Broke processing systems for LWC, MWC and HWC papers

Available technologies for LWC dry broke processing yield a tolerable pulp and coat separation, but the anionic trash problem remains unsolved. In order to overcome this difficulty, it is being proposed to largely eliminate the anionic charges by pressing the pulp prior to recirculating it to the paper machine and to neutralize the contraries in the filtrate by means of a microflotation process. When processing MWC and HWC papers, a deflaking stage is insufficient Instead, high-consistency dispergers of the type traditionally used for waste paper treatment will have to be employed. Comparative studies of a high-speed disc disperger and a low-speed kneader have revealed that for an identical energy input, the kneader is slightly superior in performance to the disc disperger. HWC processing techniques will have to be selected as required, depending on anionic trash levels and COD loads which will be released in the processing operation.