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Method for preparing modified calcium sulfate crystal whisker papermaking filler

A calcium sulfate whisker and paper-making filler technology, applied in the field of papermaking, can solve the problems of paper machine running performance reduction, paper machine equipment wear, and difficulty in dispersing, and achieve the effects of solving solid pollution, expanding application fields, and increasing added value

Inactive Publication Date: 2013-07-31
CHANGSHA UNIVERSITY OF SCIENCE AND TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Calcium sulfate whiskers have the basic properties of papermaking fillers such as high purity, high whiteness, low abrasion, acid and alkali resistance, etc., but the research found that calcium sulfate whiskers and water Hydration reaction is very easy to occur after contact, resulting in the destruction of its crystal structure and properties, and the loss of the characteristics of whiskers; when it is directly used as a papermaking filler, the retention rate of calcium sulfate whiskers in the wire section of the paper machine is very low, and due to its dissolution The white water system of the paper machine will produce a large amount of calcium ions and sulfate ions, which will lead to a series of problems such as an increase in the amount of chemicals in the wet end of the paper machine and a decrease in the running performance of the paper machine.
Document 1 (Wang Xiaoli, Yin Wanzhong, Han Yuexin, Yuan Zhitao, Research on Wet Modification of Calcium Sulfate Whisker Surface, Mining and Metallurgy, 2006, 15(3), 30-37), Document 2 (Yuan Zhitao, Wang Yubin, Han Yuexin, Li Lihe, Calcium Sulfate Hemihydrate Whisker stabilization research, Journal of Inorganic Chemistry, 2008, 24(7), 1062-1067) and literature 3 (Li Zhun, preparation of calcium sulfate whiskers by ion exchange method and its modification, master's thesis of Dalian Jiaotong University, 2009.6) The research on the hydrophobic modification of calcium sulfate whiskers was reported in , but the modified calcium sulfate whiskers cannot be used as paper-making fillers. The main problems are as follows: (1) The raw materials of the whiskers come from natural gypsum or salt solution ion exchange method , the cost is high, and it is not conducive to solving solid waste pollution such as industrial gypsum residue; (2) stearic acid is used as the hydrophobic modifier, and the dosage is 4%-5%, which is expensive, and the modified calcium sulfate crystal Whisker activation index is too high, lipophilic and hydrophobic, and it is difficult to disperse evenly in the slurry when used as papermaking filler; (3) It does not involve the characteristic quality index requirements and related preparation process of calcium sulfate whisker filler for papermaking. The length of the whiskers is 50-200μm. When used as a papermaking filler, it will cause serious wear to the paper machine equipment and is not conducive to the improvement of paper performance.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] 100g calcium sulfate whiskers with purity ≥99% and whiteness ≥90%ISO extracted from desulfurized gypsum are calcined at 350℃ for 3 hours, taken out, ground and deflocculated to 5-40μm; at 500 rpm Mix the calcined and deflocculated whiskers into a suspension with a mass concentration of 10% under stirring, add 3% titanate modifier dissolved in alcohol for organic modification, and react at 60°C for 30 minutes; The modified calcium sulfate whiskers are dried at 100°C for 3 hours at a constant temperature, taken out, ground and deflocculated to an average length of 5-40μm, and the density is 2.3-2.4g / cm. 3 , Whiteness ≥ 90% ISO, solubility ≤ 0.5%, high whiteness, low solubility, high retention rate modified calcium sulfate whisker papermaking filler.

Embodiment 2

[0019] 100g calcium sulfate whiskers with purity ≥99% and whiteness ≥90%ISO extracted from the phosphogypsum waste residue are calcined at 375℃ for 2.5 hours, taken out, ground and deflocculated to 5-40μm; at 650 revolutions / min Mix the calcined and deflocculated whiskers into a suspension with a mass concentration of 15% under stirring at a rotating speed, add 4% titanate modifier dissolved in alcohol for organic modification, and react at 75°C for 20 minutes; Take out the modified calcium sulfate whiskers, place them at 125°C for constant temperature drying for 2.5 hours, take them out, grind and deflocculate to an average length of 5-40μm, and obtain a density of 2.3-2.4g / cm 3 , Whiteness ≥ 90% ISO, solubility ≤ 0.5%, high whiteness, low solubility, high retention rate modified calcium sulfate whisker papermaking filler.

Embodiment 3

[0021] 100g of calcium sulfate whiskers with purity ≥99% and whiteness ≥90%ISO extracted from nickel ore smelting residues are calcined at 400℃ for 2 hours, taken out, ground and deflocculated to 5-40μm; at 800 rpm Mix the whiskers after calcining and deflocculation into a suspension with a mass concentration of 20% under the condition of stirring at a speed of 1 minute, add 5% titanate modifier dissolved in alcohol for organic modification, and react at 90°C for 15 minutes ; Take out the modified calcium sulfate whiskers, place them at 150°C for constant temperature drying for 2 hours, take them out, grind and deflocculate to an average length of 5-40μm, and obtain a density of 2.3-2.4g / cm 3 , Whiteness ≥ 90% ISO, solubility ≤ 0.5%, high whiteness, low solubility, high retention rate modified calcium sulfate whisker papermaking filler.

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Abstract

The invention discloses a method for preparing a modified calcium sulfate crystal whisker papermaking filler. The method is characterized by comprising the following steps of: (1) calcining a crystal whisker; (2) performing organic dissolution restraint modification; (3) drying; and (4) grinding for flocculation elimination. In the method, the used calcium sulfate crystal whisker has a wide raw material source and a wide condition, and can effectively solve the problem of solid pollution caused by various industrial gypsum waste residues or metal waste residues; the prepared modified calcium sulfate crystal whisker filler has the characteristics of high whiteness, low abrasion, high retention rate and the like and can effectively replace the conventional calcium carbonate fillers or plantfibers; simultaneously, the solubility of the prepared modified calcium sulfate crystal whisker filler is effectively controlled, and the filler is easy to disperse in papermaking aqueous pulp, so that the problems that the calcium sulfate has high water solubility and has a low retention rate, high content of white water waste ions, high possibility of scaling in a pipeline and the like when used as the papermaking filler are solved, the application field of the crystal whisker is expanded, and the additional value of the crystal whisker is improved.

Description

technical field [0001] The invention relates to a preparation method of calcium sulfate whisker papermaking filler, which belongs to the technical field of papermaking. Background technique [0002] Calcium sulfate whisker (also known as gypsum whisker, gypsum fiber) is a new type of inorganic material extracted from desulfurization gypsum, phosphogypsum and other industrial gypsum residues or metal smelting waste residues at home and abroad in recent years. Compared with other inorganic fiber materials, calcium sulfate whiskers have many excellent physical and chemical properties such as low wear, high temperature resistance, acid and alkali resistance, and dimensional stability, and have extremely broad application prospects. According to statistics, my country produces about 80 million tons of industrial gypsum waste slag every year (which contains 80%-95% calcium sulfate whiskers), and there are also a large number of calcium sulfate whiskers produced from the acid smelt...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): D21H17/69
Inventor 王玉珑刘菲菲刘艳新覃盛涛
Owner CHANGSHA UNIVERSITY OF SCIENCE AND TECHNOLOGY