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:
May. 19, 1987
Filed:
Jan. 14, 1986
Josef Bertha, Brixlegg, AT;
Austria Metall Aktiengesellschaft, Vienna, AT;
Abstract
A hydrometallurgical process for recovering pure silver from sludge formed at the anode in copper electrolysis and other sources comprises suspending the sludge, after removing Pb, Ni, and Cu, in hydrochloric acid, subsequently adding an alkali metal hypochlorite, preferably NaOCl, to the resulting suspension to convert the silver present to AgCl, filtering to separate the AgCl containing solid residue from the filtrate containing the other metallic elements, and finally working up the AgCl containing residue to obtain high purity silver. Preferably the high purity silver is obtained from the AgCl containing residue by leaching with an alkaline ammoniacal solution to dissolve the silver as the soluble silver diamine chloride, and subsequently reducing the silver diamine chloride to silver metal. The reducing agent for the silver diamine chloride is preferably either a Cu.sup.+ containing compound such as CuCl or a metal powder such as copper or bronze powder.