922

SULPHUR. —Extraction by Steam.

troublesome, as the workman has to stand in a veryinconvenient position in order to reach down to the

Fig. 9.

Fig. 10.

bottom of the retort with a shovel; whilst, at thesame time, he is exposed to the sulphurous fumeswhich are still being given off. A complete opera-tion lasts twelve hours, and each retort distils intwenty-four hours 300 kilos, (about 6 cwts.) of ore.

At Radoboi, in Croatia , the mineral is heated ina cast-iron pan, and the sulphur vapour at onceconducted into a large chamber. The vapour con-denses, and flowers of sulphur are deposited onthe walls.

7. Liquation by Means of Steam .—The great loss ofsulphur in the calcarone process has induced thetrial of numerous other plans; and a company inItaly has introduced Thomas’ apparatus, in whichthe melting of the sulphur is performed by steam,at a pressure of from 3 to 5 atmospheres. * Plate I.shows a modification of E. Thomas’ apparatus,introduced by M. Pirckiiey at the sulphur minesof Latera, in the province of Rome , where the orescontain 13 to 14 per cent, of sulphur.

The conical vessel, a, made of F-inch iron plates,is provided at both ends with cast-iron flanges, b b',through which bolts pass for making the joints.The vessel is supported by means of flanges, c c, oniron beams, d, which are carried on iron columns, ffInside this vessel is a second cone, g, made of f-inchplate, and pierced with holes. It is fastened by* “Journal of the Society of Arts,” 1st May, 1868.

bolts to the flange, V. At the lower part of thevessel, a, there is a grating, a'", formed of two semi-circular cast-iron plates, perforated with holes, andmovable about a hinge. Two screws, h, keep thegrating horizontal during the filling; and whenthey are withdrawn, the two halves hang downvertically.

The inner cone, g, serves toreceive the ore. The arrangementof the holes, their size, and theconical form of the apparatus areof the greatest importance, bothfor the liquation and subsequentremoval of the residues.

The top of the vessel, a', isclosed by means of a cast-ironcover, i, and india-rubber washer;the iron ring, is used in movingit. To the under part of thevessel, a", is fixed a cast-ironreceiver, with a steam jacket.It can be moved away on a trolly,running on rails, when the opera-tion is finished, so as to allow theresidues to be emptied. This re-ceiver is provided inside with aperforated plate of cast-iron, n.At its base is a pipe, o, with aspecially - shaped iron tap fordrawing off the condensed waterand molten sulphur. The ex-ternal vessel, a, is provided withtwo pipes:—One, p, carries thevalve and steam pipe, besides asteam-gauge and pyrometer ; theother, q, is the outlet of the steam.

The pipe and valve, r, connected with / by apipe with screw joints, leads the steam into thespace, l, and keeps the receiver at the temperatureof melting sulphur. The cocks, s, serve for clean-ing. The outer vessel, the reservoir, and pipes areall surrounded with a bad conductor of heat, kepttogether by wooden staves. The tube and cock forthe outlet are so arranged that the steam from anapparatus that has finished a charge can be drawnoff and led into another. The exhaust steam isused for warming the feed water.

The pillars, f prolonged above the beams, d,carry the beams which form the working floor, t.A tramway, x, with the trolly, x', serves to connectall the apparatuses. The tram-waggons from thepicking floors come in at the level, z, are carried bythe trolly, and tipped into any apparatus. Undereach apparatus there is a shaft, 26 feet deep ; theseshafts are connected with the mine by a level, andserve for carrying off the residues.

This arrangement may naturally be modifiedaccording to the position and requirements of themine. The important point, however, is that thisarrangement allows the residues to be removed veryrapidly. Above the top of the apparatus, and ona frame not shown in the figure, there is a smallcarriage, with a differential pulley, which serves