Sumitomo Metal Mining Company, Ltd.

Atsushi Idegami

Ryozo Ushio

Keisuke Shibayama

Hirofumi Shoji

Hiroshi Kobayashi

Yuji Aoki

Yoshitomo Ozaki

Satoshi Asano

Osamu Nakai

Hiroyuki Mitsui

Tatsuya Higaki

Hideki Ohara

Shin-ichi Heguri

Masatoshi Takano

Shinichi Heguri

Kenji Takeda

Noriyuki Nagase

Hirotaka Kawasaki

Keiji Kudou

Shinya Matsumoto

Shin-Ichi Heguri

Provided is a method of producing high-purity nickel sulfate by an impurity-element removal method for selectively removing Mg from a Ni-containing solution. The method comprises a production process of producing nickel sulfate from a Ni-containing acid solution, the acid solution being treated in order of steps (1) to (3): (1) carbonation step, adding a carbonating agent into the Ni-containing solution to make Ni contained in the Ni-containing solution into a precipitate of nickel carbonate or a mixture of nickel carbonate and nickel hydroxide, thereby forming a slurry after carbonation including the precipitate and a solution after carbonation; (2) solid-liquid separation step, separating the slurry after carbonation formed in the carbonation step into the precipitate and the solution after carbonation; and (3) neutralization step, adding a neutralizing agent into the solution after carbonation separated through the solid-liquid separation step to recover Ni contained in the solution after carbonation as a Ni-precipitate.

Method for producing high-purity nickel sulfate

A method for recovering chromite from ore slurry obtained by processing nickel oxide ore, the raw material, in a plant for the wet smelting of nickel oxide ore. In the method chromite is separated and recovered from an ore slurry obtained from a nickel oxide ore when nickel and cobalt are recovered from the nickel oxide ore. The method has a grain diameter separation step for separating the ore slurry on the basis of a predetermined classification point according to the difference in the grain diameter of particles contained in the supplied ore slurry and a sedimentation separation step for causing the oversized ore slurry separated in the grain diameter separation step to undergo sedimentation and concentration on the basis of a target classification point, and recovering the chromite. The coarse particle content of the oversized ore slurry separated in the grain diameter separation step is adjusted to 30-50%.

Method for recovering chromite, and method for wet smelting of nickel oxide ore

Disclosed herein is a method for concentrating gold contained in a leach residue obtained in a copper hydrometallurgical process for recovering copper from a copper sulfide mineral to efficiently separate and recover gold from the leach residue: a gold-bearing copper sulfide mineral is subjected to pressure leaching with sulfuric acid at a temperature higher than 102&#xb0; C. and 112&#xb0; C. or lower to obtain a leach residue, and the leach residue is subjected to flotation to separate it into a float fraction and a sink fraction; the float fraction obtained by flotation is desulfurized to obtain a desulfurized product; the desulfurized product is subjected to oxidative roasting to obtain an oxidatively-roasted product; the oxidatively-roasted product is dissolved in a sulfuric acid solution to obtain a copper solution, and a gold-bearing residue is separated and recovered from the copper solution.

Method for concentration of gold in copper sulfide minerals

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Niihama, Japan

Atsushi Idegami