Three Novel Wax Removal Methods for Wax Containing Old Corrugated Containers: Carbon Dioxide Extraction, Kraft Pulping and Agglomeration, 2001 Pulping Conference Proceedings

R. A. Venditti, J. F. Kadla, R. D. Gilbert, H. Jameel, H. -M. Chang--Three novel methods of wax removal from waxed old corrugated containers (WOCC) are described. They are (1) treatment of a WOCC/hardwood chip blend in a Kraft pulping process, (2) wax removal from WOCC using supercritical CO2 extraction, and (3) pulping/agglomeration of WOCC followed by screening and washing. Each has been shown to be technically feasible in reducing the wax content to less than 0.5% in laboratory experiments. The major advantage of the pulping WOCC with hardwood chips in a Kraft digester is that very little capital expense is needed to implement the process. Potential problems with contaminants in the fiber processing line are a drawback. The extraction of wax using supercritical CO2 allows one to recover dry wax and essentially wax-free OCC (unpulped) from WOCC but currently suffers from an economic feasibility standpoint. The pulping/agglomeration process of 100% WOCC is a relatively simple process that does not have high capital costs to implement. Issues with this process include energy consumption and the removal of the wax from a wash filtrate stream. All three of these processes, while suffering from one or more drawbacks currently, may be a useful technology if further developed or if key parameters in paper recycling, the availability of virgin fiber, landfilling, etc, change.