METHOD OF PRODUCTION OF FIBROUS HALF-FINISHED PRODUCT Russian patent published in 2005 - IPC

FIELD: production of fibrous half-finished products at different degree of delignification; wood-pulp and paper industry.

SUBSTANCE: cellulose-containing vegetable material is subjected to boiling at higher sulfidity of boiling solution, up to 100%. Used as sulfide-containing component are alkaline wastes of oil desulfurization processes which contain inorganic compounds, including sodium sulfide at concentration up to 120 g/l in Na₂O terms and residual organic compounds in form of sulfur-containing hydrocarbons C₅-C₆ and phenolates at concentration up to 15 g/l. Boiling is carried out at 130-160°C.

EFFECT: high parameters of delignification process; enhanced economical efficiency; reduction of toxic emissions.

2 tbl