A kind of preparation method of bleached straw pulp

Abstract

The invention discloses a preparation method of bleached straw pulp, which comprises the following steps: (1) adding a straw raw material and cooking liquor into cooking equipment in a weight ratio of 1:3-1:6, evenly mixing, and closing the cooking equipment, wherein the cooking liquor contains alkali; (2) introducing oxygen into the closed cooking equipment while keeping the oxygen pressure in the cooking equipment at 0.3-1.0 MPa, and cooking the straw raw material in the cooking liquor at 90-130 DEG C for 30-240 minutes; (3) washing and screening the pulp after finishing the cooking process to obtain fine pulp; and (4) bleaching the fine pulp in the step (3) with chlorine dioxide. The chlorine dioxide can bleach the straw pulp to the whiteness of higher than 80% in one bleaching process, thereby reducing two bleaching processes as compared with the CEH bleaching process usually adopted by a common alkaline method; and thus, the operating cost is lowered by 2 / 3, and the pollutant burden in the bleaching process is lowered by more than 60%.

Description

technical field [0001] The invention relates to the field of papermaking, in particular to a method for preparing bleached straw pulp for papermaking. Background technique [0002] The production of pulp from crop straw (especially straw or wheat straw) has dominated my country's pulp and paper industry for about 40 years. In the past 10 years, with the higher and higher requirements for environmental pollution control, the inherent deficiencies of grass raw materials have resulted in their clean production level being significantly lower than that of wood raw materials. In addition, the low efficiency of the pulping process has also caused people to be concerned about the pulping of grass raw materials. The problem is quite tricky. Therefore, problems such as low yield, high consumption, and high pollution in the grass pulping process seriously limit the development of the grass pulping industry. [0003] With the development of social economy, people's consumption demand...

AI Technical Summary

Problems solved by technology

In the past 10 years, with the higher and higher requirements for environmental pollution control, the inherent deficiencies of grass raw materials have resulted in their clean production level being significantly lower than that of wood raw materials. In addition, the low efficiency of the pulping process has also caused people to be concerned about the pulping of grass raw materials. The problem is quite difficult

Therefore, problems such as low yield, high consumption, and high pollution in the grass pulping process seriously limit the development of the grass pulping industry

[0003] With the development of social economy, people's consumption demand for paper products is constantly increasing and higher requirements are put forward for the quality of paper products. In the past, relatively simple and extensive grass pulping with high yield, especially mechanical pulping, was used. Due to the low quality of straw pulp, the paper products that can be produced are also greatly limited

In order to improve the quality and added value of straw pulp, the chemical pulping method is adopted, but the acquisition rate of straw pulp is not high

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