Recovery Of Sulphuric Acid Research Articles

Recovery of sulphuric acid from waste aqueous solutions containing arsenic by ion exchange

Laboratory scale experiments with anion and cation exchange resins aiming to separate arsenic from highly acidic, sulphate-containing solutions were carried out. The data obtained proved that the use of strong acid cation exchangers in the Na form gives the opportunity for arsenic/acid separation in two stages. During the period of sulphuric acid accumulation (a period in which the resin is converted from Na form to its H form), the residual sulphuric acid concentration within 3 BV is below 0.1 g/l. The arsenic concentration in the effluent remains unchanged. The acid obtained, during the period of sulphuric acid recovery by stripping with Na 2SO 4 has a higher concentration than the initial concentration in the waste acidic solution. The recovered acid has levels of As, Cu, Pb and Fe low enough to be used in the sulphuric acid production industry. As a net result, the implementation of the strong acid ion-exchange method leads to two streams: (1) low acidity water in which all the arsenic is concentrated; (2) sulphuric acid free of arsenic.

Extraction of sulphuric acid from technological solution of hydroxylamine sulphate

The extraction of sulphuric acid from solutions containing hydroxylamine sulphate and ammonium sulphate with Cyanex 923 and the acid stripping from loaded Cyanex 923 are studied at 20 and 50°C. The effect of the numbers of extraction and stripping stages and the volume phase ratios in extraction and stripping upon sulphuric acid recovery is discussed. The process can be design to obtain a high or low recovery of sulphuric acid but with its low or high concentration, respectively.

Sulfuric acid concentration with an electro-electrodialysis process

Commercial anion-exchange membranes exhibit a strong proton leakage which makes them unsuitable for use in the recovery of sulphuric acid from sulphate containing solutions resulting from some hydrometallurgy processes. Experiments are reported which compare membrane permeabilities under electro-electrodialysis conditions. With most commercial membranes, the permeability to sulphate ions decreases rapidly when the acid concentration increases in the anolyte. The highest sulphuric acid concentration is obtained with a prototype membrane which will be shortly produced on an industrial scale.