Improvements in or relating to the Treatment of Sulphide Ores or Metal-bearing Solutions and the Production of Ammonia or Ammonium Salts or other Nitrogenous Compounds.

摘要

25,506. Ashcroft, E. A. Nov. 15. Distilling zinc. - A suitable quantity of a cyanamide such as calcium cyanamide is stirred into a solution of zinc chloride, and the mixture is treated with steam under pressure at 150- 300‹ C., ammonia being evolved. The zinc oxide, after removal of calcium chloride, is suitable for smelting in an electric furnace, and contains graphitic carbon and perhaps lime which are useful for the smelting. Or a very strong zinc chloride solution may be used so that the mixture with calcium cyanamide is a stiff paste which is heated in an oven or furnace to 200-500‹ C. and finally to 600‹ C. Steam, which may be superheated, may be admitted during the heating. Or the zinc chloride solution is treated with a cyanide such as sodium or barium cyanide, which may be very impure. The residues obtained on heating calcium cyanamide with water and steam under pressure in the usual way for the production of ammonia may also be added to the zincchloride solutions and need not therefore be first washed to recover their contained ammonia. In an example, calcium cyanamide is stirred with water, any calcium carbide being thereby decomposed, and the undissolved residue separated by decantation. All or a part of the solution or residue can be added to the zincchloride solution in suitable proportions so as to obtain more or less carbon in the zinc oxide as the smelting process may require.