Patent ID: 8585863

Claim:
A process for separating and recovering lignin and lignosulfonates from a liquid hydrolyzate, said process comprising: (a) contacting a lignocellulosic material with a solution of an aliphatic alcohol, water, and sulfur dioxide to produce a mixture comprising cellulose-rich solids and a first hydrolyzate comprising hemicellulose oligomers, lignin, and lignosulfonates; (b) removing said cellulose-rich solids from said mixture, to form a second hydrolyzate; (c) removing, in a stripper column, said aliphatic alcohol and said sulfur dioxide from said second hydrolyzate, to form a third hydrolyzate, wherein said lignin precipitates to form water-insoluble lignin; (d) recovering said water-insoluble lignin from said stripper column; (e) separating and recovering said lignosulfonates from said third hydrolyzate by filtering said third hydrolyzate to remove said lignosulfonates.