The effect of retarder is as follows:

　　1)降低半水石膏的溶解度;

　　1) Decrease the solubility of hemihydrate gypsum;

　　2)減緩半水化石膏的溶解速度;

　　2) slowing down the dissolution rate of hemihydrated gypsum;

　　3)吸附結晶石膏二水化物晶體表面的離子，并將其結合到晶格中;

　　3) Adsorb the ions on the crystal surface of crystalline gypsum dihydrate and combine them into the lattice.

　　4)形成絡合物，限制離子向二水石膏晶體附近擴散。

　　4) Formation of complexes to restrict ion diffusion near dihydrate gypsum crystals.

　　常用緩凝劑主要有:堿性磷酸鹽和磷酸銨、有機酸及其可溶性鹽(如檸檬酸和檸檬酸鹽)、受損蛋白等。

　　Commonly used retarders are alkaline phosphate and ammonium phosphate, organic acid and its soluble salts (such as citric acid and citrate), damaged protein, etc.

　　學者們對幾種緩凝劑進行了測試，結果表明，緩凝劑的緩凝效果按如下順序增加。結果表明，在初始凝固時結晶較粗、較短，硬化強度低于純水。

　　Scholars have tested several retarders. The results show that the retarding effect of retarders increases in the following order. The results show that the initial solidification crystallization is coarser and shorter, and the hardening strength is lower than that of pure water.

　　學者等研究了蔗糖對巴黎石膏凝固過程的影響，發現當Ca(OH)2同時存在時，蔗糖對巴黎石膏具有明顯的緩凝作用，認為這可以用吸附理論來解釋。

　　Scholars have studied the effect of sucrose on the solidification process of Paris gypsum, and found that when Ca (OH) 2 exists at the same time, sucrose has obvious retarding effect on Paris gypsum, which can be explained by adsorption theory.

　　關于檸檬酸和檸檬酸鈉的延緩作用，專家認為檸檬酸具有延緩作用。加入少量(小于0.1%)，有輕微的緩速效果，強度略有降低。當摻量增加(超過0.2%)時，會嚴重影響二水石膏晶體的形成習慣，使晶體不能相互生長和連接。石膏漿即使完全水化，也不會凝結。

　　As for the delaying effect of citric acid and sodium citrate, experts believe that citric acid has delaying effect. Adding a small amount (less than 0.1%) has a slight slow-down effect and a slight decrease in strength. When the content increases (more than 0.2%), the formation habit of dihydrate gypsum crystals will be seriously affected, so that the crystals can not grow and connect with each other. Gypsum slurry will not coagulate even if it is completely hydrated.

　　學者們研究了檸檬酸鈉對巴黎石膏凝固的影響，發現檸檬酸鈉在含量大于0.1%時具有較強的緩凝作用，降低了硬化漿體的強度。但當摻量低于0.05%時，具有促進凝固的作用，硬化強度高于純水。他們認為這是因為在濃度超過0.1%時，由于冷凝時間長，晶體完全長大，并且它具有促進結晶生長的作用，所以結晶體的形成，硬化強度降低。但在低濃度下，情況正好相反，就像在水中一樣，會產生細小的針狀晶體。

　　Scholars have studied the effect of sodium citrate on the solidification of Paris gypsum, and found that sodium citrate has a strong retarding effect when the content of sodium citrate is more than 0.1%, which reduces the strength of hardened paste. But when the dosage is less than 0.05%, it can promote the solidification, and the hardening strength is higher than that of pure water. They think that the reason is that when the concentration exceeds 0.1%, because of the long time of condensation, the crystal grows completely, and it has the effect of promoting crystal growth, so the formation of crystals and the hardening strength decrease. At low concentrations, however, the opposite is true, as in water, where fine needle-like crystals are produced.

　　混凝劑溫和的凝血機制往往由于各種原因變得非常復雜,有時超出摻合料的佳用量本身會產生相反的效果,有時兩個或更多外面的另一個復合混合了反效果,除了進一步的研究在理論上,這些問題取決于積累經驗在生產實踐的過程中,選擇合適的劑量的添加劑品種和選擇好的。

　　The mild coagulation mechanism of coagulant often becomes very complicated for various reasons. Sometimes the best dosage of coagulant will produce the opposite effect. Sometimes the compound of two or more outside will mix the opposite effect. In addition to further research, these problems depend on the selection of the most appropriate dosage of additives in the process of production and practice. Choose the best.