Distribution of Ion Pairs between Immiscible Nonaqueous Solvents.

Latimer, George W.

doi:10.1021/ac60205a062

Cited by 9 publications

(9 citation statements)

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“…However, it was found that the separation factors were too small to be of practical use. Several metal salts (chloride, bromide, thiocyanate, and nitrate) were extracted to a diethyl ether phase that was equilibrated with a second immiscible phase, being ethanolamine, formamide, or adiponitrile [143]. These solvents could extract nearly all metal complexes from the ether phase with an extraction efficiency of more than 90%.…”

Section: Non-aqueous Solvent Extractionmentioning

confidence: 99%

Solvometallurgy: An Emerging Branch of Extractive Metallurgy

Binnemans

Jones

2017

J. Sustain. Metall.

216

187

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This position paper introduces the reader to the concept of solvometallurgy, the term used to describe the extraction of metals from ores, industrial process residues, production scrap, and urban waste using non-aqueous solutions. Here, non-aqueous is not used to imply anhydrous, but rather a low water content. The unit operations are as follows: solvent leaching; separation of the residue; purification of the leach solution by non-aqueous solvent extraction or non-aqueous ion exchange; and metal recovery by precipitation or electrolysis in non-aqueous electrolytes. Solvometallurgy is similar to hydrometallurgy in that both the branches of extractive metallurgy use lowtemperature processes, but with solvometallurgy, there is no discrete water phase. Both branches use organic or inorganic solvents (excluding water in the case of solvometallurgy). However, for solvometallurgical processes to be sustainable, they must be based on green solvents, which means that all toxic or environmentally harmful solvents must be avoided. Solvometallurgy is complementary to pyrometallurgy and hydrometallurgy, but this new approach offers several advantages. First, the consumption of water is very limited, and so the generation of wastewater can be avoided. Second, the leaching and solvent extraction can be combined to form a single step, resulting in more simplified process flow sheets. Third, solvent leaching is often more selective than leaching with acidic aqueous solutions, leading to reduced acid consumption and fewer purification steps. Fourth, solvometallurgy is useful for the treatment of ores rich in soluble silica (e.g., eudialyte) because no silica gel is formed. In short, solvometallurgy is in a position to help develop the near-zero-waste metallurgical processes, and with levels of energy consumption that are much lower than those with the high-temperature processes. The Technology Readiness Level (TRL) of this emerging branch of extractive metallurgy is still low (TRL = 3-4), which is a disadvantage for short-term implementation, but offers a great opportunity for further research, development, and innovation.

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Section: Non-aqueous Solvent Extractionmentioning

confidence: 99%

Solvometallurgy: An Emerging Branch of Extractive Metallurgy

Binnemans

Jones

2017

J. Sustain. Metall.

216

187

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“…A few preliminary studies explored utilization of some polar organic solvents to replace water in the MP phase for metal extractions; however, no superior metal separations were observed . Recently, extraction of rare earth elements and transition metals from ethylene glycol (EG) solutions showed higher extraction efficiency and higher separation factors compared to the extraction from aqueous solutions .…”

Section: Figurementioning

confidence: 99%

“…[12,13] Af ew preliminary studies exploredu tilization of some polar organic solvents to replacew ater in the MP phase for metal extractions; however, no superior metal separationsw ere observed. [14][15][16][17][18] Recently, extractiono fr are earth elements and transition metals from ethylene glycol (EG) solutions showed higher extraction efficiency and highers eparation factors comparedt ot he extraction from aqueous solutions. [19][20][21] These results clearly indicatet hat EG affectst he extraction of metals differently than water.N evertheless,h ow these polar solvents (water and EG) affect metal extraction is not clear yet, and the possibility of using other polar solvents, besides EG, to enhancem etal separations remains unknown.…”

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confidence: 99%

Enhancing Metal Separations by Liquid–Liquid Extraction Using Polar Solvents

Zhang

Smolders

et al. 2019

Chemistry A European J

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The less polar phase of liquid–liquid extraction systems has been studied extensively for improving metal separations; however, the role of the more polar phase has been overlooked for far too long. Herein, we investigate the extraction of metals from a variety of polar solvents and demonstrate that, the influence of polar solvents on metal extraction is so significant that extraction of many metals can be largely tuned, and the metal separations can be significantly enhanced by selecting suitable polar solvents. Furthermore, a mechanism on how the polar solvents affect metal extraction is proposed based on comprehensive characterizations. The method of using suitable polar solvents in liquid–liquid extraction paves a new and versatile way to enhance metal separations.

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“…These early studies did not observe superior metal separations compared to traditional SX. [4][5][6][7][8] The use of polar solvents instead of water in the extraction of metals is called non-aqueous solvent extraction (NASX). 9 Recently, a series of non-aqueous SX systems have been investigated and several enhanced separations have been obtained.…”

Section: Introductionmentioning

confidence: 99%

“…However, only very few studies explored the utilization of polar organic solvents as the solvent in the MP phase for SX of metals. These early studies did not observe superior metal separations compared to traditional SX 4‐8 . The use of polar solvents instead of water in the extraction of metals is called non‐aqueous solvent extraction (NASX) 9 .…”

Section: Introductionmentioning

confidence: 99%

Ethylammonium nitrate enhances the extraction of transition metal nitrates by tri‐n‐butyl phosphate (TBP)

Zhang

Onghena

et al. 2021

AIChE Journal

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Several molecular polar solvents have been used as solvents of the more polar phase in the solvent extraction (SX) of metals. However, the use of hydrophilic ionic liquids (ILs) as solvents has seldomly been explored for this application. Here, the hydrophilic IL ethylammonium nitrate (EAN), has been utilized as a polar solvent in SX of transition metal nitrates by tri-n-butyl phosphate (TBP). It was found that the extraction from EAN is considerably stronger than that from a range of molecular polar solvents. The main species of Co(II) and Fe(III) in EAN are likely [Co(NO 3) 4 ] 2− and [Fe(NO 3) 4 ] − , respectively. The extracted species are likely Fe(TBP) 3 (NO 3) 3 and a mixture of Co(TBP) 2 (NO 3) 2 and Co(TBP) 3 (NO 3) 2. The addition of H 2 O or LiCl to EAN reduces the extraction because the metal cations coordinate to water molecules and chloride ions stronger than to nitrate ions. This study highlights the potential of using hydrophilic ILs to enhance SX of metals.

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Distribution of Ion Pairs between Immiscible Nonaqueous Solvents.

Cited by 9 publications

References 0 publications

Solvometallurgy: An Emerging Branch of Extractive Metallurgy

Solvometallurgy: An Emerging Branch of Extractive Metallurgy

Enhancing Metal Separations by Liquid–Liquid Extraction Using Polar Solvents

Ethylammonium nitrate enhances the extraction of transition metal nitrates by tri‐n‐butyl phosphate (TBP)

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