Preprint Communication Version 1 Preserved in Portico This version is not peer-reviewed

Pyrometallurgy and Electrometallurgy of Rare Earths – Part A: Analysis of Metallothermic Reduction and its Variants

Version 1 : Received: 17 March 2021 / Approved: 18 March 2021 / Online: 18 March 2021 (09:31:48 CET)

How to cite: Rafique, M.M.A. Pyrometallurgy and Electrometallurgy of Rare Earths – Part A: Analysis of Metallothermic Reduction and its Variants. Preprints 2021, 2021030463 (doi: 10.20944/preprints202103.0463.v1). Rafique, M.M.A. Pyrometallurgy and Electrometallurgy of Rare Earths – Part A: Analysis of Metallothermic Reduction and its Variants. Preprints 2021, 2021030463 (doi: 10.20944/preprints202103.0463.v1).

Abstract

Rare earths are classified as most important and critical material for US economy and defense by Congress and a mandate has been set to increase their in-house production, domestic resource utilization and decrease reliance on foreign resources and reserves. They are widely available in earth crust as ore (bastnaesite (La, Ce)FCO3, monazite, (Ce, La, Y, Th)PO4, and xenotime, YPO4), but their so-called economic reserves are sparsely located geographically. They may be produced by various means such as beneficiation (physical, chemical, mechanical, or electrical), reduction (direct or indirect), electrolysis (of aqueous or molten / fused single or mixed salt systems) at high temperature or hydrometallurgy. Out of these, direct reduction also known as metallothermic reduction (La and Ca reduction) is mostly utilized. Its variant, high temperature electrowinning of fused salts is also practiced widely. These processes are material and application specific. In this study, author will employ thermodynamics (Ellingham diagrams, free energy of formation, reduction potential, Nernst equation, Pourbaix (Eh-pH) diagrams, E-pO-2 diagrams), kinetics and energetic of a chemical reaction (chemical metallurgy) to reduce rare earth oxide / salt to rare earth metals (REO/RES – REM). It is shown that materials and energy requirement vary greatly depending on type of mineral ore, production facility, and beneficiation / mineral processing method selected. Aim is to reduce dependence on coal deposits. It is anticipated this route will be able to produce rare earths with > 35% yield and > 98% purity which be described in subsequent studies and patents.

Keywords

metallothermy; thermodynamics; Ellingham diagrams; Nernst equation; Pourbaix (Eh-pH) diagrams; E-pO-2 diagrams

Comments (0)

We encourage comments and feedback from a broad range of readers. See criteria for comments and our diversity statement.

Leave a public comment
Send a private comment to the author(s)
Views 0
Downloads 0
Comments 0
Metrics 0


×
Alerts
Notify me about updates to this article or when a peer-reviewed version is published.
We use cookies on our website to ensure you get the best experience.
Read more about our cookies here.