Extractive metallurgy of rare earths

Gupta, Chandni; Krishnamurthy, N.

doi:10.1179/imr.1992.37.1.197

Cited by 471 publications

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“…Their unique properties make them essential for the hi-tech industry. They are used in the manufacturing of high strength permanent magnets, lasers, automotive catalytic converters, fibre optics/superconductors and electronic devices (Gupta and Krishnamurthy, 2005). They are grouped depending on the atomic number, into 'light' rare earth elements (LREE) -La, Ce, Pr, Nd, and into 'middle and heavy' HREE -Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu.…”

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A review of the potential for rare-earth element resources from European red muds: examples from Seydişehir, Turkey and Parnassus-Giona, Greece

et al. 2016

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Rare-earth elements (REE) are viewed as 'critical metals' due to a complex array of production and political issues, most notably a near monopoly in supply from China. Red mud, the waste product of the Bayer process that produces alumina from bauxite, represents a potential secondary resource ofREE. Karst bauxite deposits represent the ideal source material forREE-enriched red mud as the conditions during formation of the bauxite allow for the retention ofREE. TheREEpass through the Bayer Process and are concentrated in the waste material. Millions of tonnes of red mud are currently stockpiled in onshore storage facilities across Europe, representing a potentialREEresource. Red mud from two case study sites, one in Greece and the other in Turkey, has been found to contain an average of ∼1000 ppm totalREE, with an enrichment of light over heavyREE. Although this is relatively low grade when compared with typical primaryREEdeposits (Mountain Pass and Mount Weld up to 80,000 ppm), it is of interest because of the large volumes available, the cost benefits of reprocessing waste, and the low proportion of contained radioactive elements. This work shows that ∼12,000 tonnes ofREEexist in red mud at the two case study areas alone, with much larger resources existing across Europe as a whole.

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A review of the potential for rare-earth element resources from European red muds: examples from Seydişehir, Turkey and Parnassus-Giona, Greece

et al. 2016

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“…Rare earth oxides are the typical starting material for conversion into metals because they are the most common products of ore processing and separation operations. Therefore, in the case of the metal production methods that involve molten salt electrolysis or the reduction of rare earth halides, the conversion of rare earth oxides into their respective halides is a necessary step that allows for ease of production [5]. One viable option for this conversion is through a carbohalogenation reaction which can be performed to produce either chlorides or fluorides.…”

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“…These three methods are (1) reduction of anhydrous chlorides and fluorides, (2) direct reduction of rare earth oxides, and (3) fused salt electrolysis of rare earth chlorides or oxide-fluoride mixtures [4]. Rare earth oxides are the typical starting material for conversion into metals because they are the most common products of ore processing and separation operations.…”

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confidence: 99%

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Investigation of the Carbochlorination Process for Conversion of Cerium and Neodymium Oxides into Their Chlorides

Anderson

Mishra

2015

J. Sustain. Metall.

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This study focuses on evaluating the conversion of cerium oxide and neodymium oxide into their chlorides through the carbochlorination process. The experiments were completed inside a quartz reactor, and the % conversion was determined by performing a water leach to dissolve the soluble chloride phases present and leave behind the insoluble unreacted oxide and oxychloride phases. The process parameters chosen for this investigation were temperature, time, chlorine gas concentration, and carbon-to-rare earth oxide ratio. A rate curve was generated for both the cerium oxide and neodymium oxide carbochlorination processes. These curves showed that reactions had a significant dependence on time with 4 h being the optimal reaction time for both processes. Statistical modeling and optimization was also performed through the use of Stat-Ease Design-Expert 8 Ò software. This analysis showed that temperature had the most significant effect on the degree of reaction achieved for both processes. The reaction products were also subjected to X-ray diffraction analysis to verify the degree of reaction determination method as well as to determine whether any intermediate phases occurred during the carbochlorination process.

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“…Caustic cracking involves the decomposition of monazite using 50% (m/m) NaOH solution (Gupta and Krishnamurthy, 2005), with the aim being to break down the monazite ((Ce,La,Nd,Th)PO 4 ) into trisodium phosphate and REE hydroxides. The caustic cracking was conducted for 4 hours using 50% (m/m) NaOH solution at a temperature of 140°C, in a 5 L stainless steel reactor.…”

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The application of process mineralogy on a tailings sample from a beach placer deposit containing rare earth elements

Moila¹

2017

J. South. Afr. Inst. Min. Metall.

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The rare earth elements (REE), which constitute the lanthanide group in the Periodic Table, are a major constituent of many advanced materials, especially in the high technology and green energy sectors. This group of elements is very important in the world economy and modern technology. Resources of REE are globally distributed, but production is largely monopolised by China, which controls approximately 95% of the world's REE Market ( Wübbeke, 2013;Massari and Ruberti, 2013).Early in 2005, China as the leading REE producer decided to limit its REE exports by establishing quotas and banning the sale of some REE outside the country, so as to meet its own domestic requirements (Morrison and Tang, 2012). This resulted in a high global demand and strained supply ( Figure 1). As a result, other countries were faced with the challenge of exploring means of closing the REE demand-and-supply deficit gap created by the change in China's export regulations.The reduction in supply quotas of REE by China led to a drastic increase in global demand for REE, thus creating an opportunity for other countries to look into alternative sources of REE.Japan made plans to extend the search for highly concentrated REE in deep-sea mud of the Pacific Ocean (Gordon, 2011), as well as to recycle old batteries and electronic equipment for their REE contents and to secure alternative supplies of REE from Mongolia (Tabuki, 2010).India planned to resuscitate its REE production from Indian Rare Earths Limited (IREL), which ceased production in 2004. Other plans to enhance the development of REE supply in India and Vietnam were made by Toyota Motor Corporation in (Montgomery, 2011. This paper outlines the approaches used to investigate an alternative REE resource; a byproduct from an existing titanium recovery operation in South Africa. The process involved the characterization of the REE from the beach placer deposit before processing. The investigation was carried out subsequent to China's decision to implement new export regulations limiting REE exports. Research studies have been conducted globally on REE from carbonatite and placer deposits; in particular in China and the USA, which have the world's largest carbonatite-hosted rare earth reserves. Extensive work has been conducted on the South African carbonatiteThe application of process mineralogy on a tailings sample from a beach placer deposit containing rare earth elements by A. Moila* † , D. Chetty*, and S. Ndlovu † ‡ The rare earth elements (REE) are significant in the context of world economic growth and modern technology. This research is aimed at investigating an alternative source of REE by exploring cost-effective ways of processing REE minerals from an existing beach placer deposit operation, currently mined for titanium. In order to recover REE through economically optimum means, upfront mineralogical investigations are a necessity to reduce the ore processing costs. An approach involving mineralogical characterization and hydrometallurgical test work was therefore chosen. Th...

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Extractive metallurgy of rare earths

Cited by 471 publications

References 130 publications

A review of the potential for rare-earth element resources from European red muds: examples from Seydişehir, Turkey and Parnassus-Giona, Greece

A review of the potential for rare-earth element resources from European red muds: examples from Seydişehir, Turkey and Parnassus-Giona, Greece

Investigation of the Carbochlorination Process for Conversion of Cerium and Neodymium Oxides into Their Chlorides

The application of process mineralogy on a tailings sample from a beach placer deposit containing rare earth elements

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