RE: [GeigerCounterEnthusiasts] Radiation and Phosphogypsum (18718) # // Reply /Next/ /Previous/ * Henry Barwood Mar 15, 2010 View Source Contact the Florida Institute of Phosphate Research in Bartow , Florida (I used to work for them) and see if they can get you a bucket of PG. The really hot stuff is the scale that forms on the filter pans. Some of it is downright toxic, but I doubt you can find any today. It used to be sandblasted off outside, before anyone realized it was high in Radium. Henry Henry Barwood Professor of Science, Earth Sciences Department of Math and Physics MSCX 312G TroyUniversity Troy, Alabama 36082 hbarwood@... ------------------------------------------------------------------------ *From:* [mailto: ] *On Behalf Of *Geo>K0FF *Sent:* Sunday, March 14, 2010 11:29 AM *To:* *Subject:* [GeigerCounterEnthusiasts] Radiation and Phosphogypsum Radiation and Phosphoric Acid + The phosphoric acid produced in Florida contains much of the uranium that was present in the mined ore, but little of the radium. + In the past, uranium was valuable enough that extraction facilities at the chemical plant sites were used to concentrate and remove it from the phosphoric acid as a solid product. Since the uranium is present only at trace quantities, this was an expensive process. + Removal of uranium as a product is no longer profitable and all of the extraction facilities have been dismantled. The uranium that remains in the phosphoric acid and fertilizer products is at a low enough level that it is safe for use. Radiation and Phosphogypsum o Both natural gypsum and phosphogypsum contain radioactivity, but phosphogypsum contains more. o In the manufacture of phosphoric acid, the acid is filtered through cloth to remove solids. The radium is filtered out with the solids. The solid portion is known as phosphogypsum. o Phosphogypsum produced in North Florida contains roughly 5 – 10 picocuries per gram (pCi/g) of radium while phosphogypsum from Central Florida contains about 20 – 35 pCi/g radium. o The U.S. EPA prohibits the use of phosphogypsum. An exception is made for phosphogypsum with an average concentration less than 10 pCi/g radium which can be used as an agricultural amendment. EPA's ban was based on a single scenario which assumed that the by-product was used in road building or as an agricultural ammendment and 100 years later a house was built on the farm field or the abandoned road and the homeowner lived in the house 70 years, staying in the house 18 hours a day. Under this scenario the homeowner's risk of radon-related health concerns only slightly exceeded the EPA's acceptable limits. o Phosphogypsum is primarily calcium sulfate, and plants need the sulfur it contains. Since much of the North Florida phosphogypsum is below the EPA restriction level, it can be used as a crop amendment, but for no other use. o The Central Florida phosphogypsum is restricted to storage on land in large piles called “stacks.” o The overall radioactivity in the stacked phosphogypsum is actually less than what was in the original phosphate ore that was taken out of the ground. **NOTE: I am still seeking a gallon size container of phosphogypsum from the central Florida stacks for analysis and display purposes. Geo**