- Phosphogypsum
Phosphogypsum refers to the
gypsum formed as aby-product of processingphosphate ore intofertilizer withsulfuric acid . Phosphogypsum is radioactive due to the presence of naturally occurringuranium andradium in the phosphate ore.Marine-deposited phosphate typically has a higher level of radioactivity than igneous phosphate deposits, because uranium is present in seawater.Health Physics Society. [http://www.hps.org/publicinformation/ate/q629.html "Answer to Question #629 Submitted to "Ask the Experts"."] Posted on February 9, 2001. Last accessed June 19, 2007.]
In the United States
The
United States Environmental Protection Agency has banned most applications of phosphogypsum with a radium-226 concentration of greater than 10pico curie s/gram (pCi/g). As a result, phosphogypsum which exceeds this limit is stored in large stacks.Florida has a large quantity of phosphate deposits, particularly inBone Valley region. However, the marine-deposited phosphate ore from central Florida is highly radioactive, and as such, the phosphogypsum by-product is too radioactive to be used for most applications. As a result, there are about 1 billion tons of phosphogypsum stacked in 25 stacks in Florida (22 are in central Florida) and about 30 million new tons are generated each year.Florida Institute of Phosphate Research. [http://www1.fipr.state.fl.us/PhosphatePrimer/0/684AE64864D115FE85256F88007AC781 "Phosphogypsum and the EPA Ban."] Last accessed June 19, 2007.]Various applications have been proposed for using phosphogypsum, including using it as material for:
* road pavement
*Soil conditioner
* Cover forlandfill s
*roof tile s
*artificial reef s &oyster bedsReferences
link: http://www.fluoridealert.org/phosphate/sinkhole.htm
Wikimedia Foundation. 2010.