TREATING PROCESS WATER TO REMOVE METAL IONS; CONTACTING WITH LIGNOCELLULOSE PULP WHICH IS NOT TO BE BLEACHED

摘要

Methods of treating process water containing metal ions is disclosed including contacting the process water with a pulp comprising lignocellulose-containing material at a pH of above about 7 and a temperature of from about 50 DEG to 120 DEG C. whereby at least a portion of the metal ions are removed from the process water. Preferably the process water is produced from initially washing a pulp solution prior to a bleaching step employing hydrogen peroxide or ozone.