MANUFACTURING PROCESS FOR SODIUM SULFITE AND AMMONIUM SULFITE OR MAGMESIUM SULFITE

摘要

Process for mfg. aq. solns. of the sulphate or hydrogen sulphites of Na, NH4 or Mg, starting from CaSO3 or Ca(H3O3)2, and a soln. of the corresp. base, e.g. NaCl, NH4Cl, or MgCl2. Specifically a multi-chamber electrodialysis cell is used contg. alternate anion- and cation- selective membranes, and in which the reaction occurs by electrochemical ion exchange, the by-product being a calcium salt soln, the solns. flowing through the individual chambers in the following sequence; soln. of the base; by-product soln.; the soln. of CaSO3 or Ca(HSO3)2; and the end product, viz. a soln. of the sulphite or hydrogen sulphite of the base. Inexpensive raw materials or waste products can be employed, e.g. NaCl.