Dissolution of the socket for analysis using nitric acid and hydrofluoric acid. Separation of tin, in the form of sulphide, first from wolfram, operating in a sulfuric-tartaric solution, then from copper by transforming the sulphides into thiosals and filtering the copper sulphide. Acidification of the thiosal solution, filtration of the thioanhydrides and treatment of these with hydrochloric acid and potassium chlorate. Complexation of tin with oxalic acid, to keep it in solution, and precipitation of antimony and metals with similar behavior with hydrogen sulphide. After filtration of the sulphides, decomposition of the tin oxalic complex by evaporation to white fumes of sulfur dioxide. Precipitation of tin in the presence of ferric salt and subsequent dissolution of the filtered hydroxides in hydrochloric acid. Reduction of tin present with lead and titration of sanoc chloride with titrated iodine solution. Reactive. Equipment. Method. Expression of results.
UNI 6880-1971 history
1971UNI 6880-1971 Chemical analysis of ferroalloys. Determination of tin in ferro-tungsten. Volumetric method.