Continuous leaching of lignin or hemicellulose and lignin from steam pretreated lignocellosic particulate material

Abstract From the Canadian patent

This invention relates to a novel method of continuously leaching ligin or hemicellulose and lignin from steam pretreated lignocellulosic material as the starting substrate. In the continuous leach of lignin the starting, substrate has first had the hemicellulose removed therefrom and is then mixed with a concentrated alkali solution such, as sodium hydroxide, to adjust its pH within a range from 10.0 to 13Ø The pH adjusted substrate is then continuously leached of its lignin by an alkali solvent such as sodium, hydroxide, moving in counter-flow so that the lignin extract and the now hemicellulose and lignin depleted material can be separately recovered. The preconditioning of the substrate …