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StackFree is updated continually; these updates refer to substantive updates or upgrades.

Beneficial Uses of Phosphogypsum?

Welcome to Stack Free, the website of the international programme for Beneficial Uses of Phosphogypsum (PG).

After a successful R&D phase (2005-2009), Stack Free is now refocused on implementation of safe, beneficial uses of PG within the context of sustainable development, conservation of resources and waste prevention. The basis for the new approach is recognising that phosphogypsum is a potential resource, not a de facto waste.

A New Point of Equilibrium

The Stack Free "stretch goal" is to achieve eventual equilibrium between production and consumption of PG across the full life-cycle of a producing facility, including stockpiling PG for use after the producing facility has closed. The team will be looking at related opportunities to recycle or reuse phosphogyspum, for example in affordable sulphur recovery.

Another strategic objective is the remediation and eventual elimination of legacy stacks, or at least major reductions in their legacy footprints.

Implementation

May 2009 sees the start of the first of two implementation phases. In the first implementation phase, (IP1) 2009-2011, we will be coordinating a number of large-scale demonstration projects on phosphogypsum use.

Subject to success in the first implementation phase, in the second implementation phase (IP2) (2012-), we look to rekindle a viable global market for PG, based on a coherent and consistent set of policies, protocols and best practices regarding PG uses adopted worldwide. At the heart of these resources is the concept that PG and phosphoric acid are co-products, and should be managed through their whole life-cycles as such.

Phosphate Rock, Phosphoric Acid and PG: High level co-product model, 'end to end'

Work Plan

The work plan for the first implementation phase is mapped back to our Stack Free research findings, and to a gap analysis the Stack Free team conducted in collaboration with IAEA, Vienna, July 2008. It was agreed that the best way forward was to adopt an evidence-based approach, not least to address the concerns regarding radionuclides and heavy metals that in some countries have led to an effective ban on using PG.

Given the vast body of published, positively disposed scientific and technical literature on experimental and pilot projects using PG, the evidence gap we want to fill is now at the level of large-scale demonstration projects. What differences are there, if any, between the experimental and pilot settings and the full commercial scale? Given how much PG there already is available, and given the increasing speed with which more will be produced in future, only large-scale use is likely to make an impact.

Triple Bottom Line Assessment

To assess this impact we will be using "Triple Bottom Line" criteria to assess the outcomes of the demonstration projects; ie each large-scale use of PG must, over time, demonstrate a sustained combination of financial, social and environmental benefits. There are some compelling large-scale examples already that in principle fit these criteria (eg from Brazil, Kazakhstan, Spain, South Africa, United States) but there is as yet no common methodology or approach between them.

Stack Free projects will adopt, test and refine a common methodology, Good Phosphogypsum Management Practices, with a view to promoting best practices and a coherent and consistent approach to PG use going forward.

Specific outcomes and findings from the demonstration projects will also flow back into the proposed IAEA Safety Guide, due to be published in 2011.

Demonstration Projects

The demonstration projects themselves will be conducted in collaboration with major phosphoric acid producers in areas such as agriculture, road building, construction materials, marine and coastal remediation and landfill. These projects will be hosted by a number of different countries with different needs, climates and socio-economic contexts.

Through the Stack Free network and the dedicated website we will be sharing findings and evolving best practices. Producers / participants are free to choose how they wish to participate, but we ask everyone to follow the evidence-based approach. We wish also to rekindle the global market in PG, so commercially sensitive data and findings will be restricted. The Stack Free team will act as coordinator and provide assistance and expertise to individual projects as needed.

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 have built and continue to extend a participant network in a wide range of countries. Together, we seek 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.

Dr. Julian Hilton Dr. Brian Birky
Principal Investigators and Programme Coordinators