FMC Soda Ash Plant, Wyoming, United States of America
Soda ash or sodium carbonate is an important industrial chemical. One of its principal industrial uses is in the manufacturing of glass.
When heated to high temperatures in excess of 800ºC, in combination with sand (silicon dioxide) and calcium carbonate (CaCO3) and then 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, as it is 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 pre-eminent in the production of soda ash in the US is FMC.
The company has had a production facility and mine in Green River for more than 50 years. In February 2008, the FMC (Food Machinery and Chemical) Corporation, alkali division initiated the recommissioning of the mothballed capacity at its Granger facility in Wyoming.
On 3 August 2009, FMC announced its plans to layoff 70 employees at its Green River facility, Wyoming.
Granger facility in Wyoming, US
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 1.3mt of production a 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 was expected to be a further 100,000t a year by 2009 and the remaining 700,000t of capacity to be brought back on stream by 2012 so the plant is fully operational.
In April 2009, because of the reduced US exports caused by the global economic slowdown, FMC announced temporary suspension of operations at the Granger facility and plans to restart it in 2010. The Granger facility is capable of producing 6,00,000 short tons a year.
In January 2011, FMC announced its plans to restart the plant with an annual capacity of 500,000t. The plant was restarted in the third quarter of 2011.
In June 2011, FMC announced a second phase expansion of the plant to increase capacity to 1.2mt. The expansion project is subject to approval of FMC's board and, if approved, will be completed by 2014. FMC contracted CH2MHill to carry out detailed design engineering works for the expansion.
Market improvements and increased prices for trona
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 the US can now look toward to 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 18mt 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.