Abstract: Provided is a method for producing high density nickel powder particularly having a median diameter of 100 to 160 ?m by controlling a particle size of nickel powder. The method includes: performing an initial operation by charging a pressure vessel equipped with a stirrer with a nickel ammine complex solution containing nickel in the concentration of 5 to 75 g/L together with seed crystals in the amount of 5 to 200 g per liter of the solution, increasing the temperature of the solution, and performing a reduction reaction with hydrogen by blowing hydrogen gas into the pressure vessel, thereby obtaining the nickel contained in the nickel ammine complex solution as nickel powder; and thereafter, performing a specified operation A repeatedly at least once to obtain the nickel powder having the median diameter of 100 to 160 ?m and a bulk density of 1 to 4.5 g/cm3.

Abstract: A method for producing nickel powder sequentially includes: a mixing step of adding, to a nickel ammine sulfate complex solution, an insoluble solid as seed crystals and a polyacrylate or lignosulfonate as a dispersant to form a mixed slurry; and a reduction and precipitation step of charging a reaction vessel with the mixed slurry and blowing hydrogen gas into the mixed slurry in the reaction vessel to reduce nickel complex ions in the mixed slurry to form nickel precipitate on the surface of the insoluble solid, wherein the amount of the dispersant added in the mixing step is controlled to control the number of the nickel powder obtained by formation of the nickel precipitate in the reduction and precipitation step.

Abstract: Provided a production method for reducing the content level of sulfur and carbon which are impurities in nickel powder to improve the quality of nickel powder produced by a complexing reduction method. The method of producing nickel powder having low carbon and sulfur concentrations includes: a complexing treatment of adding a complexing agent to a nickel sulfate aqueous solution to form a solution containing nickel complex ions; maintaining the solution containing nickel complex ions at a solution temperature of 150 to 250° C. in a pressure vessel and blowing hydrogen gas into the solution containing nickel complex ions to perform hydrogen reduction to produce nickel powder; washing the nickel powder with water; and then roasting the nickel powder washed with water in a mixed gas atmosphere of nitrogen and hydrogen.

Abstract: Provided is an efficient method for producing nickel powder from a solution containing a nickel ammine complex, the method including adding seed crystals to a solution containing a nickel ammine complex and subjecting the resulting mixture to hydrogen reduction under high temperatures and high pressures to produce nickel powder, which makes it possible to maintain the quality of the nickel powder produced and reduce the amount of the seed crystals used. The method for producing nickel powder is characterized by adding seed crystals and a dispersant having an anionic functional group to the solution containing a nickel ammine complex to form a mixture slurry, and subjecting the mixture slurry to pressurized hydrogen reduction treatment by blowing hydrogen into the mixture slurry in a high temperature and high pressure atmosphere to cause a reduction reaction, thereby reducing the nickel ammine complex in the mixture slurry to obtain nickel powder.

Abstract: Provided is nickel powder obtained by adding seed crystals to a nickel ammine complex solution and performing hydrogen reduction reaction under high temperatures and high pressures, wherein the nickel powder does not produce dust during handling, and a container can be efficiently filled with the nickel powder. The method for producing nickel powder includes: adding seed crystals and a surfactant having a nonionic or anionic functional group to a solution containing a nickel ammine complex to forma mixed slurry; and subjecting the mixed slurry to hydrogen reduction under high temperature and high pressure conditions in a pressure vessel to obtain nickel powder from the mixed slurry.

Abstract: Provided is a method for producing fine nickel powder used as suitable seed crystals for producing nickel powder from a solution containing a nickel ammine sulfate complex. The method for producing nickel powder sequentially comprises: a mixing step of adding, to a solution containing a nickel ammine sulfate complex, an insoluble solid which is insoluble in the solution to form a mixed slurry; a reduction and precipitation step of charging a reaction vessel with the mixed slurry and then blowing hydrogen gas into the mixed slurry in the reaction vessel to reduce nickel complex ions contained in the mixed slurry to form nickel precipitate on a surface of the insoluble solid; and a separation step of separating the nickel precipitate on the surface of the insoluble solid from the surface of the insoluble solid to form nickel powder.

Abstract: Provided is a method for producing high density nickel powder particularly having a median diameter of 100 to 160 ?m by controlling a particle size of nickel powder. The method includes: performing an initial operation by charging a pressure vessel equipped with a stirrer with a nickel ammine complex solution containing nickel in the concentration of 5 to 75 g/L together with seed crystals in the amount of 5 to 200 g per liter of the solution, increasing the temperature of the solution, and performing a reduction reaction with hydrogen by blowing hydrogen gas into the pressure vessel, thereby obtaining the nickel contained in the nickel ammine complex solution as nickel powder; and thereafter, performing a specified operation A repeatedly at least once to obtain the nickel powder having the median diameter of 100 to 160 ?m and a bulk density of 1 to 4.5 g/cm3.

Abstract: Provided is a method for manufacturing a nickel and cobalt mixed sulfide that is capable of stabilizing nickel and cobalt concentrations in the sulfidation end solution at low levels and of limiting decreases in nickel and cobalt recovery rates without increasing cost even when processing with a sulfuric acid acidic solution containing nickel and cobalt and a high iron ions concentration as the sulfidation start solution. This method generates a sulfidation reaction by blowing hydrogen sulfide gas into a sulfuric acid acidic solution comprising nickel and cobalt to obtain a mixed sulfide, wherein: the sulfuric acid acidic solution, which is the sulfidation start solution, contains iron ions at a rate of 1.0-4.0 g/L; and the sulfidation reaction is generated by blowing hydrogen sulfide gas into the sulfidation start solution and adding sodium hydrogensulfide (NaHS) obtained by absorbing hydrogen sulfide gas-containing exhaust gas, generated by the sulfidation, in an alkaline solution.

Abstract: Provided is a method for producing nickel powder from a nickel ammine sulfate complex solution, comprising treatment steps of: (1) a seed crystal production step of producing nickel powder having an average particle size of 0.1 to 5 ?m; (2) a seed crystal addition step of adding the nickel powder obtained in the step (1) as seed crystals to form a mixed slurry; (3) a reduction step of forming a reduced slurry containing nickel powder formed by precipitation of a nickel component in the mixed slurry on the seed crystals; and (4) a growth step of performing solid-liquid separation to separate and recover the nickel powder as a solid phase component and then blowing hydrogen gas into a solution prepared by adding the nickel ammine sulfate complex solution to the recovered nickel powder to grow the nickel powder to form high purity nickel powder.

Abstract: Provided is a method for producing fine nickel powder used as suitable seed crystals for producing nickel powder from a solution containing a nickel ammine sulfate complex. The method for producing nickel powder sequentially includes: a mixing step of adding, to a solution containing a nickel ammine sulfate complex, a dispersant containing a sulfonate and an insoluble solid which is insoluble in the solution to form a mixed slurry; a reduction and precipitation step of charging a reaction vessel with the mixed slurry and then blowing hydrogen gas into the mixed slurry in the reaction vessel to reduce nickel complex ions contained in the mixed slurry to form nickel precipitate on a surface of the insoluble solid; and a separation step of separating the nickel precipitate on the surface of the insoluble solid from the surface of the insoluble solid to form nickel powder.

Abstract: Provided is a method for manufacturing a nickel and cobalt mixed sulfide that is capable of stabilizing nickel and cobalt concentrations in the sulfidation end solution at low levels and of limiting decreases in nickel and cobalt recovery rates without increasing cost even when processing with a sulfuric acid acidic solution containing nickel and cobalt and a high iron ions concentration as the sulfidation start solution. This method generates a sulfidation reaction by blowing hydrogen sulfide gas into a sulfuric acid acidic solution comprising nickel and cobalt to obtain a mixed sulfide, wherein: the sulfuric acid acidic solution, which is the sulfidation start solution, contains iron ions at a rate of 1.0-4.0 g/L; and the sulfidation reaction is generated by blowing hydrogen sulfide gas into the sulfidation start solution and adding sodium hydrogensulfide (NaHS) obtained by absorbing hydrogen sulfide gas-containing exhaust gas, generated by the sulfidation, in an alkaline solution.

Abstract: A method for producing nickel powder sequentially includes: a mixing step of adding, to a nickel ammine sulfate complex solution, an insoluble solid as seed crystals and a polyacrylate or lignosulfonate as a dispersant to form a mixed slurry; and a reduction and precipitation step of charging a reaction vessel with the mixed slurry and blowing hydrogen gas into the mixed slurry in the reaction vessel to reduce nickel complex ions in the mixed slurry to form nickel precipitate on the surface of the insoluble solid, wherein the amount of the dispersant added in the mixing step is controlled to control the number of the nickel powder obtained by formation of the nickel precipitate in the reduction and precipitation step.

Abstract: Provided are a method for producing nickel seed crystals that maintains and improves the quality of nickel powder at a low cost while suppressing production cost and environmental load in the production of nickel powder, by optimizing the amount of hydrazine added when producing fine nickel powder as seed crystals using hydrazine; and a method for producing nickel powder using the nickel seed crystals. The method for producing seed crystals used for producing hydrogen-reduced nickel powder, including adding, to an acid solution containing nickel ions that is maintained at a temperature of 50 to 60° C., hydrazine of 1 to 1.25 mol per 1 mol of a nickel component contained in the acid solution to produce the seed crystals.

Abstract: Provided is nickel powder obtained by adding seed crystals to a nickel ammine complex solution and performing hydrogen reduction reaction under high temperatures and high pressures, wherein the nickel powder does not produce dust during handling, and a container can be efficiently filled with the nickel powder. The method for producing nickel powder includes: adding seed crystals and a surfactant having a nonionic or anionic functional group to a solution containing a nickel ammine complex to forma mixed slurry; and subjecting the mixed slurry to hydrogen reduction under high temperature and high pressure conditions in a pressure vessel to obtain nickel powder from the mixed slurry.

Abstract: Provided a production method for reducing the content level of sulfur and carbon which are impurities in nickel powder to improve the quality of nickel powder produced by a complexing reduction method. The method of producing nickel powder having low carbon and sulfur concentrations includes: a complexing treatment of adding a complexing agent to a nickel sulfate aqueous solution to form a solution containing nickel complex ions; maintaining the solution containing nickel complex ions at a solution temperature of 150 to 250° C. in a pressure vessel and blowing hydrogen gas into the solution containing nickel complex ions to perform hydrogen reduction to produce nickel powder; washing the nickel powder with water; and then roasting the nickel powder washed with water in a mixed gas atmosphere of nitrogen and hydrogen.

Abstract: Provided is an efficient method for producing nickel powder from a solution containing a nickel ammine complex, the method including adding seed crystals to a solution containing a nickel ammine complex and subjecting the resulting mixture to hydrogen reduction under high temperatures and high pressures to produce nickel powder, which makes it possible to maintain the quality of the nickel powder produced and reduce the amount of the seed crystals used. The method for producing nickel powder is characterized by adding seed crystals and a dispersant having an anionic functional group to the solution containing a nickel ammine complex to form a mixture slurry, and subjecting the mixture slurry to pressurized hydrogen reduction treatment by blowing hydrogen into the mixture slurry in a high temperature and high pressure atmosphere to cause a reduction reaction, thereby reducing the nickel ammine complex in the mixture slurry to obtain nickel powder.

Abstract: Provided is a method for producing nickel powder from a nickel ammine sulfate complex solution, comprising treatment steps of: (1) a seed crystal production step of producing nickel powder having an average particle size of 0.1 to 5 ?m; (2) a seed crystal addition step of adding the nickel powder obtained in the step (1) as seed crystals to form a mixed slurry; (3) a reduction step of forming a reduced slurry containing nickel powder formed by precipitation of a nickel component in the mixed slurry on the seed crystals; and (4) a growth step of performing solid-liquid separation to separate and recover the nickel powder as a solid phase component and then blowing hydrogen gas into a solution prepared by adding the nickel ammine sulfate complex solution to the recovered nickel powder to grow the nickel powder to form high purity nickel powder.

Abstract: Provided are a method for producing nickel seed crystals that maintains and improves the quality of nickel powder at a low cost while suppressing production cost and environmental load in the production of nickel powder, by optimizing the amount of hydrazine added when producing fine nickel powder as seed crystals using hydrazine; and a method for producing nickel powder using the nickel seed crystals. The method for producing seed crystals used for producing hydrogen-reduced nickel powder, including adding, to an acid solution containing nickel ions that is maintained at a temperature of 50 to 60° C., hydrazine of 1 to 1.25 mol per 1 mol of a nickel component contained in the acid solution to produce the seed crystals.

Abstract: Provided is a method for producing fine nickel powder used as suitable seed crystals for producing nickel powder from a solution containing a nickel ammine sulfate complex. The method for producing nickel powder sequentially comprises: a mixing step of adding, to a solution containing a nickel ammine sulfate complex, an insoluble solid which is insoluble in the solution to form a mixed slurry; a reduction and precipitation step of charging a reaction vessel with the mixed slurry and then blowing hydrogen gas into the mixed slurry in the reaction vessel to reduce nickel complex ions contained in the mixed slurry to form nickel precipitate on a surface of the insoluble solid; and a separation step of separating the nickel precipitate on the surface of the insoluble solid from the surface of the insoluble solid to form nickel powder.

Abstract: Provided is a method for producing fine nickel powder used as suitable seed crystals for producing nickel powder from a solution containing a nickel ammine sulfate complex. The method for producing nickel powder sequentially includes: a mixing step of adding, to a solution containing a nickel ammine sulfate complex, a dispersant containing a sulfonate and an insoluble solid which is insoluble in the solution to form a mixed slurry; a reduction and precipitation step of charging a reaction vessel with the mixed slurry and then blowing hydrogen gas into the mixed slurry in the reaction vessel to reduce nickel complex ions contained in the mixed slurry to form nickel precipitate on a surface of the insoluble solid; and a separation step of separating the nickel precipitate on the surface of the insoluble solid from the surface of the insoluble solid to form nickel powder.