PURIFICATION OF YELLOW PHOSPHORUS

1354224 Purification of phosphorus KNAPSACK AG 27 June 1972 [16 July 1971] 29974/72 Heading C1A Purified yellow phosphorus is obtained by mixing liquid phosphorus with 0À5 to 5% by weight of an aqueous suspension of active carbon containing 50 to 500 kg/m3 of active carbon, the percentages being based on the weight of phosphorus, allowing to stand for 0À5 to 15 minutes and filtering off the carbon to obtain purified phosphorus. The carbon filter cake may be removed by centrifuging. The phosphorus and carbon suspension may be passed in counter-current through a mixing zone which zone may be in the form of a U- shaped tube. Preferably the active carbon used has an inner surface area of at least 800 m.2/gram. The process may be repeated several times until the resultant phosphorus contains less than 0À001% by weight of organic contaminants.