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Title:
METHOD FOR THE FINE REFINEMENT OF GOLD
Document Type and Number:
WIPO Patent Application WO2004081245
Kind Code:
A8
Abstract:
The invention relates to a method for the fine refinement of gold containing metallic impurities, According to said method, the gold to be refined is first dissolved in hydrochloric acid and hydrogen peroxide. The dissolution of the gold is controlled by separate dosing of said substances and/or by means of the mixture ratio thereof, enabling gold having an increasingly high purity to be obtained by successive dosing. The depletion of the impurities can be controlled by targeted heat supply and/or by influencing the heat rejection. The dissolved gold is then precipitated by stirring a sodium bisulfate solution into the hydrochloric acid gold solution, the precipitation of the gold being stimulated by avoiding an excess of sodium bisulfite solution. The precipitation is monitored by measuring the redox potential and is controlled by adapted dosing of the sodium bisulfite solution. The precipitated gold is then filtered again, washed and dried and provided for another use. The dissolution of the gold creates waste gas containing chlorine and a small proportion of metallic impurities. Said impurities are washed out of the waste gas in a washing device and are recovered from the used wash solution, while the chlorine is depleted from the waste gas by reaction with powdery gold in a corresponding filter device. The inventive method is especially suitable for refining powdery, ground, small-particle, film-type or wire-shaped gold.

Inventors:
HERRMANN SIGRID (DE)
LANDAU UWE (DE)
Application Number:
DE2004000466W
Publication Date:
November 11, 2004
Filing Date:
March 09, 2004
Export Citation:
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Assignee:
OTB OBERFLAECHENTECHNIK IN BERLIN GMBH & CO.
HERRMANN, SIGRID
LANDAU, UWE
International Classes:
C22B3/00; C22B3/10; C22B3/44; C22B7/00; C22B9/02; C22B11/00; (IPC1-7): C22B11/06; C22B3/10; C22B7/00; C22B9/02
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