Benefits of Using Enzymes to Improve Flotation Deinking of Office Paper Furnishes, 1998 Recycling Symposium Proceedings

In today’s competitive deinked market pulp environment, mills are struggling to stay in business and retain their customers. One way to ensure success is to produce the highest quality pulp using the least expensive recovered paper grades. The addition of enzymes to the pulping process is one way to improve final pulp quality by significantly improving flotation deinking performance. This reduction in final deinked pulp dirt count can provide two possible benefits. The mill can more consistently produce a better quality product enabling them to obtain and retain more customers which leads to a more profitable plant running at till capacity. Or it will provide the opportunity to use cheaper more contaminated office paper furnishes thus reducing the largest operational cost, recovered paper. In addition, consistently improved dirt removal efficiencies allow mills to spend less time in recirculation mode or making a lower, less profitable grade.

Bench-scale and mill trial data illustrate the impact of cellulase and amylase enzymes used in conjunction with conventional flotation aids on the dirt removal of various office waste furnishes. When compared to flotation aids alone, these enzymes provided superior flotation Dirt Removal Efficiencies (DRE). Lab work showed an 83% improvement in DRE from a dual pulper treatment of 0.02% cellulase and 0.02% amylase versus a surfactant only control. Two mill trials using 0.025% each of cellulase and amylase resulted in primary flotation stage DRE improvements of 34% and 54%. The ppm dirt count data from the finished product during the first commercial trial was reduced 36% versus the previous day’s data.