What factors affect the stability of gypsum calcining equipment

The influence of gypsum calcining equipment on product stability is determined by many factors, such as equipment type, heat exchange mode, equipment structure, control mode, process parameters, heating mode, feeding mode, etc; Equipment structure, heat exchange mode, heating mode and feeding mode are common influencing factors.

When the equipment structure is reasonable, the gypsum raw materials tend to be uniformly heated in the calcination equipment, the heating degree and heating time of the raw materials in the calcination equipment tend to be consistent, the dehydration degree is very close, and the equipment with better structure treatment can even reach the different fineness of raw materials. After the raw materials enter the calcination equipment, the fine powdery materials and granular gypsum all leave the calcination equipment at the different calcination time that they just reach the better calcination; Thus, the proportion of semi aqueous phase is relatively high, the unstable ratio affecting product quality is relatively low, and the proportion of dihydrate gypsum affecting setting time is relatively low.

Different heat transfer forms have different effects on the heat transfer process. At present, there are two common forms of heat exchange, such as direct heat exchange and indirect heat exchange; Direct heat exchange means that the hot flue gas generated by fuel combustion is introduced into the calcination equipment to directly contact with gypsum raw materials for heat exchange. In order to achieve higher output, this type of equipment generally uses the flue gas with higher temperature to quickly contact with gypsum for heat exchange, with higher heat exchange efficiency and faster heat exchange speed.

Because the heat exchange process is high temperature and quick contact, it is difficult to control the process. The temperature fluctuation of high temperature flue gas, the fluctuation of gypsum particle size and feeding amount, and the fluctuation of air flow will affect the heat exchange effect. The uniformity of the heat exchange process is difficult to control. The proportion of hemihydrate gypsum phase in the product is relatively low, and the proportion of dihydrate gypsum phase and AIII phase is high. Therefore, the quality of gypsum products fluctuates greatly, and the product setting time is fast;

The temperature curve of heat transfer process is obvious; In the process of heat exchange, the small fluctuation of heat medium and feeding amount needs a process to affect the calcination effect;

The heat exchange time in the gypsum calcining equipment is long, and it is easier to be uniform through the continuous churning of logistics in the dynamic heat exchange process; The thermal medium does not pollute gypsum products during calcination, which is conducive to the recycling of tail gas.