Enhancement of Strength Performance of Mechanical Pulp, 2000 Pulping / Process & Product Quality Conference Proceedings

M. Sain, D. Fortier--Novel impregnation technology to enhance performance characteristics of mechanical pulp in absence of sulfonation reaction has been developed. In the present study separate post treatments of groundwood, thermomechanical, chemi- thermomechanical pulps with reactive ultra-thin film forming chemical precursors has been investigated. Chemical impregnation after pulp screening and latency removal in an aqueous pulp suspension demonstrated 20 to 25% increase in their strength properties without affecting the scattering coefficient, pulp freeness and yield. Chemical precursors charge used in the treatment process was less than 0.02% on oven dry basis of pulp. Moreover, the chemical reaction was found to be highly effective under ambient temperature and pressure conditions and the efficiency was increased with increasing pulp temperature. The latter process is specially beneficial for refiner-based mechanical and chemi-mechanical pulps because pulp temperature after refining or latency removal is somewhat higher than ambient.

The effect of recycling of filtrate after filtration was investigated. It has been found that repeated recycling of the filtrate and wash water by adjusting the precursor concentration would retain the efficiency performance. Anther process advantage of the novel technology is that there is no additional capital investment because the treatment process can be suitably adopted in the conventional process stage of mechanical and chemi-mechanical pulping operation.