METHOD FOR RECYCLING SULFUR DIOXIDE FROM SULFITE PULPING LIQUORS

摘要

Combined acidification and evaporative concentration of sulfite based chemical and sulfite based semichemical spent liquors expel massive amounts of gaseous sulfur dioxide and water vapor from the spent liquor. The concentration of the expelled sulfur dioxide is sufficiently high so that the sulfur dioxide and water vapor can be recycled directly, without further separation, to produce fresh sulfite pulping liquor.