SU31216A1 - The method of obtaining cellulose from the husk of cotton seeds and other plant materials - Google Patents

Description

Until now, the methods of chemical processing of the husks of cotton plants and other products of cotton for cellulose were based on the well-known alkaline methods of cooking wood and other materials. - -Takj, for example, in the paper industry magazine No. 10-11 for 1928, in the article “On the creation of the paper industry in Central Asia, describes the explorations carried out by the NTS and baking industry, the processing of cotton seeds, first in 5% sodium hydroxide solution, taken in the amount of 29% of the dry starting material at a pressure of 1 at for 4 hours. The yield of bleached pulp was 25% of the starting material at a consumption of bleach about 18%.

The proposed method is intended to simplify the processing for cellulose of cotton seed husks by carrying out processes at atmospheric pressure and to reduce the time required for performing all operations.

The method consists in the fact that the husks of cotton seeds as they are

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is obtained from cotton mills, or after preliminary extraction of tannins from it, it is treated with an aqueous solution of nitric acid at. heating up.

As a result of this treatment, part of the encrusted substances of the husk becomes water-soluble, and the remainder is easily removed during subsequent alkaline cooking in an open vessel. This produces a sulfur mass consisting of cotton fiber (delint), as well as the cellulose residue of the husk itself. If it is necessary to obtain separately cotton fiber and separately the cellulose of the husk itself, the mass before or after bleaching can be subjected to light rubbing, (grinding), after which the long / cotton fibers can be easily separated from the short fibers by the husk itself by washing on a mesh filter.

Example. 10 g of cotton seed husks are poured with 3% HNOj solution and heated for some time until the natural brown color of the husk turns to a uniformly bright orange.

The hats and time are selected depending on the grade of the husk itself, and on the requirements for the final product — cellulose. For the existing sample from the cotton mill in Kaunchi, good results were achieved when processing 3% HNOj.

At - 10 minutes 90 ° - 15, 80 20. . , 60-65 ° - 1 hour

After treating the HNOs, the husks are washed with water to remove excess acid and are boiled in alkali (e.g., 2% NaOH solution) taken in an amount sufficient to neutralize and saponify the incrustation substances (actual NaOH consumption is about 7.5-10 % - of the initial weight of the husk) for 1-1.5 hours. in an open vessel. I

After washing, a mild sulfur mass is obtained, it is easily milled and can be bleached using well-known methods (NaOCl, CaOS, etc.).

The consumption of HNOi during cooking is significant (from 3 to 10% by weight of the material).

The proposed method is also applicable to the production of cellulose from cotton stalks, wood, for example, from pine chips (it is advisable to remove resinous substances beforehand), etc. With appropriate processing

after the step by selecting the appropriate concentration of HNOj, close to the indicated one (it is necessary to take into account the moisture content of the processed material), and the temperature is quite likely to be limited by the processing time specified in the example. to brownish. shade.

In this way, it is possible to process fairly coarse chips (in laboratory experiments for rosin and guzap and up to 3-5 sls in length, 1-2 cm in width, 0.2-0.5 cm thick). Oh, it is easy to process in this way the guza-pa (st) ebel of cotton), which has a loose structure.

The subject matter of the invention.

The method of obtaining cellulose from the husks of cotton seeds and other plant materials, because the husks of cotton seeds are first heated at a general pressure with a weak aqueous solution of the nitric acid and washed; after that, they are cooked with alkali or other liquors The preparations are usually wired to remove the crusting substances, and are whitened to obtain a white product using conventional means.