Gold wet purification process

Abstract

The invention relates to a process for purifying gold by the wet method. Firstly, aqua fortis is used to remove silver; secondly, nitric acid is used to remove impurities such as bismuth and copper, etc.; the separation is performed by filtering; in the richly contained gold solution, the gold is reduced to gold powder deposited by an oxalic acid reducing agent with strong reducibility, and the impurities such as platinum, the bismuth and the copper, which are reduced simultaneously, are redissolved by nitric acid added later and enter the solution, and the solution is subjected to the filtering separation to obtain pure gold powder; and the pure gold powder is made to be ingot-shaped by fushion casting, and the finished gold ingots with a gold content of 99.99 percent are obtained. In theinvention, the reduction reaction is made by oxalic acid at a low temperature, so that the process of the invention has the advantages of not causing environmental pollution, favorability for the heath of operators, lowering cost, shortening the period and obvious economic and social benefits.

Description

technical field [0001] The invention relates to the purification of precious metals, in particular to a gold wet purification process. Background technique [0002] As a precious metal, gold is difficult to mine, high in mining cost, and has good physical properties. It is characterized by a high melting point of 1064.43 degrees Celsius. Gold is not easy to melt and has a high density of 19.31 grams per cubic centimeter (at 18°C). , good toughness and ductility, good conductivity. China's gold production jumped to a record high of 276 tonnes last year, up 12 percent from 2006, while South Africa produced 272 tonnes. From 2000 to 2007, the price of gold rose from about US$270 per ounce to over US$850. In 2008, it hit a record high of US$1033.9 per ounce, but the global gold mining volume fell by 6.7%. And it is imperative to increase the added value of gold. [0003] At present, the following methods are usually used to deal with gold and silver-containing materials: [0...

AI Technical Summary

Problems solved by technology

Since the method is in a boiling state during the third leaching, in order to maintain a certain solid solution ratio, the hydrochloric acid solution of 1:1 is continuously added dropwise, the high-temperature acid mist will pollute the environment greatly, the loss of hydrochloric acid is large, and the production cost is high; And the reduction with oxalic acid is still a heating operation

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