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Preparation method of sodium gold sulfide solution for cyanide-free gold plating

A gold sodium sulfite and cyanide-free gold plating technology, which is applied in chemical instruments and methods, inorganic chemistry, gold compounds, etc., can solve the problems of low conversion rate, low gold utilization rate, and low impurity content, and achieve stable separation, The effect of high utilization rate and high conversion rate

Active Publication Date: 2017-05-10
GUANGDONG GUANGHUA SCI TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The Chinese invention patent application with the application number 200910227579.4 discloses a preparation method of sodium gold sulfite complex for cyanide-free gold plating. Precipitate - the product obtained by drying and pulverizing the precipitate", because this method does not carry out solid-liquid separation after alkali neutralization, the product contains a large amount of chloride, resulting in low purity of the product. In addition, alkali neutralization is to remove Au 3+ Precipitation is in the form of gold hydroxide, and gold hydroxide is unstable, easily dehydrated and converted into gold oxide, and then decomposed into elemental gold, resulting in low utilization rate of gold
[0004] The Chinese invention patent application with the application number 201510942820.7 discloses a method for preparing a cyanide-free gold plating reagent, sodium gold sulfite. Solid-liquid separation-cleaning-complexation reaction-concentrated crystallization", although the above method has solid-liquid separation after alkalization, the precipitation of gold hydroxide obtained after alkali neutralization has poor stability and is not easy to wash and separate. For products with low content, the process is complicated, and the conversion rate of gold hydroxide and sodium sulfite complexed into sodium gold sulfite is not high, which will cause low utilization rate of precious metal gold

Method used

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  • Preparation method of sodium gold sulfide solution for cyanide-free gold plating

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Effect test

Embodiment 1

[0022] (1) Cut 8.2g of gold (containing 99.99% gold), slowly put it into a flask with an acid tail gas absorption device, add 50g of newly prepared aqua regia, slowly heat to 60°C under stirring, and keep warm until the gold is completely dissolved;

[0023] (2) Connect the decompression device, control the vacuum degree to be lower than -0.08Mpa, turn on the water bath for heating, control the above solution within 90°C and concentrate it under reduced pressure. When the distillation speed is slow, add 16g of hydrochloric acid in 3 times, Until no reddish-brown gas of nitrogen oxides is produced, continue to concentrate until the gold concentration in the solution is detected to be 48%, stop heating, cool to room temperature, and separate out chloroauric acid crystals;

[0024] (3) Add 24g of pure water to the chloroauric acid crystals to dissolve, adjust the gold concentration to 20%, add 54.7g of 30% sodium thiosulfate solution under stirring conditions, and stir at room tem...

Embodiment 2

[0029] (1) Cut 8.3g of gold (containing 99.99% gold), slowly put it into a flask with an acid tail gas absorption device, add 50g of newly prepared aqua regia, slowly heat to 55°C under stirring, and keep warm until the gold is completely dissolved;

[0030] (2) Connect the decompression device, control the vacuum degree to be lower than -0.08Mpa, turn on the water bath for heating, control the above solution to be concentrated under reduced pressure within 90°C, and when the distillation speed is slow, add 20g of hydrochloric acid in 4 times, Until no reddish-brown gas of nitrogen oxides is produced, continue to concentrate until the concentration of gold in the solution is detected to be 45%, stop heating, cool to room temperature, and separate out chloroauric acid crystals;

[0031] (3) Add 25g of pure water to the chloroauric acid crystals to dissolve, adjust the gold concentration to 20%, add 55g of 30% sodium thiosulfate solution under stirring conditions, stir and react ...

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Abstract

The invention provides a preparation method of a sodium gold sulfide solution for cyanide-free gold plating. The method comprises the following steps: firstly, dissolving and nitrating elemental gold by aqua regia to obtain a chlorate gold solution; secondly, adding sodium thiosulfate in the chlorate gold solution and reacting to generate a sodium gold thiosulfate; thirdly, adding ethanol and separating out sodium gold thiosulfate precipitation; fourthly, adding a sodium sulfide solution for complexing; and finally, carrying out filtering by using activated carbon to remove sulfur, thus obtaining the sodium gold sulfide solution. The preparation method provided by the invention is simple in process and convenient to operate; the yield of the sodium gold thiosulfate generated by reacting gold chlorate with the sodium thiosulfate is high, and the loss is less; in addition, the sodium gold thiosulfate is stable and is easy to separate; the complexing conversion rate of the sodium gold thiosulfate and the sodium sulfide is high, so that a product obtained by the method provided by the invention is high in purity; and in addition, the utilization rate of precious metal gold is also high, and the prepared sodium gold sulfide solution is more stable.

Description

technical field [0001] The present invention relates to a kind of preparation method of water-soluble gold salt, relate in particular to a kind of preparation method of water-soluble gold salt for cyanide-free gold plating, more specifically relate to a kind of preparation method of sodium gold sulfite solution for cyanide-free gold plating. Background technique [0002] At present, there are two types of gold plating processes commonly used at home and abroad: cyanide gold plating process and cyanide-free gold plating process. Due to the high stability of cyanide solutions and wide application conditions, the cyanide gold plating process has been widely used for a long time. However, due to the presence of highly toxic cyanide in the plating solution, it will seriously pollute the environment and cause great harm to the human body. It has a bad effect on the resist, so it is gradually eliminated. Although the National Development and Reform Commission issued a notice in 20...

Claims

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Application Information

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IPC IPC(8): C25D3/48C01G7/00
CPCC01G7/006C25D3/48
Inventor 谭泽黄永润肖定军何为王翀陶志华
Owner GUANGDONG GUANGHUA SCI TECH
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