Abstract: The disclosure relates to a method for preparing unbleached biomechanical pulp by hot steam and biological enzyme treatment and full utilization of by-products thereof, and belongs to the technical field of papermaking technology and comprehensive utilization of waste. The present disclosure proposes a method for preparing high-strength unbleached biomechanical pulp, using whole wheat straw as a raw material, by using hot water in coordination with an alkaline biological enzyme to treat whole wheat straw, thereby meeting the requirements for the production of unbleached linerboard and paper-based materials, and recycling by-products thereof to prepare biomass compound fertilizers, which creates wealth from solid waste and realizes the high-value full utilization of wheat straw. The preparation method of the disclosure is simple, green, clean and efficient, and has good practical application value and broad application prospects.

Abstract: The application relates to a method for preparing dissolving pulp by totally chlorine-free bleaching of poplar kraft pulp, including: preparing poplar kraft pulp by pre-hydrolysis kraft process with poplar as raw material; ZOQP bleaching of poplar kraft pulp to obtain dissolving pulp, wherein Z denotes ozone bleaching, O denotes oxy delignification, Q denotes chelation treatment, and P denotes hydrogen peroxide bleaching. In this way, washing and bleaching wastewater can be recycled in entire preparation process described above, achieving “zero” discharge. The dissolving pulp prepared by the method has no residual toxic substances, and exhibits that all indexes exceed the requirements of qualified products in dissolving pulp industry standard (QB/T 4898-2015), and most of indexes meet those of excellent products; thus, it can replace imported dissolving pulp. The use of the method significantly solved the problems of large pollution in the production and shortage of raw materials for viscose fibers.