Low-temperature hydrogen fluoride industrial test successfully

The trial production of a hydrogen fluoride process industrial pilot plant by the low-temperature method developed by Zhang Zhixin, a former senior engineer at the Nanchang Institute of Technology, was successful. The test facility built at Nanchang Xinxin Chemical Technology Co., Ltd. produced two types of hydrofluoric acid containing 40% fluorine and 55% of fluorine. All the tested products reached the national standard. Compared with the traditional process, the low-temperature process has short process flow, low energy consumption, low investment, no waste of raw materials, low unit product consumption, and also avoids "three wastes" emissions, and economic and environmental benefits are all significant.
At present, domestic and international hydrogen fluoride production plants use sulfuric acid and fluorite powder as raw materials and are produced by the converter method. The disadvantage of the converter method is that a small amount of fluorite powder covered with calcium sulfate does not come into contact with sulfuric acid and the reaction is incomplete. The unreacted fluorite powder and the resultant gypsum are mixed together to form a fluorogypsum waste residue. At the same time, temperatures as high as 500° C. in the furnace cause some of the sulfuric acid volatiles, decomposition products, and a small amount of fluorspar dust to enter the body of hydrogen fluoride gas, causing subsequent refining difficulties. In addition, this method is prone to leakage of fluorinated hydrogen in vitro. The discharged fluorogypsum waste contains not only a small amount of fluorite powder but also a small amount of hydrogen fluoride gas, causing environmental pollution.
The low-temperature process also uses sulfuric acid and fluorite powder to produce hydrogen fluoride. However, the process involves adding fluorite powder to a liquid reaction medium that has a certain solubility to calcium fluoride. After the calcium fluoride is slightly dissolved by stirring, sulfuric acid is added. The reaction; the reaction is carried out in the liquid phase and under stirring conditions, and the temperature is controlled to about 90° C. with proper heating, so that it is not easy to form the calcium sulfate coating, and the purified hydrogen fluoride gas is directly obtained. The reaction speed is fast and the reaction is complete.

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