Pulping technology of cotton linter

Abstract

The invention discloses a pulping technology of cotton linters, comprising the following pulping steps by linters: taking the cotton linters as a raw material; at the normal pressure and the temperature below 85DEG C, adding 2.5-3.5% of alkali, boiling for 25-35 minutes to obtain cotton pulp; or directly bleaching without dipping in alkali or boiling, and processing for 30-50 minutes under the condition of 3.5-5.2% of chlorine and pH of 3.2-4.4 to obtain the cotton pulp; and black liquor silicon precipitation: carrying out neutralization reaction for dilute black liquor from a pulp washer by taking flue gas as a neutralizer for precipitating the silicon, wherein the use level of the flue gas for the neutralization reaction is 1250-1450m3/m<3> dilute black liquor by counting via containing 3.3-3.7% of CO2. According to the pulping technology, the strength and the utilization rate of the cotton pulp can be improved, consumption and cost are lowered, and pollution is reduced or eliminated.

Description

Technical field [0001] The invention relates to a papermaking process, in particular to a method for making papermaking cellulose. Background technique [0002] The non-cellulose content of cotton fiber itself is very low, and the main impurity in cotton linters is the mechanical impurities-cotton seed cortex, which is difficult to remove in the pulping process. [0003] At present, high pressure (5Kg / m), high temperature (150℃), strong alkali (8-12%) and long-time cooking (4-8) hours are mainly used in China to puff, soften and dissolve the cottonseed hulls, and then pass through a single-stage hypochlorite Remove pigment and bleach fiber to prepare cotton pulp. However, this method severely decomposes cellulose, lowers the strength of the cotton fiber itself, lowers the utilization rate of cotton pulp, and causes serious black liquor pollution (COD up to 30000-35000mg / l). [0004] Foreign countries such as the United Kingdom and France use dry cleaning before pulping to remove co...

AI Technical Summary

Problems solved by technology

However, this process method is only suitable for one line of linters in our country, and the cotton linters below the second line cannot be cleaned by dry cleaning because the fibers are too short, and the cottonseed husks cannot be removed during the pulping process, so it is not applicable

In addition, the price of hydrogen peroxide is high, resulting in high cost of cotton pulp

In addition, although the foreign black liquor treatment technology has excellent equipment, standardized technology and good treatment effect, its investment is too large to be used by large, medium and small paper mills in my country that are generally difficult to fund.