About Dr. Pickles
Written by Meghan Fotak, Mining Student Professor Chris Pickles is one of the leading engineers in the field of research that uses microwaves to extract metals. The objectives of his research are to better understand new metal extraction processes, while increasing recycled products, and to improve sustainability. Lucky for us in The Robert M. Buchan Department of Mining, Dr. Pickles is doing his research at Queen’s currently and with a team of Queen’s Masters Students.
Professor Pickles has three main topics of research: new energy sources for the recovery and recycling of metals; electric furnace dust processing and lead-acid battery residue treatment; and caustic leaching process design. His current research is mostly focused on new energy sources for the recovery and recycling of metals, specifically researching the use of microwaves in extractive metallurgy.
Microwaves Current metal extraction processes require heat to be generated from outside the ore, typically with a flame or resistance heater, and these processes require the combustion of carbonaceous materials or hydrocarbons which results in the release of greenhouse gases. In these processes the heat is not only transferred to the material but also into the containment vessel, surroundings and waste by-products of the reaction, making them very energy inefficient. Microwave use as a method of heating is advantageous in numerous ways. Environmentally, microwaves are greener than our current methods, as their source is controlled electrically, and the source of electricity can be relatively green, thus reducing production of greenhouse gasses. Dr. Pickles and his team have been researching specific applications for the use of microwaves as a method of metal extraction. Some of these applications include the use of microwaves in the segregation process for nickel lateritic ores, in the process of gold recovery, and for drying of lowrank sub-bituminous coal.
Lateritic ores can contain up to 30 percent moisture, which can make the segregation process difficult as it requires a lot of energy for moisture removal. The research conducted found that ore drying rates were higher than with conventional processes.
Various processes are being considered in the development of methods for nickel recovery, which include a hybrid of conventional and new microwave techniques. These hybrid techniques were found to have comparable recoveries and grades to those achieved by traditional processes.
Graduate Student John Forster’s design set-up for his research on microwave vacuum reduction processing of nickel laterites.
Microwaves show promising application in the recovery of gold, in the reduction of energy used for the separation of gold, and for improving recovery rates of gold during milling. These improvements could result in economic improvements for gold mining companies.
Often the moisture content of coals can be too high, and moisture needs to be extracted before further processing can take place. The use of microwaves to dry sub-bituminous coal have shown several advantages over conventional drying, and result in overall improvement of both the drying rates and the final moisture contents of coals.
Electric Arc Furnace (EAF) Dust EAF dust is generated by steel mills and contains zinc. Methods of extracting this zinc from the EAF dust had been investigated, however the dust is highly contaminated which makes the process uneconomical compared to zinc extraction from natural ores. The research that Dr. Pickles is conducting investigated the pyrometallurgical extraction of the non-ferrous metals in the dust. The thermodynamics of various reducing agents has been investigated. The current research being conducted explores the magnetic separation of the EAF dust, thermodynamic effects, and the amount of reducing agent needed for both the magnetic and non-magnetic components.
Furnace set up for Richard Elliot, Master’s Student
Caustic Leaching Dr. Pickles developed a technique for the treatment of lead-acid batteries that resulted in lower sulphur dioxide and lead emissions than current conventional methods.
Past Research Past research that Dr. Pickles has conducted includes: thermodynamic analysis of the sulphation roasting of enargite concentrates, sulphidation and flotation of nickeliferous lateritic ore, reduction and magnetic separation of iron from high iron bauxite ore, carbothermic reduction roasting of a nickeliferious limonitic laterite ore, and silver loss during the oxidative refining of silver-copper alloys. He has over 100 publications on numerous topics in extractive metallurgy.
Future Perspectives and How to Get Involved Although diverse, all fields of Dr. Pickles research focus on maximizing recyclable materials, reducing carbon footprints, and improving energy efficiency of the metal extraction systems we currently use. His research will lead to new methods of processing and recycling materials crucial to our economy and everyday lives. As an educator, Dr. Pickles wants his students to develop their critical thinking skills: “As our society progresses we will be recycling more and the associated problems will become more complex. Thus we will need engineers who understand both the principles and the limitations of physical and chemical separation techniques. We need to transform and broaden mineral and metal extraction and develop recycling engineers who can solve our society’s environmental problems.” -Dr. Pickles in International Innovation: Ever- Evolving Environment He is at the forefront of metal extraction research and his research on microwaves is innovative. The opportunity to do hands-on work with such novel research is unique to the Queen’s Mining Department. Any students interested in Dr. Pickles’ research should contact him, or stop by his office in Goodwin Hall. If you’re interested in applying to do a Master’s degree in the Mining Department with Dr. Pickles, please contact Kate Cowperthwaite for details about the application process and deadlines.