Process for the concentration of dilute sulfuric acid solutions

Abstract From the Canadian patent

Abstract of the Disclosure, The invention relates to a process for the concentration of metal salt-containing dilute sulfuric acid solutions. The solution is first preconcentrated by indirect heating and evaporation to a concentration at which no substantial amounts of the salts are precipitated under the reaction conditions, then the preconcentrate is reconcentrated by mixing it with a sufficient amount of hot highly con-, centrated sulfuric acid to produce evaporation of water from the solution, and the salts which precipitate are then removed. In this way a concentrated, and to some extent purified, sulfuric acid solution is obtained without the usual difficulties of metal salt …