LIGNIN SEPARATION FROM LIGNOCELLULOSIC HYDROLIZATES AND ACIDIFIED PULP MILL LIQUORS

The invention provides methods and compositions for the removal of lignin from water suspensions originating from lignocellulosic feedstocks. The method involves adding coagulants and flocculants to the suspension. While hydrolysis does remove some lignin, the pitch in many feedstocks prevents the hydrolysis from coming into contact with all of the lignin or so effectively blocks it that the lignin can re-condense. This is especially the case with low lignin grass based lignocellulosic feedstock. But wWith the addition of the inventive coagulants and flocculants, a phase separation substantially accelerates and lignin forms flocs that forms that physically separates the lignin from the pitch and the cellulose thereby makes removal the lignin from aqueous suspensions by decanting and filtration effective and easy.