RECYCLED PULP WASHING .1. COMPARISON OF WASHING EQUIPMENT AND SUBSYSTEMS

Washing efficiency results for the removal of ash, dissolved solids an d ink particles were obtained for different washing equipment currentl y in use in four commercial installations in North America. These inst allations are producing newsprint from ONP/OMG or tissue from mixed of fice waste. The process configuration of each washing system is presen ted with its water recirculation strategy. The washing sub-systems are compared in terms of contaminant removal efficiency, yield loss and e ffect on product quality at the outlet of the sub-system. The experime ntal results obtained have demonstrated the implications of using diff erent types of equipment in a washing sub-system. Furthermore, many pr ocess variables, in addition to the equipment selected, affect the was hing efficiency of contaminants and process yield. All need to be cons idered in the selection of the best washing sub-system.