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Method for precipitating gold from cyanogen-containing gold-plated waste liquid

A technology of precipitating gold and waste liquid, which is applied in the field of precipitating gold, can solve the problems of complex treatment process, high reaction temperature, incomplete gold adsorption of waste liquid, etc., achieve the effects of reducing environmental pollution, simple treatment process, and improving resource utilization

Inactive Publication Date: 2013-03-20
DALIAN DONGTAI INDAL WASTE TREATMENT
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The Zn powder replacement method has high reaction temperature and complex treatment process. It has poor effect when used in cyanide-containing gold plating waste liquid, and the gold precipitation rate is low. In addition, new chemical substances are produced during the precipitation process, which increases the burden of wastewater treatment.
Activated carbon adsorption method active regeneration is difficult, waste liquid gold adsorption is not complete

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] Add cyanogen content to 1000ml beaker and be 108.0mg / L, the gold content is 5.449mg / L cyanogen-containing electroplating waste liquid 400ml, dropwise add the NaOH that mass concentration is 10% to adjust pH to 12, dropwise add mass concentration is 11% NaClO adjusted the oxidation-reduction potential (ORP) to 350mv, and carried out the first step of oxidation, and the reaction time was 30min; the mass concentration of 10% H 2 SO 4 Adjust the pH to 7.5, add NaClO dropwise to adjust the ORP to 650mv, carry out the second oxidation step, and the reaction time is 30min. The cyanide in the waste liquid was detected by silver nitrate titration method, and the cyanide in the waste liquid was less than 1mg / L.

[0019] Add 82.0 g of a pre-prepared aqueous solution of 40% sodium dimethyldithiocarbamate to the waste liquid after the cyanide has been destroyed at room temperature, stir for 30 minutes, and filter. Gold ions in the filtrate were detected by atomic absorption spectr...

Embodiment 2

[0021] Replace sodium dimethyl dithiocarbamate with sodium diethyldithiocarbamate, and other conditions for destroying cyanide and gold precipitation are completely the same as in Example 1. Gold ions were detected in the filtrate, but no gold ions were detected. Add NaClO solution to the filtrate to adjust the ORP to 50mv, filter, and discharge the filtrate up to the standard.

Embodiment 3

[0023] Replace its 40% solution with 32.8g sodium dimethyl dithiocarbamate solid to join in the waste liquid after the cyanide is destroyed, and other operating methods are completely with embodiment 1. Gold ions were detected in the filtrate, but no gold ions were detected. Add NaClO solution to the filtrate to adjust the ORP to 50mv, filter, and discharge the filtrate up to the standard.

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PUM

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Abstract

The invention provides a method for precipitating gold from a cyanogen-containing gold-plated waste liquid. The method comprises the following steps of: (1) adding the cyanogen-containing gold-plated waste liquid containing 1-500mg / L gold ions into a container, adjusting the pH to 12 with 10wt% NaOH, adding NaClO to adjust the redox potential to 350mv, and reacting for 30 minutes; adding 10wt% H2SO4 to adjust the pH to 7.5, adding NaClO to adjust the redox potential to 650mv, and reacting for 30 minutes so that the cyanogen concentration in the waste liquid is damaged to less than 1mg / L; and (2) adding a gold precipitator into the cyanogen-containing gold-plated waste liquid with damaged cyanogen, stirring for reaction and filtering. The method provided by the invention can be used for protecting environment, precipitating gold and improving the utilization rate of resources.

Description

technical field [0001] The invention belongs to the technical field of chemical engineering, and in particular relates to a method for precipitating gold from cyanide-containing gold plating waste liquid. Background technique [0002] Gold plating is required in the production process of Printed Circuit Board (referred to as PCB). Cyanide electroplating has not been widely used because of its good quality, high corrosion resistance, stable plating solution, and wide operating temperature range. Cyanide plating is completely replaced. The discharge of the cyano group (CN-) in the cyanide electroplating waste liquid into the environment will cause serious pollution, and the waste liquid usually contains 10-300mg / L gold, and the direct discharge into the environment will cause a waste of resources. [0003] In order to comprehensively utilize cyanide-containing gold-plating waste liquid resources, the current general enrichment and precipitation technologies mainly include: Zn...

Claims

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Application Information

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IPC IPC(8): C22B11/00C22B7/00
CPCY02P10/20
Inventor 殷国元高麒麟李俊马振彦官香元刘晶张秋玲崔明玉姚晓琳刘佳丽
Owner DALIAN DONGTAI INDAL WASTE TREATMENT
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