PROCESS TO REGENERATE KRAFT LIQUOR

摘要

This is a process for regenerating white liquor from residual kraft liquors. The process comprises reacting at least one metal oxide member selected from ferric oxide and/or titanium dioxide with a sodium carbonate product derived from a residual kraft black liquor under vigourous oxidation condition that is near but below the eutectic temperature of the derived product and of the selected member, to form particles comprising a mixture of sodium sulfate and of at least one sodium member of the class consisting of sodium ferrite and sodium titanate, reducing the particles in solid phase by converting the sodium sulfate in the particles to sodium sulfide in the presence of a reducing gas. The reduced particles are then dissolved in an aqueous medium to form a white liquor, and to convert the sodium member into sodium hydroxide soluble in the white liquor and into an insoluble metal oxide of the selected member. The insoluble metal oxide is separated leaving the white liquor composed of dissolved sodium sulfide and sodium hydroxide in an aqueous solution.