SBIR-STTR Award

This Small Business Innovation Research Phase I project will evaluate a novel approach to biooxidize refractory chalcopyrite ore concentrates. Chalcopyrite is a sulfidic copper ore which has a negative environmental impact upon smelting due to SO2 production, but which has proven difficult to process by approaches such as biooxidation.The proposed work will evaluate leach rates from a chalcopyrite ore concentrate in a novel integrated bioleaching system. . The dissolution of chalcopyrite should be greatly accelerated due to system electrochemistry, favorable thermodynamics at elevated temperature, the presence of microbial Fe (II) and sulfur oxidizers, and control of particular operational parameters. Analytical techniques such as ESCA and SEM/EDX will be used to monitor reactions on pyrite and chalcopyrite surfaces. Metal solubilization will be monitored by inductively coupled plasma spectroscopy (ICP). The research objectives of this project are to verify the acceleration of copper leach rates and to demonstrate thermodynamic and electrochemical control of surface reactions under a defined set of system parameters. This investigation, if successful, would directly result in the development of a new process for utilizing reserves of refractory chalcopyrite ores. The potential market is estimated to be in the hundreds of millions of dollars. The technology could easily be integrated to scale with current mining practices and will substantially reduce the dependence of the mining industry on smelting.

This Small Business Innovation Research Phase II project is developing a novel electrobiochemical leaching (EBL) approach to recover copper from chalcopyrite, providing an alternative to smelting. Chalcopyrite is the most common copper ore, yet it is difficult to process hydrometallurgically because it passivates due to formation of refractory surface layers. The EBL approach in Phase 1 was shown to prevent this passivation and to result in faster and more complete copper extraction than conventional bioleaching approaches. The Phase II research objectives are to: 1) demonstrate the versatility of the process by determining the extent of copper extraction from different sources of chalcopyrite ore; 2) determine the optimum bioreactor configurations for the EBL approach; and 3) make a large laboratory scale (50 to 100 kg) demonstration of the process for determining preliminary process economics. The research will measure the extent of copper extraction and extraction kinetics by EBL, including the determination of metallurgical balances. The results of the Phase II research will provide the data required to establish preliminary economic feasibility of the process and to convince investors or operators (mining company) to support a pilot scale demonstration. If successful, the EBL approach will provide a new technology in mineral extractions that will open additional reserves of copper in the US and elsewhere and reduce smelting of copper.