THE MANUFACTUKE OF PHOSPHOEUS. 169 



thus separated from the lime is filtered and evaporated to a sympy 

 ■consistency. It is mixed with granular retort charcoal, heated in a 

 reverberatory furnace, and treated in an electric furnace, the arc 

 issuing impetuously between the electrodes and traversing the 

 mass. An atmosphere of hydrogen is produced by injecting 

 petroleum spirit pulverized in the furnace. 



CHbVs Furnace.— In this furnace, which was specially designed 

 •for the manufacture of phosphorus, the electric current instead of 

 •traversing the whole of the mass, passes without interruption into 

 ■an intermediate circuit of great resistance, such as a cylinder of 

 retort charcoal placed above the charge. This cylinder becomes 

 incandescent and the arch of the furnace reflects the heat as in a 

 reverberatorv furnace. 



Irvine s !F«r«ace.— Eeadman's process was modified in Irvine's 

 1901 patent. The charge is made up as in the original method ; 

 Ihowever, phosphates of alumina or calcium may be used indifferently 

 with the silica or basic flux. The tv/o electrodes of retort charcoal 

 •are suspended vertically, and their lower parts reunited at the 

 beginaing of the operation by coal through which the current first 

 passes. When the charge has melted, the slag formed collects on 

 the top and reunites the two electrodes ; that is, henceforth it is 

 through this slag that the current passes. The fusion is continued, 

 the excess of slag is run off as it is produced, so that the extremities 

 ■of the electrodes are never uncovered. 



Duncan's Patent. — In Duncan's process, patented in 1903, 

 seventy-seven parts of ground phosphate are taken, whether of organic 

 -or mineral origin, twenty-three parts of ground coal, and mixed with 

 tar acting as an agglutinant. The paste is dried, and after heatmg, 

 which is done for economy in a hydrogen flame, a bye-product of the 

 manufacture, the product is placed in an electrical furnace; this 

 •continuously produces phosphide of calcium. This phosphide m 

 .contact with water in an atmosphere of hydrogen, gives off phos- 

 phuretted hydrogens, which, when heated, are converted into red 

 and white phosphorus according to the temperature at which con- 

 'densation is effected. 



Parker s Patent. — This process, which was patented in Great 

 Britain by Parker in 1902, concerns the treatment of phosphate of 

 aluminium. This phosphate is treated by sulphuric acid, then by a 

 sulphate capable of forming an alum with the sulphate of aluminium, 

 which is produced. All the alumina is separated by crystallization 

 •of the alum, and before the electric treatment. The residual liquid 

 is mixed with coal or other bodies rich in carbon, and reduced in an 

 ■electric furnace. 



Landis Method. — The American Phosphorus Company of 

 Philadelphia possesses a factory at Yorkhaven where phosphorus 

 iis extracted from wavellite, using a method designed by G. G. 



