The Application of Membrane in Ash Content Decrement of Black Liquor from Alkaline Sulfite Pulping Process

摘要

In this paper,the ultrafiltration(UF)and membrane-assisted electrolysis(MAE)were applied to decrease the ash content of black liquor from alkaline sodium sulfite anthraquinone(AS-AQ)pulping process.In the experiments,some parameters which may affect the efficiency of ash content decrement in black liquor were investigated.The sulfate ash content decreased to 23.8%(or decreased by 7.6 %)and the lignin cutoff rate was 70.8% when the optimized conditions were as follows: the molecular weight cut-off 10000,the percentage of permeation filtrate volume 60%,black liquor solids content 10% and operating pressure 0.25 MPa.The optimum conditions of the MAE experiments were as follows:the solids content 8%,the alkali concentration 0.1 mol/L,the electrolysis voltage 8 V and the electrolysis time 3h,on this condition,the sulfate ash content decreased to 19.7%(or decreased by 11.7%).