Development of the Tripuhyite Technology for Remediating Antimony-Contaminated Waters and Recovering Antimony

Antimony (Sb) is classified as a priority pollutant in the United States and European Union because ingestion of Sb-bearing fluids or inhalation of Sb-bearing particles can lead to lung, heart and stomach diseases. The major source of Sb in the environment is mine wastes, which contain 10s to 100s of parts per million of Sb. It has been estimated that the quantity of solid mine waste generated throughout the world matches that of Earth materials moved by fundamental global geological processes, at approximately several thousand million tonnes per year. This figure is predicted to grow over the next 100 years due to increasing demand for mineral resources, coupled with lower ore grades. Therefore, the amount of mine waste-derived Sb will also increase. Dissolution of the Sb-bearing materials in mine wastes can lead to Sb contamination of waters and to Sb uptake in plants and animals (including humans). Though precise numbers of people directly affected by mine waste-derived Sb are not available, they are likely to be in the range of 10s to 100s of thousands, given that 10,000 inhabitants are impacted in the Sb mining area of Xikuangshan, China alone. Other sources of Sb in the environment are largely industrial, including flame retardants, batteries, chemical, ceramics and glass. Mining companies, government bodies and others responsible for providing clean water are required to reduce the risk of Sb contamination by remediating the water to reduce Sb concentrations to levels considered safe by regulatory authorities. This risk can be mitigated, and Sb-contaminated waters remediated, by the precipitation of minerals, especially those that are relatively insoluble and have low bioaccessibility (i.e., low ability to be taken up by plants, animals and humans). The mineral tripuhyite (iron antimonate oxide, FeSbO4) is such a mineral, and it could therefore be used for remediation and improvement of ecosystem and human health in Sb-contaminated environments worldwide. In addition, tripuhyite could be used as a means of recovering and recycling the Sb for other uses (e.g., semiconductor devices, metal alloys, flame-retardant materials, paints, enamels, glass, pottery). For this Pathfinder project we propose to develop the 'Tripuhyite Technology', a method for precipitating and stabilizing tripuhyite for use in remediation of antimony-contaminated mine waters and for recovery of Sb for industrial uses. The Pathfinder proposal aims to (i) evaluate the market opportunity and commercial need in order to develop a business model for developing the tripuhyite technology and (ii) carry out 'Technical Milestone I' work to determine the feasibility of the Tripuhyite Technology. These aims will be achieved by commissioning market research and conducting scientific experiments. The results of the Pathfinder project will increase the likelihood of commercial adoption of the Tripuhyite Technology by providing comprehensive experimental data on mechanisms for tripuhyite precipitation and scale-up of the technology and opportunities for engagement with additional project partners and potential stakeholders.

Stakeholders will benefit from the project through knowledge of the antimony market, and of the potential for precipitating tripuhyite from Sb-contaminated mine waters. A Follow-on project will increase the likelihood of commercial adoption by providing comprehensive experimental data on mechanisms for tripuhyite precipitation and scale-up of the Tripuhyite Technology, and opportunities for engagement with additional project partners and potential stakeholders (which will be identified in the Pathfinder market and end-user assessment).