Ammonium Hydrogen Fluoride Vapor Synthesis Process Development

Ammonium bifluoride is an inorganic fluoride salt, whose consumption and output exceed tmi thousand of tons in China. It is mainly used as glass etchent, chemical reagent, boiler purgemt, disinfector for ferment industry and used for surface treatment. The market need of ammonium bifluoride has been ever-increasing since it was used as corrosive in decoration technique of aluminum surface. Ammonium bifluonde is mainly produced with the method of liquid phase in our countly now, with low investment and simple technique. However, the method results in a little high content of water in aminonium bifluoride and low purity, slow dissolution speed of product and short storage period. Comparatively, some special requirements from pharmaceutical and electric industries can be met through gas phase meth4to produce ammonium biiluoride with low content of water, high purity and long storage period. In this paper, the reactive mechanism is theoretically researched, and the preparation method of powder granule used in gas phase method is expounded, which provides a theory for the technique of gas phase method. There are several reversible reactions in this synthetic reaction, and its equilibrium constant is subject to reactive medium and temperature. An in-depth theoretical research proves that the water in ammonium biiluoride is difficult to be removed through common drying method, then several key process parameters are got for gas phase method. By virtue of these parameters, several different processed are designed and the optimal one is elected after experiments. In this paper. a piloted experiment with yield of 500 tons per year is provided, which paves the way for the industrialization of this process. The synthetic process of ammonium bifluoride with phase method developed in this paper will provide well-founded basis for the improvement of product quality and the modification of productive technique.