FMC Soda Ash Plant, Green River, Wyoming, USA

Soda ash or sodium carbonate is an important industrial chemical. One of its principal industrial uses is in the manufacture of glass. When heated to high temperatures in excess of 800ºC in combination with sand (silicon dioxide) and calcium carbonate (CaCO3), and cooled very rapidly the result is basic soft all-purpose soda glass.

Soda ash can be mined as a hydrated ore and then processed into the required anhydrous sodium carbonate or alternatively it may be produced industrially by using the Solvay process. This is where sodium chloride is reacted in large towers with ammonia and carbon dioxide to give sodium hydrogen carbonate which can then be reprocessed to give sodium carbonate. The choice of either process depends upon the economics of mining as opposed to the energy used in industrial production.

GREEN RIVER DEPOSITS

In the US hydrated sodium bicarbonate carbonate ((Na3HCO3CO3·2H2O) or trona is mined to produce the majority of the country's requirements (most economically viable). The trona of the Green River Formation in Wyoming is the largest and best-known deposit in the world, being formed in layered evaporite deposits from 800ft to 1,600ft below ground. It was first discovered in 1938.

The trona was originally deposited in a lake during the Palaeogene period. One of the companies preeminent in the production of soda ash in the US is FMC. The company has had a facility and mine in Green River for over 50 years. In February 2008 FMC (Food Machinery and Chemical) Corporation, alkali division initiated the recommissioning of the mothballed capacity at its Granger facility in Wyoming.

GRANGER FACILITY

The Granger facility in Wyoming was all but shut down in 2001 due to poor market conditions for the soda ash market. The facility uses coal as an energy source, which is plentiful in Wyoming. The facility has a total capacity of 1.3 million tons of production per year.

By 2005 the market had improved and 250,000t of capacity was restarted using solution mining. In 2006 a further 250,000t was brought back on-line. In February 2008 the remaining capacity of the plant was restarted. The initial increment of increase in production will be a further 100,000t per year by 2009 and the remaining 700,000t of capacity will be brought back on stream by 2012 so the plant is fully operational.

Ed Flynn, FMC Corporation Alkali Division manager, commented: "The growth of soda ash demand in the export market, and improved business profitability, allow us to take advantage of our entire mothballed capacity at the Granger facility. The low cost of soda ash production in Wyoming means we are very well positioned to supply the growing soda ash markets in Latin America, Asia and other parts of the world."

MARKET IMPROVEMENT

The price of trona has doubled over the last ten years to around $100/t and demand has increased in many areas of the world. This means that the US can now look toward not only supplying the domestic market but also other interested markets across the world (Pacific Rim, South America and to some extent China).

In 2007 around 18 million tons were mined in Wyoming and there was further demand. The biggest markets are glass making and also the production of household chemicals and cleaning products.

Around 90% of US soda ash output comes from Wyoming's Green River Basin and the area is benefiting from the new demand.

China has no natural trona deposits and produces all of its soda ash industrially but the requirements are so great that it is possible that US exports will have to make up the shortfall.