Continuously decomposing waste bleaching liquor

摘要

A method for continuously decomposing bleaching liquor (BL) involves: (i) intensively and continuously mixing technical NaOH or KOH BL, contg. active chlorine at a concn. of 100-150 g/l, with a stoichiometric excess of 10-30 wt.% sulphuric or hydrochloric acid, at 25-60 deg C and 1-1.2 bars; (ii) passing the mixt., of pH 1 or less, at 25-60 deg C through a steady state column; and (iii) recovering chlorine from the head of the column and aq. salt soln. from the sump.