METHOD OF LOWERING CHLORIDE CONTENT IN CHEMICAL REAGENT REGENERATION SYSTEM FOR PULPING Russian patent published in 1997 - IPC

FIELD: pulp-and-paper industry. SUBSTANCE: invention aims to provide environmental safe method for lowering chloride content in summary alkali liquor of chemical pulp mill. According to invention, in system of regeneration of sulfur- and alkali metal-containing reagents, deposited dust formed in heat- recovery boiler is collected and withdrawn by way of dissolving in water and being subjected to electrolysis to produce chlorine or hydrochloric acid in anolyte. As dust, as a rule, contains large amount of sodium sulfate, electrolysis may also yield sulfuric acid and sodium hydroxide. To reduce impurity content, pH of aqueous solution before electrolysis is adjusted to about 10 resulting in depositing inorganic substances which are then separated together with flocculated and non-dissolved substances. EFFECT: reduced chloride content in alkali liquor. 10 cl, 1 dwg, 1 tbl