What is phosphogypsum waste?
Phosphogypsum, a waste product from manufacturing fertilizer, emits radon, a radioactive gas. It also contains the radioactive elements uranium, thorium and radium.
What is phosphogypsum used for?
Phosphogypsum is used in agriculture for soil amendment or as fertilizer, as well as in the brick and cement industry, and in road construction.
What is in Piney Point wastewater?
On March 26, a leak sprung at Piney Point, a phosphate mine and fertilizer plant that’s been defunct since 2001. The facility—one of more than two dozen in the state, nine of which are still active—houses stacks of phosphogypsum, a toxic, radioactive byproduct of the fertilizer production process.
Is phosphogypsum toxic?
Phosphogypsum (calcium sulfate) is a toxic byproduct of phosphoric acid created during the production of fertilizers. It is acidic, radioactive, and contains heavy metals such as arsenic, lead, nickel, cadmium, chromium, silver, antimony, copper, mercury, and thallium.
What are stacks of phosphogypsum?
Phosphogypsum stacks are formed to store the phosphogypsum and associated process water that comes from the chemical manufacturing of phosphoric acid and related fertilizer products, according to the Florida Department of Environmental Protection. Phosphogypsum is watery when it is first put on the stack.
How much radium is in phosphogypsum?
Radium concentrations at phosphogypsum stacks range from 0.4 – 1.3 Bq/g (11 – 35 pCi/g). Stacks are constructed with little or no soil preparation.
How is phosphogypsum formed?
Phosphogypsum is a by-product of the chemical reaction called the “wet process,” whereby sulfuric acid is reacted with phosphate rock to produce the phosphoric acid needed for fertilizer production. There are approximately five tons of phosphogypsum produced for every ton of phosphoric acid produced.
What is wrong with Piney Point?
Water laden with nitrogen and other nutrients pours from a pipe at the Piney Point site in the aftermath of the early April crisis at the former Manatee County fertilizer plant. A few months later, the bay and then much of Florida’s west coast was caught in the grip of a ghastly red tide that caused massive fish kills.
Is Piney Point water Toxic?
The Piney Point gypstack is a mountain of toxic waste, topped by an impoundment of hundreds of millions of gallons of process wastewater, stormwater and tons of dredged spoil from Port Manatee.
How do you neutralize phosphogypsum?
The phosphogypsum admixtures are also eliminated by using a combined method when phospho- gypsum is washed with a smaller amount of water, and the rest of the acid admixtures are neutralized by adding the following additives: Ca(OH)2, CaCO3, K2CO3, KOH, Portland cement, NH4OH, etc.
How does phosphogypsum become radioactive?
Phosphogypsum is radioactive due to the presence of naturally occurring uranium and thorium, and their daughter isotopes radium, radon, polonium, etc. Marine-deposited phosphate typically has a higher level of radioactivity than igneous phosphate deposits, because uranium is present in seawater.
What is the half life of phosphogypsum?
1,600-year
Phosphogypsum is the radioactive waste from processing phosphate ore into phosphoric acid, which is predominantly used in fertilizer. Radium-226, found in phosphogypsum, has a 1,600-year radioactive decay half-life.
What happens to phosphogypsum as it dries out?
As the phosphogypsum dries out, a crust forms on the stack. The crust thickens over time, reducing the amount of radon that can escape and helping keep the waste from blowing in the wind. Some of the water can leak out the bottom and pollute local groundwater.
What is the concentration of radium in phosphogypsum?
Typical concentrations of radium ( 226 Ra) in phosphogypsum are 2003000 Bq kg − 1 (US Environmental Protection Agency, 1990 ). They are similar to those in phosphate ores.
How much phosphogypsum is produced in the world?
Annual world production of phosphogypsum is estimated to be ~300 Mt ( Yang et al., 2009 ). This by-product is contaminated by various impurities, both chemical and radioactive, and is usually stockpiled within special areas.
What kind of contaminants are found in phosphogypsum?
In addition to radionuclides, phosphogypsum contains some trace contaminants which may pose health and environmental hazards, such as arsenic, lead, cadmium, chromium, fluorine, zinc, antimony, and copper (US Environmental Protection Agency, 1990 ).