Sulfur is extracted from both surface and underground deposits and is also recovered as a byproduct of various industrial processes. There are three main techniques used in sulfur mining: conventional underground mining, open-pit mining, and the Frasch method. Approximately 90% of all mined sulfur is obtained through the Frasch process. The Frasch method, along with sulfur recovery processes and sulfuric acid production, are described below.(Understanding the Operation of Grinding Mills in the Mining and Mineral Processing Industry – NEWS – SMMVIK Machinery, n.d.).
In the Frasch mining method, a well is drilled into underground sulfur deposits, and superheated water (~170°C) is injected to melt the sulfur. Compressed air is then used to push the molten sulfur to the surface, where it cools and solidifies for collection. This technique yields high-purity sulfur but requires careful management of environmental impacts, including water use, thermal pollution, and potential ground subsidence(Frasch Process | Sulfur Mining, Superheated Water, Subterranean | Britannica, n.d.).
Recovered elemental sulfur is mainly a byproduct of refining crude oil and processing sour natural gas, produced to meet environmental regulations. Sulfur is extracted by converting hydrogen sulfide—present in natural gas and formed from sulfur compounds in oil—into elemental sulfur using the Claus process. This involves partial combustion of hydrogen sulfide to form sulfur dioxide, followed by catalytic reactions to produce sulfur, which is then condensed and collected in liquid form. Any remaining sulfur gases are incinerated before release to minimize emissions(Wessel & Ober, 1980).
Is it surprising that most of the world’s sulfur isn’t “mined” at all?
Reference:
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Frasch process | Sulfur Mining, Superheated Water, Subterranean | Britannica. (n.d.). Retrieved September 23, 2025, from https://www.britannica.com/technology/Frasch-process
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Understanding the operation of grinding mills in the mining and mineral processing industry—NEWS – SMMVIK Machinery. (n.d.). Retrieved September 17, 2025, from https://www.millvik.com/news/understanding-the-operation-of-grinding.html
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Wessel, G. R., & Ober, J. (1980). 1 Joyce Ober, “Sulfur,” from Mineral Commodity Summaries, U.S. Bureau of Mines, January 1995, pp. 166-167.
