DEVELOPMENT OF TECHNOLOGY FOR PRODUCTION OF DISSOLVING WOOD PULP

The work is devoted to the study of possibility and expediency of ECF bleaching for semi-chemical pulp with production of dissolving pulp, which is very popular in Russia and in the world. Production of dissolving wood pulp is important to replace cotton pulp obtained from imported raw materials. The conditions of bleaching and alkali treatment of sulfite pulp are investigated. CA dissolving pulp grade P was produced. To this end, new environmentally reliable short bleaching and alkali treatment schemes of sulfite pulp have been developed using only two oxidizing reagents: hydrogen peroxide and sodium chlorite. The bleaching schemes are based on the ECF technology developed earlier by the authors. Bleached dissolving pulp CA grade P was obtained according to all proposed schemes, including the shortened scheme Pa–E–Ch1–HAT–Ch2–A; pulp with increased yield was obtained due to good selectivity of the used chemicals under the developed conditions of delignification and bleaching, which contributes to the economy of wood. The possibility of obtaining pulp for viscose according to the above scheme is also shown. The results of studies have shown the possibility of obtaining wood pulp CA grade P from these raw materials by TCF technology with the use for delignification and bleaching (after alkali treatment) of hydrogen peroxide in an acidic and traditional alkaline medium, respectively.