Impurity Control in Extraction and Refining of Scandium Oxide
Chris Hartley, Technical Director1 and Lunzhi Liao, Senior Manager R&D 2, Strategic Materials
Bloom Energy Corp, 1299 Orleans Drive, Sunnyvale, CA 94089, USA
ABSTRACT
Scandium oxide can be recovered as a by-product from process streams in a number of chemical and
metallurgical plants including TiO2 sulphate pigment, Ni/Co laterite, zirconium oxychloride and uranium
operations. The feed materials available for processing can be either mid or end of process streams
containing many species in solution. This paper describes the strategies available to limit co-extraction of
elements into scandium containing streams from TiO2 pigment production and the removal of these
elements to deliver high purity scandium oxide.
A critical part of process development is to work within the constraints of the main process in terms of
introducing new unit processes and producing minimal additional process intermediates and residues. This
requires flexibility in designing flowsheets and plants to find novel process routes that avoid production of
intermediates and/or the introduction of reagents that can compromise the main process operations.
Bloom Energy has developed novel solvent extraction processes for the extraction and refining of
scandium oxide that minimise impacts on core process streams within TiO 2 pigment plants. The additional
unit processes are designed to have minimal contact with pigment plant process streams to produce a
concentrate that is refined to nominal 3N purity scandium oxide in a simple, small scale commercial plant.
KEYWORDS
Scandium oxide, extraction, refining, process development
1
2
Chris Hartley, Technical Director Strategic Materials, chris.hartley@bloomenergy.com (corresponding author)
Lunzhi Liao, Senior Manager R&D Metallurgical Processes, Strategic Materials, lunzhi.liao@bloomenergy.com