Generally, we only know that gypsum powder is used in construction industry, but seldom know that gypsum powder plays a very important role in agricultural production. The original application scope of gypsum powder is so wide. Hongtai gypsum introduces three major applications of gypsum powder in agriculture.

　　1、改良土壤，調(diào)節(jié)ph值，適宜鹽堿地、紅壤改良。

　　1. Improve the soil, adjust the pH value, suitable for the improvement of saline-alkali land and red soil.

　　2. 食用菌可作為鈣、硫復(fù)合礦質(zhì)肥料，調(diào)節(jié)培養(yǎng)基的ph值。

　　2. Edible fungi can be used as calcium and sulfur compound mineral fertilizer to regulate the pH value of the medium.

　　3.用于畜禽飼料的復(fù)合礦物飼料添加劑。

　　3. Compound mineral feed additives for livestock and poultry feed.

　　在生產(chǎn)中，由于石膏模具固有的易變性，使得石膏模具的質(zhì)量難以穩(wěn)定控制。這種變化的一個(gè)方面是膏體水比和膏體濃度對石膏模型性能的影響。一般來說，膏體水比小，模型孔隙率高，強(qiáng)度低，使用壽命短。膏體水比大，孔隙率低，強(qiáng)度高，使用壽命長。膏水比變化的影響與石膏粉的老化時(shí)間有關(guān)，尤其是新燒石膏粉與熟化石膏粉的差異。新燒石膏粉未發(fā)生變質(zhì)、均質(zhì)，溫度高，表面活性強(qiáng)，混水能力大。立即用于成型，模型表面會形成許多氣泡，整體強(qiáng)度較低。一般情況下，新炒制石膏粉需存放兩周后再敷。

　　In production, because of the inherent variability of gypsum mould, the quality of gypsum mould is difficult to control steadily. One aspect of this change is the influence of water ratio and concentration of gypsum on the performance of gypsum model. Generally speaking, the paste has small water ratio, high porosity, low strength and short service life. The paste has high water ratio, low porosity, high strength and long service life. The change of gypsum water ratio is related to the aging time of gypsum powder, especially the difference between newly fired gypsum powder and mature gypsum powder. The newly fired gypsum powder has no deterioration, homogenization, high temperature, strong surface activity and high water mixing capacity. When used immediately, many bubbles will be formed on the surface of the model, and the overall strength is low. Generally, the newly fried gypsum powder needs to be stored for two weeks before it is applied.

　　國外學(xué)者的研究結(jié)果表明，石膏粉的含水率和流變特性隨貯存時(shí)間的變化而變化，這是由于空氣中石膏的老化過程造成的。該工藝可分為兩個(gè)階段:一是可溶性無水石膏(無水石膏)快速水化形成半水石膏;半水石膏吸收水分的速度非常慢，使晶體轉(zhuǎn)化完成，混合水量逐漸下降。在空氣相對濕度較低的情況下，石膏粉經(jīng)水溶性硬石膏反應(yīng)后，其含水量可以達(dá)到一定的水平。如果空氣相對濕度偏高，水化反應(yīng)繼續(xù)，可形成二水石膏，對石膏粉質(zhì)量和生產(chǎn)穩(wěn)定控制帶來不利影響。一般來說,石膏粉的企業(yè)存儲和使用它的性能進(jìn)行測試,這樣可以判斷石膏粉模具需求,同時(shí)根據(jù)石膏粉的性能指數(shù)調(diào)整生產(chǎn)石膏模型的參數(shù),以滿足模具的要求。

　　The research results of foreign scholars show that the moisture content and rheological properties of gypsum powder vary with the storage time, which is due to the aging process of gypsum in the air. The process can be divided into two stages: one is the rapid hydration of soluble anhydrous gypsum (anhydrous gypsum) to form hemihydrate gypsum; the absorption rate of water by hemihydrate gypsum is very slow, so that the crystal transformation is completed, and the mixed water volume gradually decreases. When the relative humidity of air is low, the water content of gypsum powder can reach a certain level after the reaction of water-soluble anhydrite. If the relative humidity of air is relatively high and the hydration reaction continues, dihydrate gypsum can be formed, which has adverse effects on the quality and production stability control of gypsum powder. Generally speaking, gypsum powder enterprises store and use its performance to test, so as to judge the demand of gypsum powder mould, and adjust the parameters of the production model according to the performance index of gypsum powder to meet the requirements of the mould.