The invention relates to a cleaning process for extracting high quality
fiber with high efficiency, high yield and low
energy consumption from
plant raw materials by a
combination method of
chemistry and machinery in a sectional type. The process comprises the following steps: a
raw material is fully immersed in a NaOH solution or a KOH solution or
limewater with low concentration (
black liquor is used for supplementing into the corresponding alkaline for repeated and circular use) under the normal temperature or certain temperature, wherein the concrete immersion temperature and immersion time can be determined according to the types and the
water content of the raw materials so that the alkaline liquor is fully, uniformly and properly absorbed and diffused into plants;
steaming under normal pressure or
steaming with pressure or no liquid
steaming with pressure is used; the steamed material can be selected according to the
paper quality requirement by using a blowout slurrying mode or a mode of pulp refining after blowing to form
slurry or by using thread rolling and pulp refining to relief material once or multitime to prepare
slurry. The novel process combines the advantages of
chemical treatment and mechanical pulping, so that the uniform
mass transfer and uniform
heat transfer can be ensured and the damage to
cellulose and
hemicellulose by excessive alkali can be reduced, the yield of
fiber is raised to about 75% from about 45% of the prior art, so that the novel pulping process is capable of avoiding the usage of auxiliary agents like sulfured and
anthraquinone, conveniently extracting and using the
cellulose and
lignin in
black liquor, and overcoming the influence on environment during the process of pulping and post-treating
lignin.