A new smelting process for phosphate ores could open up the world’s lower grade reserves, while solving the industry’s waste problem. The solution has been licensed to an Australian company with plans to take it to the global market. TONY HESELEV reports
Pyrophos to meet needs of a growing market for phosphate fertiliser
Phosphorus in the form of phosphate, is an irreplaceable component in fertiliser with an estimated global market worth US$51.6 billion. Demand for phosphate fertiliser is predicted to increase as a growing world population puts pressure on the food supply chain.
However, global phosphate producers are grappling with increasing production costs as the world's better quality reserves are depleted.
The industry is also looking for solutions to phosphogypsum – the problematic waste byproduct created by the predominant phosphate process used today known as "wet acid". About three tonnes of phosphogypsym waste is created for every tonne of phosphate produced using wet acid, resulting in about three billion tonnes being stockpiled annually.
Solution for low grade phosphate ores, no phosphogypsum waste
A new CSIRO-developed process solution aims to solve these problems by making low grade reserves economical to mine and reducing problematic waste.
It has been licensed to Australian company Pyrophos who are leading the technology commercialisation to meet the needs of phosphate producers.
"We've identified an opportunity in the phosphate market and licensed the IP to Pyrophos, which is taking the solution to market," CSIRO research group leader, Keith Barnard, says.
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The new smelting-based process offers producers significant cost and environmental advantages over the predominant wet acid process.
In contrast to wet acid, the new process involves applying heat to phosphate ores, resulting in a safe gravel byproduct. The gravel byproduct could be valuable for construction as a road base aggregate or used in Portland cement production. As phosphates tend to occur in sandy areas, it is common for these regions to be short of gravel-type construction materials.
Reduced plant footprint to save producers two-thirds on capital costs
Another key benefit of the Pyrophos process is that it has a much smaller plant footprint than the wet acid process, incorporating two processes in one unit, while replacing the more expensive sulphur with coke.
This means that producers could save about two-thirds on capital costs than with current sulphur or wet acid plants, while benefiting from substantially lower operating costs. This meets the needs of an industry in which there have been no major technical breakthroughs in 20 years and that produces a commodity product with large volumes and tight margins.
The IP underpinning the Pyrophos licence agreement is partly new and partly conventional. It is built on top submerged lance (TSL) technology, which was originally developed by CSIRO and is applied commercially in copper, tin and zinc smelting.
The new aspect applies CSIRO's advanced simulation techniques and bespoke facilities to extend the TSL technology into the operating conditions required for phosphate processing.
CSIRO's Steven Wright, an expert on high temperature mineral processing, spent two years building on the ideas of TSL and related technologies to discover the most effective and efficient ways of processing phosphate via smelting.
Mr Wright and his CSIRO colleagues have also undertaken thermodynamic modelling, bench scale experimental tests and techno-economic assessments of the technology. Tests indicate that the proposed process could be technically and economically viable.
Licensed to Pyrophos to bring to the global phosphate market
"CSIRO has developed the core IP and will be the R&D centre supporting our design engineers for our work with individual producers," Pyrophos managing director, Mark Muzzin, says.
"We bring industry knowledge to the partnership – from the economics, to the processes and people. It's now up to us to evolve the IP and convert it into commercially proven technology.
The technology's development has also involved commercial guidance and industrial design input from technical advisers at WorleyParsons who have extensive experience and relationships in the phosphate industry.
Pyrophos now has plans to market the pyrometallurgical technology in up to 30 countries. The largest phosphate producers are in China, Morocco and Western Sahara, the US, Russia and Jordan. Australia also has phosphate resources where the process may provide an economic advantage.
Aspects such as the technology's safety, environmental performance, operational stability, constructability, maintainability and economic performance will also continue to be improved. Pyrophos will progress this work in collaboration with a broad range of phosphate producers.
CSIRO will continue to provide R&D expertise through testing services involving a number of stages of increasing complexity. These services include mathematical evaluation, desktop analysis, scoping, pre-feasibility studies and use of CSIRO’s high temperature pilot plant in Clayton, Victoria.