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Title:
METHOD FOR THE REFINEMENT OF GOLD
Document Type and Number:
WIPO Patent Application WO2004081244
Kind Code:
A8
Abstract:
The invention relates to a method for refining gold containing metallic impurities. According to said method, the proportion of metal oxides is increased in a targeted manner by annealing the gold at preferably between 450 and 550 DEG C for between 1.5 to 2.5 hours. The gold is then treated with concentrated hydrochloric acid at a controlled redox potential, enabling a large part of the metal oxides and metals to dissolve immediately. In order to create identical reaction conditions, the gold used preferably has essentially the same particle size or gold concentration. Air can then be guided through the softened gold, in order to oxidise the previously formed monovalent copper chloride in a strong exothermic reaction. Said reaction is monitored by measuring the temperature and is optionally controlled as required. The gold is then post-treated with concentrated hydrochloric acid and a small amount of hydrogen peroxide at a controlled redox potential, and the purification effect can be controlled by the mixing ratio of said two substances. The refined gold is then washed with concentrated hydrochloric acid and deionised water and, according to requirement, is either further purified by a subsequent fine refinement method or is directly supplied elsewhere for a different use. The inventive method is especially suitable for the refinement of powdery, ground, small-particle, film-type or wire-shaped gold.

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Inventors:
HERRMANN SIGRID (DE)
LANDAU UWE (DE)
Application Number:
PCT/DE2004/000465
Publication Date:
November 11, 2004
Filing Date:
March 09, 2004
Export Citation:
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Assignee:
OTB OBERFLAECHENTECHNIK BERLIN (DE)
HERRMANN SIGRID (DE)
LANDAU UWE (DE)
International Classes:
C22B1/02; C22B3/00; C22B3/06; C22B3/10; C22B9/14; C22B11/00; C22B11/02; (IPC1-7): C22B11/06; C22B1/02; C22B3/10
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