GB1004382A - Production of phosphorus - Google Patents

Abstract

<PICT:1004382/C1/1> Elemental phosphorus is produced by reacting at a temperature of from 1020 DEG to 1500 DEG C. in a fluidized bed on solid particulate mixture of phosphate ore and an electrically conductive form of carbon, present in such amounts as substantially to surround the particles of phosphate ore, resistance heating being applied by passing an electric current between the electrically conductive particles. The ore may be any naturally occurring phosphatic material reducible to elemental phosphorus on heating with carbon. The carbon may be present at least in part as a coating on the ore particles. A liquid high molecular weight hydrocarbon may be used for the carbonization, but preferably a hydrocarbon having not more than 8 carbon atoms in the molecule, e.g. natural gas, is used in a "fluid coking" process, when the hydrocarbon may be added to the fluidized reaction mixture so as partially to replenish the carbon during the reaction. The process may be batchwise or continuous; a continuous process may utilize a multi-stage fluid bed reactor as in Fig. 2. 21 is a multi-compartment reactor fitted with gas distribution plates 22a-22e carrying solids in beds 23a-23e fed from bin 26. Fluidizing gas heated in one of stoves 28, 29 is fed into the base of unit 21. Electrical energy is supplied by sets of electrodes 25a, 25b, 25c and 26a, 26b, 26c. Gas leaving with 21 is freed of solids in cyclone 30 and passes through condensers 32, 33 into which water is sprayed from 34, 35. Condensed phosphorus is withdrawn via valve 36, 37. Examples are given. Specifications 807,884 and 854,884 are referred to.