Patent ID: 7273599

Claim:
A method for decoloring concentrated sulfuric acid containing organic matter comprising the steps of: a) feeding the concentrated sulfuric acid containing organic matter to a reactor and heating it at a temperature of from 40° C. to 60° C.; b) adding potassium chlorate at a proportion of from 10 to 50 g per acid ton; c) stirring the sulfuric acid mixed with potassium chlorate in order to favour the dissolution of the potassium chlorate; d) adding hydrogen peroxide at a 50% concentration at a proportion of from 25 to 80 ml per acid ton; e) stirring the acid containing potassium chlorate and hydrogen peroxide in order to favour a dispersion of the hydrogen peroxide; f) settling the acid during sufficient time until the acid obtains a redox potential of 700 mV and a color index of less than 30 APHA unities.