| 摘要 |
Acid ammonium fluoride having a HF/NH3 molar ratio of 1.50 to 2.10 is prepared by mixing at 230-240 DEG C. anhydrous HF gas with NH3 gas in the desired molar ratio, the latter being maintained constant within a maximum tolerance of 1% based on the total flow of the reactants, condensing the resulting gaseous reaction product, and cooling the molten condensate, which is maintained at a temperature between the melting point of the solid product and 170 DEG C., on a surface kept at a temperature not exceeding 100 DEG C. The temperature of between 230-240 DEG C. may be maintained solely by the heat of reaction at ambient pressure. The reactant gases may be contacted at the intersection of two tubes, one horizontal, the other vertical. The reaction mixture is condensed in a suitable heat-exchanger and passed into a vessel maintained at a temperature slightly in excess of the melting temperature of the product. A rotating cylinder may be arranged inside, the surface of which is cooled by water flowing within. The product is solidified on the cylinder surface, removed therefrom by cutters and collected by gravity feed through a hopper in storage bins. |
