Solvent extraction and separation of rare-earths from phosphoric acid solutions with TOPS 99

In-line extraction of REE from Dihydrate (DH) and HemiDihydrate (HDH) wet processes

“…1, approximately 80% of the feed REE reported to PG and about 65% of them were LREE while HREE constitute 64% of REE reported to the product acid. These results indicate that LREEs were easily co-crystalized with PG: it is believed that REE-ions cocrystalize with PG in an isomorphism substitution with Ca 2+ ions, REE having ionic radius closer to Ca 2+ ion (Nd, Pr, La, and Ce) is the most abundant in PG (Habashi, 1985;Radhika et al, 2011;Koopman and Witkamp, 2000).…”

“…They are rare not due to their abundance in earth crust but because they are rarely found in economic and mineable deposits. REEs are critical to several fast growing industries such as clean technology, hybrid cars, electronics, advanced military applications as well as traditional industries such as metallurgy, surgical instruments, battery, and nuclear energy (Radhika et al, 2011;IAMGOLD, 2011). Five of them (yttrium, dysprosium, europium, neodymium, and terbium) are designated as critical rare earth elements (CREEs) and are expected to be in short supply in the next 15 years.…”

“…Phosphate rock (PR) contains 100-1000 g REE per each tonne of ore, depending on phosphate type and origin (Radhika et al, 2011;Koopman and Witkamp, 2000;Preston et al, 1996). Even though the concentration of REE in PR is very small, their extraction as by-product may have an economic value since large tonnage of PR is mined and used in fertilizer production annually.…”

Optimization of the process of obtaining RE 2 O 3 from xenotime using statistical design

“…Optimization of the process of obtaining RE 2 O 3 from xenotime using statistical design (Otimização do processo de obtenção de RE 2 O 3 a partir da xenotima usando planejamento estatístico) Resumo Xenotime, a phosphate, and some RE-carrying clays are the main sources of supply of rare earth elements from the heavy fraction [6,7]. Xenotime is a phosphate mineral with rare earth crystal structure (space group I4 1 /amd, Z=4), which typically consists of 25% Y 2 O 3 and other heavy elements, but may have as much as 60% Y 2 O 3 and 40% other rare earth oxides [8,9].…”

Solvent extraction of Pr and Nd from chloride solutions using ternary extractant system of Cyanex 272, Alamine 336 and TBP

“…Solvent extraction is now a commonly used technique in industrial processes for the separation and purification of rare earth elements (REEs) due to its high selectivity and significant capital and operation cost savings [3][4][5][6][7][8]. Among the commercial acidic organophosphorus extractants used in the extraction of metals, such as Cyanex 272 (bis(2,4,4-trimethylpentyl) phosphinic acid), EHEHPA (2-ethylhexyl 2-ethylhexylphosphonate) and D2EHPA (di-(2-ethylhexyl) phosphoric acid), Cyanex 272 shows the best separation efficiency between adjacent REEs [9].…”