摘要 |
In the alkaline digestion of silica- contaminated paper pulp raw material, an addition of a hydrated aluminum oxide, e.g. bauxite, is made to the liquor, to insolubilize silica as a sodalite precipitate, and thereby minimize scaling during evaporation, avoid undesirable increase in the viscosity of the liquor, as well as assuring recovery of lime by avoiding formation of calcium silicate during causticizing. |