New Advanced Technology on Waste Resourcelization of the Black Pulping Liquor

Combining the characteristics of the black pulping liquor that contains a lot of lignin and other biomass resources,the technology of comprehensive waste utilization is employed.The reconstructive preparation of modified urea-formaldehyde glue by adding black pulping liquor and the application in extruding the medium density fibre board using this modified urea-formaldehyde glue is researched.Results show that when applying the preparation technology that alkaline reaction and then weak acid reaction,the appropriate preparation process is as follows:the adding urea process is divided into three stages(proportion 2∶1∶1);the pH value is 8.0,and the reaction time is 40 min in the addition reaction stage;the pH value will be naturally reduced to 3.5-5.0,and the reaction time is 45 min in the aggregation reaction stage;the pH value is 8.0 in the urea complement stage.And the optimal condition of the reconstructive preparation the modified urea-formaldehyde glue is adding the condensed black pulping liquor after hydroxymethylation in the beginning of polycondensation reaction by 5% proportion.The application in extruding medium density fibre board with this modified urea-fosmaldehyde glue is proved feasible.