Beneficial Uses of Phosphogypsum?
Welcome to StackFree, the website of the international research project into Beneficial Uses of Phosphogypsum. The project is planned to run from May 2005 to April 2011.
If you would like to discuss participation in this project, or make any suggestions to the Principal Investigators, Dr. Vaughn Astley, Dr. Brian Birky and Dr. Julian Hilton, please email info@stackfree.com.
In particular, we are engaged in drafting white papers on a number of topics, including “Good Phosphogypsum Management Practices”, which will be posted for review and comment in the coming months.
Stakeholder Participation
Beneficial Uses of Phosphogypsum seeks to involve all stakeholders in reviewing what the risks and benefits may be of using phosphogypsum, rather than classing it as a waste with no commercial value. We are building a participant network in a wide range of countries to ensure that scientific, technical and regulatory standards and best practices against which these risks and benefits may be assessed are robust, transparent and internationally recognised.
For those who are interested in following our progress, please visit this site periodically. Progress reports and white papers will be posted here and we welcome suggestions and comments from interested individuals and organisations.
We are also keen to hear from suitably qualified researchers, and public or private sector organisations engaged in some way with producing, using, overseeing or simply researching into the production and use of phosphoric acid and phosphogypsum.
Phosphogypsum
Phosphogypsum (calcium sulphate) is a naturally occurring part of the process of creating phosphoric acid (P2O5), an essential component of many modern fertilizers. For every ton of phosphoric acid made, from the reaction of phosphate rock with acid, commonly sulphuric acid, some four to five tons of phosphogypsum are created. The amount of phosphogypsum being produced each year closely mirrors therefore, the industrial output of P2O5.
Managing Phosphogypsum
There are three options for managing phosphogypsum:
- disposal or dumping
- stacking
- use – in, for example, agriculture, construction, or landfill.
In some jurisdictions these options are constrained. For example in the United States, option 2, stacking is the standard procedure, with limited exceptions for certain types of phosphogypsum, for use, for example, in peanut farming.
In other jurisdictions, dumping is permitted, mostly into open waters such as the Atlantic Ocean.
In many jurisdictions where a mixture of use and disposal is common practice, changing environmental legislation is causing a new emphasis on stacking in the short term, and on potential beneficial uses in the longer term.
Piney Point, Tampa Bay, Florida – A Reference Case for Stack Closure
In the world’s largest phosphoric acid producing area, central Florida, the phosphogypsum stack has become one of the dominant features of the landscape. In fact, Florida has some 20 stacks in all, of which many cluster along side State Road 60 which runs from Tampa to Bartow and then further East.
Following the bankruptcy of Mulberry Phosphates Inc. in 2001, one of the stacks owned by that corporation, located on Piney Point on the edge of Tampa Bay started to pose a significant environmental threat as a result of the very large quantity of acidic water stored on top of the Piney Point stack – some 1 billion gallons. In a year of high rainfall, a crisis occurred when the water level rose above the safe “freeboard” limit adopted for such a stack. Since then, some $300 million US has been spent on rectifying the problems of the stack, by impounding the stacks with a lined cover to prevent water recharge. In addition, treatment by lime neutralization of the voluminous acidic pond water so as to render it suitable for discharge both to Tampa Bay and also by discharging via barging into the Gulf of Mexico has dramatically reduced the water volume and transformed the environmental liability of the site.
The longer-term consequence of the Piney Point episode has been to draw attention to wider issues concerning the costs, technical challenges and the environmental and legal liability issues involved in the management of both active and closed stacks.
The End to End Process 
A key premise of this project is that for a solution to be found to the challenges posed by phosphogypsum, and the closely associated issues of process water management, an “end to end” view needs to be taken. At least four main stages apply:
Mining and beneficiation
Processing
Use and uptake in humans, animals and plants
End points, in the environment, or in construction.
Outcome
Can phosphogypsum be safely regarded as a resource, rather than as a waste with no commercial value? Can concerns about the presence of naturally occurring radioactive materials (NORM), and other potentially harmful components such as cadmium, in the source rock and the processed gypsum be sufficiently met that phosphogypsum can be licensed as a product accepted again in international commerce? If not, can a single best practice standard be adopted for managing the phosphogypsum legacy in a safe way?
Participants and Sponsors
This project is designed to benefit Participating and/ or sponsoring organisations as of July 2005 include:
Aleff Group, London, UK and, Lakeland, Florida
Dr. Phosphate Inc. Lakeland, Florida
Florida Institute of Phosphate Research, Bartow, Florida
Rothamsted Research, UK.
Numerous regulatory authorities are being consulted about the project.
A number of other organisations are currently in the process of joining the research effort.
There is also ongoing collaboration with the International Fertilizer Association, Paris.
Links
Brief Project Overview - 2005-2011
For further information please contact:
Julian Hilton
Aleff Group
53, Skylines
Limeharbour, LONDON E14 9TS
Tel: + 44 20 7515 9009
www.aleffgroup.comVaughn Astley
Dr. Phosphate, Inc.
2120 Clubhouse Road,
Lakeland, Fl 33813, USA .
Tel: 1-863-619-9765
vaughnastley@drphosphate.com