Wastewater Recycling Process Silver Cyanide Rinse

Electroplating industry, one of three polluting industries in the world, has the characteristic of high energy consumption, large amount of sewage (waste) and heavy toxicity pollutant, and silver plated is one of the important electroplating. Cyanide silver plating rinse wastewater contains a certain amount of cyanide and precious metals-silver, if it direct emissions not only caused resources waste but also cause serious environmental problems, what wore is the price of silver growing, we must deal with the wastewater to recovery the silver. The traditional recycling silver method is common in high energy consumption, easy to cause secondary pollution, poor effect to the low content of silver recovery, so in this paper, we mainly used the methods of membrane enrichment-ionization to recycling silver form wastewater. Wastewater rinsed by NF and RO, and then electrolytic the enrichment liquid to recovery silver. In this paper, we study the effect of total feed flow water and the shade ratio to the silver recovery, and make a simple discussion on the electrolysis of silver precipitation. The mainly conclusions are following:1) Wastewater pretreated in layered filter, with combination of carbon filter-microfiltration-ultrafiltration technology, the SDI is less than4, meet the requirements of reverse osmosis.2) After the experiment, we learn that the best operating conditions for NF is that inflow for16L·min-1and outlet shades proportion4:2.2, and RO inflow is8L·min-1, outlet flow for shading ratio of5:3.3) Along with the increase of inlet flow rate, concentrated multiple and concentration, and shading percentage of decrease in produced water, the work pressure of NF and RO increases, and it has greater impact on silver intercept rate.4) The best conditions in sing the electrolysis to recovery silver:polar distance is3cm, current is0.15A, temperature is57.5℃, pH is10, and electrolytic promoter is11.7g, the silver recovery rate can reach98.1%, the crude silver purity is93.43%.5) Do the industrial design based on the experiment, and evaluate the process technology and economic. And this technology has good prospects for application. If invested, it will make good economic and environmental benefits.Experiments show that it has a good effect in recycling treatment cyanide silver plating wastewater using the method of membrane-electrolysis, and the best conditions and conclusion obtained can provide reference for industrial application below.