METHOD FOR CELLULOSE NITRATE GRINDING Russian patent published in 2019 - IPC C06B21/00 C08L1/18 

FIELD: technological processes.

SUBSTANCE: invention relates to the technology of producing cellulose nitrates (CN) with nitrogen content of 209.0 ml NO/g and more, made from wood-based cellulose raw materials of the CA brand and cotton raw material of the CC brand, specifically to the technology of industrial grinding thereof on a disk mill MD-31 and subsequent fractionation of ground fibers on an industrial factionalist. Method involves preliminary condensation of the initial CN suspension to concentration of 3–9 wt% and subsequent grinding of the condensed mass of the CN continuously and in one step at the MD-31 mill, having thin knives and a working gap between the rotor and stator knives ranging from 0.07 up to 0.10 mm. Then the ground CN suspension is sent to sort the fibers along their length into the factionalist where the business, coarse and fine fractions of the product are separated, wherein business (main) fraction of crushed CN, having a narrow fraction composition throughout the length of the fiber in range of 0.20 to 0.60 mm, is fed into the lavatory for final stabilization and subsequent processing into pyroxylin powder, large fraction of product with fiber length of 0.60 mm and more is returned to production for additional milling, and fine fraction – with fiber length of less than 0.20 mm is recycled into production of pellet powder.

EFFECT: method enables to obtain, under industrial conditions, qualitative and homogeneous pyroxylin No 1 according to fractional composition, which corresponds to required standards and suitable for subsequent processing thereof into different powders.

4 cl, 1 dwg, 2 tbl