Process for producing low-magnetic nickel protoxide

Abstract

The application relates to the technical field of inorganic functional material preparation, and is a production process of low-magnetic nickel protoxide, which comprises the following steps: pretreatment of a nickel chloride solution: pretreating nickel chloride hexahydrate to obtain pretreated nickel chloride solution; preparation of coarse nickel protoxide: pumping the pretreated nickel chloride solution into a centrifugal atomizer of a spray pyrolysis device to form fine mist droplets, the mist droplets entering a pyrolysis furnace along with compressed air, three temperature zones being arranged in the pyrolysis furnace, and the coarse nickel protoxide being prepared by precisely controlling temperature and gas amount; and preparation of a low-magnetic nickel oxide product; the application takes the nickel chloride solution as raw material, controls the pretreatment complexing agent, optimizes spray pyrolysis atomization parameters and carries out low-temperature ball milling dispersion, so that the magnetic property is reduced, the particles are uniformly dispersed and there is no obvious agglomeration phenomenon, the low-magnetic, small-particle-size nickel protoxide product is prepared, and the problems of high product magnetic property, large particle size and serious agglomeration in the preparation of the nickel protoxide by taking the nickel chloride solution as raw material in the prior art are solved.

Description

Technical Field

[0001] This invention relates to the field of inorganic functional materials preparation technology, and in particular to a production process for low-magnetic nickel oxide. Background Technology

[0002] Nickel suboxide (NiO) possesses excellent electrical, magnetic, and catalytic properties, and is widely used in battery materials, catalysts, magnetic devices, ceramic pigments, and other fields. With the continuous expansion of high-end applications (such as precision electronic components and low-magnetic-sensitivity catalytic systems), higher requirements are being placed on the performance of nickel suboxide, especially low magnetic properties and small particle size uniformity, which have become key indicators.

[0003] Currently, the main methods for preparing nickel suboxide include high-temperature calcination, precipitation, hydrothermal methods, and spray pyrolysis. Among these, the high-temperature calcination method uses nickel salts as raw materials, which are decomposed at high temperatures to obtain the product. However, this method suffers from problems such as high reaction temperature, high energy consumption, easy particle agglomeration of the product, and difficulty in removing magnetic impurities. The precipitation method adjusts the pH value to form nickel ions into hydroxide or carbonate precipitates, which are then calcined to obtain nickel suboxide. Although particle size can be controlled, the precipitation process easily introduces impurity ions, making subsequent washing difficult, and particle agglomeration still easily occurs during the calcination stage, affecting magnetic properties. The hydrothermal method can prepare nano-sized nickel suboxide, but the reaction cycle is long, the production efficiency is low, and the equipment cost is high, making it difficult to achieve industrial-scale production.

[0004] Spray pyrolysis has gradually become the preferred technology for the large-scale production of inorganic powder materials due to its advantages such as high raw material utilization, continuous process, and uniform product composition. In existing technologies, spray pyrolysis using nickel chloride solution as raw material can rapidly prepare crude nickel suboxide powder, but it has two major problems: First, the crude product is prone to residual incompletely decomposed chloride impurities, and may be accompanied by the formation of high-valence nickel oxides (such as Ni2O3, which has strong ferromagnetism), leading to enhanced product magnetism; second, during spray pyrolysis, the particles formed by droplet drying and pyrolysis are prone to agglomeration, increasing interparticle interface interactions and further exacerbating the magnetic superposition effect, making it difficult to obtain low-magnetic products with small particle size (such as submicron) and good dispersibility.

[0005] Therefore, developing a method for preparing nickel suboxide using nickel chloride solution as raw material, through spray pyrolysis combined with efficient post-treatment, that can synergistically reduce magnetism from three aspects: "impurity removal, phase regulation, and structure optimization," while simultaneously achieving small particle size and industrial feasibility, has become a pressing technical problem to be solved in this field. Summary of the Invention

[0006] This invention provides a production process for low-magnetic nickel oxide, which overcomes the shortcomings of the prior art. It can effectively solve the problems of high magnetic properties, large particle size and severe agglomeration in the existing nickel oxide production process when nickel oxide is prepared using nickel chloride solution as raw material.

[0007] To address the above problems, the present invention provides a low-magnetic nickel oxide production process, comprising the following steps: Nickel chloride solution pretreatment: Nickel chloride hexahydrate was pretreated to obtain a pretreated nickel chloride solution; Preparation of crude nickel oxide: The pretreated nickel chloride solution is pumped into the centrifugal atomizer of the spray pyrolysis device to form fine droplets. The droplets are carried into the pyrolysis furnace with compressed air. The pyrolysis furnace is set with three temperature zones. Crude nickel oxide is prepared by precise temperature control and gas volume regulation. Preparation of low-magnetic nickel oxide products: crude nickel suboxide is subjected to acid washing to remove impurities, low-temperature ball milling and low-temperature calcination to obtain low-magnetic nickel oxide products.

[0008] The above-mentioned pretreatment of nickel chloride hexahydrate to obtain a nickel chloride solution includes: Nickel chloride hexahydrate was dissolved in deionized water to prepare an initial solution with a nickel chloride concentration of 0.5-2.0 mol / L. Add a complexing agent to the initial solution and stir until completely dissolved. Then, add dilute hydrochloric acid to adjust the pH of the solution to 3.0-4.0. Stir at a constant temperature of 40-60℃ for 1-2 hours to obtain a pretreated nickel chloride solution.

[0009] The aforementioned pyrolysis furnace is equipped with three temperature zones. Crude nickel suboxide is prepared through precise temperature control and gas flow regulation, including: First section - Drying zone: Temperature 200-250℃, residence time 10-15s, used for dehydration and drying of droplets to form solid particles; The second stage - pyrolysis zone: temperature 500-600℃, residence time 20-30s, to allow the dried nickel chloride particles to undergo a pyrolysis reaction; The third section is the reduction zone, with a temperature of 450-500℃. A reducing gas is introduced into this zone and the residence time is 15-20 seconds. On the one hand, the high-valence nickel oxide that may be generated in small amounts during pyrolysis is reduced to NiO, eliminating the ferromagnetism of the high-valence nickel oxide. On the other hand, the reducing atmosphere can promote the removal of residual chloride impurities in the form of HCl, reducing the chloride content in crude nickel oxide. The pyrolysis products were collected by a cyclone separator to obtain crude nickel oxide powder with a particle size range of 1-5 μm and a magnetic strength reduced to 8-12 emu / g.

[0010] The above-mentioned process of removing impurities from crude nickel suboxide through acid washing, low-temperature ball milling, and low-temperature calcination yields low-magnetic nickel oxide products, including: Pickling to remove impurities: Add crude nickel oxide powder to a 0.1-0.5 mol / L dilute nitric acid solution, control the solid-liquid ratio, and pickle at 50-70℃ for 30-60 min. After pickling, separate the solid by vacuum filtration and wash repeatedly with deionized water until the pH of the filtrate is neutral. Then, vacuum dry at 80-100℃ for 2-4 h to obtain the pickled powder. Low-temperature ball milling: The acid-washed powder and grinding media are added to the ball mill together, the ball-to-material ratio is controlled, anhydrous ethanol is used as the dispersant, and the ball milling is carried out at a speed of 200-300 r / min for 4-8 hours; after the ball milling is completed, the grinding media is removed by centrifugation, and the dispersant is evaporated to dryness at 60-80℃ to obtain the ball-milled powder. Low-temperature calcination: The ball-milled powder is placed in a muffle furnace and calcined at a constant temperature of 300-400℃ for 2-3 hours under an inert atmosphere. After calcination, the powder is cooled to room temperature in the furnace to obtain a low-magnetic nickel oxide product.

[0011] The complexing agent mentioned above is either citric acid or disodium ethylenediaminetetraacetate; the molar ratio of the complexing agent to nickel ions is 0.1-0.3:1.

[0012] The rotational speed of the centrifugal atomizer is 10000-15000 r / min; the flow rate of the compressed air is 5-10 L / min.

[0013] In the third section above, the reducing gas is a mixture of hydrogen and nitrogen, with hydrogen comprising 5%-10%.

[0014] In the above-mentioned acid washing and impurity removal, the solid-liquid ratio is 1:10-1:20 g / mL; in the low-temperature ball milling, the ball-to-material ratio is 10-20:1; in the low-temperature ball milling, the solid-liquid ratio of the dispersant is 1:5-1:8; in the low-temperature calcination, the inert atmosphere is nitrogen or argon, and the flow rate is 2-5 L / min.

[0015] This invention uses nickel chloride solution as raw material. Through pretreatment complexing agent regulation, spray pyrolysis atomization parameter optimization, and low-temperature ball milling dispersion, the magnetic properties are reduced while the particles are uniformly dispersed without obvious agglomeration. This results in the preparation of low-magnetic, small-particle-size nickel oxide products, which solves the problems of high magnetic properties, large particle size, and severe agglomeration in the preparation of nickel oxide using nickel chloride solution as raw material in the prior art. Detailed Implementation

[0016] The present invention is not limited to the following embodiments, and the specific implementation can be determined according to the technical solution of the present invention and the actual situation.

[0017] Example 1: This embodiment of the invention discloses a production process for low-magnetic nickel oxide, including the following steps: S1, Nickel chloride solution pretreatment: Nickel chloride hexahydrate is pretreated to obtain a pretreated nickel chloride solution; S2, Preparation of crude nickel oxide: The pretreated nickel chloride solution is pumped into the centrifugal atomizer of the spray pyrolysis device to form fine droplets. The droplets are then carried by compressed air into the pyrolysis furnace, which is equipped with three temperature zones. Crude nickel oxide is prepared by precise temperature control and gas flow regulation. The rotation speed of the centrifugal atomizer is 10000-15000 r / min; the flow rate of the compressed air is 5-10 L / min. S3, Preparation of low-magnetic nickel oxide products: Crude nickel suboxide is subjected to acid washing to remove impurities, low-temperature ball milling and low-temperature calcination to obtain low-magnetic nickel oxide products.

[0018] In step S1, nickel chloride hexahydrate is pretreated to obtain a nickel chloride solution, including: Nickel chloride hexahydrate was dissolved in deionized water to prepare an initial solution with a nickel chloride concentration of 0.5-2.0 mol / L. Add a complexing agent to the initial solution and stir until completely dissolved. Then, add dilute hydrochloric acid to adjust the pH of the solution to 3.0-4.0. Stir at a constant temperature of 40-60℃ for 1-2 hours to obtain a pretreated nickel chloride solution. The complexing agent is either citric acid or disodium ethylenediaminetetraacetate; the molar ratio of the complexing agent to nickel ions is 0.1-0.3:1.

[0019] In step S2, three temperature zones are set up inside the pyrolysis furnace. Crude nickel oxide is prepared through precise temperature control and gas flow regulation, including: First section - Drying zone: Temperature 200-250℃, residence time 10-15s, used for dehydration and drying of droplets to form solid particles; The second stage - pyrolysis zone: temperature 500-600℃, residence time 20-30s, to allow the dried nickel chloride particles to undergo a pyrolysis reaction; The third section – the reduction zone – has a temperature of 450-500℃. A reducing gas is introduced into this zone for 15-20 seconds. This reduces any small amount of high-valence nickel oxide that may be generated during pyrolysis to NiO, eliminating the ferromagnetism of the high-valence nickel oxide. Furthermore, the reducing atmosphere promotes the removal of residual chloride impurities in the form of HCl, reducing the chloride content in the crude nickel oxide. The reducing gas is a mixture of hydrogen and nitrogen, with hydrogen comprising 5%-10% of the total gas. The pyrolysis products were collected by a cyclone separator to obtain crude nickel oxide powder with a particle size range of 1-5 μm and a magnetic strength reduced to 8-12 emu / g.

[0020] In step S3, crude nickel oxide is subjected to acid washing to remove impurities, low-temperature ball milling, and low-temperature calcination to obtain a low-magnetic nickel oxide product, including: Acid washing to remove impurities: Add crude nickel oxide powder to a 0.1-0.5 mol / L dilute nitric acid solution, control the solid-liquid ratio, and stir and acid wash at 50-70℃ for 30-60 min; after acid washing, separate the solid by vacuum filtration, and wash repeatedly with deionized water until the pH of the filtrate is neutral, and then vacuum dry at 80-100℃ for 2-4 h to obtain the acid-washed powder; the solid-liquid ratio is 1:10-1:20 g / mL; Low-temperature ball milling: The acid-washed powder and grinding media are added to a ball mill together. The ball-to-powder ratio is controlled. Anhydrous ethanol is used as the dispersant. The ball milling is carried out at a speed of 200-300 r / min for 4-8 hours. After the ball milling is completed, the grinding media is removed by centrifugation. The dispersant is then evaporated to dryness at 60-80℃ to obtain the ball-milled powder. The ball-to-powder ratio is 10-20:1. The solid-liquid ratio of the dispersant is 1:5-1:8. Low-temperature calcination: The ball-milled powder is placed in a muffle furnace and calcined at a controlled temperature of 300-400℃ for 2-3 hours under an inert atmosphere. After calcination, the powder is cooled to room temperature in the furnace to obtain a low-magnetic nickel oxide product. The inert atmosphere is nitrogen or argon, with a flow rate of 2-5 L / min.

[0021] Example 2: (1) Pretreatment of nickel chloride solution: Nickel chloride hexahydrate was dissolved in deionized water to prepare an initial solution with a nickel chloride concentration of 0.5 mol / L. Citric acid was added to the initial solution at a molar ratio of citric acid to nickel ions of 0.1:1. After stirring until completely dissolved, dilute hydrochloric acid was added to adjust the pH of the solution to 3.0. The solution was stirred at a constant temperature of 40℃ for 1 h to obtain a pretreated nickel chloride solution.

[0022] (2) Preparation of crude nickel oxide: The pretreated nickel chloride solution from step (1) is pumped into the centrifugal atomizer of the spray pyrolysis device. The centrifugal atomizer rotates at 10,000 r / min to form fine droplets. The droplets are then carried by compressed air (flow rate of 5 L / min) into the pyrolysis furnace. The pyrolysis furnace is equipped with three temperature zones. Crude nickel oxide is prepared by precise temperature control and gas flow regulation. ① First section (drying zone): Temperature 200℃, residence time 10s, used for dehydration and drying of droplets to form solid particles; ② Second stage (pyrolysis zone): Temperature 500℃, residence time 20s, to allow the dried nickel chloride particles to undergo a pyrolysis reaction; ③ Third section (reduction zone): Temperature 450℃. A mixture of hydrogen and nitrogen is introduced into this zone, with hydrogen comprising 5% and a residence time of 15s. On the one hand, this reduces the small amount of high-valence nickel oxide that may be generated during pyrolysis to NiO, eliminating the ferromagnetism of the high-valence nickel oxide; on the other hand, the reducing atmosphere promotes the removal of residual chloride impurities in the form of HCl, reducing the chloride content in crude nickel oxide. The pyrolysis products were collected by a cyclone separator to obtain crude nickel oxide powder with a particle size range of 1.0 μm and a magnetic strength reduced to 8.0 emu / g.

[0023] (3) Post-treatment of nickel oxide: ① Acid washing to remove impurities The crude nickel oxide powder was added to a 0.1 mol / L dilute nitric acid solution, and the solid-liquid ratio was controlled at 1:10. The mixture was stirred and acid-washed at 50℃ for 30 min. After acid washing, the solid was separated by vacuum filtration and repeatedly washed with deionized water until the pH of the filtrate was neutral. Then, the filtrate was vacuum-dried at 80℃ for 2.0 h to obtain the acid-washed powder.

[0024] ② Low-temperature ball milling The acid-washed powder and grinding media were added to a ball mill, with a ball-to-powder ratio of 10:1. Anhydrous ethanol was used as the dispersant, and the solid-liquid ratio was controlled at 1:5. The mixture was ball-milled for 4 hours at a speed of 200 r / min. After ball milling, the grinding media were removed by centrifugation, and the dispersion was then evaporated to dryness at 60°C to obtain the ball-milled powder.

[0025] ③ Low-temperature roasting The ball-milled powder was placed in a muffle furnace and calcined at a constant temperature of 300℃ for 2 hours under nitrogen protection, with a nitrogen flow rate of 2.0 L / min. After calcination, the powder was cooled to room temperature in the furnace to obtain a low-magnetic nickel oxide product.

[0026] Example 3: (1) Pretreatment of nickel chloride solution: Nickel chloride hexahydrate was dissolved in deionized water to prepare an initial solution with a nickel chloride concentration of 1.0 mol / L. Citric acid was added to the initial solution at a molar ratio of citric acid to nickel ions of 0.2:1. After stirring until completely dissolved, dilute hydrochloric acid was added to adjust the pH of the solution to 3.5. The solution was stirred at a constant temperature of 50℃ for 1.5 h to obtain a pretreated nickel chloride solution.

[0027] (2) Preparation of crude nickel oxide: The pretreated nickel chloride solution from step (1) is pumped into the centrifugal atomizer of the spray pyrolysis device. The centrifugal atomizer rotates at 12000 r / min to form fine droplets. The droplets are then carried by compressed air (flow rate of 8 L / min) into the pyrolysis furnace. The pyrolysis furnace is equipped with three temperature zones. Crude nickel oxide is prepared by precise temperature control and gas flow regulation. ① First section (drying zone): temperature 220℃, residence time 12s, used for dehydration and drying of droplets to form solid particles; ② Second stage (pyrolysis zone): Temperature 550℃, residence time 25s, to allow the dried nickel chloride particles to undergo a pyrolysis reaction; ③ Third section (reduction zone): Temperature 475℃. A mixture of hydrogen and nitrogen is introduced into this zone, with hydrogen comprising 7% of the total gas volume and a residence time of 18s. On the one hand, this reduces the small amount of high-valence nickel oxide that may be generated during pyrolysis to NiO, eliminating the ferromagnetism of the high-valence nickel oxide. On the other hand, the reducing atmosphere promotes the removal of residual chloride impurities in the form of HCl, reducing the chloride content in the crude nickel oxide. The pyrolysis products were collected by a cyclone separator to obtain crude nickel oxide powder with a particle size range of 2.0 μm and a magnetic strength reduced to 10.0 emu / g.

[0028] (3) Post-treatment of nickel oxide: ① Acid washing to remove impurities The crude nickel oxide powder was added to a 0.2 mol / L dilute nitric acid solution, and the solid-liquid ratio was controlled at 1:15. The mixture was stirred and acid-washed at 55℃ for 40 min. After acid washing, the solid was separated by vacuum filtration and repeatedly washed with deionized water until the pH of the filtrate was neutral. Then, the filtrate was vacuum-dried at 90℃ for 3.0 h to obtain the acid-washed powder.

[0029] ② Low-temperature ball milling The acid-washed powder and grinding media were added to a ball mill, with a ball-to-material ratio of 15:1. Anhydrous ethanol was used as the dispersant, and the solid-liquid ratio was controlled at 1:6. The mixture was ball-milled for 5 hours at a speed of 250 r / min. After ball milling, the grinding media were removed by centrifugation, and the dispersion was then evaporated to dryness at 70°C to obtain the ball-milled powder.

[0030] ③ Low-temperature roasting The ball-milled powder was placed in a muffle furnace and calcined at a constant temperature of 350℃ for 2.5 hours under nitrogen protection, with a nitrogen flow rate of 3.5 L / min. After calcination, the powder was cooled to room temperature in the furnace to obtain a low-magnetic nickel oxide product.

[0031] Example 4: (1) Pretreatment of nickel chloride solution: Nickel chloride hexahydrate was dissolved in deionized water to prepare an initial solution with a nickel chloride concentration of 2.0 mol / L. Disodium ethylenediaminetetraacetate was added to the initial solution at a molar ratio of 0.3:1 to nickel ions. After stirring until completely dissolved, dilute hydrochloric acid was added to adjust the pH of the solution to 4.0. The solution was stirred at a constant temperature of 60℃ for 2 hours to obtain a pretreated nickel chloride solution.

[0032] (2) Preparation of crude nickel oxide: The pretreated nickel chloride solution from step (1) is pumped into the centrifugal atomizer of the spray pyrolysis device. The centrifugal atomizer rotates at 15000 r / min to form fine droplets. The droplets are then carried by compressed air (flow rate of 10 L / min) into the pyrolysis furnace. The pyrolysis furnace is equipped with three temperature zones. Crude nickel oxide is prepared by precise temperature control and gas flow regulation. ① First section (drying zone): Temperature 250℃, residence time 15s, used for dehydration and drying of droplets to form solid particles; ② Second stage (pyrolysis zone): Temperature 600℃, residence time 30s, to allow the dried nickel chloride particles to undergo a pyrolysis reaction; ③ Third section (reduction zone): Temperature 500℃. A mixture of hydrogen and nitrogen is introduced into this zone, with hydrogen comprising 10% and a residence time of 20s. On the one hand, this reduces the small amount of high-valence nickel oxide that may be generated during pyrolysis to NiO, eliminating the ferromagnetism of the high-valence nickel oxide; on the other hand, the reducing atmosphere promotes the removal of residual chloride impurities in the form of HCl, reducing the chloride content in the crude nickel oxide. The pyrolysis products were collected by a cyclone separator to obtain crude nickel oxide powder with a particle size range of 5.0 μm and a magnetic strength reduced to 12 emu / g.

[0033] (3) Post-treatment of nickel oxide: ① Acid washing to remove impurities The crude nickel oxide powder was added to a 0.5 mol / L dilute nitric acid solution, and the solid-liquid ratio was controlled at 1:20. The mixture was stirred and acid-washed at 70℃ for 60 min. After acid washing, the solid was separated by vacuum filtration and repeatedly washed with deionized water until the pH of the filtrate was neutral. Then, the filtrate was vacuum-dried at 100℃ for 4.0 h to obtain the acid-washed powder.

[0034] ② Low-temperature ball milling The acid-washed powder and grinding media were added to a ball mill, with a ball-to-material ratio of 20:1. Anhydrous ethanol was used as the dispersant, and the solid-liquid ratio was controlled at 1:8. The mixture was ball-milled for 8 hours at a speed of 300 r / min. After ball milling, the grinding media were removed by centrifugation, and the dispersion was then evaporated to dryness at 80°C to obtain the ball-milled powder.

[0035] ③ Low-temperature roasting The ball-milled powder was placed in a muffle furnace and calcined at a constant temperature of 400℃ for 3 hours under argon protection, with an argon flow rate of 5.0 L / min. After calcination, the powder was cooled to room temperature in the furnace to obtain a low-magnetic nickel oxide product.

[0036] In summary, this invention uses nickel chloride solution as raw material and, through pretreatment complexing agent regulation, spray pyrolysis atomization parameter optimization, and low-temperature ball milling dispersion, achieves low magnetic properties while ensuring uniform particle dispersion and no obvious agglomeration, thus preparing a low-magnetic, small-particle-size nickel oxide product. This solves the problems of high magnetic properties, large particle size, and severe agglomeration in the preparation of nickel oxide using nickel chloride solution as raw material in the prior art.

Claims

1. A production process for low-magnetic nickel suboxide, characterized in that, Includes the following steps: Nickel chloride solution pretreatment: Nickel chloride hexahydrate was pretreated to obtain a pretreated nickel chloride solution; Preparation of crude nickel oxide: The pretreated nickel chloride solution is pumped into the centrifugal atomizer of the spray pyrolysis device to form fine droplets. The droplets are carried into the pyrolysis furnace with compressed air. The pyrolysis furnace is set with three temperature zones. Crude nickel oxide is prepared by precise temperature control and gas volume regulation. Preparation of low-magnetic nickel oxide products: crude nickel suboxide is subjected to acid washing to remove impurities, low-temperature ball milling and low-temperature calcination at 300-400℃ to obtain low-magnetic nickel oxide products; The process of pretreating nickel chloride hexahydrate to obtain a nickel chloride solution includes: Nickel chloride hexahydrate was dissolved in deionized water to prepare an initial solution with a nickel chloride concentration of 0.5-2.0 mol / L. Add a complexing agent to the initial solution and stir until completely dissolved. Then, add dilute hydrochloric acid to adjust the pH of the solution to 3.0-4.

0. Stir at a constant temperature of 40-60℃ for 1-2 hours to obtain a pretreated nickel chloride solution. The pyrolysis furnace is equipped with three temperature zones. Crude nickel oxide is prepared through precise temperature control and gas flow regulation, including: First section - Drying zone: Temperature 200-250℃, residence time 10-15s, used for dehydration and drying of droplets to form solid particles; The second stage - pyrolysis zone: temperature 500-600℃, residence time 20-30s, to allow the dried nickel chloride particles to undergo a pyrolysis reaction; The third section is the reduction zone, with a temperature of 450-500℃. A reducing gas is introduced into this zone and the residence time is 15-20 seconds. On the one hand, the high-valence nickel oxide that may be generated in small amounts during pyrolysis is reduced to NiO, eliminating the ferromagnetism of the high-valence nickel oxide. On the other hand, the reducing atmosphere can promote the removal of residual chloride impurities in the form of HCl, reducing the chloride content in crude nickel oxide. The pyrolysis products were collected by a cyclone separator to obtain crude nickel oxide powder with a particle size range of 1-5 μm and a magnetic strength reduced to 8-12 emu / g.

2. The production process for low-magnetic nickel suboxide according to claim 1, characterized in that, The process of removing impurities from crude nickel suboxide through acid washing, low-temperature ball milling, and low-temperature calcination to obtain a low-magnetic nickel oxide product includes: Pickling to remove impurities: Add crude nickel oxide powder to a 0.1-0.5 mol / L dilute nitric acid solution, control the solid-liquid ratio, and pickle at 50-70℃ for 30-60 min. After pickling, separate the solid by vacuum filtration and wash repeatedly with deionized water until the pH of the filtrate is neutral. Then, vacuum dry at 80-100℃ for 2-4 h to obtain the pickled powder. Low-temperature ball milling: The acid-washed powder and grinding media are added to the ball mill together, the ball-to-material ratio is controlled, anhydrous ethanol is used as the dispersant, and the ball milling is carried out at a speed of 200-300 r / min for 4-8 hours; after the ball milling is completed, the grinding media is removed by centrifugation, and the dispersant is evaporated to dryness at 60-80℃ to obtain the ball-milled powder. Low-temperature calcination: The ball-milled powder is placed in a muffle furnace and calcined at a constant temperature of 300-400℃ for 2-3 hours under an inert atmosphere. After calcination, the powder is cooled to room temperature in the furnace to obtain a low-magnetic nickel oxide product.

3. The production process for low-magnetic nickel oxide according to claim 1, characterized in that, The complexing agent is either citric acid or disodium ethylenediaminetetraacetate; the molar ratio of the complexing agent to nickel ions is 0.1-0.3:

1.

4. The production process for low-magnetic nickel suboxide according to claim 1, characterized in that, The rotational speed of the centrifugal atomizer is 10000-15000 r / min; the flow rate of the compressed air is 5-10 L / min.

5. The production process for low-magnetic nickel suboxide according to claim 1, characterized in that, In the third section - reduction zone, the reducing gas is a mixture of hydrogen and nitrogen, wherein the hydrogen gas fraction is 5%-10%.

6. The production process for low-magnetic nickel oxide according to claim 2, characterized in that, In the acid washing and impurity removal process, the solid-liquid ratio is 1:10-1:20 g / mL; in the low-temperature ball milling process, the ball-to-material ratio is 10-20:1; in the low-temperature ball milling process, the solid-liquid ratio of the dispersant is 1:5-1:8; in the low-temperature calcination process, the inert atmosphere is nitrogen or argon, and the flow rate is 2-5 L / min.