Study On Control Of Stickies With Stickaway And Surfactant Treatment In Recycled Pulp

With the increasing use of recycled fibers and utilization of white water system, the removal and control of adhesive contaminants has become more and more important. During the recycling process of recycled paper, stickies cause various operation problems in different stages of papermaking process which originated from ink binding adhesives, coating adhesives, hot melt adhesives, pressure-sensitive adhesives from waste papers, as well as lipophilic wood components released during the repulping processes. The contaminants form troublesome deposits on the forming wire, press section and dryer section or even the paper surface, deteriorate paper machine runnability and influence product quality. The pulp characteristics in terms of fiber-bonding strength and properties of paper sheets decrease due to the hornification and mechanical damage of fibers with the increase of recycling times. Consequently, control of stickies in the recycling process plays a key role in producing high-quality products. In recent years, the use of enzymes in the pulp and paper industry has grown rapidly. Enzymatic method becomes one of efficient ways to stickies control and fiber quality improvement.In this work, waste paper pulp and recycled whitewater are treated with either esterase or a mixture of both esterase and surfactant, so that stickies in the process of paper recycling could be controlled. The stickies removing efficiency of StickAway treatment is investigated by quantitative analyzing of the macro-stickies and micro-stickies in the waste pulp and recycled whitewater, and the optimal surfactant is chosen by comparing the stickies removing efficiency. In addition, the optimal proportion and the conditions are determined. After finishing the selection of the optimal surfactant and optimal proportion and the conditions, the experiment scheme is applied to factory test in order to test the practical effect.The optimal surfactant is selection from other four surfactants. When the OCC pulp and recycled whitewater are treated with a mixture of both esterase and surfactant, the optimal surfactant is L64. As for OCC pulp, the optimal proportion of StickAway and L64 are 2 LU/g and 0.25 kg/t, respectively. The amount of the macro-stickies reduce about 24.12%. As for recycled whitewater, the optimal proportion of StickAway and L64 are 11.25 LU/100m Land 7.50 g/m3, respectively. The amount of the micro-stickies reduce about 15.65%. Forthermore, When the DIP pulp and recycled whitewater are treated with a mixture of both esterase and surfactant, the optimal surfactant is TDA100. As for DIP pulp, the optimal proportion of StickAway and TDA100 are 3 LU/g and 0.25 kg/t, respectively. The amount of the macro-stickies reduce about 65.98%. As for recycled whitewater, the optimal proportion of StickAway and L64 are 11.25 LU/100mL and 7.50 g/m3, respectively. The amount of the micro-stickies reduce about 17.67%. The adhesion status of macro-stickies in the black filter paper show that, when the pulp is treated with either esterase or a mixture of both esterase and surfactant, the stickiness of stickies could be reduced. The results show that potential secondary stickies are removed effectively after StickAway treatment. With StickAway dosage is 30 LU/100mL process waters,when DIP process waters are treated,turbidity difference varies from 1.78NTU to 0.74 NTU,and as for OCC process waters, it varies from 1.42 NTU to 0.66 NTU. Moreover, application of esterase or a mixture of both esterase and surfactant has no negative effect on the properties of the OCC pulp and Pulp filtration performance.Based on the results, the enzyme has been applied successfully in some factory. And the test is very successful, Stickies problems of one white board production line have got a very good solution.The amount of Stickies have been reduced, and the stickiness of Stickies have reduced, machine cleaning time has also been reduced.