A pretreatment method for cooking black liquor in the manufacture of recycled pulp by diffusion dialysis

Abstract

The invention relates to a pretreatment method for cooking black liquor in the production of recycled pulp by diffusion dialysis, and belongs to the technical field of pulp production. Add a flocculant to the cooking black liquor with a sodium hydroxide concentration of 8-30g / L for flocculation, so that the concentration of the flocculant is 5-10mg / L, and then filter through a filter cloth with a pore size of 1100-1300g / m2 Machine filtration treatment, and then through microporous filtration membrane filtration treatment with a pore size of 0.1-1 micron to reduce the concentration of large particle impurities, recover lignin, and obtain a pretreatment solution for diffusion dialysis treatment of cation exchange membranes. The invention adopts a specific pretreatment method to treat the cooking black liquor, and then enters the diffusion dialysis process, which improves the recovery rate of alkali and hemicellulose in the cooking black liquor, reduces the damage of the alkali liquor to the diffusion dialysis membrane system, and prevents the diffusion The clogging of the dialysis membrane improves the service life of the membrane and ensures the smooth progress of the diffusion dialysis and subsequent processes.

Description

technical field [0001] The invention relates to a method for material treatment in chemical production, more specifically, the invention relates to a pretreatment method for cooking black liquor in pulp production recovered by diffusion dialysis, which belongs to the technical field of pulp production. Background technique [0002] In the viscose fiber production process in the chemical fiber industry, an alkaline liquid containing a high concentration of organic matter (mainly hemicellulose) will be produced. If it is allowed to be discharged directly, it will cause serious environmental pollution. If the lye is treated by neutralization, a large amount of acid will be consumed, and a large amount of inorganic salt will be formed in the lye, so the alkali in the lye is recovered, and the organic matter in it can be harmless Disposal of solid matter is a more environmentally friendly disposal method. [0003] In the pulping process, the cotton linters are cooked with a str...

AI Technical Summary

Problems solved by technology

[0018] The present invention aims to solve the existing problems and defects of the existing diffusion dialysis technology for cooking black liquor used in the production of recovered pulp, and provides a pretreatment method for cooking black liquor in the production of recycled pulp by diffusion dialysis. In the cation exchange membrane diffusion dialysis process of cooking black liquor in the recovery of pulp manufacturing, a specific pretreatment method is used to treat the cooking black liquor with specific indicators to reduce the COD value, and then enter the cation exchange membrane to diffuse after obtaining a suitable pretreatment liquid During the dialysis process, the recovery rate and amount of alkali and hemicellulose in the cooking black liquor can be improved, the damage of the alkali solution to the diffusion dialysis membrane system can be reduced, the service life of the membrane can be improved, and the smooth progress of the diffusion dialysis and subsequent processes can be ensured.

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