Bleaching and delignifying cellulose using caroate/caro's acid and production of same
AssigneePeroxid-Chemie GmbH
InventorsMAXIMILIAN DORN, MICHAEL GNANN, SVEN GUTEWORT, WERNER SEBB
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Abstract
The invention relates to a method of bleaching and/or delignifying cellulose, in which (a) a sodium hydroxide solution and a peroxydisulphate solution are first of all produced by electrolysis of a sulphate, (b) the peroxydisulphate solution is converted by hydrolysis into a Caro's acid/caroate solution, (c) said Caro's acid/caroate solution is left to cool and (d) used immediately as a bleaching solution for bleaching and/or delignifying cellulose, the Caro's acid/caroate solution becoming neutralised upon introduction into the bleaching solution.
Claims8
A method of bleaching and/or delignifying cellulose, in which
- (a) a sodium hydroxide solution and a peroxydisulphate solution are first of all produced by electrolysis of a sulphate
- (b) the peroxydisulphate solution is converted by hydrolysis into Caro's acid/caroate solution
- (c) said Caro's acid/caroate solution is left to cool and
- (d) used immediately as a bleaching solution for bleaching and/or delignifying cellulose, the Caro's acid/caroate solution becoming neutralised upon introduction into the bleaching solution.
A method according to one of the preceding claims, characterized in that the hydrolysis of the peroxydisulphate solution in step (b) is carried out at 50° C. to 90° C.
A method according to one of the preceding claims, characterized in that the hydrolysis of the peroxydisulphate solution in step (b) is carried out in 1 to 4 N sulphuric acid.
A method according to one of the preceding claims, characterized in that the Caro's acid/caroate solution is allowed to cool to 0° C. to 50° C.
A method according to one of the preceding claims, characterized in that sulphate formed during the bleaching and/or delignification of cellulose is recovered.
A method according to one of the preceding claims, characterized in that a sulphate selected from the group comprising sodium sulphate, potassium sulphate and/or calcium sulphate is used.
Dependencies are inferred from the claim text.