Improved lime mud recovering process and its application for producing neutral glue blending paper

Abstract

The invention is a kind of improved white clay reclaiming process and its application in neutral glue executing paper production. The original green liquid in flocculation: lime cream=30:1-1.2; they are stirred under 90-100 degrees for 20-40 minutes; when in assisting causticization, the white clay: clear green liquid =5-8:1; 90-100 degrees; rinses the residual alkali, the white clay: water =1:8-10; the white clay is grinded into particle with radius smaller than 20-30 micro meter. The density is 12-18%w / w; the white degree is 80-95%; the residual alkali is less than 0.5%; the active CaO is less than 0.5%; the pH value is from 9 to 11; the deposited volume in ten minutes is 3-10 ml / g; the dust degree is less than 0.5mm2 / g; 325 items residual is less than 0.055; when filling, the absolute dry pulp: talc powder: reclaimed white clay: positie ion starch=1;0-0.2:0.15-0.4:0.015-0.02, the AKD emulsion quantity is 15-18 kg / T paper.

Description

technical field [0001] The invention belongs to the recycling and utilization of three wastes in the papermaking industry, and in particular relates to an improved lime mud recycling process and its application in the production of neutral sizing paper. Background technique [0002] In many countries in the world, the main raw material for papermaking is wood pulp. However, due to the impact of resources in my country's papermaking industry, the main raw material for papermaking is straw pulp, reed pulp, sugarcane pulp or a mixture of the above-mentioned pulp and wood pulp. Due to the influence of straw pulp raw materials, the silicon content in the by-product caustic lime mud in the waste liquid alkali recovery process is relatively high, so it is not suitable for the conventional calcination method, and the chemical method and water washing method commonly used in the industry, or because of The cost is too high and it is not suitable for the national conditions; or the qu...

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Problems solved by technology

[0004] Publication number CN 1084413C discloses a kind of " papermaking black liquor alkali recovery green liquor causticization new process ", adopts green liquor pretreatment, and excess lime causticizes green liquor twice, according to its report, obtains recyclable caustic soda solution and Light calcium carbonate; its disadvantage is: the process is cumbersome, and only the light calcium carbonate recovered from the wood pulp method green liquor can meet the national standard quality requirements; the straw pulp method green liquor recovery light calcium carbonate can not meet the national standard quality requirements

[0005] Publication No. CN 1349861A discloses a "white mud recovery process", which is an improvement on the basis of the existing "washing method" and retains the CO 2 The carbonation treatment process of gas increases the "grinding" process, which improves the whiteness and fineness; it has been recycled and tested in a small area, and the recovered "calcium carbonate" particles are relatively loose in texture, and the fineness and whiteness are poor. , and the printing process still often "falls powder", it is difficult to meet the printing needs, so it cannot be applied to paper production

[0006] Therefore, at present, the "causticized lime mud" produced by many pulp and papermaking enterprises is still discharged beyond the standard or landfilled, which not only pollutes the environment, but also causes a great waste of resources

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