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Sulfur is one of the chemical industry’s most important raw materials.
It is used principally as the derivative (sulfuric acid) in many chemical and
industrial processes and is particularly important in the manufacture of phosphate
fertilizers, the single largest end use for sulfur. Sulfur’s great importance
to industrial economies and its relative ease of transportation have made it
a commodity of major international interest. Unlike other chemicals in the
mineral industry, sulfur is not produced intentionally as a primary product.
It is derived as a by-product from operations such as petroleum refining, tar
sands recovery, heavy oil and natural gas processing, and from coking and metallurgical
plants.
The development of the natural gas industry and the oil refining industry
has significantly changed the nature of the sulfur industry. Natural gas resources
often contain a significant level of sulfur-containing gases that must be removed
before the gas can be used commercially. Lately, the amount of world sulfur
produced as a by-product of natural gas production has exceeded the volume
produced electively from native sulfur and Frasch deposits and recovered as
sulfuric acid from pyrites. In addition, environmental regulations governing
the desulfurization of transportation fuels have also resulted in significant
quantities of sulfur being recovered from refinery operations and will continue
to lead to increased recovery of by-product sulfur. For many years, sulfuric
acid recovered at nonferrous smelters has been the main concern. Of greater
significance today is the recovery of elemental sulfur from crude oil refineries
as the sulfur content of crudes has increased and as regulations on the sulfur
content of oil and gasoline products have become increasingly stringent. Ultra-low-sulfur
diesel fuel will soon be the major form sold.
World sulfur production in 2004 was approximately 68 million metric tons,
with an estimated fob value of about $1.6 billion. World sulfur production
(and apparent consumption) was about 61 million metric tons in 1989 and declined
by almost 14% to a level of approximately 53 million metric tons in 1993. In
the past five years, it has been on the increase. It is expected that over
half of the world’s production of elemental sulfur in coming years will
come from gas processing. A moderate increase of about 15% with an annual growth
rate of about 2.8% is expected during the forecast period. The supply/demand
situation is projected to be relatively tight for the next couple of years
with remelts from inventories utilized to supply requirements. By 2007, sulfur
from oil refining operations and gas processing operations should add considerable
inventory levels. The supply will be even higher if product from Kazakhstan
and Qatar is not reinjected as planned. On the demand side, nonfertilizer use
of sulfur is on the increase with sulfur-based asphalt and concrete gaining
significance. World sulfur production and consumption are projected to exceed
the historical high during the forecast period.
The following graph shows world supply/demand for sulfur in all forms:
Fertilizers are the ultimate end use of about 50% of the world’s sulfur
production. Phosphate fertilizer production accounts for about 85% of this
total, but ammonium sulfate production is also significant. Thus, the sulfur
market is very dependent upon the cyclical world phosphate fertilizer market.
Global phosphate fertilizer consumption spiked in 2004–2005. However,
it is expected to grow at a nominal rate of about 1.9% during 2004–2009.
Demand from downstream products like phosphoric acid–based superphosphate
and potassium sulfate contributes to sulfur demand. There is no substitute
for phosphates in their role as a plant nutrient.
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