Method for preparing crystal whisker of gypsum

A technology of gypsum whiskers and dihydrate gypsum whiskers, which is applied in the direction of calcium/strontium/barium sulfate, etc., can solve the problems of large investment, high cost and price of whiskers, difficulty in popularization and large-scale application, etc., and achieve simple process Effect

Active Publication Date: 2006-07-05
SHANGHAI DONGSHENG NEW MATERIALS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In China, high-quality natural gypsum and hydrothermal method are used to produce gypsum whiskers, which requires large investment and high cost, and there is no special pilot production line for research and improvement.
This kind of production process, equipment and product quality are basically unqualified, and because of the lack of application test research, the cost and price of whiskers are high, so it is difficult to promote and apply in large quantities

Method used

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Examples

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Effect test

preparation example Construction

[0010] The invention is a preparation method of gypsum whiskers, which is characterized in that: chemical gypsum (including some industrial waste residues) is purified into relatively pure dihydrate gypsum by screening and flotation processes, and the purified chemical gypsum is ground by a stirring ball mill , and the obtained slurry is poured into a glass-lined reactor. Add hydrochloric acid or chloride salt, boil until the gypsum dissolves; send the dissolved solution to the crystallization tank, stir and cool, and crystallize dihydrate gypsum whiskers until all the crystals come out, which takes about 8 hours; put out the crystallization product through The continuous drying machine dries, and the remaining liquid is returned for reuse. The dried dihydrate gypsum whiskers are neutralized, and then dried to obtain wet dihydrate gypsum whiskers. The wet dihydrate gypsum whiskers are passed through a stirring dryer or a primary cyclone dryer to obtain dry dihydrate gypsum whi...

Embodiment 1

[0013] Purify phosphogypsum into relatively pure dihydrate gypsum by screening and flotation processes, grind and refine the purified chemical gypsum CaSO4. The concentration of slurry and hydrochloric acid is 15%, and the boiling temperature is 98°C. When the gypsum is dissolved, the dissolved solution is sent to the crystallization tank, and the dihydrate gypsum whiskers are crystallized while stirring and cooling. It takes about 8 hours until all the crystals are crystallized. hour, propose the crystalline product to the continuous drying machine to dry, and the remaining liquid returns to reuse, and the dried dihydrate gypsum whiskers are neutralized, and then dried to obtain the wet dihydrate gypsum whiskers primary product, wet dihydrate gypsum whiskers Whiskers are passed through a stirring dryer with a hot air temperature of 185°C to produce dry dihydrate gypsum whiskers; dried dihydrate gypsum whiskers are passed through a secondary cyclone dryer with a hot air tempera...

Embodiment 2

[0015] Purify salt gypsum or desulfurized gypsum into relatively pure dihydrate gypsum with a screening process, use a stirring ball mill to grind the purified chemical gypsum CaSO4.2H2O>95%, and put the obtained slurry into a glass-lined reaction kettle; The concentration of the batching slurry and chlorine salt is 16%, and the boiling temperature is 102°C until the gypsum is dissolved, and the dissolved solution is sent to the crystallization tank, and the dihydrate gypsum whiskers are crystallized while stirring and cooling, until all crystallization takes time About 9 hours, the crystallized product was put forward to the continuous drying machine to dry, and the remaining liquid was returned for reuse; the dried dihydrate gypsum whiskers were neutralized, and then dried to obtain the wet dihydrate gypsum whiskers primary product, wet dihydrate gypsum whiskers The water gypsum whiskers are passed through a stirring dryer with a hot air temperature of 210°C to produce dry di...

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Abstract

This invention describes a process for producing gypsum whiskers, which includes the the following processes: a)purification of chemical gypsum into dihydrate gypsum; b)levigation of the purified chemical gypsum, and then injection of the slurry thus obtained into an enamelled reactor; c)adding chloric acid or salts into the reactor, and boiling to the dissolution of the gypsum; d)stirring and cooling the solution to the recrystallization into dihydrate gypsum whiskers; e)swing-drying the recrystallization product; and f)neutralizing the swing-dried dihydrate gypsum to obtain a first product of wet dihydrate gypsum whiskers. In this invention the estimated production cost of the gypsum whiskers produced is 800-1900 RMB per ton, only 1/40-1/200 the price of the whiskers in the market. Besides, the overall process of this invention is easy to operate, and all the equipment utilized is common chemical equipment. The produced gypsum whiskers are mainly used for paper manufacturing and the corresponding paper products, while a minor part of them are used for reinforced materials of rubber and plastic products.

Description

Technical field: [0001] The invention belongs to the technical field of gypsum whiskers in chemical products. It uses chemical gypsum as a main raw material and adopts a dissolution and recrystallization process to prepare the gypsum whiskers. Background technique: [0002] In 1974, the Americans first published the production technology of gypsum whiskers (also known as microfibers). In the 1980s, industrial countries such as the former Soviet Union, Germany, France and Japan successively carried out research on gypsum whiskers. [0003] Before and after the 1980s, Wang Ruilin of the Shanghai Academy of Construction Sciences began to study and produce gypsum whiskers by the hydrothermal method, and tried it out in papermaking. A few years ago, with the help of Wang Gong, Shanxi Province built a pilot production line of gypsum whiskers by hydrothermal method. At the same time, Northeastern University and other units have also trial-produced gypsum whiskers by hydrothermal ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F11/46C04B11/05
Inventor 丁大武施晓旦
Owner SHANGHAI DONGSHENG NEW MATERIALS
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