Process for bleaching pulp without using chlorine containing che

Details Process for bleaching pulp without using chlorine containing che Process for bleaching pulp without using chlorine containing che

1993-05-11

1995-05-16

Alvo, Steve

Paper making and fiber liberation

Processes of chemical liberation, recovery or purification...

With regeneration, reclamation, reuse, recycling or...

162 60, 162 65, 162 78, D21C 9147, D21C 9153, D21C 916

Patent

active

054157340

ABSTRACT:
A process is disclosed for bleaching pulp without chlorine containing chemicals and for greatly reducing total washing filtrate discharge, comprising the steps of: 1) sending pulp that has been subjected to continuous digestion, oxygen-delignification and then washing, through a washing press; 2) treating, with agitation, the delignified washed pulp with sulfuric acid and a chelating agent; 3) washing the pulp in a washing apparatus; 4) bleaching with hydrogen peroxide in a reaction vessel; 5) washing the hydrogen peroxide bleached pulp; 6) adding sulfuric acid and ozone with mixing of the pulp; 7) reacting the pulp with ozone in a reaction vessel; and 8) washing the ozone reacted pulp, wherein the majority of liquid filtrate from the bleaching process that is waste not to be recycled is drawn off from the washing apparatus of step 3, the washings in step 3 and 5 have at least 85% efficiency, filtrate from washing step 5 is recirculated to the washing apparatus of step 3, and filtrate from the washing apparatus of step 8 is recirculated and used in the washing apparatus for the washing of pulp after oxygen-delignification.

REFERENCES:
patent: 3348390 (1967-10-01), Richter
patent: 3563891 (1971-02-01), Richter
patent: 3963561 (1976-06-01), Richter
patent: 4372812 (1983-02-01), Phillips et al.
patent: 4436586 (1984-03-01), Elmore
patent: 4547264 (1985-10-01), Sherman et al.
patent: 4668340 (1987-05-01), Sherman
patent: 4840047 (1989-06-01), Richter et al.
patent: 4854819 (1989-08-01), Gullichsen
patent: 4971694 (1990-11-01), Richter
patent: 4976586 (1990-12-01), Richter et al.
patent: 5053108 (1991-10-01), Richter
patent: 5069752 (1991-12-01), Richter
patent: 5080755 (1992-01-01), Backlund
patent: 5131980 (1992-07-01), Chamblee et al.
Bleaching a Softwood Kraft Pulp Without Chlorine Compounds, N. Liebergott, et al. pp. 323-332 Liebergott et al.
Emerging Technologies Today and in the Future, Copyright 1992, pp. 1-6, Basta et al.
1981 Oxidative Bleaching, Denver Hilton, Denver, Colo., Oct. 22, Copyright 1981, pp. 75-78, Schleinkofer.
Optimized Hydrogen Peroxide Bleaching in Closed White-Water Systems, Rolf Anderson, et al pp. 111-115.
Tritshler et al, "Commercial Manufacture and Ind. Use of Ozone As An Oxidant".

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