METHOD TO PURIFY SEWAGE OF CELLULOSE SEMI-FINISHED GOODS PRODUCTION Russian patent published in 2003 - IPC

FIELD: pulp and paper industry. SUBSTANCE: the invention may be used for purification of sewage of cellulose semi-finished goods production. The method is realized using electrocoagulation of sewage with a soluble anode. Before electrocoagulation the sewage should be previously diluted with water in the ratio from 1:1 up to 1:5, Electrocoagulation is conducted using current density of 0.005-0.008 A/cm². Then electrocoagulated waste water is subjected to filtration and obtained filtrate shall be passed through a sorbent with subsequent return for preliminary thinning. The solid sediments separated after electrocoagulation and filtration shall be treated with inorganic acid, and used as a sorbent at the stage of clearing filtrate. In the case they use aluminum or iron anode as the soluble one and the sulfuric or hydrochloric acid as the inorganic acid. Treatment of the solid sediments with an inorganic acid is exercised under temperature of t=145-2500 C and ratio of the inorganic acid and the solid sediments masses from 0.5 : 1 up to 0.75 : 1. EFFECT: Method allows to create a turnaround system water services of cellulose semi-finished goods productions with simultaneous obtaining of the sorbent used at the stage of the cellulose production turnaround system water services of tertiary treatments. 4 cl, 2 tbl