Sulfur vulcanization sulfur is not miscible in the polymer prior to vulcanization and attention is paid to prevent sulfur bloom, where it migrates to the surface of the article. Accelerators act much like catalysts allowing vulcanisation to be performed cooler yet faster and with a more efficient use of sulfur. They achieve this by reacting with and breaking the sulfur ring to form a reactive intermediate, referred to as a sulfurating agent. This in turn reacts with cure sites in the rubber to bring about vulcanization. There are two major classes of vulcanization accelerators: primary accelerators and secondary accelerators (also known as
Frasch process Frasch process The Frasch process is a method to extract sulphur from underground deposits. It is the only industrial method of recovering sulphur from elemental deposits. Most of the world's sulfur was obtained this way until the late 20th century, when sulfur recovered from petroleum and gas sources became more commonplace (see Claus process). In the Frasch process, superheated water is pumped into the sulphur deposit; the sulfur melts and is extracted. The Frasch process is able to produce high purity sulfur. The Frasch sulfur process works best on either salt domes or bedded evaporite deposits, where sulfur is found