Method for use in the defibration or refining of lignocellulose-containing fibrous materials
AssigneesSunds Defibrator AB, Eka AB
InventorsSven G. Akerlund, Jan-Erik Hook
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Abstract
A method of producing peroxide bleached pulp. Lignocellulose fiber material is impregnated with an aqueous silicate solution containing a sequestering agent. The impregnated lignocellulose is preheated with saturated steam at a temperature corresponding to the defibrating temperature to precipitate silic acid on and in the fibers. The preheated fiber mass is defibrated between two grinding disc in an atmosphere of saturated steam at a temperature of 100.degree.-170.degree. C. Alkaline peroxide solution free of silicate is introduced into the grinding space.
Claims6
In the method of producing peroxide-bleached pulp from silicate impregnated lignocellulosic fiber material which is defibrated in an atmosphere of saturated steam at a temperature ranging between 100.degree. C. and 170.degree. C. within a grinding space defined between a pair of grinding discs which rotate relative to one another in a defibrating apparatus, the improvement preventing precipitation of silicic acid and insoluble silicates on the grinding discs and minimizing loss of peroxide, comprising the steps of
- (a) preheating a mass of lignocellulosic fiber material impregnated with an aqueous silicate solution containing a sequestering agent with saturated steam at a temperature corresponding substantially to the defibrating temperature to thereby precipitate silicic acid in and on the fiber,
- (b) passing said preheated impregnated fiber mass into said grinding space, and
- (c) reacting said preheated fiber mass with an alkaline peroxide solution free of silicate in said grinding space
Dependencies are inferred from the claim text.