METHOD FOR TREATING AND RECOVERING PRIMARY SLUDGE CONTAMINATED WITH MINERAL FILLERS GENERATED IN THE CELLULOSE AND PAPER INDUSTRY, AND THE PRODUCT THUS OBTAINED

摘要

The present invention patent concerns a method for treating and recovering primary sludge contaminated with mineral fillers generated in the paper and cellulose industry, and the product thus obtained, belonging to the chemical sector. More specifically, the invention concerns a method for treating and recovering primary sludge, obtaining unbleached and pre-bleached clean cellulose for use in the manufacture of paper in general. The present invention discloses a method that involves the separation of the mineral fillers and the organic contaminants contained in the fibres by means of a simultaneous physical-chemical and mechanical process that purifies the primary sludge into clean cellulose. The method for treating and recovering contaminated primary sludge includes the following steps: 1.1 Feed for cellulose-purification process, 1.2 Dilution and washing of contaminated primary sludge (physical-chemical process), 1.3 Separation of inorganic contaminants, i.e. mineral fillers and soluble organic fillers (physical-mechanical process), 1.4 Separation of cellulose and densification of pulp, 1.5 Pre-bleaching of fibres, 1.6 Dewatering and concentration of fibres for application and reuse, and 1.7 Treatment of waste water.