IFDC FOCUS ON FERTILIZERS AND FOOD SECURITY

About 1 ton of sulfur is needed to produce 3 tons of sulfuric acid—enough to manufacture about 2 tons of merchant grade phosphoric acid (50─54% P₂O₅). More than 2 tons of diammonium phosphate (DAP) can be manufactured from the 2 tons of P₂O₅ and the original ton of sulfur.

High demand and shortfalls in supply have led to a global shortage of sulfuric acid, and prices have more than doubled over the past year. Factors driving the shortage include high phosphate fertilizer demand and sulfuric acid plant outages in some regions, according to the General Electric Market Report.

A sulfuric acid plant in Albania

China is the world’s largest importer of sulfur.  China consumed about 10 million tons of sulfur in 2007; most was used to manufacture phosphate fertilizers. About two-thirds of the sulfur was imported, according to China’s Sulfur Market Report—2008.  

China’s largest fertilizer plants became operational in 2002, reducing the need to import phosphate fertilizer but consuming dramatically more sulfur. By 2005, China was one of the world’s largest fertilizer exporters. But China imposed 130% to 135% tariffs on fertilizer exports in 2008 to curtail outflow and protect the domestic fertilizer supply.

Sulfur is one of the more common constituents of the earth’s crust. Most of the sulfur available on the world market today is extracted from natural gas and oil. (Crude oil contains from 0.1% to 2.8% sulfur.) Some sulfur is recovered from coal. Sulfur is also recovered from the roasting of sulfides in metallurgical processing. A minor amount of sulfur is recovered by mining of pyrites or other extraction methods.

The global output of sulfur is about 40 million tons/year and is expected to reach about 55 million tons/year by 2011, according to the China Sulfur Market Report. In the long term, the increase in world sulfur supply is expected to overcome current shortages. 

Analysis

An adequate supply of sulfur is essential to provide the world adequate fertilizers. The current sulfur situation, coupled with sulfuric acid shortages, could affect world fertilizer production and use and worsen food prices and availability.

Solutions

World leaders are debating import and export policies, but solutions will be difficult to develop. Primary fertilizer producers are exploring alternatives to sulfuric acid for fertilizer production. Meanwhile, more sulfur supply and marketing opportunities are needed in the short term, and new fertilizer research initiatives are needed in the long term to develop technologies for efficient NPK fertilizer production.

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