Abstract: A method of increasing the extraction of tellurium from copper electrorefining slime comprises leaching the slime with dilute sulphuric acid in a reactor under a partial oxygen pressure of up to 150 psi and at an elevated temperature between about 100.degree. and 200.degree. C. until copper, nickel and substantially all of the tellurium is dissolved, thereby forming a leach slurry, and contacting the slurry with an appropriate reducing agent immediately after the leaching operation has been halted and the leaching reactor brough back to atmospheric pressure to reprecipitate any excessive quantities of silver and selenium solubilized during the leaching operation.

Abstract: A continuous silver refining cell comprises a tank containing an electrolyte, at least one vertical cathode disk mounted on a rotating horizontal shaft placed above the tank so that slightly less than half of the disk is immersed in the electrolyte, at least one anode basket containing impure silver anodes immersed in the electrolyte adjacent the cathode disk, and a diaphragm separating the cathode disk from the anode basket to form cathode and anode compartments. A scraper is provided for continuously removing pure silver crystals from the cathode and directing it to the side of the cell. A chain tubular conveyor may be provided for continuously or semi-continuously withdrawing a mud containing gold and other precious metals from the bottom of the cell.

Abstract: A method is provided for removing arsenic from arsenic and copper containing electrolytes by electrolysis while minimizing or substantially reducing the formation of arsine gas, through the application of a periodically reversed or interrupted current during such electrolysis. The method is particularly suitable for the purification of copper refinery electrolyte.

Abstract: A method for the oxidation of organic material present in concentrated sulfuric acid is disclosed. The method comprises the steps of diverting a portion of a concentrated sulfuric acid stream, diluting the diverted stream with water to about 40-70% sulfuric acid concentration, passing the diluted stream through an electrolysis apparatus to oxidize some of the sulfuric acid to form a predetermined quantity of peroxosulfuric acids, and returning the diverted stream back to the main stream to oxidize the organic material and decolorize the main stream of concentrated sulfuric acid.

Abstract: A method is provided for removing arsenic from arsenic and copper containing electrolytes by electrolysis while minimizing the formation of arsine gas, through the application of a periodic reverse current during such electrolysis. The method is particularly suitable for the purification of copper refinery electrolyte.

Abstract: An auxiliary electrode for direct introduction into a static-or fluidized bed main electrode comprises a conductive base material selected from the group consisting of lead or lead alloys, and a non conductive screen material preferably made of a synthetic, organic fiber screen cloth partially embedded into the conductive base material so as to insulate the auxiliary electrode from the static-or fluidized-bed main electrode.

Abstract: A fluidized bed electrode system comprises an electrode chamber having a porous base, a main electrode consisting of a bed of fine solid particles contained in such chamber and selected from the group consisting of metals, metal coated glass beads and metal coated plastic beads, a current feeder extending into the bed, means for leading air or inert gas through the porous base at a predetermined velocity and pressure to fluidize the bed, and means for introducing a solution to be treated into the electrode chamber at a point above the porous base and for circulating such solution through the bed at a predetermined flow rate.