Two stage bleaching of cellulose pulp with hydrogen peroxide
Номер патента: AU5794486A
Опубликовано: 04-12-1986
Автор(ы): Bernard Dubreaux
Принадлежит: Atochem SA
Опубликовано: 04-12-1986
Автор(ы): Bernard Dubreaux
Принадлежит: Atochem SA
Реферат: A two-stage hydrogen peroxide bleaching treatment of chemical pulp at a temperature of about 90 DEG -100 DEG C. comprising subjecting said pulp in a first stage to hydrogen peroxide and to at least about 3 grams/1 of bath of a metal ion sequestering agent selected from nitrogen containing sequestering agents or agents derived from polyphosphoric or polyphosphonic acids at a pH of 8.5 to 9.5 so that hydrogen peroxide of about 0.3 to 2.5 wt. % relative to dry pulp weight is consumed, and subjecting said pulp in a second stage to hydrogen peroxide and to at least about 3x10-3 gram-atoms per 100 grams of dry pulp of magnesium in the form of magnesium hydroxide and a pH of at least about 11 so that about 2 to 5 weight % of hydrogen peroxide per weight of dry pulp is consumed during the two stages.
Method of bleaching of cellulose and other cellulose and lignocellulose fibrous materials and three-stage method of bleaching of cellulose and lignocellulose materials
Номер патента: RU2141016C1. Автор: Льюис Д. Шекфорд,Уильям Дж. Миллер,Брайан П. Рой,Лироп Барбара Ван,Ричард М. Берри. Владелец: Палп энд Пейпер Рисерч Инститьют ов Кэнеда. Дата публикации: 1999-11-10.