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F&S Compact system for silver recovery and cyanide decontamination

11.11.2013

F&S Compact system for silver recovery and cyanide decontamination using UV/H2O2

The F&S Compact system efficiently recovers metal and decontaminates silver cyanide, as well as its rinsing baths, within a very compact space

In the first step of the process, the silver content is reduced to ~100 mg/litre by the high-performance electrolytic recovery cell. The system electronically monitors the pH, temperature, exhaust air stream and each individual anode and regulates them if necessary. If, for example, the pH falls, caustic solution is added fully automatically to maintain the highest possible power yields. Initial oxidation of the cyanide takes place as an anodic reaction during the cathodic deposition of the silver. Once electrolytic depletion has reach the required metal content, the solution then passes via a column with recyclable ion exchange resins in the bypass line and is further reduced to zero mg of silver per litre. Electrolytic depletion down to the lowest concentrations, which is often used and makes little sense in energy terms, thus becomes redundant. This solution, now virtually free of silver, undergoes the final decontamination process. Free cyanide, followed by complex bound cyanide, is safely and cost-effectively decontaminated using the state-of-the-art UV/H2O2 method. The batch is neutralised following final analytical testing. Any metal hydroxides are retained by means of bag filters and the clear phase can be legally discharged into the sewage system. All values are generally well below the limit values.
The recovered silver, either in the form of cathodically deposited metal or ion exchange resins saturated with silver, can be sold as recycled materials!