漂白廃液の回収とその影響 ＩＩＩ 漂白廃液の回収に伴う薬品回収工程への影響

Abstract

Some effects associated with recovery of bleachery effluent to chemical recovery process were investigated. In oxidation process, little effect was observed on oxidation of sodium sulfide and methyl mercaptan by pH decrease of black liquor. But sulfide oxidation was slightly accelerated by some organics in bleachery effluent at low concentration of sodium sulfide. In evaporation process, the release of hydrogen sulfide was affected by the mixing of bleachery effluent, but release of methyl mercaptan was independent. Slight increase of black liquor viscosity during evaporation and precipitation from black liquor were observed by recovery of bleachery effluent. These changes depended on pH decrease or organics contained in bleachery effluent. But swelling volume of black liquor changed little. From these results, it seemed to be feasible to recover the neutralized bleachery effluent with alkali to chemical recovery process.