TCF bleaching in closed and open systems - Results are worth noting

Loop closure at the bleaching plant leads to increased concentrations of or ganic and inorganic substances, and this may impair bleachability and cause precipitation on fibres and process equipment. Analysing both pulp and fil trates from each bleaching stage, gives a general picture of the situation at tie mill. The objectives were to compare TCF bleaching of softwood pulp on the mill scale under closed conditions,vith bleaching on the laboratory scale using a totally open system.