CHAPTER VI.

MANUFACTURE OF PHOSPHORUS.

Operations included in the ordinary method of preparing phosphorus; Burning the bones to ash; Kiln used for this purpose 117

Improved form of kiln proposed by Fleck; Mode of operation with a kiln of this construction 118

Quantity of substance which remains after burning the bones; Composition of bone ash; Conversion of the bone ash into a coarse powder; Decomposition of the bone ash by sulphuric acid 119

Separate processes which have to be distinguished; Embodiment of these processes in equations 120

Actual yield of phosphorus; Methods by which the formation of calcium phosphate may be effected; Process without the assistance of heat 121

Decomposition of the bone ash in the warm way 122

Apparatus for hot lixiviation 123

Evaporation of the liquor; Mixing the fluid with charcoal 124

Yield of so-called distilling mass; Utilization of the liquor obtained in treating bones for the manufacture of glue with hydrochloric acid; Concentration of the liquor for crystallization 125

Mode of obtaining the calcium phosphate contained in the mother-liquor; Drying the crystals 126

Mixing the crystals with charcoal; Evaporating pans; Treatment of the residue of basic calcium phosphate left in the manufacture of phosphorus; Distillation of the phosphorus; Conversion of the acid calcium phosphate into calcium metaphosphate and reduction of the latter; Retorts and furnace for distilling the mixture of acid calcium phosphate and charcoal; The galley-furnace 127

Modification of the galley-furnace, described and illustrated 128

Furnaces for the use of coke as fuel; Receivers for collecting the phosphorus distilling over 129

Process of distillation; Indication of the commencement of distillation 130

Removing the phosphorus from the receivers; Regaining the phosphoric acid contained in the water from the receivers; Constitution of crude phosphorus 131

Refining and purifying the phosphorus; Various methods of purification; Percentage of loss of phosphorus 132

Distillation of the crude product in order to obtain pure phosphorus; Retorts and distilling apparatus for this purpose, described and illustrated 133

Process of distillation; Different qualities of the phosphorus passing over in the various stages of distillation; Separation of the phosphorus passing over according to quality 134

Moulding the refined phosphorus; Seubert’s apparatus for this purpose 135

Disadvantages of Seubert’s apparatus; Improved apparatus by which the operation is rendered perfectly free from danger, described and illustrated 136

Moulding the phosphorus in wedge-shaped sheet-metal boxes 137

Mode of storing and shipping phosphorus; Manufacture of phosphorus with the assistance of electricity; Mixture used for the operation 138

Furnace employed for the electrolytic manufacture of phosphorus, described and illustrated 139

Mode of operating the furnace 140