Keywords: phosphogypsum, stacking, sustainability, comprehensive extraction, zero waste, life cycle management.
Phosphogypsum, the calcium sulphate co-product of the phosphate fertiliser industry, has been long vilified within certain regulatory regimes as ‘toxic waste’ or ‘radioactive waste.’ These labels and the fears they engender spawned regulations that effectively removed phosphogypsum from commerce and created a culture of waste management and disposal.
If left unchallenged, phosphogypsum would continue to be stacked on land in the billions of tonnes or discharged to the seas of the world. These practices are environmentally unsound and unsustainable by definition. However, some scientists and regulators started to question the underlying assumptions and analyses used to justify the restrictions on phosphogypsum use.
The foundation of phosphogypsum regulation is its Naturally Occurring Radioactive Materials (NORM) content. Can this foundation stand up to closer scrutiny?
The large volume of phosphogypsum under regulation for its radioactivity caught the attention of the International Atomic Energy Agency (IAEA) in its review of NORM industries. The IAEA examined the evidence base for regulation of phosphogypsum as a radioactive material, and the barriers to its use began to subside internationally.
As a less restrictive era dawns and new drivers emerge to return phosphogypsum to global commerce, we must examine phosphogypsum use in the context of sustainability and of environmental, economic, and social factors. In this sustainability context, phosphogypsum life cycle management is no longer a topic confined to the on-site stack, but must consider the needs of the community, the generations of people to follow, and the impacts of phosphogypsum in a wide variety of beneficial applications versus indefinite storage or sea disposal.
Gary Albarelli and Brian Birky, Florida Industrial and Phosphate Research Institute, 1855 W. Main Street, Bartow, FL 33830-7718, USA.
28 pages,13 figures, 2 tables, 25 references