Production of ferric chloride and phosphorus trichloride

摘要

Phosphorus trichloride and ferric chloride are obtained by mixing fully chlorinated ferrophosphorus with unchlorinated ferrophosphorus at 270-486 DEG C., whereupon phosphorus trichloride is evolved, and chlorinating the residue at 315-486 DEG C. whereupon ferric chloride sublimes. In the illustrated continuous process ferrophosphorus is chlorinated at 500-1200 DEG C. on a grate in vessel 2, the liquid product collecting in 3. Gases evolved are passed through a bed 4 of finely divided ferrophosphorus which absorbs phosphorus and titanium compounds, leaving silicon tetrachloride which is condensed at 5. The chlorinated and unchlorinated materials are mixed in vessels 6, 61 alternately while the residue in the other vessel is being chlorinated. The ferric chloride is collected in vessel 8. The impure phosphorus trichloride is condensed at 7 and redistilled at 10 to produce gaseous fractions of silicon tetrachloride and phosphorus trichloride and a solid residue containing titanium tetrachloride and phosphorus oxychloride, which are separated as described in Specification 805,154, by treating with ferric chloride to liberate titanium tetrachloride and phosphorus oxychloride, and recycling the residue to 3. Specification 312,685, [Class 1 (ii)], also is referred to.