Process for preparing white mud calcium carbonate from green liquor recovered from wood pulp sulfate-method pulping alkali

A sulfate method, calcium carbonate technology, applied in the regeneration of lye, calcium carbonate/strontium/barium, lime production and other directions, to achieve the effect of simple process flow

Inactive Publication Date: 2012-09-12
QILU UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In order to solve the above problems that the alkali recovery white mud of kraft wood pulp mill has color and is not easy to be reused, the invention provides a kind of utilization of wood pulp kraft Process of preparing lime mud calcium carbonate from recycled green liquor by French pulping alkali

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] (1) Take 300mL of green liquor and add it to a 500mL three-neck bottle, add 7.17mg of green liquor purification aid, Tmax=90±5°C, keep warm for 20 minutes, stir at 100rpm, and filter to obtain purified green liquor;

[0039] (2) Weigh 21.07 grams of quicklime (calcium oxide content 84.42%, total iron content 0.078%), add 32.86mg quicklime purifying agent, control quicklime concentration to 15%, T=85±5℃, reaction time 60 minutes, Stirring speed is 100rpm, after reaction, filter and dry for later use;

[0040] (3) Weigh 2.5% of the total amount of the above-mentioned purified quicklime and add it to the purified green liquor for pre-causticization, Tmax=90±5°C, holding time for 20 minutes, stirring speed at 120rpm, and filter the green liquor for later use after pre-causticization;

[0041] (4) Weigh 97.5% of the total amount of purified quicklime in step (2) and add it to the filtered green liquor in the above step (3) for causticization, Tmax=90±5°C, holding time 120 mi...

Embodiment 2

[0047] (1) Take 300mL of green liquid and add it to a 500mL three-necked bottle, add 22.698mg of additives, Tmax=90±5°C, keep warm for 20 minutes, stir at 100rpm, and filter to obtain purified green liquid;

[0048] (2) Weigh 18.47 grams of quicklime (calcium oxide content is 84.42%, total iron content is 0.078%), add 86.44mg quicklime purifying agent, control quicklime concentration to 25%, T=85±5℃, reaction time is 60 minutes, Stirring speed is 100rpm, after reaction, filter and dry for later use;

[0049] (3) Weigh 15% of the total amount of the above-mentioned purified quicklime and add it to the purified green liquor for pre-causticization, Tmax=90±5°C, holding time for 20 minutes, stirring speed at 120rpm, and filter the green liquor for later use after pre-causticization;

[0050] (4) Weigh 85% of the total amount of quicklime purified in step 2 and add it to the above-mentioned filtered green liquor for causticization, Tmax=90±5°C, holding time 120 minutes, stirring sp...

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Abstract

The invention relates to the field of recovering black liquor in alkaline method pulping in the technical field of pulping and papermaking, in particular to a process for preparing white mud calcium carbonate from green liquor recovered from wood pulp sulfate-method pulping alkali. The process comprises the following steps of: (1) purifying the green liquor; (2) purifying calcined lime; (3) pre-causticizing the green liquor; and (4) causticizing the green liquor. According to the process, most of divalent ferrum ions in the green liquor are masked by adding an aid, trivalent ferrum ions in the calcined lime are masked by purifying the calcined lime, reaction of the trivalent ferrum ions in the calcined lime and the divalent ferrum ions in the green liquor is inhibited, and the generation quantity of hydroxides or sulfides of divalent ferrum in the causticizing process is reduced, so that the high-whiteness white mud calcium carbonate is obtained. The green liquor recovered from the wood pulp sulfate-method pulping alkali is treated by the process, a process flow is simple, and used chemicals are clean and environment-friendly.

Description

[0001] technical field [0002] The invention relates to the field of black liquor recovery in alkaline pulping in the technical field of pulping and papermaking, and in particular to a process for preparing white mud calcium carbonate by recovering green liquor from alkali in kraft pulping of wood pulp. [0003] Background technique [0004] The treatment of alkaline pulping black liquor in the pulp and paper industry is a worldwide environmental problem. At present, the main method of black liquor treatment is to recover heat energy and lye through combustion, that is, the alkali recovery process. For specific process descriptions, please refer to "Pulping Principles and Engineering" (Edited by Chen Jiaxiang, China Light Industry Press, 1990): The evaporating and concentrated black liquor is burned by the alkali furnace and the melt is added to dilute alkali liquor to become green liquor. The components are sodium carbonate, sodium sulfide and sodium hydroxide, and the gre...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F11/18D21C11/04
CPCY02P40/40
Inventor 吴朝军王代启李书平于冬梅李荣刚赵传山
Owner QILU UNIV OF TECH
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