NETFLOC System - The Tool to Remove Extractives and NPE, 1996 Minimum Effluent Mills Symposium Proceedings

C. Rampotas, H . Terelius, K. Jansson

Kemira Chemicals

The Kemira NetFloc system is used to remove extractives and NPE (Non-Process Elements) from filtrates in chemical and mechanical pulp mills. Removal efficiencies of more than 90% have been documented. The process is based on addition of polyethylene oxide (PEO) to the filtrate. Extractives will react with PEO forming a pitch sludge, which easily can be removed from the filtrate by flotation or screening. The NetFloc system was jointly developed at the MoDo, Domsjö mill by MoDo and Kemira. The removal of extractives from the process filtrate made it possible to close up the bleach plant. The Domsjö mill was the first totally effluent free chemical pulp mill in the world . This would not have been possible without the NetFloc system. Nordic kraft mills, with interest in TCF and TEF bleaching, are expecting problems with elevated concentrations of detrimental components such as NPE. It is possible to remove metals by employing the NetFloc system as a kidney. The removal will improve the peroxide stability and the oxygen delignification.