ±20ppm); and the high-purity sulfur-containing active nickel particle has a dense structure, a smooth surface, and a regular shape.

[0014] In order to achieve the above purpose, the present invention adopts the following technical solution: The invention discloses a method for preparing high-purity sulfur-containing active nickel particles. The method comprises the following steps: adding a nickel-sulfur / nickel complex to a nickel melt, refining the nickel-sulfur melt under electromagnetic stirring to obtain a nickel-sulfur melt, then casting the nickel-sulfur melt in a mold to obtain a high-purity nickel-sulfur ingot, performing hot isostatic pressing to obtain a dense ingot, and cutting the ingot according to the finished product size to obtain the high-purity sulfur-containing active nickel particles. The nickel-sulfur / nickel complex is selected from one of a nickel block wrapped with a nickel-sulfur compound, a nickel foil wrapped with a nickel-sulfur compound, and a nickel sintered body containing a nickel-sulfur compound.

[0015] The preparation method of the present invention is different from the electrochemical preparation scheme used in the existing sulfur-containing active nickel products. It is the first to use smelting to prepare high-purity sulfur-containing active nickel products. Considering that the melting point and boiling point of sulfur are low (115.21°C and 444.72°C, respectively), which are far lower than the melting point of nickel (1455°C), direct addition will cause a large loss of sulfur. The present invention introduces sulfur into nickel in the form of a nickel-sulfur / nickel complex that is wrapped or contains nickel-sulfur compounds, that is, the nickel-sulfur compound is wrapped in a nickel block, nickel foil or contained in a nickel sintered body, and is added to the nickel melt after the nickel is completely melted, so as to avoid premature exposure of the nickel-sulfur compound and thermal decomposition, resulting in loss or introduction of impurity elements. At the same time, continuous electromagnetic stirring during the entire vacuum smelting process ensures the uniform distribution of sulfur in the ingot. The smelting process can effectively ensure the high purity of the nickel-sulfur ingot, and the sulfur content is stable and evenly distributed. On the other hand, in view of the problem that nickel-sulfur ingots are difficult to be processed by conventional plastic deformation methods such as extrusion, forging, and drawing, the present invention first adopts hot isostatic pressing treatment and then cuts the nickel particles according to the finished size. This can ensure that the high-purity sulfur-containing active nickel particles have a dense structure and uniform shape and size. The residual billet after cutting can still be used as the raw material for the next smelting, effectively reducing the preparation cost.

[0016] In a preferred embodiment, the purity of the high-purity sulfur-containing active nickel particles is ≥4N, and the sulfur content ranges from 50ppm to 300ppm, preferably 200ppm.

[0017] In a preferred embodiment, the nickel-sulfur compound is selected from at least one of NiS, NiS2, Ni3S2, and Ni9S8, preferably NiS2.

[0018] In a preferred embodiment, the nickel-sulfur / nickel composite is a nickel block wrapped with a nickel-sulfur compound. In actual operation, the nickel block wrapped with the nickel-sulfur compound is quickly added to the nickel melt after the nickel is completely melted; the inventors have found that compared with wrapping with nickel foil or preparing a high-purity nickel sintered body containing a nickel-sulfur compound by powder metallurgy, wrapping the nickel-sulfur compound with a nickel block can more quickly immerse it in the nickel melt, further reducing the loss of sulfur elements, and at a lower cost.

[0019] In a preferred embodiment, the nickel sintered body containing the nickel-sulfur compound is prepared by powder metallurgy.

[0020] In a preferred embodiment, the nickel melt is obtained by sequentially sandblasting, cleaning and drying high-purity nickel and the nickel-sulfur residual blank after cutting, and then adding the high-purity nickel and the nickel-sulfur residual blank into a crucible and smelting them under vacuum until they are melted. In the present invention, the nickel-sulfur residual blank after cutting is the nickel-sulfur residual blank remaining after the ingot is cut into the finished product size to obtain high-purity sulfur-containing active nickel particles.

[0021] Further preferably, the purity of the high-purity nickel is ≥4N.

[0022] Further preferably, the sandblasting time is 10 min to 20 min, preferably 15 min.

[0023] Further preferably, the cleaning adopts ultrasonic cleaning method, the cleaning medium can be selected from clean water, organic solvent, semi-aqueous cleaning agent, preferably semi-aqueous cleaning agent, and the ultrasonic cleaning time is 15min~30min, preferably 20min.

[0024] Further preferably, the crucible material is selected from alumina, zirconia, graphite, etc., preferably alumina.

[0025] Further preferably, during the smelting process of obtaining the nickel melt, the vacuum degree is ≤10 -1 Pa, preferably ≤10 -2 Pa, the melting temperature is 1500℃~1600℃, preferably 1550℃.

[0026] In the actual operation process, corresponding preparations are made according to different ways of adding nickel-sulfur compounds. The nickel block of the nickel-sulfur compound is obtained by cutting a rectangular parallelepiped on a nickel ingot, processing a non-through hole on the end face to accommodate the nickel-sulfur compound, and processing a nickel cylinder at the same time to fill the nickel-sulfur compound powder and then close the aforementioned hole; the nickel foil wrapped with the nickel-sulfur compound is obtained by unfolding the nickel foil, pouring the nickel-sulfur compound powder on one side of the surface of the nickel foil, rolling up the nickel foil from one side of the nickel-sulfur compound, and finally folding the two ends to completely wrap it to avoid leaving gaps; the nickel sintered body containing the nickel-sulfur compound is obtained by weighing a certain amount of high-purity nickel powder and nickel-sulfur compound powder, mixing powder, ball milling, mixing with glue, drying, pressing, pre-sintering, and sintering to obtain a nickel sintered body containing a certain component of nickel-sulfur compound, and each time according to needs, a certain mass is cut and added to the melt.

[0027] According to the mass of each smelting ingot, the nickel and sulfur content in a single sulfur-nickel ingot is calculated according to the sulfur mass percentage, and high-purity nickel is prepared (if nickel blocks are used for wrapping, the above-mentioned rectangular nickel blocks with holes and nickel cylinders are included), nickel foil (if nickel foil is used for wrapping, the mass of nickel foil should be calculated in the prepared high-purity nickel), nickel sintered body (when adding nickel sintered body, the mass of nickel in nickel sintered body should be counted in the prepared high-purity nickel), nickel-sulfur residual billet and nickel-sulfur compounds. Except for nickel-sulfur compounds and nickel foil, the remaining raw materials are processed in advance according to the above-mentioned sandblasting and ultrasonic cleaning schemes, dried and set aside; the nickel-sulfur compound powder is filled in the hole of the rectangular nickel block or wrapped with nickel foil, and the upper end of the hole of the rectangular nickel block is closed with a nickel cylinder. The nickel block, nickel foil or nickel sintered body containing nickel-sulfur compounds wrapped with nickel-sulfur compounds are clamped in the corresponding position in the vacuum induction furnace in advance, and the remaining high-purity nickel, nickel-sulfur residual billets, etc. are placed in a crucible for vacuum melting first. After the nickel is completely melted, the nickel block, nickel foil or nickel sintered body containing nickel-sulfur compounds wrapped with nickel-sulfur compounds are added.

[0028] The preferred solution is to control the vacuum degree during refining to ≤10 -1 Pa, preferably ≤10 -2 Pa, the refining temperature is 1500℃~1550℃, preferably 1520℃, and the refining time is 10min~30min, preferably 20min.

[0029] In a preferred embodiment, the electromagnetic stirring rate is 5 rpm to 20 rpm, preferably 10 rpm.

[0030] In a preferred embodiment, the casting temperature is 1480° C. to 1520° C., preferably 1500° C., and the casting rate is 0.1 kg / s to 0.3 kg / s, preferably 0.2 kg / s.

[0031] In a preferred embodiment, the casting mold is made of a material selected from cast iron, graphite, and silicon carbide, preferably graphite; the inner surface of the mold is coated with a boron nitride coating, and a nickel-sulfur cooling pad is placed at the inner bottom. The mold used in the present invention is a combined mold without upper and lower end surfaces, the inner cavity size can be adjusted as needed, a cooling pad is placed inside, and the boron nitride coating is used as a high temperature resistant lubricating coating.

[0032] Further preferably, the cooling pad is made of nickel-sulfur. The cooling pad made of nickel-sulfur will not introduce other impurity elements during the solidification process of the nickel-sulfur melt.

[0033] In a preferred embodiment, the temperature of the hot isostatic pressing treatment is 1000°C to 1200°C, preferably 1100°C, the pressure is 20MPa to 40MPa, preferably 30MPa, and the time is 2h to 4h, preferably 3h. By performing hot isostatic pressing treatment under the above parameters, the high-purity nickel-sulfur ingot can be made dense in structure, and finally high-purity sulfur-containing active nickel particles with dense structure, smooth surface and regular shape can be obtained by cutting.

[0034] The preferred solution is to cut the ingot into finished product size by cutting the ingot from the bottom upward to obtain a blank, grinding the blank, and then cutting the ground blank into nickel-sulfur granules according to the required size, which is then ground, cleaned and dried to obtain the final product.

[0035] In actual operation, the ingot is sawn from the bottom upward into a billet of fixed thickness until a riser appears; the two cross-sections of the billet obtained in the above step are polished to reduce the roughness of the billet end surface and further reduce the billet thickness; the billet is cut according to the diameter size of the sulfur-containing active nickel particles, and the remaining part is retained as raw material for the next smelting.

[0036] Further preferably, the slitting process is: sawing the ingot with a sawing machine until a riser appears, and controlling the thickness of the ingot obtained by sawing to reserve a grinding allowance of 0.2mm~0.4mm, preferably 0.3mm, on the length of the sulfur-containing active nickel particles.

[0037] In a further preferred embodiment, the blank is placed on a grinding machine and the two cut surfaces are ground. The roughness of the blank end surface is reduced by grinding, and the blank thickness is further reduced. After grinding, the blank thickness reaches the length size of the sulfur-containing active nickel particles.

[0038] Further preferably, the cutting method is selected from laser cutting, water jet cutting, and wire cutting, preferably water jet cutting.

[0039] According to a preferred solution, the sulfur-containing active nickel particles obtained after the ingot is cut into the finished product size are placed in a grinder for grinding to remove burrs and sharp corners on the cutting edges and improve the surface finish; the ground particles are subjected to multiple ultrasonic cleanings to remove residual dirt and impurities on the surface, and the cleaned sulfur-containing active nickel particles are dried and vacuum-packed.

[0040] Further preferably, the grinder is a horizontal grinder, and the grinding abrasive is spherical aluminum oxide particles; the mass ratio of sulfur-containing active nickel particles to abrasive is 1:1~1.5, preferably 1:1.2; the total volume of sulfur-containing active nickel particles and abrasive after adding water is 85%~95% of the total volume of the grinding chamber, preferably 90%; the grinding time is 20min~40min, preferably 30min.

[0041] Further preferably, during the multiple ultrasonic cleaning, an aqueous solution with washing powder added, an aqueous solution with detergent added, clean water, and anhydrous ethanol are used as ultrasonic cleaning media in sequence, the concentration of washing powder in the aqueous solution with washing powder added is 1g / L~3g / L, preferably 2g / L, the concentration of detergent in the aqueous solution with detergent added is 2mL / L~4mL / L, preferably 3mL / L, the volume mass ratio of the ultrasonic cleaning medium to the particles is 2L / kg~4L / kg, preferably 3L / kg; the time for each ultrasonic cleaning is 10min~30min, preferably 20min. The above steps are used to ensure that the sulfur-containing active nickel particles are cleaned.

[0042] Further preferably, the drying method may be at least one of constant temperature drying oven drying, natural air drying, and hot air gun drying, preferably hot air gun drying.

[0043] The present invention also provides a high-purity sulfur-containing active nickel particle prepared by the method.

[0044] Principles and advantages Sulfur-containing active nickel has high activity and is not easily passivated during the electroplating process. It is an excellent anode material for nickel plating. While the market demand increases year by year, higher requirements are also placed on its purity, sulfur content stability, defect control, and shape and size. The production process of sulfur-containing active nickel products such as nickel cakes, nickel crowns, and nickel beads on the market is not environmentally friendly and has high energy consumption. The prepared sulfur-containing active nickel products have low purity, large fluctuations in sulfur content, rough surfaces, and irregular shapes, which cannot meet the needs of high-quality nickel plating.

[0045] The present invention adopts a smelting scheme to prepare high-purity sulfur-containing active nickel particles with low comprehensive cost, no waste liquid is generated, and the environmental pollution is small. At the same time, the prepared sulfur-containing active nickel particles have high purity, stable sulfur content, few defects, regular shape, and uniform size. Selecting appropriate additives and adding them at the right time is the key to ensuring the high purity and stable sulfur content of sulfur-containing nickel products. The present invention solves the problem of stable control of sulfur content in high-purity sulfur-containing active nickel products. In combination with the melting point and density differences between nickel and sulfur, nickel-sulfur compounds are selected instead of elemental sulfur as additives. The nickel-sulfur compounds are wrapped in nickel blocks, nickel foils, or sintered in nickel sintered bodies in advance, and the above-mentioned nickel-sulfur / nickel complex is added after the nickel is completely melted, thereby avoiding premature exposure of nickel-sulfur compounds and thermal decomposition to cause sulfur loss or introduce impurity elements. At the same time, continuous electromagnetic stirring during the entire smelting process ensures the uniform distribution of sulfur elements in the ingot. The smelting process can effectively ensure the high purity (4N or above) of nickel-sulfur ingots, stable sulfur content and uniform distribution. On the other hand, in view of the problem that nickel-sulfur ingots are very brittle and it is difficult to close internal casting defects using conventional plastic deformation processing methods such as extrusion, forging, and drawing, the present invention ensures that the high-purity sulfur-containing active nickel particles have a dense structure and uniform shape and size by designing processes such as hot isostatic pressing, billet sawing, and cutting to size. The residual billet after cutting can still be used as raw material for subsequent smelting, effectively reducing the preparation cost.

[0046] The present invention fills the gap in the demand for high-purity active nickel particles with stable sulfur content for electroplating anodes in the high-quality nickel plating market. The technical solution has been verified by production and has the feasibility of batch and stable production. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 The figure shows the appearance comparison of several sulfur-containing active nickel products currently on the market and the sulfur-containing active nickel particles provided by the present invention. As can be seen from the figure, the sulfur-containing active nickel particles obtained by the technical solution of the present invention have more regular shapes, more uniform sizes, smoother surfaces, and fewer defects.

[0048] Figure 2 The appearance of the sulfur-containing active nickel particles product in Example 1.

[0049] Figure 3 Example 1 Composition test results of sulfur-containing active nickel particle products.

[0050] Figure 4 The appearance of the sulfur-containing active nickel particles product in Example 2.

[0051] Figure 5 Example 2 Composition test results of sulfur-containing active nickel particle products.

[0052] Figure 6 The appearance of the sulfur-containing active nickel particles product in Example 3.

[0053] Figure 7 Example 3 Composition test results of sulfur-containing active nickel particle products.

[0054] Figure 8 Appearance of sulfur-containing active nickel particles that were not subjected to hot isostatic pressing in Comparative Example 2. DETAILED DESCRIPTION

[0055] Example 1

[0056] Prepare high-purity sulfur-containing active nickel particles with a sulfur content of 200ppm. Prepare high-purity nickel with a purity of 4N (one of the pieces has holes and nickel cylinders processed in advance), nickel-sulfur residual billets, and NiS2 powder; sandblast the high-purity nickel and residual nickel-sulfur billets for 15 minutes, then use ultrasonic cleaning in clean water for 20 minutes and dry naturally; then fill the NiS2 powder into the holes of the nickel block, seal it with a nickel cylinder, and clamp the whole on the robot arm in a vacuum induction furnace. Coat a layer of high-temperature resistant boron nitride coating on the inner wall of the graphite mold, dry it and set it aside; assemble the mold into an inner cavity with a size of 330×135×70mm and put it into a vacuum induction furnace, and place a nickel-sulfur cooling pad on the bottom of the inner side. Add high-purity nickel and residual nickel-sulfur billets into an alumina crucible and place it in a vacuum of 10 -2 Pa, the melting temperature is 1550 ° C, and after the nickel is completely melted, a nickel block filled with NiS2 powder is added. During the melting period, electromagnetic stirring is continuously performed at a rate of 10 rpm. The vacuum degree during refining is 10 -2Pa, temperature is 1520℃, and refining time is 20min. After refining, the nickel-sulfur melt is cast into a graphite mold, the casting temperature is 1500℃, the casting rate is 0.2kg / s; the ingot in the mold is taken out after it is completely cooled. The ingot is placed in a hot isostatic pressing furnace for treatment, the hot isostatic pressing temperature is 1100℃, the pressure is 30MPa, and the time is 3h. The hot isostatic pressing ingot is cut from the bottom to the top into a fixed thickness billet with a billet thickness of 15.3mm using a sawing machine. The cut billet is placed on a grinder, and the thickness reaches 15.0mm after grinding the two cut surfaces. After grinding, water jet cutting is performed on the billet surface according to the diameter size of 10mm for sulfur-containing active nickel particles. The cut particles are placed in a horizontal grinder for grinding, the mass ratio of sulfur-containing active nickel particles to alumina abrasive particles is 1:1.2, the total volume after adding water is 90% of the grinding chamber, and the grinding time is 30min. The ground sulfur-containing active nickel particles were ultrasonically cleaned with an aqueous solution of washing powder and an aqueous solution of dishwashing liquid as the cleaning medium, the ratio of washing powder and dishwashing liquid to water was 2 g / L and 3 mL / L respectively, the volume / mass ratio of the cleaning medium to the sulfur-containing nickel particles was 3 L / kg, and the ultrasonic cleaning time was 15 min; then, the particles were ultrasonically cleaned with clean water for 15 min, the volume of clean water and the mass ratio of the sulfur-containing active nickel particles was 3 L / kg; finally, the particles were ultrasonically cleaned in anhydrous ethanol for 10 min, taken out, dried with a hot air gun, and vacuum packaged.

[0057] Figure 2 This is the appearance of the product obtained in Example 1. Figure 3 The following are the results of component testing of the product of Example 1.

[0058] The sulfur-containing active nickel particles obtained in Example 1 have regular shapes, good size consistency, smooth surfaces and no defects. By sampling and testing the upper, middle and bottom parts of the nickel-sulfur ingot, it is confirmed that its composition meets the design requirements, each impurity element is below the limit, the sulfur content is within the design value fluctuation range, and the purity reaches 4N.

[0059] Example 2 Prepare high-purity sulfur-containing active nickel particles with a sulfur content of 220ppm. Prepare high-purity nickel ingots, nickel foil and NiS2 powder with a purity of 4N. After sandblasting the high-purity nickel ingot for 15 minutes, ultrasonically clean it in clean water for 25 minutes, and then blow it dry with a hot air gun; wrap the NiS2 powder with high-purity nickel foil for later use. Coat the inner wall of the graphite mold with boron nitride coating, dry it, and combine it into an inner cavity size of 330×135×70mm. Put it in a vacuum induction furnace, and place a nickel-sulfur pad on the bottom of the inner side. Add high-purity nickel to an alumina crucible and smelt it under vacuum conditions with a vacuum degree of 10 -2Pa, the melting temperature is 1520℃, and after the nickel is completely melted, high-purity nickel foil wrapped with NiS2 powder is added under vacuum. During the melting period, electromagnetic stirring is continuously performed at a rate of 10rpm. The vacuum degree is controlled at 10 -2 Pa, refining temperature is 1500℃, and refining time is 30min. After refining, the nickel-sulfur melt is cast into a graphite mold, the casting temperature is 1480℃, and the casting rate is 0.3kg / s; the ingot in the mold is taken out after it is completely cooled. The ingot is placed in a hot isostatic pressing furnace for treatment, the hot isostatic pressing temperature is 1150℃, the pressure is 35MPa, and the time is 3h. The ingot is cut by a sawing machine, the thickness of the ingot is 15.2mm, and then the ingot is placed on a grinder for grinding, and the thickness is 15.0mm to reduce the end surface roughness. After grinding, nickel-sulfur particles with a diameter of 10mm are cut from the ingot by water jet cutting. The cut particles are placed in a horizontal grinder for grinding, the mass ratio of sulfur-containing active nickel particles to alumina abrasive particles is 1:1.2, the total volume after adding water is 95% of the grinding chamber, and the grinding time is 30min. The above-mentioned ground sulfur-containing active nickel particles are successively ultrasonically cleaned with an aqueous solution added with laundry detergent and an aqueous solution with detergent, the ratios of which to water are 2 g / L and 3 mL / L respectively, the volume / mass ratio of the cleaning medium to the sulfur-containing nickel particles is 3 L / kg, and the ultrasonic cleaning time is 15 min; then, ultrasonic cleaning is performed with clean water for 20 min, and the ratio of the clean water volume to the mass of the sulfur-containing active nickel particles is 3 L / kg; finally, ultrasonic cleaning is performed in anhydrous ethanol for 10 min, and the ratio of the volume of anhydrous ethanol to the mass of the sulfur-containing active nickel particles is 2.5 L / kg, and the particles are blown dry with a hot air gun and vacuum packaged.

[0060] Figure 4 This is the appearance of the product obtained in Example 2. Figure 5 This is the ingredient test result of the product in Example 2.

[0061] The sulfur-containing active nickel particles obtained in Example 2 have no significant difference in appearance from the product in Example 1, and have the same regular shape, good size consistency, smooth surface and no defects. The composition meets the design requirements, the composition is high-purity, the impurity elements do not exceed the limit, and the sulfur content is within the design value fluctuation range (200ppm~240ppm).

[0062] Example 3 Prepare high-purity sulfur-containing active nickel particles with a sulfur content of 200ppm. Prepare a rectangular nickel material, drill a hole on the end face, and take part of the nickel material to process a nickel cylinder. According to the mass of the nickel-sulfur ingot, calculate and weigh the required high-purity nickel (including the nickel material with holes drilled and the nickel cylinder) and Ni3S2 powder; after sandblasting the high-purity nickel for 15 minutes, ultrasonically clean it in clean water for 25 minutes, and then blow it dry with a hot air gun; fill the Ni3S2 powder into the holes of the nickel block, and use the nickel cylinder to block it to prevent leakage. The inner wall of the graphite mold is coated with boron nitride coating, and after drying, it is combined into an inner cavity size of 330×135×70mm. A nickel-sulfur pad is placed on the bottom of the inner side and placed in a vacuum induction furnace. Add high-purity nickel into an alumina crucible and smelt it under vacuum conditions with a vacuum degree of 10 -2 Pa, the melting temperature is 1580℃, and after the nickel is completely melted, the nickel block wrapped with Ni3S2 powder is added under vacuum. Electromagnetic stirring is carried out throughout the melting process, and the electromagnetic stirring rate is 10rpm; the vacuum degree during refining is 10 -2 Pa, temperature is 1550℃, and refining time is 30min. After refining, the nickel-sulfur melt is cast into a graphite mold, the casting temperature is 1520℃, and the casting rate is 0.1kg / s; the ingot in the mold is taken out after it is completely cooled. The ingot is placed in a hot isostatic pressing furnace for treatment, the hot isostatic pressing temperature is 1100℃, the pressure is 30MPa, and the time is 3h. The ingot is cut by a sawing machine, and the thickness of the ingot is 15.4mm. The ingot obtained in the above link is put into the grinder for grinding and ground to a thickness of 15.0mm. Water jet cutting is performed on the ingot according to the diameter size of 10mm. The particles obtained by cutting are put into a horizontal grinder for grinding, the mass ratio of sulfur-containing active nickel particles to alumina abrasive particles is 1:1.3, the total volume after adding water is 95% of the grinding chamber, and the grinding time is 30min. The above-mentioned ground sulfur-containing active nickel particles are successively used as ultrasonic cleaning media with an aqueous solution added with washing powder and an aqueous solution with dishwashing liquid, the ratios of the two to water are 2 g / L and 3 mL / L respectively, the volume / mass ratio of the cleaning medium to the sulfur-containing nickel particles is 3 L / kg, and the ultrasonic cleaning time is 15 min; then, ultrasonic cleaning is carried out with clean water for 20 min, and the ratio of the clean water volume to the mass of the sulfur-containing active nickel particles is 3 L / kg; finally, the particles are taken out after ultrasonic cleaning in anhydrous ethanol for 10 min, and the ratio of the anhydrous ethanol volume to the mass of the sulfur-containing active nickel particles is 2.5 L / kg. After drying with a hot air gun, the particles are vacuum packaged.

[0063] Figure 6 This is the appearance of the product obtained in Example 3. Figure 7 This is the ingredient test result of the product in Example 3.

[0064] The sulfur-containing active nickel particles obtained in Example 3 have no significant difference in appearance from the products of Example 1 and Example 2, the sulfur content is close to that of Example 1 (considering the detection error), the impurity elements are all controlled below the limit, and the composition meets the requirements.

[0065] Table 1 lists the purity and sulfur content range of sulfur-containing active nickel products currently on the market and sulfur-containing active nickel particles prepared using the technical solution of the present invention.

[0066]

[0067] Note: The theoretical sulfur content of the sulfur-containing active nickel particles listed in Table 1 is 200 ppm.

[0068] It can be seen from the table that, compared with the products of the prior art, the sulfur-containing active nickel particles provided by the present invention have higher purity, smaller fluctuation of sulfur content, and more uniform size.

[0069] Comparative Example 1 The other conditions of Comparative Example 1 are the same as those of Example 1, except that the nickel-sulfur compound is not added in the form of a nickel block, nickel foil wrapping or nickel sintered body, but is directly added after the nickel is completely melted. The sulfur content in the obtained sulfur-containing active nickel particles is far lower than the designed value, which does not meet customer needs.

[0070] Comparative Example 2 Comparative Example 2 The other conditions are the same as those of Example 3, except that no hot isostatic pressing treatment is performed. The surface quality of the sulfur-containing active nickel particles obtained is poor, and there are many holes ( Figure 8 ).

Claims

1. A method for preparing high-purity sulfur-containing active nickel particles, characterized in that: A nickel-sulfur / nickel complex is added to a nickel melt, refined under electromagnetic stirring to obtain a nickel-sulfur melt, then cast in a mold to obtain a high-purity nickel-sulfur ingot, and hot isostatic pressing is performed to obtain a dense ingot. The ingot is cut according to the finished product size to obtain high-purity sulfur-containing active nickel particles; the nickel-sulfur / nickel complex is selected from a nickel block wrapped with a nickel-sulfur compound, a nickel foil wrapped with a nickel-sulfur compound, and a nickel sintered body containing a nickel-sulfur compound.

2. The method for preparing high-purity sulfur-containing active nickel particles according to claim 1, characterized in that: The purity of the high-purity sulfur-containing active nickel particles is ≥4N, and the sulfur content ranges from 50ppm to 300ppm.

3. A method for preparing high-purity sulfur-containing active nickel particles according to claim 1 or 2, characterized in that: The nickel-sulfur compound is selected from at least one of NiS, NiS2, Ni3S2, and Ni9S8, The nickel-sulfur / nickel composite is a nickel block coated with a nickel-sulfur compound; The nickel sintered body containing the nickel-sulfur compound is prepared by powder metallurgy.

4. The method for preparing high-purity sulfur-containing active nickel particles according to claim 1 or 2, characterized in that: The nickel melt is obtained by sequentially sandblasting, cleaning and drying high-purity nickel and the nickel-sulfur residual blank after cutting, then adding the high-purity nickel and the nickel-sulfur residual blank into a crucible, and smelting them under vacuum conditions until they are melted; The purity of the high-purity nickel is ≥4N; The sandblasting time is 10min~20min; The cleaning adopts ultrasonic cleaning, the cleaning medium is selected from at least one of clean water, organic solvent, and semi-aqueous cleaning agent, and the ultrasonic cleaning time is 15min~30min; The crucible material is selected from one of alumina, zirconia and graphite; In the smelting process of obtaining the nickel melt, the vacuum degree is ≤10 -1 Pa, the smelting temperature is 1500℃~1600℃.

5. The method for preparing high-purity sulfur-containing active nickel particles according to claim 1 or 2, characterized in that: Control vacuum degree during refining ≤10 -1 Pa, refining temperature is 1500℃~1550℃, time is 10min~30min; The electromagnetic stirring speed is 5 rpm to 20 rpm; The casting temperature is 1480° C. to 1520° C., and the casting rate is 0.1 kg / s to 0.3 kg / s.

6. The method for preparing high-purity sulfur-containing active nickel particles according to claim 1 or 2, characterized in that: The material of the mold is selected from one of cast iron, graphite and silicon carbide. The inner surface of the mold is brushed with a boron nitride coating, and a nickel-sulfur cooling pad is placed on the inner bottom.

7. The method for preparing high-purity sulfur-containing active nickel particles according to claim 1 or 2, characterized in that: The hot isostatic pressing treatment is performed at a temperature of 1000° C. to 1200° C., a pressure of 20 MPa to 40 MPa, and a time of 2 h to 4 h.

8. The method for preparing high-purity sulfur-containing active nickel particles according to claim 1 or 2, characterized in that: The process of cutting the billet into finished product size is as follows: the billet is cut from the bottom to the top to obtain a billet, the billet is ground, and the ground billet is cut into nickel-sulfur granules according to the required size, and then the final product is obtained by grinding, cleaning and drying. The slitting process is as follows: sawing the ingot with a sawing machine until a riser appears, controlling the thickness of the sawn ingot, and reserving a grinding allowance of 0.2 mm to 0.4 mm on the length of the sulfur-containing active nickel particles; Place the blank on the grinding machine and grind the two cut surfaces; The cutting method is selected from one of laser cutting, water jet cutting and wire cutting.

9. The method for preparing high-purity sulfur-containing active nickel particles according to claim 1 or 2, characterized in that: The sulfur-containing active nickel particles obtained after the blank is cut into finished product sizes are put into a grinder for grinding, the ground particles are subjected to multiple ultrasonic cleanings, and the sulfur-containing active nickel particles after cleaning are dried and vacuum packed; The grinding machine is a horizontal grinding machine, and the grinding abrasive is aluminum oxide spherical particles; the mass ratio of sulfur-containing active nickel particles to abrasive is 1:1-1.5, the total volume of sulfur-containing active nickel particles and abrasive after adding water is 85%-95% of the total volume of the grinding chamber, and the grinding time is 20min-40min; During the multi-pass ultrasonic cleaning, an aqueous solution with washing powder added, an aqueous solution with detergent added, clean water, and anhydrous ethanol are used as ultrasonic cleaning media in sequence, the concentration of the washing powder in the aqueous solution with washing powder added is 1g / L~3g / L, the concentration of the detergent in the aqueous solution with detergent added is 2mL / L~4mL / L, the volume mass ratio of the ultrasonic cleaning medium to the particles is 2L / kg~4L / kg, and the ultrasonic cleaning time is 10min~30min; The drying method is selected from at least one of constant temperature drying oven drying, natural air drying, and hot air gun drying.

10. A high-purity sulfur-containing active nickel particle prepared by the preparation method according to any one of claims 1 to 9.

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