Technical sulfur: properties, types and applications

Technical sulfur (S) is one of the most important products of the chemical industry, occupying a key place in the production of sulfuric acid, mineral fertilizers and carbon disulfide. Sulfur is a chemical element of Group VI of the periodic system, atomic number 16, atomic mass 32.065. Natural sulfur consists of four stable isotopes, the most abundant being ³²S (95.02%). The sulfur content in the Earth's crust is 0.034% by mass, and in sea and ocean water — 0.09%.

Historical Background

Sulfur has been known since ancient times: it was used in Egypt around 2000 BC for disinfection and bleaching fabrics. Sulfur was part of combustible mixtures for military purposes (e.g., Greek fire) and was used for fumigation in religious rituals. In China in the 8th century, sulfur was used to make gunpowder and pyrotechnic mixtures. During the period of Arab alchemy, the mercury-sulfur theory of metal composition arose, according to which sulfur was revered as the "father" of all metals. The elemental nature of sulfur was established by A. Lavoisier in 1777.

Physicochemical Properties

Sulfur is a solid crystalline substance of yellow colour, brittle, insoluble in water. It is readily soluble in carbon disulfide, toluene, benzene and other organic solvents. The melting point of monoclinic sulfur is 119.3 °C, and of rhombic sulfur — 112.8 °C. When heated above 160 °C, sulfur transforms into a viscous dark brown liquid, and at 444.6 °C it boils. Sulfur burns with a blue flame to form sulfur dioxide SO₂. Sulfur is a combustible substance.

Classification and Grades

According to GOST 127.1-93, technical sulfur, depending on the production method, is produced as liquid, lump, granular and ground. The standard applies to technical natural sulfur obtained from native sulfur and polymetallic sulfide ores, and technical gas sulfur obtained during the purification of natural and coke gases, as well as off-gases from oil and shale processing.

Liquid technical sulfur is a brown liquid. The presence of mechanical impurities (paper, wood, sand, etc.) is not allowed. The mass fraction of sulfur in the highest grade is at least 99.99%, in the first grade — at least 99.98%. The mass fraction of ash does not exceed 0.008% for the highest grade and 0.010% for the first.

Lump technical sulfur is produced in the form of irregularly shaped pieces. In lump sulfur, an increase in the mass fraction of water up to 2% is allowed, with recalculation of the actual batch mass to the standard moisture content. Lump sulfur is produced in several grades, including 9995 (sulfur content at least 99.95%).

Granular technical sulfur is obtained from liquid sulfur by the "dry process" and consists of hemispherical granules resistant to flaking and dusting, with minimal moisture content and high bulk density. Granular sulfur is convenient for transportation, storage and precise dosing. Grade 9998 (TU 20.13.66-134-31323949-2018) corresponds to a sulfur content of at least 99.98%.

Production Technology

The main sources of technical sulfur are natural sulfur ores, associated gases from oil and gas processing, and hydrogen sulfide extracted during natural gas purification. The largest industrial method for producing sulfur from hydrogen sulfide is the Claus process, which includes thermal and catalytic stages of H₂S oxidation to elemental sulfur. The resulting sulfur can be stored in liquid form at 140 °C in special tanks or granulated for subsequent transportation. Liquid sulfur is transported in special four-axle tank cars designed to operate at ambient temperatures down to minus 50 °C.

Applications

Sulfuric acid production. This is the largest consumption area for sulfur — it accounts for a significant share of global demand. Sulfur is burned to form sulfur dioxide, which is then oxidised to sulfur trioxide and absorbed by water to form sulfuric acid.

Mineral fertilizer production. Sulfur is used to produce phosphate fertilizers, as well as a component of complex NPK fertilizers. Adding sulfur to the soil improves the uptake of nitrogen and phosphorus by plants.

Agriculture. Granular sulfur is used to increase soil acidity when growing acid-loving plants: blueberries, bilberries, cranberries, lingonberries, hydrangeas. Sulfur is used for disinfecting greenhouses, vegetable stores and treating agricultural equipment.

Chemical industry. Sulfur serves as a feedstock for the production of carbon disulfide, dyes, rubber products, matches and gunpowder, as well as for producing sulfides and other chemical compounds.

Pulp and paper and textile industries. Sulfur is used in bleaching and processing pulp and fabrics.

Rubber industry. Sulfur is used in the vulcanisation of rubbers and rubber compounds, providing cross-linking and imparting elasticity to rubber products.

Construction. Sulfur is used in the production of sulfur concrete and sulfur asphalt concrete — composite building materials with high strength and chemical resistance.

Feed additives. Sulfur is used in animal husbandry as a feed additive to increase live weight gain, milk yield and improve product quality.

Global Market

According to the U.S. Geological Survey (USGS), 84 million tonnes of sulfur were produced worldwide in 2025. Global sulfur production capacity is estimated at 85 million tonnes, with actual utilisation close to full capacity, and additional supply growth is limited. Global sulfur production in 2025 grew by only 2.28%, significantly lower than the 2024 growth rate (about 4%).

The sulfur market is estimated to have moved into a deficit state by the end of 2025 — up to 3% of demand. The main drivers of demand growth were traditional agriculture (phosphate fertilizer production) and a new segment — new energy technologies, in particular the production of lithium iron phosphate (LFP) batteries. Global LFP battery production reached 3.77 million tonnes in 2025.

Sulfur prices in 2025 showed significant growth. In the Middle East, FOB prices rose from about USD 170 per tonne at the beginning of the year to about USD 520 per tonne by the end of the year. The Chinese sulfur market grew by more than 160% over the year, exceeding CNY 4,000 per tonne.

The Asia-Pacific region is the largest sulfur market. The Middle East accounts for more than 30% of global sulfur production. The largest producers are China, the USA, Russia, Canada and the Middle East countries. Main market trends include the transition to low-carbon technologies, growing demand from new energy technologies and tightening environmental requirements for sulfur emissions.

Production in Russia

Russia is one of the world's largest producers and exporters of sulfur. In January–November 2025, technical sulfur output in Russia decreased by 20.6% compared to the same period in 2024 — to 3.985 million tonnes. However, in November 2025, the decline rate slowed to 36.2% year-on-year, while month-on-month growth was 1.6 times — to 318,000 tonnes.

In November 2025, the Russian government imposed a temporary ban on the export of technical sulfur, which is a critical raw material for mineral fertilizer production. Sulfur production in Russia is concentrated at oil and gas complex and gas processing enterprises. The largest producers are Gazprom, Bashneft, Tatneft and others.

Safety and Storage

Sulfur is classified as a combustible substance. Sulfur dust is explosive. When burning, sulfur releases sulfur dioxide SO₂, which irritates the respiratory tract and mucous membranes. When working with sulfur, personal protective equipment must be used: respirators, protective goggles and protective clothing. Sulfur storage is carried out in closed warehouses or on special asphalted areas with concrete fencing. Liquid sulfur is stored in heated tanks at about 140 °C. During transportation and storage, contamination of sulfur with organic substances and moisture must be prevented.

Conclusion

Technical sulfur remains one of the key products of the global chemical industry, providing for the production of sulfuric acid, mineral fertilizers, carbon disulfide and many other products. Growing demand for phosphate fertilizers, the development of new energy technologies (LFP batteries) and expanding applications in construction and agriculture create sustained demand for this essential product. Russia, possessing significant production capacities, maintains its position as one of the leading players in the global sulfur market.