DITIONAL AND NATRIUM BOUR HYDRID REDUCTION PREPARATION

摘要

Method of reducing an aq. suspension of wool paste at pH 4.5-7 or a clay paste at pH 2.8-4.5 using Zn acid sulphites of Zn and/or Na is claimed. The acid sulphite ion is converted into ionic by prods. contg. S and the paste is sepd. from the by prods. Specifically, Na borohydride is added to the material to convert the by-products into ionic species contg. S which induce a more powerful reaction. S-contg. cpds. are recovered from bleaching soln. the effluent from which would otherwise prevent a danger of pollution.