| 摘要 |
<p>1371302 Removal of ZnCl2 from solutions SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ BV 11 May 1973 22532/73 Heading C1A ZnCl2 is removed from solutions containing Zn <++>, Cl- and SO4 = (Zn<++> : Clratio more than 0À5) by liquid-liquid extraction with an organic solvent containing a tetrahydrocarbyl ammonium thiocyanate, the extract, which may first be washed with water, being then regenerated by contact with ammonia solution giving the solvent which may be re-used and an aqueous solution. This aqueous solution which contains tetra-ammine zinc chloride may be boiled down in the presence of ammonia chloride to precipitate di-ammine zinc chloride. This may be decomposed by heat to give ZnCl2 and NH3. The tetrahydrocarbyl ammonium thiocyanate, which may have one methyl and three alkyl groups containing 8 to 10 C atoms, may be 0À3- 0À6 M in the organic solvent. Toluene is exemplified and other solvents are listed. The starting solution may be an aqueous zinc sulphate solution containing chloride ions for use in the electrolytic preparation of zine or a solution obtained by dissolving zinc waste containing Cl from fluxes in H2SO4 and the raffinate is then a chloride-free aqueous solution of zinc sulphate. The term tetrahydrocarbyl ammonium thiocyanate is defined as tetrahydrocarbyl aminonium thiocyanate whose hydrocarbyl groups may or may not be substituted.</p> |
