STUDY ON NITROGEN COMPOUNDS PRETREMENT TECHNOLOGY IN WHEAT STRAW CMP PROCESSING

摘要

The technology of urea-potassium hydroxide for pretreating wheat straw was studied in this paper. The dosages of urea and potassium hydroxide, temperature, time and liquor ratio were investigated in order to produce a chemi-mechanical pulp which the unscreened yield of the pulp was beyond 65%. The process parameter of the pretreatment wheat straw by potassium hydroxide-potassium sulfide technology was studied, the results shown that the chemi-mechanical unscreened yield was 70% when the dosages of urea, potassium hydroxide and potassium sulfide were 16%, 8%，4% respectively, and pretreatment temperature, heating time and keeping time at the high temperature were 150°C, 60min, 45min separately. The physical properties of the hand sheet were as follow: the ring crush compression resistance index was 7.87N·m/g, breaking length was 4.52km and the tight degree was 0.58g/cm2, the physical properties had achieved the national standard A grade level (GB/T 2679.6―1996) of the corrugated paper.