METHOD FOR PRECIPITATION OF SULPHONATED LIGNIN FROM SULFITE LIQUORS

摘要

There is provided a method for the precipitation of lignin sulphonates from sulfite liquors by the use of polyimines with a low polarity as polycations whereby there is separated an alkali-soluble precipitation complex and the polyimine can be recovered by extraction with organic solvents. The novel method provides the advantage that the sulfite liquor can be used as it is discharged from the boiler without further treatment such as thickening.