FREMGANGSMAADE TIL FREMSTILLING AF ET TITANGARVNINGSMIDDEL OG ANVENDELSE DERAF VED GARVNING AF LAEDER

Method for preparation of a titanium tanning agent from titanium-iron-sulphate solutions, in which one introduces into said solution an oxidation agent consisting of a sulphuric acid solution of a peroxytitanium complex, followed by adding of ammonium sulphate and sulphuric acid for precipitation of a double salt of titanyl and ammonium sulphate in the monohydrate form (NH4)2TiO(SO4)2.H2O. The precipitation of this salt occurs preferably prior to the formation thereof in a quantity of 75 to 85 per cent, based on TiO2. The resulting salt is separated and washed; the filtrate and the washing water are combined and treated with ammonium sulphate for further precipitation of the salt, which is separated and recirculated back to the starting solution. The salt prepared in this way is used for tanning of hides, which are pretreated with a tanning promoter: sodium salt of disulphodinaphthylmethane or phthalic acid anhydride, aluminium alum or a mixture of aluminium alum and urotropine, ammonium titanyl sulphate or phenol oligomers dispersed in lignosulphonic acids. The tanning of decalcified or decalcified and pickled or decalcified, pickled and chrome-tanned hides is done with use of the titanium tanning agent in presence of lactic acid, aluminium alum or the condensation product of synthetic fatty acids and triethanolamine. The invention is valuable within the leather industry.