METHOD FOR PRODUCING BLEACHED POWDER AND FIBROUS CELLULOSE FROM PLANTS OF UMBRELLA FAMILY, BASTER CROPS AND WASTE OF THEIR PROCESSING (EMBODIMENTS) Russian patent published in 2023 - IPC D21C3/00 D21C5/00 D21C9/00 D21C1/02 

FIELD: cellulose industry.

SUBSTANCE: group of inventions relates to the production of cellulose from plant herbaceous raw materials and can be used to produce bleached cellulose for sanitary and hygienic products. Stems of herbaceous plants of the Umbelliferae family and bast-fiber crops (flax, hemp, nettle, abaca), as well as waste from their processing, are used as the initial cellulose-containing material. To obtain fibrous cellulose, the outer fibrous part of the plant stem is used, and to obtain powdered cellulose, the inner loose part of the stem is used – the parenchyma. The group of methods includes washing the raw material with water, microwave processing of the raw material (5-10 min) in order to reduce the cooking time, delignification in a nitric acid solution, and subsequent cooking in a sodium hydroxide solution. For bleaching, treatment is used in a 0.5-1.0% hydrogen peroxide solution with the addition of sodium hydroxide for 30-90 minutes at 60-80°C. To obtain separately fibrous and powdered cellulose, a preliminary separation of the fibrous tissues of the stems from the parenchyma for cooking in different loads is used. In another embodiment of the invention, pulping is carried out without preliminary separation of the raw material, and the separation of cellulose into fibrous and powder fractions is carried out after bleaching, washing and drying by known methods, for example, on vibrating screens.

EFFECT: improved bleaching efficiency.

8 cl, 4 dwg, 1 tbl, 11 ex