New technique of no pollution discharge for treating black liquor from papermaking

Abstract

The invention relates to a method for processing pollution of black liquor created by papermaking, particularly a new technology without pollution discharging for the black liquor created by soda and sulfate pulp processing. Seven continuous processing steps are used to realize tractional centrifugal subsidence, main components in black liquor are separated out as form of precipitant step by step, remained neutral liquid is used to prepare hydrolyzate for extracting xylose. The main components of the precipitant being centrifugal subsided are: cellulose and half cellulose, saccharides, lignin, alkali fusion protein, silica gel, sodium sulfate and hydolyzate for extracting xylose.

Description

technical field

[0001] The invention relates to the pollution control of papermaking black liquor, in particular to a new process for pollution-free discharge control of black liquor from alkali and kraft pulping. Background technique

[0002] As we all know, the paper industry is a large water user and a major polluter of the earth's water environment. For example, in 1995, the wastewater discharge of papermaking enterprises at or above the county level in China was 2.4 billion tons, accounting for 10.8% of the total industrial wastewater discharge in the country, ranking first in the world. The third place, among which the chemical oxygen demand [CODcr, the same below] is 3.214 million tons, accounting for 41.8% of the national total, ranking first. If papermaking wastewater is not treated, it will flow into rivers, lakes, seas and some farmland at will, which will cause the loss of the function of the water body on the earth's surface, cause a large number of fish to die,...