摘要：

1304781 Hydrogen fluoride ALLIED CHEMICAL CORP 1 July 1970 [11 Nov 1969] 31954/70 Heading C1A Hydrogen fluoride is produced continuously by introducing substantially equimolar amounts of fluorspar and sulphuric acid, together with calcium sulphate, at or near to one end of a rotary furnace heated to a temperature of 250 to 650 F., withdrawing solid material, consisting mainly or wholly of calcium sulphate, from the furnace at a point at which the production of hydrogen fluoride from the fluorspar is more than 70% complete, and recycling this withdrawn material to the input end of the furnace as the source of calcium sulphate, the amount of calcium sulphate in the system being such that the molar proportion thereof in the reaction mixture at the input end of the furnace is more than 3 moles and up to 10 moles for every mole of fluorspar introduced. Examples compare the reaction with or without the presence of calcium sulphate. In Example 2, 13,300 lb./hour of sulphuric acid, 11,000 lb./hour of acid grade fluorspar and 4 moles of recycled calcium sulphate for every mole of fluorspar fed are added to a rotary furnace at 350 to 450 F.

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