Sulfur is extracted by mainly two processes: the Sicilian process and the Frasch process.
The Sicilian process, which was first used in Sicily, was used in ancient times to get sulfur from rocks present in volcanic regions. In this process, the sulfur deposits are piled and stacked in brick kilns built on sloping hillsides, and with airspaces between them. Then powdered sulfur is put on top of the sulfur deposit and ignited. As the sulfur burns, the heat melts the sulfur deposits, causing the molten sulfur to flow down the sloping hillside. The molten sulfur can then be collected in wooden buckets.
The Frasch process is a method to extract sulfur from underground deposits. Holes are drilled down through the overlying rock into the sulfur deposits. A series of concentric perforated pipes are then inserted into the drill hole. The outer pipes contain superheated steam (usually about 160 °C) which is pumped down into the deposit. Since the melting point of sulfur is so low (115.21 °C, just a little over the boiling point of water), it readily liquefies. As the sulfur becomes molten, it is removed by pumping air down the central pipe. When the molten sulfur reaches the surface, it is pumped onto wooden blocks where the sulfur again solidifies.
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