METHOD OF CELLULOSE PRODUCING FOR ETHERS AND ESTERS Russian patent published in 2017 - IPC D21C9/00 D21C9/08 

FIELD: pulp and paper industry.

SUBSTANCE: invention relates to production of cellulose for cellulose ethers and esters and can be used in pulp and paper industry. Method involves cellulose-containing raw material acid cooking in boiling device with bisulfite solution on sodium base in presence of deresinator and boiling product hot refinement with sodium hydroxide in presence of additive. Boiling product hot refinement is carried out in stages, hot refining first stage is performed in presence of complexing agent in amount of 0.1–0.2 % in terms of absolutely dry fiber mass, second stage is performed with separation of spent solution, which is supplied to refining first stage in amount of 20–30 % of total sodium hydroxide consumption at first stage, and boiling product hydrothermal processing is performed between first and second refining stages at temperature of 60–70°C for 50–60 minutes.

EFFECT: as a result obtained cellulose has following properties: high content of alpha-cellulose, higher viscosity and low content of lignin.

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