Department of Materials Science & Metallurgy

Derek Fray FREng FRS

Derek Fray portrait

Professor and Director of Research

BSc Imperial College
PhD Imperial College

+44 (0)1223 334306
djf25@cam.ac.uk
www.msm.cam.ac.uk/djf/

Sustainability, Ionic solids, Nanostructures and Recycling

Our motivation is to apply materials chemistry to problems that are scientifically interesting and technologically challenging.

Reduction of metal oxides

A novel electrochemical method has been discovered for the reduction of metal oxide where the oxide is made the cathode in a bath of a molten electropositive chloride.  The oxygen ionises, dissolves in the electrolyte and is discharged at an anode, leaving a pure metal or alloys at the cathode.   This technology is being commercialised by a University spin-out company, Metalysis – www.metalysis.com.  Furthermore, the oxide, found naturally on PV silicon, can also be reduced to form a surface structure which can greatly increase the efficiency of light absorbance. The process can also be used for the recycling of used nuclear fuel rods.

Applications of solid electrolytes

Solid electrolytes are used in sensors and electrochemical devices. Sensors have been developed to measure hydrogen in molten aluminium and other gases and these are being marketed by a University spin-out company -Environmental Monitoring and Control Ltd – www.emclimited.co.uk.  An electrochemical device, based upon Nafion which is room temperature proton conductor, has been developed to separate pure oxygen from air which is then fed to wounds to greatly increase the rate of healing. This has been particularly successful for the treatment of ulcers and the device is being sold by InotecAMD – www.inotecamd.com, a University spin-out company.

Preparation of carbon based nanostructures

A novel method of generating carbon nanotubes, carbon nanoparticles, nanodiamonds and graphene has been created by intercalating lithium into graphite from a molten salt.  These products are being investigated as anodes in lithium-ion batteries, abrasives, and coatings for electronic products and composite materials.

Recycling

The world has finite resources so it is becoming more urgent to be able to recycle used products, especially printed circuit boards (PCBs). Processes for the total recycling of PCBs to generate, tin, lead, copper, gold, silver, platinum, bromine and silica have been demonstrated in the laboratory.  Rare earth metals are increasing used in high technology products but are in short supply.  A process has been developed which can take mixed rare earth oxides and simultaneously refine and reduce the oxides.  This is called the Chinuka Process and is being commercialised by White Mountain Corporation – www.wmtcorp.com.

 

Surface of the moon
TEM picture showing tin filled carbon nanotubes and nanoparticles
  • R. Das Gupta, C. Schwandt & D.J. Fray, “Preparation of tin-filled carbon nanotubes and nanoparticles by molten salt electrolysis” Carbon 70, 142-148 (2014).
  • E. Juzeliunas, A. Cox & D.J. Fray, “Silicon surface texturing by electro-deoxidation of a thin silica layer in molten salts” Electro. Chem. Comm., 12(10), 1270-1274 (2010).
  • Y.J. Park & D.J. Fray, “Recovery of high purity precious metals from printed circuit boards” J. Hazard. Mat., 164, 1152-1158 (2009).
  • D.T.L. Alexander, C. Schwandt & D.J. Fray, “Microstructural kinetics of phase transformations during electrochemical reduction of titanium dioxide in molten calcium chloride” Acta Materialia, 54(11), 2933-2944 (2006)