Coagulation of sulfate lignin by aluminum sulfate

The influence of Al-2(SO4)(3) on aggregation stability and coagulation of a queous sulfate lignin (SL) dispersion was studied in a wide range of alumin um sulfate concentration (10(-5)-10(-3) mol 1(-1)) and pH values (1.8-12.0) . Al-2(SO4)3 was shown to have a high coagulation ability with respect to S L. An increase in the aluminum sulfate concentration leads to the pH monoto nic shift of the beginning of SL coagulation to a less acidic and further t o a more alkaline region of pH up to about 10.0 [10(-3) mol 1(-1) Al-2(SO4) 3] The optimal conditions (aluminum sulfate concentration and pH) for the S L coagulation separation from the alkaline solutions were determined.