Method for extracting lignosulphonate from sodium sulfite bamboo pulp waste liquor

Abstract

The invention relates to a method for extracting lignin-sulphonate from the waste solution of sodium sulfite bamboo pulp, which is characterized in that: red liquor is filtered for removing fibrils by a sieve; the filtered red liquor is delivered into a filtering machine for removing parenchyma cells, solid impurities and particles; then the red liquor is delivered into a purification and separation system for eliminating inorganic salt, organic carboxylate, small molecular saccharides substances and small molecular lignin-sulphonate; the purified red liquor is concentrated to proper concentration after evaporation; the concentrated red liquor can be directly or added with material to be put into a drying system for becoming dry powder, thus obtaining a finished product. The method has the advantages that the method solves problems interfering in the development of paper making enterprises of China that uses a sulphite method for pulping, provides an effective implementation technicalproposal and builds a production line with advanced environmental friendliness, typicality and practicability, which contributes to the waste solution treatment and discharge of the paper making industry of China.

Description

Technical field [0001] The invention relates to a treatment method for waste liquid treatment and discharge of sodium sulfite pulping enterprises. Background technique [0002] The pulping and cooking method (sulfite method) has been used in the paper industry, including acid sulfite method, neutral sulfite method and alkaline sulfite method. The mainstream treatment method for the waste liquid is to concentrate and burn the waste liquid to recover alkali and heat energy. However, at this stage, domestic sodium sulfite cooking waste liquor is not suitable for alkali recovery. The reason is that the annual output of domestic pulping enterprises using sodium sulfite method is below 100,000 tons, and it is not beneficial to use alkali recovery for small scale. What is more important is which compound is in Harmful gases such as carbon dioxide will be produced during combustion, which fails to achieve the purpose of recycling. [0003] Although the sulf...

AI Technical Summary

Problems solved by technology

[0006] The biggest difference between red liquor and acid process wood raw material waste liquor is that it contains more degradation products of hemicellulose xylan, and the average molecular weight of the main components of lignosulfonate and polysaccharide materials in red liquor is higher than that of acid method The similar substances in the waste liquid of woody raw materials are much lower, so the red liquid used for the production of lignosulfonate must be purified in advance, otherwise, the produced lignosulfonate has too many impurities and is very easy to be damp and sticky , affecting normal use