A PROCESS FOR THE CONVERSION OF SOLUBLE THIOSULFATE IN AN EFFLUENT LIQUOR TO SULFATES

摘要

, Soluble thiosulphates present in aqueous redox systems comprising at least one salt Or an anthraquinone di-sulphonic acid and at least one water soluble compound of metal having at least two stable oxidation states, for example a vanadate, are converted to sulphates by introducing oleum or sulphuric acid into the lower f of a vessel containing said thiosulphate containing redox solution wherein the sulphuric acid has a concentration of from 10 - 98% w/w H2SO4 and the amount of said sulphuric acid to such that the gram molecular weight ratio of sulphuric acid to thiosulphate is from 1:2 to 1:3, and thereafter separating the sulphate formed for example by using a solubility lowering technique. The process is carried out at ambient temperature and at a temperature of from 70.degree.C up to the boiling temperature of the acidic mixture.