Title:
METHOD FOR DETOXIFYING CYANIDE GOLD SOLUTION IN GOLD REFINING, AND METHOD AND APPARATUS FOR RECOVERING GOLD
Document Type and Number:
Japanese Patent JP2021001384
Kind Code:
A
Abstract:
To solve the problem in which: in the conventional cyanide process of gold refining, cyan is not completely decomposed and waste liquid treatment is incomplete and environmentally problematic; and the gold recovery process also includes a method of adding zinc powder for replacement and a method of adding activated carbon or ion exchange resin and recovering by adsorption, but the equipment is complicated and there is a lot of loss.SOLUTION: The current gold cyanide solution is concentrated using an NF membrane, and is placed in a pressure vessel, and raw steam is blown into it and is allowed to retain at 180°C for a certain period of time in order to cause a thermal hydrolysis reaction where free cyan and copper, zinc, iron, and other metal cyano complexes are decomposed. The metal precipitates as an oxide. The gold-silver cyano complex does not decompose at this temperature. The treatment liquid flowing out from the first stage is heated to 210°C or higher in the pressure vessel of the second stage to completely decompose the cyano complex of noble metals such as gold and silver, and the noble metal is precipitated as metal powder of elementary substance. Cyanide-decomposing agents are unnecessary and cyan is completely detoxified. The noble metal recovery yield is also almost 100%. Waste heat is recovered by a heat exchanger.SELECTED DRAWING: Figure 2
More Like This:
Inventors:
OONISHI AKITOSHI
Application Number:
JP2019127212A
Publication Date:
January 07, 2021
Filing Date:
June 20, 2019
Export Citation:
Assignee:
AQUATECH CO LTD
International Classes:
C22B11/08; B01D61/02; C02F1/02; C22B3/22