Provided is a nickel powder manufacturing method capable of efficiently manufacturing a high-quality nickel powder using as little ammonium gas or ammonium water as possible. The nickel powder manufacturing method according to the present invention is characterized by comprising: a first step for generating a post-neutralization slurry including nickel hydroxide by mixing a nickel sulfate aqueous solution and a neutralizing agent; a second step for causing a complex-forming reaction by mixing an ammonium sulfate aqueous solution with the post-neutralization slurry and obtaining a post-complexation slurry including a nickel ammine complex aqueous solution; and a reducing step for obtaining a nickel powder and a post-reduction solution by contacting hydrogen gas with the nickel ammine complex aqueous solution. Further, it is preferable that a post-complexation solution obtained in the reduction step be repeatedly used as the ammonium sulfate aqueous solution to be added to the post-neutralization slurry.

Provided is a method for manufacturing coarse particles of a so-called high-purity nickel powder with a small amount of impurities, particularly having a low sulfur grade, from a nickel sulfate amine complex solution using a fine nickel powder. A method for manufacturing a nickel powder includes the following treatment steps (1) to (6) in a process for manufacturing a nickel powder from a nickel sulfate solution: (1) a hydroxylation step; (2) a complexation step; (3) a reduction step; (4) a solid/liquid separation step; (5) a nickel recovery step of repeatedly supplying the recovered nickel powder to step (2) and/or step (3), sulfurating the recovered final reduction solution, and then solid/liquid separating the sulfurated solution to generate nickel sulfide and a nickel post-reduction solution; and (6) a nickel regeneration step of oxidatively leaching the nickel sulfide obtained in step (5) and repeatedly supplying the obtained nickel sulfate solution to step (1).

Provided is a method for manufacturing coarse particles of a so-called high-purity nickel powder with a small amount of impurities, particularly having a low sulfur grade, from a nickel sulfate amine complex solution using a fine nickel powder. A method for manufacturing a nickel powder includes the following treatment steps (1) to (6) in a process for manufacturing a nickel powder from a nickel sulfate solution: (1) a hydroxylation step; (2) a complexation step; (3) a reduction step; (4) a solid/liquid separation step; (5) a nickel recovery step of repeatedly supplying the recovered nickel powder to step (2) and/or step (3), sulfurating the recovered final reduction solution, and then solid/liquid separating the sulfurated solution to generate nickel sulfide and a nickel post-reduction solution; and (6) a nickel regeneration step of oxidatively leaching the nickel sulfide obtained in step (5) and repeatedly supplying the obtained nickel sulfate solution to step (1).

Provided is a production method for maintaining the quality while keeping a high operating rate of the reaction by continuously feeding a solution, seed crystals, and hydrogen gas into a reactor to produce nickel powder, and continuously discharging the resulting powder. The method for producing nickel powder comprises feeding a nickel ammine sulfate complex solution and seed crystals into a reactor, and feeding hydrogen gas into the reactor to subject a nickel complex ion in the nickel ammine sulfate complex solution to a reduction treatment and to thereby produce nickel powder, wherein, in the reduction treatment, while the nickel ammine sulfate complex solution is being continuously fed into the reactor, a temperature inside the reactor is controlled within the range of 150 to 185 C. and the feed rate of hydrogen gas is controlled to maintain an inner pressure of the reactor in the range of 2.5 to 3.5 MPa.

Provided is a production method for maintaining the quality while keeping a high operating rate of the reaction by continuously feeding a solution, seed crystals, and hydrogen gas into a reactor to produce nickel powder, and continuously discharging the resulting powder. The method for producing nickel powder comprises feeding a nickel ammine sulfate complex solution and seed crystals into a reactor, and feeding hydrogen gas into the reactor to subject a nickel complex ion in the nickel ammine sulfate complex solution to a reduction treatment and to thereby produce nickel powder, wherein, in the reduction treatment, while the nickel ammine sulfate complex solution is being continuously fed into the reactor, a temperature inside the reactor is controlled within the range of 150 to 185 C. and the feed rate of hydrogen gas is controlled to maintain an inner pressure of the reactor in the range of 2.5 to 3.5 MPa.

Provided is a production method for maintaining the quality while keeping a high operating rate of the reaction by continuously feeding a solution, seed crystals, and hydrogen gas into a reactor to produce nickel powder, and continuously discharging the resulting powder. The method for producing nickel powder comprises feeding a nickel ammine sulfate complex solution and seed crystals into a reactor, and feeding hydrogen gas into the reactor to subject a nickel complex ion in the nickel ammine sulfate complex solution to a reduction treatment and to thereby produce nickel powder, wherein, in the reduction treatment, while the nickel ammine sulfate complex solution is being continuously fed into the reactor, a temperature inside the reactor is controlled within the range of 150 to 185 C. and the feed rate of hydrogen gas is controlled to maintain an inner pressure of the reactor in the range of 2.5 to 3.5 MPa.

A method is disclosed of forming magnetically tunable photonic crystals comprising: synthesizing one or more precursory nanoparticles with anisotropic shapes; coating the one or more anisotropic precursory nanoparticles with silica to form composite structures; converting the one or more anisotropic precursory nanoparticles into magnetic nanomaterials through chemical reactions; and assembling the anisotropic magnetic nanoparticles into photonic crystals in a solvent.

A method is disclosed of forming magnetically tunable photonic crystals comprising: synthesizing one or more precursory nanoparticles with anisotropic shapes; coating the one or more anisotropic precursory nanoparticles with silica to form composite structures; converting the one or more anisotropic precursory nanoparticles into magnetic nanomaterials through chemical reactions; and assembling the anisotropic magnetic nanoparticles into photonic crystals in a solvent.

The invention relates to the production of highly dispersed metal-containing powders and can be used to produce powders of iron and its compounds from technogenic waste of groundwater treatment plants, also known as sediments or sludge of wash water filters of iron removal plants. The method for producing highly dispersed iron-containing powders from technogenic waste of groundwater treatment plants consists of the following successive stages: dispersion of wash water sludge by treatment that ensures an equivalent particle diameter of not more than 100 microns for at least 90% of particles of the total number of particles. dehydration of wash water sludge from groundwater treatment plants to a relative humidity of not more than 90%; loading or in-line feeding of wash water sludge from groundwater treatment plants to a reaction chamber or reactor; reduction of iron compounds contained in wash water sludge from groundwater treatment plants in a reaction chamber or reactor in a gaseous environment having a reduction potential and consisting of at least 95% of a mixture of carbon monoxide and carbon dioxide and at 300 to 900 degrees Celsius; separation of particles of the target product iron compounds having ferromagnetic properties from the components of the raw mixture obtained in the reduction reaction; cooling to 90 degrees Celsius or less to reduce the chemical activity of the obtained iron-containing powders in order to prevent premature oxidation due to exposure to oxidizing agents, including atmospheric oxygen.

The technical result of the invention is obtaining a technology which will be enable production of finely dispersed and nanodispersed iron-containing powders from the waste of groundwater treatment plants, with an iron content (by mass) of at least 40% of the total mass of the obtained iron-containing powder on a dry basis, having an equivalent particle diameter of not more than 100 microns for at least 90% of particles of the total number of particles. 2 tables, 2 figures.

The invention relates to the production of highly dispersed metal-containing powders and can be used to produce powders of iron and its compounds from technogenic waste of groundwater treatment plants, also known as sediments or sludge of wash water filters of iron removal plants. The method for producing highly dispersed iron-containing powders from technogenic waste of groundwater treatment plants consists of the following successive stages: dispersion of wash water sludge by treatment that ensures an equivalent particle diameter of not more than 100 microns for at least 90% of particles of the total number of particles. dehydration of wash water sludge from groundwater treatment plants to a relative humidity of not more than 90%; loading or in-line feeding of wash water sludge from groundwater treatment plants to a reaction chamber or reactor; reduction of iron compounds contained in wash water sludge from groundwater treatment plants in a reaction chamber or reactor in a gaseous environment having a reduction potential and consisting of at least 95% of a mixture of carbon monoxide and carbon dioxide and at 300 to 900 degrees Celsius; separation of particles of the target product iron compounds having ferromagnetic properties from the components of the raw mixture obtained in the reduction reaction; cooling to 90 degrees Celsius or less to reduce the chemical activity of the obtained iron-containing powders in order to prevent premature oxidation due to exposure to oxidizing agents, including atmospheric oxygen.

The technical result of the invention is obtaining a technology which will be enable production of finely dispersed and nanodispersed iron-containing powders from the waste of groundwater treatment plants, with an iron content (by mass) of at least 40% of the total mass of the obtained iron-containing powder on a dry basis, having an equivalent particle diameter of not more than 100 microns for at least 90% of particles of the total number of particles. 2 tables, 2 figures.