Method for preparing calcium sulfate whiskers by using chemical gypsum and calcium sulfate whiskers prepared by method

Abstract

The invention relates to a method for preparing calcium sulfate whiskers by using chemical gypsum and the calcium sulfate whiskers prepared by the method. The method comprises the following steps: 1)casting molding: uniformly mixing the chemical gypsum, hemihydrate gypsum whiskers and water in a mass ratio of (41-61): (11-23): (29-35), pouring the mixture into a mold, standing and solidifying toobtain gypsum blocks, and demolding to obtain gypsum blocks to be autoclaved; 2) high-temperature autoclaved treatment: stacking the obtained gypsum blocks to be autoclaved, and carrying out high-temperature autoclaved treatment at 135-200 DEG C for 2-10 hours; and 3) post-treatment: drying the autoclaved gypsum blocks in hot air at 60-200 DEG C, and grinding to obtain the calcium sulfate whiskers. Based on the application method, a large amount of chemical gypsum can be consumed to prepare the calcium sulfate whiskers, and the method is simple in process, low in cost and green and environment-friendly.

Description

technical field [0001] The invention relates to the technical field of resource utilization of industrial waste residues, in particular to a method for preparing calcium sulfate whiskers by utilizing chemical gypsum and the calcium sulfate whiskers prepared therefrom. Background technique [0002] Whiskers are artificially grown fibrous single crystals with micron-nano diameters. Whiskers of the same kind have the highest strength and elastic modulus, so they are widely used as reinforcing and toughening components of composite materials. At the same time, the high cost and low yield of whiskers of various substances limit the more general application of whiskers, so it is of great significance to develop methods for preparing whiskers with high yield and low cost. [0003] Calcium sulfate whisker refers to the fibrous single crystal whose main chemical composition is calcium sulfate. In fact, there are three kinds of phase composition: gypsum (calcium sulfate dihydrate, CaS...

AI Technical Summary

Problems solved by technology

[0005] The advantage of the hydrothermal method is that it does not use chemicals such as acids and alkalis, and has less environmental impact. The main disadvantage is that it cannot be continuously produced, and the volume of the high-pressure reactor cannot be too large, so the production capacity of a single secondary equipment is low, and the corresponding cost It will be higher; the advantage of the normal pressure acidification method is that the reaction is carried out under normal pressure, without the need for high temperature and high pressure equipment, and quasi-continuous production can be realized, but its disadvantages are also very obvious. The reaction process uses a large amount of inorganic acid, which will cause serious corrosion to the equipment , or higher requirements for production equipment

In addition, in order to increase the solubility and dissolution rate during dissolution, the reaction temperature is often increased, which may cause acid mist. On the one hand, it will corrode equipment, on the other hand, it will pose a potential threat to the environment. In addition, subsequent washing consumes water and produces a large amount of acid water. If it is not treated It will cause environmental pollution, and its cost is not low if it is treated

In many published documents, hydrochloric acid is used for acid hydrolysis, Cl - Ion residues will also affect the subsequent use of gypsum whiskers and pose a potential threat to equipment and the environment during subsequent use

It can be seen from the above that there are still many technical problems that have not been overcome in the prior art, and it is still difficult to achieve the purpose of relieving environmental pressure by utilizing chemical gypsum as a large resource.

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