US: Fertiliser company Mosaic is seeking approval from the Environmental Protection Agency (EPA) to test using phosphogypsum on a pilot road project at its New Wales site in Mulberry, Florida. It hopes to test using the substance in three 60m sections of road, according to correspondence seen by the Tampa Bay Times newspaper. The proposed test road will use a mixture of sand with up to 50% phosphogypsum in a 25cm base. The road will then be monitored over the next 18 months.
The EPA originally approved the limited use of phosphogypsum in road construction in 2020. However, this was then subsequently blocked. Local legislation in Florida allowing the Florida Department of Transportation to study the use of phosphogypsum in road construction has been approved by the Florida Senate and House of Representatives but is yet to be signed off by Governor Ron DeSantis.
The Florida Industrial and Phosphate Research Institute estimates that around 1Bnt of phosphogypsum is stored in over 20 sites in the state. Over 25Mt/yr of phosphogypsum is generated, typically from fertiliser production. Environmental groups in the state have opposed Mosaic’s proposed use of phosphogypsum in road building due to its higher level of radioactivity compared to other forms of gypsum.
