In production, the quality of gypsum mold is difficult to control stably because of the inherent variability of gypsum mold. One aspect of this variability is the influence of paste water ratio and slurry concentration on the performance of gypsum model. Paste water ratio is generally small, porosity is high, strength is low, service life is short. The paste has high water ratio, low porosity, high strength and long service life. The influence of the change of paste water ratio is related to the aging time of gypsum powder, especially the difference between the newly baked gypsum powder and the fully aged gypsum powder. The newly fried gypsum powder has not been metamorphosed and homogenized yet. It has high temperature, strong surface activity and large mixing water. When it is used to make the model immediately, many bubbles will form on the model surface, and the overall strength is low. Generally speaking, the newly fried gypsum powder needs to be stored for two weeks before reuse.

　　国外学者的研究结果表明，石膏粉的含水率和流变特性随贮存时间的变化而变化，这是由于空气中石膏的老化过程造成的。该过程可分为两个阶段:首先，将可溶性硬石膏(一种无水石膏)快速水化成半水合物;从那以后，半水石膏吸收水的速度非常慢，使晶体完整，导致混合水的量逐渐减少。当空气相对湿度较低，水溶性硬石膏反应完全时，石膏粉可达到一定的含水量。如果空气相对湿度较高，则水化反应继续，会形成二水石膏，对石膏粉质量和生产稳定性控制带来不利影响。一般来说，企业在石膏粉的储存和使用前的性能测试，所以可以判断石膏粉的模具要求，同时根据石膏粉的性能调整石膏的生产模具参数，达到模具的要求。

　　The research results of foreign scholars show that the moisture content and rheological properties of gypsum powder change with the change of storage time, which is caused by the aging process of gypsum in the air. The process can be divided into two stages: first, the soluble anhydrite (a kind of anhydrous gypsum) is rapidly hydrated into a hemihydrate; since then, the rate of water absorption of hemihydrate is very slow, making the crystal complete, leading to the gradual reduction of the amount of mixed water. When the relative humidity of air is low and the reaction of water-soluble anhydrite is complete, the gypsum powder can reach a certain water content. If the relative humidity of the air is high, the hydration reaction will continue, and dihydrate gypsum will be formed, which will bring adverse effects on the quality of gypsum powder and production stability control. Generally speaking, the enterprise's performance test before the storage and use of gypsum powder can judge the mold requirements of gypsum powder, and adjust the production mold parameters of gypsum according to the performance of gypsum powder to meet the mold requirements.

　　以上是济南石膏粉厂家为大家介绍的相关内容，想要了解更多内容，欢迎访问网站：https://www.jnfhjc.comThe above is the relevant content introduced by Jinan gypsum powder manufacturer. To learn more, please visit the website: https://www.jnfhjc.com