Treatment of spent pickle liquors by electrodialysis

Abstract

The disposal of spent liquors from the pickling of iron by an electrodialytic process is described, sulphuric acid of a concentration suitable for re‐use and metallic iron being recovered. The power cost of the treatment is a function of the current efficiency and the voltage across the cell. Current efficiencies for various concentrations of recovered acid are experimentally obtained and shown to apply to all pickle liquor compositions. Experiments on one synthetic pickle liquor have established a basis for calculating the cell voltage. It is then possible to deduce the quantitative effect on the power cost of the treatment, of operating procedure, electrode‐membrane distances, the iron content of the treated liquor, the proportion of iron in the spent pickle liquor and the total concentration of the spent liquor.

pH Changes at Anion Selective Membranes under Realistic Flow Conditions

“…For flowing systems it is also desirable to provide information on flow distribution so that one can ascertain that the noted effects are not seriously complicated by stagnant regions within the compartment. The value of F-diagrams (30,31) in this respect does not appear to have been appreciated.…”