Citation: Sampath, A.H.J.; Wickramasinghe, N.D.; de Silva, K.M.N.; de Silva, R.M. Methods of Extracting TiO 2 and Other Related Compounds from Ilmenite. Minerals 2023, 13, 662. https://doi.org/10.3390/ min13050662 Academic Editors: Vasilios Melfos, Panagiotis Voudouris and Grigorios Aarne Sakellaris Received: 9 April 2023 Revised: 6 May 2023 Accepted: 9 May 2023 Published: 11 May 2023 Copyright: © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). minerals Review Methods of Extracting TiO 2 and Other Related Compounds from Ilmenite A. H. Janaka Sampath , Nadeera Dilshan Wickramasinghe, K. M. Nalin de Silva and Rohini M. de Silva * Centre for Advanced Materials and Devices (CAMD), Department of Chemistry, University of Colombo, Colombo 00300, Sri Lanka; janaka@chem.cmb.ac.lk (A.H.J.S.); nadeerawickramasinghe88@gmail.com (N.D.W.); kmnd@chem.cmb.ac.lk (K.M.N.d.S.) * Correspondence: rohini@chem.cmb.ac.lk; Tel.: +94-714406263 Abstract: Although ilmenite and rutile are extensively used to extract TiO 2 at the industrial level, through the sulphate and chloride processes, they can also be recognized to possess the potential to be employed as the raw material to synthesize other titanium compounds as well. The Pulmoddai mineral sand deposit in Sri Lanka is considered as a valuable resource containing pure ilmenite and can be used as a very good source of both titanium and iron. Because of the lower TiO 2 content compared to rutile, processes, such as the Becher process, Laporte process and Kataoka process, have been developed to upgrade ilmenite into higher grade synthetic rutile. Additionally, research studies have been carried out to develop methods, such as the hydrochloride process, H 3 PO 4 /NH 3 process, alkaline roasting process, aluminothermic reduction method, alkaline decomposition method, molten salt electroreduction method and magnesiothermic reduction method, to synthesize TiO 2 and other related titanium compounds, such as titanium and iron oxides, composites and alloys, from naturally occurring ilmenite where these methods possess both rewards as well as drawbacks over the others. Keywords: synthetic rutile; lower-grade ilmenite; batch process; continuous process; calcination; alloys; composites 1. Introduction Among a diverse range of dense mineral reserves found across the world, only il- menite and rutile ores are capable of yielding titanium compounds, specifically titanium dioxide, through industrial processes. Since titanium containing compounds possess the ca- pability to be applied in numerous applications, such as environmental remediation, energy technologies, the pharmaceutical industry, paint industry and textile industry, exploration of the ability of these ore materials to yield titanium species is highly significant in the field of research as well as the industrial sector [1–13]. Ilmenite and rutile exhibit a major contrast in their chemical compositions, where ilmenite comprises a significant fraction of both titanium dioxide and ferrous oxide, represented as FeTiO 3 or FeO.TiO 2 , and rutile primarily consists of TiO 2 [1,2]. Being more abundant and less expensive, ilmenite has gained higher merits as a superior raw material compared to rutile for the aforementioned purpose [3,14]. The global deposits of commercial ilmenite can be widely categorized into three groups: large-scale hard-rock deposits, deposits linked with alluvial tin and those associated with beach sand. Sri Lanka does not possess massive hard-rock deposits, which typically contain ilmenite, magnetite and hematite. However, such deposits exist in other locations worldwide, including the Allard Lake deposit in Canada, Sanford Lake deposits in the United States of America and the Tellanes deposit in Norway [15,16]. Similarly, Nigeria and Malaysia are two countries where ilmenite deposits associated with tin have mostly been discovered [17]. Particularly, ilmenite beach sand deposits (black sand) are found in numerous countries, such as Sri Lanka, India, South Africa, Australia and Brazil [18]. Minerals 2023, 13, 662. https://doi.org/10.3390/min13050662 https://www.mdpi.com/journal/minerals