Dowa Mining Co., Ltd.

Kaoru Saruta

Yoshiyuki Watanabe

Toyohisa Fujita

Hitoshi Masuda

Norihito Ishimori

Manabu Kanno

Akira Narumi

A method of leaching zinc from a zinc concentrate comprising leaching a zinc concentrate in an aqueous solution containing free sulfuric acid and ferric ions, whereby elemental sulfur is deposited on the zinc concentrate, and grinding the zinc concentrate under atmospheric pressure in the aqueous solution to provide particles of the zinc concentrate having surfaces, wherein the elemental sulfur and other by-products which form on the surfaces of the particles of the zinc concentrate are stripped by the grinding.

Method for leaching zinc concentrate

A sulfurous compound such as a sulfur-rich &ldquo;float&rdquo; (concentrate) obtained by flotation of the residue from the leaching of a zinc concentrate is heated at a temperature not lower than the melting point of sulfur but below its boiling point, preferably not higher than 200&deg; C., more preferably not higher than 140&deg; C., and the evolving gas containing sulfur vapor is cooled at a temperature less than the melting point of sulfur, preferably at ordinary temperature, to condense sulfur.

Method of recovering sulfur from minerals and other sulfur-containing compounds

A method for directly leaching a zinc concentrate in one of the stages contained in the hydrometallurgical process for the production of electrolytic zinc. The method comprises: a neutral leach step, a zinc concentrate leach step, and an iron oxidation step. In the zinc concentrate leach step, a neutral leach residue and an iron sediment returned from the iron oxidation step are repulped by the spent electrolyte followed by adding thereto zinc concentrate to extract zinc from the zinc concentrate by carrying out a leaching under atmospheric pressure and at a temperature of not lower than 90&deg; C., but not higher than the boiling point of the solution. According to this method, the concentration of Fe(III) ions in the zinc concentrate leach solution is significantly increased. Due to this Fe(III) ion concentration, the leaching rate of the zinc concentrate is enhanced.

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Gojome-cho, Japan

Kaoru Saruta