From the hydrochloric solution of the sample, after precipitation of the sulphates with barium chloride, reduction of the arsenic with ferrous chloride and of the iron with sodium hypophosphite, lead, copper and zinc are precipitated simultaneously as sulphides by means of hydrogen sulphide in the presence of a little oxalic acid. The sulfides obtained are dissolved in nitric acid and the lead is separated from the solution in the form of lead sulphate by treatment with sulfuric acid. In the filtrate the copper is precipitated again in the form of sulphide and after redissolving the precipitate it is determined electrolytically. Finally, in the solution from which the copper sulphide has been separated, zinc is precipitated in a formic environment, in the form of sulphide and, after calcination, it is determined as an oxide. Solutions and reagents. Proceedings. Calculations.
UNI 3869-1957 history
1957UNI 3869-1957 Procedures for chemical analysis of minerals. Determination of the lead, copper and zinc content of iron minerals. Gravimetric method.