Patent GB-238543-A (GB)
Title: Improved process for converting hafnium and zirconium phosphates into other hafnium and zirconium compounds
IPC: C01G25/00
Filed: 1925-08-08
Abstract: Hafnium and zirconium phosphates which may be obtained from the ores by treatment with sulphuric and phosphoric acids are separated from the mother liquor, which contains compounds of the other metals, and dissolved in alkali with the addition of certain organic compounds containing a plurality of alcohol or alcohol and carboxyl groups, complex compounds being produced.  The organic compounds used are those which contain an alcoholic hydroxyl group attached to one carbon atom and an alcoholic hydroxyl or a carboxyl group attached to an adjacent carbon atom.  Thus suitable compounds are glycerine, glucose, cane sugar, pyrocatechin, pyrogallol, lactic and tartaric acids, and divalent alcohols having adjacent alcohol groups, whereas compounds such as hydroquinone and phloroglucin, which contain alcohol groups attached to carbon atoms which are not adjacent, are not suitable. From the solution thus obtained, the hafnium and zirconium may be precipitated in various ways, the solution being first purified from iron if necessary by means of sulphuretted hydrogen.  The phosphoric acid may be removed from the alkaline solution by precipitation with barium chloride, whereupon zirconium hydroxide may be precipitated by carefully neutralizing.  Hafnium and zirconium compounds free from phosphoric acid may be precipitated by alcohol from a solution of the phosphates in glycerine and alkali.ALSO:Hafnium and zirconium phosphates which may be obtained from the ores by treatment with sulphuric and phosphoric acids are separated from the mother-liquor, which contains compounds of the other metals, and dissolved in alkali with the addition of hydrogen peroxide or certain organic compounds containing a plurality of alcohol or alcohol and carboxyl groups, complex compounds being produced.  The organic compounds used are those which contain an alcohol group attached to one carbon atom and an alcohol or carboxyl group attached to an adjacent carbon atom. Thus suitable compounds are glycerine, glucose, cane sugar, pyrocatechin, pyrogallol, lactic and tartaric acids, and divalent alcohols having adjacent alcohol groups, whereas compounds such as hydroquinone and phloroglucin, which contain alcohol groups attached to carbon atoms which are not adjacent, are not suitable.  From the solution thus obtained, the hafnium and zirconium may be precipitated by hydroferrocyanic acid.ALSO:Hafnium and zirconium phosphates which may be obtained from the ores by treatment with sulphuric and phosphoric acids are separated from the mother-liquor which contains compounds of the other metals, and dissolved in alkali with the addition of hydrogen peroxide or certain organic compounds containing a plurality of alcohol or alcohol and carboxyl groups, complex compounds being produced.  The organic compounds used are those which contain an alcoholic hydroxyl group attached to one carbon atom and an alcoholic hydroxyl or a carboxyl group attached to an adjacent carbon atom. Thus suitable compounds are glycerine, glucose, cane-sugar pyrocatechin, pyrogallol, lactic and tartaric acids, and divalent alcohols having adjacent alcohol groups, whereas compounds such as hydroquinone and phloroglucin, which contain alcohol groups attached to carbon atoms which are not adjacent, are not suitable.  From the solution thus obtained, the hafnium and zirconium may be precipitated in various ways, the solution being first purified from iron if necessary by means of sulphuretted hydrogen.  The phosphoric acid may be removed from the alkaline solution by precipitation with barium chloride, whereupon zirconium hydroxide may be precipitated by carefully neutralizing; or after adding some acid to the alkaline liquor free from phosphoric acid, the organic substance may be destroyed by oxidation for instance by potassium persulphate and the hafnium and zirconium precipitated by a base; or the alkaline liquor free from phosphoric acid may be evaporated to dryness and the organic compounds thus decomposed; or a small quantity of acid may be added to the solution free from phosphoric acid and the peroxides of hafnium and zirconium precipitated by hydrogen peroxide; or the hafnium and zirconium may be precipitated by chromic acid, hydroferrocyanic acid, or ammonium oxalate; or the original alkaline solution, without removal of the phosphoric acid, may be treated with acid until it is slightly alkaline to phenolphthalein, when the oxides are precipitated; or hafnium and zirconium compounds free from phosphoric acid may be precipitated by alcohol from a solution of the phosphates in glycerine and alkali; or oxides of hafnium and zirconium may be precipitated by heating the solution of the hafnium and zirconium phosphates in hydrogen peroxide and alkali.