Minerals Information
Sulfur is one of the few elements that occurs in the native, or elemental, state. It also occurs combined with iron and base metals and sulfide minerals and with the alkali metals and alkali earths as sulfate minerals. In petroleum, sulfur is found in a variety of complex organic compounds and in natural gas as hydrogen sulfide. In coal, sulfur occurs in complex organic compounds and as "coal brasses" (pyrites-marcasite). Commercial production of sulfur in the United States is accomplished by a variety of methods dictated by the source of the sulfur.
The primary source of elemental sulfur is classified as recovered sulfur. It is recovered during the refining of crude oil and the purification of natural gas. The next largest type of elemental sulfur is Frasch sulfur. With this method, native sulfur is extracted through a hot water process that is named after its inventor. Sulfuric acid is recovered as a byproduct during the smelting of copper, lead, molybdenum, and zinc. Sulfur in other forms is also produced (i.e., pyrites, hydrogen sulfide, and sulfuric dioxide), but on a minor scale.