GB801246A - Processing an aqueous phosphorus emulsion - Google Patents

Abstract

Phosphorus pentoxide is produced by burning a mixture of an aqueous phosphorus emulsion and substantially pure liquid yellow phosphorus, preferably at a temperature of 80-90 DEG C. Admixing may be effected at the same temperature by a stirrer or by injection of an inert gas. The mixture may be covered with a layer of water in which case stirring may be by a slowly operating blade stirrer. The mixture may be stored in a tank kept at a constant temperature by means of a heating jacket. The emulsion may be a phosphorus sludge obtained by precipitating with water previously dust-freed phosphorus vapour from a phosphate reduction furnace. Such sludge may contain 25-75 per cent of phosphorus and 2-4 per cent of solid impurities. It is preferred to use a sludge containing 40-60 per cent of phosphorus and 2 per cent of solid impurities. The proportion to sludge to pure phosphorus may be 1 : 1-10 and is preferably 1 : 5. The sludge is preferably washed with water before admixing. The phosphorus pentoxide produced may be hydrated to produce an anhydrous phosphoric acid and may be further diluted to any desired concentration. Suspended impurity in the aqueous phosphoric acid may be removed by filtration.