Glossary

Alkylation
In refinery processing the introduction of an alkyl group into a molecule; sulphuric acid is a catalyst in alkylation.

Brimstone
Brimstone, which refers solely to sulphur produced in its elemental form, is used to distinguish elemental sulphur from other sulphur-containing compounds. Brimstone can be recovered from sour oil and gas streams, or mined by processes such as Frasch or as native refined sulphur.

Caprolactam
Nylon-6 fiber, an end-use for sulphuric acid.

Chemical properties of sulphur
Sulphur combines directly with almost all the elements with the exception of gold, platinum and the noble gases. In its native form, sulphur is a yellow crystalline solid. It can be found as a pure element or as sulphate or sulphide minerals. The crystallography of sulfur is complex. Depending on the specific conditions, the sulfur allotropes form several distinct crystal structures, with rhombic and monoclinic S8 best known.

Diammonium phosphate
Major phosphate fertilizer; sulphuric acid is input for phosphate fertilizer manufacture.

Flowers of sulphur (sublimed sulphur)
Powdered form of sulphur produced by sublimation; may contain up to 30% of the amorphous allotrope; used in rubber vulcanization, agricultural dusts, pharmaceutical products, stock feeds.

Formed, solid sulphur
Sulphur formed to a specific shape, such as prills, granules, pellets, pastilles, or flakes; see prilled sulphur.

Frasch process
After Herman Frasch, (1851-1914), hot-water sulphur mining process.

Hydrogen sulphide
Sulphide occurs naturally in mineral ores, oil and coal deposits. Natural waters containing elevated concentrations of hydrogen sulphide are used for therapeutic baths and have been consumed for medical purposes. Hydrogen sulphide (H2S), which exists as a colorless gas under normal conditions, has a characteristic odor of rotten eggs and occurs naturally in coal, natural gas, oil, volcanic gases, and sulphur springs and lakes; H2S is a central participant in the sulphur cycle, the biogeochemical cycle of sulphur on earth. Sulphides form an indispensable link in the sulphur cycle (the reversible interconversion of sulphide and sulphate) in nature. Petroleum refineries and gas processing plants extract H2S when making “clean fuels” and use it as a feed stock to produce sulphur and water.

Liquid sulphur
Sulphur in melted and liquid form (at 127-143º C, or 260-290º F).

Lump and coarse grained sulphur
Sulphur in the form of a mixture of lumps and fines resulting from mechanical breaking of large blocks of solid sulphur; shipments may contain 50 wt % fines and lump diameters up to 20 cm or more.

Molten sulphur
See liquid sulphur.

Native sulphur
Sulphur that occurs in nature in the elemental form.

Oil sands
Tar sands-natural sand formations containing about 10% bitumen and with high hydrogen sulphide content.

Phosphogypsum
Calcium sulphate by-product from phosphate production.

Prills
Formed, solid sulphur in spherical shape; produced by cooling molten sulphur with air or water.

Pyrites
Pyrites are a common mineral comprised of iron and sulphur compounds. Pyrites include a range of sulphide materials, such as marcasite, pyrite, and pyrrhotite.

Roll sulphur
Formed, solid sulphur cast into convenient cylindrical sizes; uses include chemical manufacturing, burned for curing, fumigating, and preserving or bleaching effects.

Smelting
A roasting process to obtain metals from their ores; sulphuric acid is obtained from the process if sulphur dioxide is removed.

Sour crude and gas
Petroleum oil and natural gas, respectively, with high content of hydrogen sulphide.

Specialty sulphur
Prepared or refined grades of elemental sulphur that include amorphous, colloidal, flower, precipitated, wettable, or paste sulphur.

Sulphur
Sulfur is the preferred spelling in the United States, but the formal name of The Sulphur Institute is spelled with a "ph."

Sulphur dioxide
Also referred to as sulphurous anhydride, sulphur dioxide has the chemical formula SO2. It is produced by volcanoes and in various industrial processes. Sulphur dioxide, which exists as a colorless gas uder normal conditions, has a characteristic strong odor and is highly soluble in water. Sulphur dioxide is used in many industrial processes such as chemical preparation, refining, pulp-making and solvent extration and also is the feed stock to manufacture sulphuric acid. Sulphur dioxide is also used in the preparation and preservation of food because it prevents bacterial growth and browning of fruit.

Sulphur flour
Crude sulphur ground through 50-74 µm sieves (300-200 mesh), depending on the brand; used in rubber vulcanization, dyes, gun powder, agricultural dusts, dusting and wettable sulphur.

Sulphuric acid
Sometimes referred to as the "king of chemicals," sulphuric acid is a strong mineral acid with the formula H2SO4. It is soluble in water at all concentrations. Sulfuric acid has many applications, and is produced in greater amounts than any other chemical besides water. Principal uses include ore processing, fertilizer manufacturing, oil refining, wastewater processing, and chemical synthesis.

Sulphur in other forms (SOF)
Sulphur in other forms includes forms other than brimstone or pyrites, where sulphur is produced in the form of sulphuric acid or other sulphur compounds without prior refining to brimstone. Most SOF originates from the smelting of non-ferrous metals, led by copper, follwed by zinc, lead, and nickel.

Sulphur in all forms
Sulphur in all forms is used to indicate the aggregate of brimstone, the equivalent sulphur content of pyrites, and the equivalent SOF. Sulphur can also be classified as discretionary (voluntary) and non-discretionary (non-voluntary) regarding the intent of its production. Discretionary sulphur is produced where there is an economic case for doing so. This normally includes Frasch, native sulphur, and pyrites. Non-discretionary sulphur has to be recovered, regardless of the economics of sulphur recovery, either for environmental/regulatory or process reasons. Recovered sulphur and SOF are almost always non-discretionary.

Sulphur uses
The major derivative of sulphur is sulphuric acid (H2SO4), the highest production volume chemical, used as an industrial raw material. The largest single use of sulphuric acid is for the manufacture of phosphoric acid, a precursor to phosphate fertilizers and non-fertilizer phosphates. Sulphur and its derivatives are also used in metallurgical ore leaching, caprolactam, pigments, hydrofluoric acid, pulp and paper chemicals, sulphur fertilizers, petroleum refining, batteries, detergents, fungicides, carbon disulphide, pharmaceuticals, personal care products, cosmetics, leather tanning, rubber vulcanization, plasticizers, dyestuffs, explosives, aramid fibers, construction materials, sugar manufacture, dehydrating agent in organic chemical and petrochemical processes, water treatment, and steel pickling.

Virgin sulphuric acid
Acid obtained from burning elemental sulphur.
Sulphur — an advantaged element®

Sulphur is present wherever you look, from the food we eat to the medicine we take. Click here to learn why TSI calls it "an advantaged element".