What are the methods of palladium carbon refining? How to purify palladium?

Palladium carbon recovery purification with palladium chemical refining method mainly has sulfuric acid leaching method, nitric acid palladium fractionation method, king water palladium method, oxalic acid reduction method, electric potential control method, automatic catalytic reduction refining method, chlorine ammonia purification method, palladium carbon recovery refining process, extraction method, etc.

Sulfuric acid leaching method This method is applicable to the refining of gold-silver alloy palladium containing not more than 33% gold, less than 10% copper and not more than 0.25% lead. In the high temperature with concentrated sulfuric acid for boiling, so that the alloy of palladium and copper and other base metals to generate sulfate and be removed, in order to achieve the purpose of purification of palladium. The consumption of concentrated sulfuric acid in this method is very large, about 3 to 5 times the mass of the alloyed gold.

When the leaching, first the alloy gold melting and water quenching into granular or cast (or pressed) into a thin sheet, placed in a cast iron pot, adding concentrated sulfuric acid in several times, in 160 ~ 180 ℃ stirring leaching 4 ~ 6h or more long. During the leaching, impurities such as palladium and copper are converted into sulfate. After the completion of the leaching, cooling, pouring into the village lead tank, heating water 2 ~ 3 times diluted and filtered. Palladium carbon and wash with hot water to remove silver, copper and other sulfates. Palladium carbon recovery and then add new concentrated sulfuric acid for heating leaching, by repeated leaching and washing 3 ~ ~ 4 times, the final output of palladium powder by washing and drying, the grade of gold can reach more than 95%, dried and melted with a melting agent, the output of gold color can reach 99.6% ~ 99.8%, leaching sulfate solution and washing solution, after replacing silver with copper (such as palladium in the alloy, the dissolved palladium is also reduced together with silver), palladium carbon Recovery and then replace the copper with iron, the remaining liquid by evaporation and concentration to remove impurities after the recovery of crude sulfuric acid.