Over the years, the world's production of hydrofluoric acid fluorite industrial routes are almost all the use of various forms of rotary kiln process carried out. In the reaction process, the state of the material in the rotary kiln and the reaction process has a great relationship. When the degree of reaction is 0 ~ 40% and 70% ~ 80%, the material is corrosive to the reactor. Therefore, how to design the rotary kiln to avoid corrosion to extend the service life of the process has been one of the key issues. According to the structure of the rotary kiln can be divided into simple rotary kiln, with pre-mixer rotary kiln, with pre-reactor rotary kiln, in the slag rotary kiln, pre-reactor slagging rotary kiln and with pre-reactor, Back to the slag, broken rotary kiln.

In order to reduce the corrosion of hydrofluoric acid on the rotary kiln and prolong the service life, the pre-reactor is developed. The pre-reactor is made of expensive high-nickel corrosion-resistant alloy. The corrosion stage of the reaction is 30% ~ 60% in order to strengthen the heat transfer and reduce corrosion, the development of the slag back process, a large number of hot gypsum carry heat from the back end of the rotary kiln feed end, the rapid heat transfer to the reactor of the material, and can reduce the corrosion of the rotary kiln body. These two rotary kilns require a large amount of high-nickel alloy because of the huge investment in the reactor.

Continuous use of rotary kiln technology to produce hydrofluoric acid from the current equipment and technology has been fully developed, from the production and maintenance, operating costs, equipment cost, raw material consumption has been difficult to further reduce. The hidden dangers of environmental pollution is also difficult to eliminate.