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flj�t�ti c.�,vv\-O—o,,vL-f Y <br /> OPERATING INSTRUCTIONS FOR ELECTROLYTIC SILVER RECOVERY <br /> TREATMENT UNITS <br /> A. How to Operate an Electrolytic Silver Recovery Treatment Unit <br /> 1. Principle of Operation <br /> An electrolytic silver recovery unit operates by using the principles of electrolysis. A <br /> low DC voltage of about .5 volts is applied between a cathode and several anodes and <br /> silver is "plated out" from silver bearing fixer and other solutions onto the cathode. <br /> An electrolytic silver recovery unit iss-a relatively supple device that typically converts <br /> incoming high voltage of 120 VAC to a very low DC voltage of about .5 volts and to <br /> a high DC current between 2 and 35 amps. There are two electrodes in an electrolytic <br /> cell, an anode and cathode. The low DC voltage and DC current flow through the <br /> electrolyte from the positive anode to the negative cathode. The electrolyte solution <br /> (silver-bearing used fixer)usually is a mild acid solution consisting of many chemical <br /> complexes. This discussion will only address the most significant reaction, that of <br /> silver and thiosulfate. The silver in used fixer carries a positive charge, and thiosulfate <br /> is attracted to the negative charged cathode, and the negative charged thiosulfates are <br /> attracted to positive charges anodes. The silver will plate on the cathode, and <br /> thiosulfates will react at the anode(s) and the sulfites are consumed. A rule of thumb: <br /> for every gram of silver plated on a cathode, a gram of sulfite is consumed. When too <br /> much sulfite is consumed, free sulfur ions are formed, commonly referred to as <br /> "sulfiding". <br /> 2. Common Characteristics of all Electrolytic Units <br /> a. Anodes (+) <br /> b. Cathodes (-) <br /> e <br /> �c aec <br /> c. Agitation TRANS <br /> RzCnTM <br /> d. Current Control <br /> ANaoe(+) .tee(+). <br /> i.� rim SOLMOM cam(-1 <br /> �! .Z ei.;z'ranirn) <br />