A method of physicochemical treatment of the wood pulp based on cold refining

We develop a universal method of physicochemical refining of the market wood pulp to the level given by the requirements of State standards for fibrous semi-finished products for deep chemical processing into various functional derivatives and artificial materials (Na-CMC, colloxylin, pyroxylin, viscose and cordage fibers). An experimental laboratory modular setup was designed and manufactured at the Semenov Institute of Chemical Physics (RAS). The modification includes the following stages: preparation of the raw materials, chemical modification, washing, and drying of the final product. At the first stage the original market pulp was dispersed to obtain a homogeneous suspension, cleaned and dried. After washing, the refined cellulose was dried in two stages: i) microwave drying to a moisture content of 45 - 50%; ii) convective drying with warm air to a moisture content of 5 - 9%. The basis of chemical modification is the stage of cold refining. Compared to other methods of refining wood pulp (acid-alkali treatment, hot refining) cold refining does not require special equipment which operate at elevated temperature and pressure. The developed procedure of physicochemical modification of the market wood pulp is universal, since it has no restrictions on the brand of the initial raw material. Depending on the quality requirements to the final product, the proposed method provides obtaining all brand of cellulose for chemical processing — viscose cellulose, acetate cellulose, cord cellulose. Mass fraction of the alpha-cellulose in the final product ranges from 93 to 99%.

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