Frasch process

The Frasch process was developed by Hermann Frasch in 1890 and serves the recovery of elemental sulfur from deep sulfur deposits without previous mining degradation by the so-called Frasch probe.

Implementation

For this, a 25 cm thick pipe is first driven to the deposits. This tube is introduced through two more nested tubes diameter of about 15 cm and 7 cm.

In the interval between the first, second and outer pipe superheated water is pressed from 155 ° C at high pressure into the bearings. This penetrates at the end of a through small lateral openings in the sulfur and bring it to melt. By the innermost tube hot compressed air is then pressed and thus promoted the liquid sulfur in the central tube top. The sulfur remains liquid by the superheated water in the outer jacket.

This Frasch probe underground sulfur deposits can be exploited in up to 1000 m depth. Depending on the deposit is funded sulfur of very high purity. Frasch sulfur per probe are promoted per day up to 300 tons. To this end the about 10 to 15 times the amount needed to superheated steam.

While were on the Frasch process, won in 1901 by the Union Sulphur about 3,000 tons of sulfur, founded by Hermann Frasch, 1903 there were already 23,000 tons. 1904 was able to cover all of the sulfur requirement of the United States, the Frasch process. For economic reasons, the working with the Frasch process plants have been shut down since 2000, no sulfur is more encouraged by this process in the United States.