Rare Metal Extraction & Processing: Rare Earth Elements I
Sponsored by: TMS Extraction and Processing Division, TMS: Hydrometallurgy and Electrometallurgy Committee
Program Organizers: Hojong Kim, The Pennsylvania State University; Shafiq Alam, University of Saskatchewan; Harald Oosterhof, Umicore; Neale Neelameggham, Ind LLC; Takanari Ouchi, The University of Tokyo
Monday 2:00 PM
February 27, 2017
Location: San Diego Convention Ctr
Session Chair: Shafiq Alam, University of Saskatchewan; Takanari Ouchi, MIT
2:00 PM Keynote
The Economics of the Search Minerals Direct Extraction Process for Rare Earth Recovery: David Dreisinger1; 1Search Minerals
The Foxtrot deposit of Search Minerals contains a range of rare earth element containing minerals including allanite, fergusonite and bastnasite. The Search Minerals Direct Extraction Process for treating these minerals involves coarse crushing of the ore to -6 mesh (3.45 mm), acid treatment at 200 C in a novel reactor configuration, water leaching, various purification steps to reject iron, aluminum and uranium/thorium (present in small amounts) and finally precipitation of rare earths as a oxalate and calcination to form a mixed rare earth oxide product for refining. The economics of the process are presented.
Recovery of Critical Rare Earth Elements for Green Energy Technologies: Rajesh Kumar Jyothi1; Jin-Young Lee1; 1Korea Institute of Geoscience and Mineral Resourses (KIGAM)
21st century is electronic revolution in human lives as well as energy is a one of the most significant task. Rare earth elements (REEs) occupies key role in our daily life as well as high-tech industrial applications. REEs are one of the energy critical elements, for sustainable growth, it depends on their utilization and re-use, reduce, recycling policy employments. The rapid growth of population and their needs will raise the demand of certain REEs. Global wide REE deposits mainly located at China, from 2010 onwards China made policy to control exports of REE’s to foreign countries. REEs are utilized in many modern electrical and electronic devices such as smart phones, computers, LED lights etc. Recovery of the REEs from secondary resources is one of the best solution and alternative option, it needs co-ordination between nations as well as sustainable environmental regulations and implications and certain education to undeveloped countries
3:00 PM Student
Selective Reduction and Separation of Europium from Mixed Rare-earth Oxides from Waste Fluorescent Lamp Phosphors: Mark Strauss1; Brajendra Mishra1; Gerald Martins2; 1WPI; 2Colorado School of Mines
Europium is a critical material required for LED, florescent lamps, and flat panel display production. The recycling of europium from waste lamp phosphors is an innovative method to supply europium for high technology applications. Waste phosphor powder from recycled lamps is retorted, sieved, and leached to produce a europium/yttrium leach solution. The separation of europium and yttrium from the pregnant leach solution is conducted by selectively reducing Eu(III) to Eu(II) via zinc powder and precipitating europium (II) sulfate from solution using sulfuric acid as the precipitating agent. After one stage of selective reduction and precipitation, the purity and recovery of europium (II) sulfate was greater than 95% and 80%, respectively.
Application of Rare Earths for Higher Efficiencies in Energy Conversion: William Judge1; Z.W. Xiao1; Georges Kipouros1; 1University of Saskatchewan
Rare earths have taken a prominent position in the Hi-Tech field after the discovery of the NdFeB permanent magnets. Their use in the magnets spark miniturization of the communication devices such as computers and mobile phones and are being considered in many more applications. Potential applications are energy conversion devices that require strong motors and photovoltaics where rare earths can be used to improve the efficiencies of silicon. The presentation is summarizing the role of rare earth elements in every category of the energy conversion devices and the sustainability of these operations given the restrictions in availability of resources, limitation of production methods and environmental consequencies.
3:50 PM Break
Microwave Treatment for Extraction of Rare Earth Elements from Phosphogypsum: Adrian Lambert1; Jason Tam1; Gisele Azimi1; 1University of Toronto
Many advanced technologies in modern society require the use of rare earth elements (REEs). Since these technologies are dominating the world, the demand for REEs is increasing fast. Therefore, finding new sources for them is highly of interest. One of the secondary sources for REEs is phosphogypsum (PG) that is a waste product generated by phosphoric acid production. This research builds upon our previous studies investigating the hydrometallurgical recovery of REEs from PG. Here we investigate the effect of microwaving the PG sample before leaching in acid. Microwave radiation results in the dielectric heating of water molecules in the PG crystals and vaporization, causing the formation of breaks and pores in these particles as the vapor escapes. The lixivant would then be able to penetrate and diffuse further into the PG particles, bringing more REEs into solution. Our results show that REEs leaching efficiency increases when microwave treatment is used.
4:35 PM Student
Selective Separation of Rare Earth Elements Utilizing Vapor Phase Extraction: Katelyn Lyons1; Jerome Downey1; Jannette Chorney1; 1Montana Tech of the Univesity of Montana
A new method of extracting and refining rare earth elements (REEs) from mineral ores and concentrates was investigated. The relative stabilities of various REE compounds at elevated temperatures were evaluated using thermogravimetric and differential thermal analyses (TGA/DTA). The results, in combination with thermodynamic analyses, revealed that vapor phase extraction and selective condensation is a potentially viable separation method for rare earth halides. Selective vaporization and condensation experiments were performed on selected rare earth chlorides. A series of close-coupled tube furnaces provided a temperature gradient ranging from 1250oC to 400oC. Within the condensation regions, a series of one-inch-diameter ceramic tube sections were packed with stainless steel (316L) wool to create high surface area for condensate collection. The ceramic tube sections and stainless steel wool were leached in 18 MΩ water. Analysis of the leachate samples revealed that selective separation had occurred but oxychlorides were detected in the non-volatile matter.
5:00 PM Student
Observation of Oxidation of Nd-Magnet In High Temperature Recycling/Recovery Process: Muhamad Firdaus1; M Rhamdhani1; W Rankin2; Kathie Mcgregor2; Yvonne Durandet1; Nathan Webster2; 1Swinburne University of Technology; 2CSIRO Minerals Resources
There is growing interest in the recycling/recovery of rare earth elements from permanent magnets. A number of processing techniques are currently being developed, but these are highly sensitive to the oxidation state of the rare earth contained in the waste magnet. This study investigates the microstructural and compositional changes during thermal oxidation of a Nd-based magnet and the behaviour of Nd oxides. In-situ high temperature XRD analysis was performed on powdered sample (~10 Ám) heated to 1473 K. Microstructure observation using a high temperature microscope and SEM-EDS analyses were conducted on the heated bulk samples. Metallographic analysis revealed multiple oxidation zones. The outer oxidation layer did not inhibit diffusion of oxygen. The thickness of this layer increased rapidly at temperatures greater than 973 K. The results indicate that the micro-mechanisms of oxidation at higher temperatures are more complex than at temperatures below 773 K.