Process for recycling white mud generated by pulping and papermaking

Abstract

The invention discloses a process for recycling white mud generated by pulping and papermaking (the main component is CaCO3). The process is characterized by comprising the following steps of: diluting and stirring, washing again in a pre-hung filter, delivering qualified white mud (the content of residual alkali is less than 0.8 percent and dryness is over 55 percent), and pulverizing in ceramicfactories. The process comprises the following specific steps of: 1, diluting and stirring, namely extracting the white mud from pulping and papermaking enterprises by using the pre-hung filter, adding into a white mud stirring tank, adding water for diluting, and adding into a white mud washer for precipitating; 2, washing again in the pre-hung filter, namely adding the white mud into the pre-hung filter, and washing again to ensure that the content of the residual alkali of the discharged white mud is less than 0.8 percent and the dryness of the discharged white mud is over 55 percent; 3, delivering the qualified white mud, namely transporting the qualified white mud to the ceramic factories by using a special transport vehicle; and 4, pulverizing in the ceramic factories, namely addingthe qualified white mud into the ceramic factories, further grinding into powder, and preparing ceramic from the powder instead of an auxiliary material calcite (CaCO3) according to a proportion in aproduction process of the ceramic factories. Cost is reduced, and the quality of a finished product is consistent with that of a finished product prepared from the calcite.

Description

technical field [0001] The invention relates to a process for recycling white mud, in particular to a process for recycling white mud produced in pulping and papermaking. Background technique [0002] Judging from the research and development of comprehensive utilization of lime mud at home and abroad, there are indeed various technical obstacles in the comprehensive utilization of lime mud for pulping and papermaking, or it is difficult to popularize due to the influence of economic benefits. These results are not ideal and cannot completely solve the problem of white mud The purpose of mud comprehensive utilization. [0003] At present, there are still many problems in the comprehensive utilization of lime mud in pulping and papermaking. About 200 pulp enterprises in our province discharge nearly 20 million tons of lime mud annually. The process is simple and easy, and the investment is small, but it will occupy a large amount of green ecological land resources, 20 millio...

AI Technical Summary

Problems solved by technology

[0002] Judging from the research and development of comprehensive utilization of lime mud at home and abroad, there are indeed various technical obstacles in the comprehensive utilization of lime mud for pulping and papermaking, or it is difficult to popularize due to the influence of economic benefits. These results are not ideal and cannot completely solve the problem of white mud The purpose of mud comprehensive utilization

[0003] At present, there are still many problems in the comprehensive utilization of lime mud in pulping and papermaking. About 200 pulp enterprises in our province discharge nearly 20 million tons of lime mud annually. The process is simple and easy, and the investment is small, but it will occupy a large amount of green ecological land resources, 20 million tons / 4000 mu / year, and this landfill is endless, and the waste of land resources is also endless), according to the current state of the country The policy should not be promoted; 2. Calcination method (this method can convert lime mud into refined calcium carbonate and calcium oxide for non-polluting utilization, but the investment is large and the cost is high, and many paper-making enterprises cannot afford it); 3. Soil Improver (after washing the white mud, it can be used as a soil improver, but this product can only be used in some acidic or weakly acidic soils, and it is difficult to consume a large amount of discharged white mud); 3. As a flue gas desulfurizer (white mud and Pulverized coal is mixed according to a certain proportion for combustion and power generation, which achieves certain economic and environmental benefits. However, the PH value of the lime mud is high, and the flue gas generated at high temperature is easy to corrode the equipment and easily cause the burst tube to leak. Therefore, the combustion furnace needs to be corrosion-resistant. 4. As building products (using white clay as raw material, adding other auxiliary materials in proportion, alkali slag bricks can be prepared, but because of the high content of soluble chloride salts in white clay, It causes serious frosting on the product, reduces the practical value of the product, and also limits the application of this technology, and the site where the white mud is accumulated needs to be treated, which requires a large investment); 5 as a decontamination powder (washing the white mud , drying, dry powder screening, ingredient mixing and other processes to produce decontamination powder, but the consumption of decontamination powder in the society is small, which is not an effective way to solve the pollution problem)

Images