Method for preparing sodium metasilicate and light calcium carbonate with green liquid generated in alkali recovery in papermaking by straw pulp

A light calcium carbonate, straw pulp papermaking alkali technology, applied in the direction of alkali metal silicate, calcium carbonate/strontium/barium, silicate, etc., can solve the destruction of land resources, pollution of land and groundwater, ecological environment damage, etc problems, to achieve the effect of improving strength and whiteness, significant economic benefits, and eradicating environmental pollution

Active Publication Date: 2014-05-07
赵琪
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AI Technical Summary

Problems solved by technology

So far, the silicon-containing crude calcium carbonate cannot be reused as a resource
Therefore, most straw pulp and papermaking enterprises can only simply landfill or directly dump and accumulate silicon-containing crude calcium carbonate. serious damage

Method used

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  • Method for preparing sodium metasilicate and light calcium carbonate with green liquid generated in alkali recovery in papermaking by straw pulp

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] (1) Preparation of sodium metasilicate: Take 1L of green liquor produced by the conventional process of recycling straw pulp and papermaking alkali, and vacuum filter it with a 4G sand core funnel at room temperature to obtain clear and transparent green liquor; the purified green liquor Carbon dioxide gas was introduced into the medium, and after a certain period of reaction, the green liquid began to be cloudy. As the reaction progressed, a large number of white flocs appeared in the green liquid. When the pH of the liquid was measured to be 9, the reaction was stopped and a silicic acid suspension was obtained. ;The silicic acid suspension was subjected to vacuum filtration to obtain a silicic acid filter cake, and the mass of the silicic acid filter cake was weighed to be 114.5g; In the acid filter cake, the quality of silicon dioxide is 6.396g. Put 114.5g of silicic acid filter cake into a 250mL beaker, then add 8.67g of caustic soda with a sodium hydroxide content ...

Embodiment 2

[0029](1) Preparation of sodium metasilicate: Take 10L of green liquor produced by the conventional process of recycling straw pulp and papermaking alkali, and vacuum filter it with a 4G sand core funnel at room temperature to obtain clear and transparent green liquor; the purified green liquor Carbon dioxide gas was introduced into the medium, and after a certain period of reaction, the green liquid began to be cloudy. As the reaction progressed, a large number of white flocs appeared in the green liquid. When the pH of the liquid was measured to be 9, the reaction was stopped and a silicic acid suspension was obtained. ; The silicic acid suspension was vacuum filtered to obtain a silicic acid filter cake, and the quality of the silicic acid filter cake was 980g; the volume of the mother liquor (green liquid after filtering out silicic acid) was 9L; In the cake, the mass of silica is 60g. Put 980g of silicic acid filter cake into a 3000mL beaker, then add 81g of caustic soda w...

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Abstract

The invention provides a method for preparing sodium metasilicate and light calcium carbonate with a green liquid generated in alkali recovery in papermaking by straw pulp. The method comprises steps of purifying a green liquid generated in a conventional alkali recovery technology in papermaking by straw pulp, introducing carbon dioxide gas into the purified green liquid so as to form a silicic acid suspension liquid, carrying out solid-liquid separation on the silicic acid suspension liquid so as to prepare silicic acid; heating up and reacting the silicic acid and caustic soda so as to obtain liquid sodium metasilicate; causticizing the mother liquid with silicic acid filtered and calcium hydroxide so as to obtain liquid sodium hydroxide and crude silicone-free calcium carbonate, then refining the crude calcium carbonate so as to obtain light calcium carbonate slurry for papermaking. The method overcomes the technical obstacle that silicon resource in the green liquid generated in alkali recovery in papermaking by straw pulp cannot be recycled, thoroughly solves the problem of environment pollution caused by alkali recovery in papermaking by straw pulp, and thoroughly recycles available resource in alkali recover in papermaking by straw pulp and realizes cyclic utilization. The technological process is simple and clean, does not discharge pollutants, is easy to implement, and has remarkable social environment benefits and obvious economic benefits.

Description

technical field [0001] The invention relates to an alkali recovery technology for straw pulp papermaking, in particular to a method for preparing sodium metasilicate and light calcium carbonate by using straw pulp papermaking alkali to recover green liquor. Background technique [0002] The paper industry uses bamboo, reed, bagasse, wheat straw and other herbaceous plants as raw materials, and the paper pulp produced by chemical methods such as caustic soda method and sulfate method is called straw pulp. The brown-black liquid produced in the pulping process is collectively referred to as black liquor, which is the main source of serious pollution in the paper industry. Although domestic paper and pulping enterprises have installed and put into production advanced and practical alkali recovery technology and equipment, which have played a certain role in energy conservation and emission reduction, but because herbaceous plants are different from woody plants and have the cha...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/32C01F11/18
Inventor 赵琪
Owner 赵琪
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