Method for extracting gold from electronic waste

Abstract

The invention discloses a method for extracting gold from electronic waste. The method comprises the following steps that S01, nitric acid or mixed acid of nitric acid and sulfuric acid is used for treatment; s02, filtering is carried out; s03, the gold content of the gold-containing filter residues is estimated, pure silver, pure zinc and the gold-containing filter residues are mixed, the mass ratio of the pure silver to the gold content is 2.5: 1 or above, the mass ratio of the pure zinc to the pure silver is 1: 2.5-1: 2, borax is added, and a mixture A is obtained; s04, heating the mixture A to a molten state to form an alloy; s05, stopping heating, cooling step by step, and taking out the alloy; and S06, the alloy is put into 10-20% nitric acid, the nitric acid is heated to be slightly boiled till impurity metal except gold is completely dissolved, and the gold powder is obtained. The problems that in the prior art, when the gold element is extracted from the electronic waste, harm to the environment is large, and safety is poor are solved. Or the problems of great environmental harm, strict requirements on equipment and poor purification effect exist; or the problems of great environmental harm, poor safety and strict requirements on equipment exist.

Description

technical field [0001] The invention relates to a method for extracting gold from electronic waste, belonging to the technical field of gold extraction. Background technique [0002] Electronic waste is currently growing rapidly and is a global problem. Since electronic waste contains gold, the extraction of gold has high economic value. [0003] Existing methods for extracting gold from electronic waste mainly include the following: [0004] 1) Chemical extraction method: [0005] The main representatives of the chemical extraction method are the cyanide method and the aqua regia method. The main idea for the extraction of gold is to oxidize and dissolve the gold by chemical means first, and then use a reducing agent to reduce the gold. [0006] Due to the special chemical properties of gold element, oxidation and dissolution have always been a widespread problem. Most of the current methods of use have adverse effects on the environment, causing secondary pollution or br...

AI Technical Summary

Problems solved by technology

For the gold in the ore, the amalgamation method can be enriched, but for the gold in the electronic waste, it has been fully enriched after pretreatment, and the application of the amalgamation method cannot fully integrate and remove impurities.

[0014] c. Mercury has poor affinity to form amalgams with metals such as iron, copper, lead, and zinc. When extracting gold-containing wastes with various metal impurities such as electronic waste, it cannot fully form amalgam alloys with impurity metals. , Mercury is still a large amount of impurity metals in gold, the separation effect is poor, and it is difficult to obtain gold with higher purity in the later stage of purification.

[0015] To sum up, most of the chemical extraction methods and physical extraction methods have the problems of great environmental hazards and poor safety; the aqua regia method also has strict requirements on equipment, is not easy to scale, and has an effect on the extraction and purification of gold elements from electronic waste. Bad problem; there are hidden dangers of toxic substances in the amalgamation method, and the effect of extracting and purifying gold elements from electronic waste is not good.

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