Abstract: A process for purifying and refining platinum group metals such as platinum, iridium, palladium, rhodium and the like by an electrochemical process using ammonium chloride as the electrolyte to form ammonium chloride platinum group salts as a "slime" followed by the use of ammonia hydroxide to dissolve and separate said salts from other materials in the slime. A further step to precipitate the platinum metals from the ammonia hydroxide may be employed.

Abstract: A novel gold purification method is provided which comprises electrolyzing gold into a novel pregnant electrolyte, segregating the dissolved gold ions from the cathode by a semipermeable barrier, separating insoluble impurities from the gold-containing liquidus, and then selectively reducing the gold to metallic form from the liquidus by a selective chemical reducing agent. The electrolyte is impregnated with a catalyst for leveling the overvoltage of gold and preferably contains a peroxide or a nascent oxygen source. A unitary apparatus for the method is provided.