The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 01, 1987
Filed:
Dec. 02, 1986
Froystein Dyvik, Odda, SE;
Thomas K Mioen, Stockholm, SE;
Boliden Aktiebolag, Stockholm, SE;
Abstract
The present invention relates to a method for manufacturing zinc hydrometallurgically from zinc-containing starting materials. The method comprises one or more leaching stages, one or more solution purifying stages and one or more electrowinning stages for recovering metallic zinc from the leaching solution obtained. The method is operating with a closed solution circuit. A predetermined part volume of the solution obtained in the electrowinning stage or stages is withdrawn and concentrated by evaporation so as to precipitate any magnesium and manganese present in the part volume in the form of metal salt crystals. The precipitated crystal mass is separated from the residual liquid phase. The liquid phase in this manner purified with respect to magnesium and manganese can be recycled to the leaching process or utilized for some other purpose. When the process is carried out in a sulphate environment, the solution obtained in the electrowinning stage or stages is concentrated to a sulphuric acid concentration of at least 60% by weight. The precipitated crystal mass, which has but a small volume, may be dumped to no disadvantage. In accordance with a preferred embodiment, the crystal mass is re-dissolved in a small quantity of water, thereby enabling practically all the zinc content to be recovered in metallic form, by electrowinning.