scholarly journals Adsorption of rare earth elements using bio-based sorbents

2018 ◽  
Vol 245 ◽  
pp. 18001 ◽  
Author(s):  
Arina Kosheleva ◽  
Iryna Atamaniuk ◽  
Natalia Politaeva ◽  
Kerstin Kuchta
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Removal Efficiency ◽  
Permanent Magnets ◽  
Ph Value ◽  
Batch Adsorption ◽  
Freundlich Isotherms ◽  
Residual Biomass ◽  
Mixed Aqueous Solution ◽  
Alternative Sources

Rare earth elements (REEs) have recently received significant attention due to their irreplaceable industrial application for the number of crucial advanced technologies in production of permanent magnets, batteries, luminescence lamps, lasers and other electronic and electrical goods. These technologies have been strongly affecting present consumption of REEs as well as looking for alternative sources, that would guarantee their sufficient supply for the future demand. This study investigates one of the possible and widely employed techniques for the efficient and at the same time, environmentally friendly recovery of REEs by adsorption using bio-based adsorbents. Overall, three bio-sorbents with different composition (residual biomass originated from agriculture and bio-refineries) were examined to study removal efficiency of the 7 most commonly used REEs in mixed aqueous solution. Batch adsorption experiments were carried out at the room temperature, varying the pH value (pH=1,54; 4,24) and different initial concentration of REEs to determine optimum condition for their recovery. Results revealed that removal efficiency for most of the REEs was much higher at pH=4,24 and reached 70-100% for the minimal concentrations and 30-40 % at maximal initial concentrations respectively. Adsorbent containing residual biomass and chitosan showed to be the most effective bio-sorbent for recovery of most of the REEs. In order to describe and fit the obtained data Langmuir and Freundlich isotherms models were employed.

scholarly journals Separation of Radionuclides from a Rare Earth-Containing Solution by Zeolite Adsorption

Minerals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 20
Author(s):  
Deniz Talan ◽  
Qingqing Huang
Keyword(s):  
Rare Earth ◽  
Rare Earths ◽  
Contact Time ◽  
Separation Efficiency ◽  
Ph Value ◽  
Solid Phase ◽  
Separation Performance ◽  
Solution Ph ◽  
Zeolite Sample ◽  
Alternative Sources

The increasing industrial demand for rare earths requires new or alternative sources to be found. Within this context, there have been studies validating the technical feasibility of coal and coal byproducts as alternative sources for rare earth elements. Nonetheless, radioactive materials, such as thorium and uranium, are frequently seen in the rare earths’ mineralization, and causes environmental and health concerns. Consequently, there exists an urgent need to remove these radionuclides in order to produce high purity rare earths to diversify the supply chain, as well as maintain an environmentally-favorable extraction process for the surroundings. In this study, an experimental design was generated to examine the effect of zeolite particle size, feed solution pH, zeolite amount, and contact time of solid and aqueous phases on the removal of thorium and uranium from the solution. The best separation performance was achieved using 2.50 g of 12-µm zeolite sample at a pH value of 3 with a contact time of 2 h. Under these conditions, the adsorption recovery of rare earths, thorium, and uranium into the solid phase was found to be 20.43 wt%, 99.20 wt%, and 89.60 wt%, respectively. The Freundlich adsorption isotherm was determined to be the best-fit model, and the adsorption mechanism of rare earths and thorium was identified as multilayer physisorption. Further, the separation efficiency was assessed using the response surface methodology based on the development of a statistically significant model.

A DETERMINATION OF THE SHEAR FORCE OF THIN HIGH-COERCIVITY PERMANENT MAGNETS MADE FROM THE ALLOY WITH RARE-EARTH ELEMENTS

2021 ◽  
pp. 24-30
Author(s):  
A. Ya. Krasilʼnikov ◽  
A. A. Krasilʼnikov
Keyword(s):  
Rare Earth ◽  
Magnetic Flux ◽  
Rare Earth Elements ◽  
Standard Method ◽  
Shear Force ◽  
Permanent Magnets ◽  
High Coercivity ◽  
Research Results ◽  
Magnetic Couplings

The article considers the possibility of using a standard method for calculating the shear force of thin, high-coercivity neodymium–iron–boron type permanent magnets in magnetic clutches (couplings). The research results allowed to introduce a correction coefficients in the method of calculating the transmitting torque in magnetic clutches (couplings) with thin magnets. The possibility of 08H22N6T brand steel using for magnetic flux conductors manufacturing in a magnetic couplings.

scholarly journals Effects and mechanistic aspects of absorbing organic compounds by coking coal

2017 ◽  
Vol 76 (9) ◽  
pp. 2280-2290 ◽  
Author(s):  
Kejia Ning ◽  
Junfeng Wang ◽  
Hongxiang Xu ◽  
Xianfeng Sun ◽  
Gen Huang ◽  
...  
Keyword(s):  
Organic Compounds ◽  
Ph Value ◽  
Freundlich Isotherm ◽  
Systemic Circulation ◽  
Batch Adsorption ◽  
Phenol Removal ◽  
Coal Consumption ◽  
Coking Coal ◽  
Freundlich Isotherms ◽  
Novel Method

Abstract Coal is a porous medium and natural absorbent. It can be used for its original purpose after adsorbing organic compounds, its value does not reduce and the pollutants are recycled, and then through systemic circulation of coking wastewater zero emissions can be achieved. Thus, a novel method of industrial organic wastewater treatment using adsorption on coal is introduced. Coking coal was used as an adsorbent in batch adsorption experiments. The quinoline, indole, pyridine and phenol removal efficiencies of coal adsorption were investigated. In addition, several operating parameters which impact removal efficiency such as coking coal consumption, oscillation contact time, initial concentration and pH value were also investigated. The coking coal exhibited properties well-suited for organics' adsorption. The experimental data were fitted to Langmuir and Freundlich isotherms as well as Temkin and Redlich–Peterson (R-P) models. The Freundlich isotherm model provided reasonable models of the adsorption process. Furthermore, the purification mechanism of organic compounds' adsorption on coking coal was analysed.

scholarly journals Selective Roasting of Nd–Fe‒B Permanent Magnets as a Pretreatment Step for Intensified Leaching with an Ionic Liquid

2019 ◽  
Vol 6 (1) ◽  
pp. 91-102 ◽  
Author(s):  
Martina Orefice ◽  
Amy Van den Bulck ◽  
Bart Blanpain ◽  
Koen Binnemans
Keyword(s):  
Ionic Liquid ◽  
Rare Earth ◽  
Rare Earth Elements ◽  
Permanent Magnets ◽  
Metallic Phase ◽  
Process Step ◽  
Mechanical Removal ◽  
Oxidative Roasting ◽  
Roasting Temperature ◽  
The Rare Earth

AbstractOxidative roasting of Nd–Fe‒B permanent magnets prior to leaching improves the selectivity in the recovery of rare-earth elements over iron. However, the dissolution rate of oxidatively roasted Nd–Fe‒B permanent magnets in acidic solutions is very slow, often longer than 24 h. Upon roasting in air at temperatures above 500 °C, the neodymium metal is not converted to Nd2O3, but rather to the ternary NdFeO3 phase. NdFeO3 is much more difficult to dissolve than Nd2O3. In this work, the formation of NdFeO3 was avoided by roasting Nd–Fe‒B permanent magnet production scrap in argon atmosphere, having an oxygen content of $$ p_{{{\text{O}}_{2} }} \, \le \,10^{ - 20} \;{\text{atm}}, $$pO2≤10-20atm, with the addition of 5 wt% of carbon as an iron reducing agent. For all the non-oxidizing iron roasting conditions investigated, the iron in the Nd–Fe‒B scrap formed a cobalt-containing metallic phase, clearly distinct from the rare-earth phase at microscopic level. The thermal treatment was optimized to obtain a clear phase separation of metallic iron and rare-earth phase also at the macroscopic level, to enable easy mechanical removal of iron prior to the leaching step. The sample roasted at the optimum conditions (i.e., 5 wt% carbon, no flux, no quenching step, roasting temperature of 1400 °C and roasting time of 2 h) was leached in the water-containing ionic liquid betainium bis(trifluoromethylsulfonyl)imide, [Hbet][Tf2N]. A leaching time of only 20 min was sufficient to completely dissolve the rare-earth elements. The rare-earth elements/iron ratio in the leachate was about 50 times higher than the initial rare-earth elements/iron ratio in the Nd–Fe‒B scrap. Therefore, roasting in argon with addition of a small amount of carbon is an efficient process step to avoid the formation of NdFeO3 and to separate the rare-earth elements from the iron, resulting in selective leaching for the recovery of rare-earth elements from Nd–Fe‒B permanent magnets.

scholarly journals The Potential Utilizing of Critical Element from Coal and Combustion Residues

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4710
Author(s):  
Yunhu Hu ◽  
Mu You ◽  
Guijian Liu ◽  
Zhongbing Dong ◽  
Facun Jiao ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Energy Efficient ◽  
High Tech ◽  
Critical Element ◽  
Recycled Materials ◽  
Critical Elements ◽  
High Concentrations ◽  
Alternative Sources ◽  
Combustion Residues

Strategically critical elements are becoming significant for the rising demand of emerging energy-efficient technologies and high-tech applications. These critical elements are mostly geologically dispersed, and mainly recovered from recycled materials. Coal with high concentrations of critical elements is supposed to stable alternative sources. The abundances of critical elements in coal varies widely among different deposits and regions. The high concentrations of critical elements are found in many Chinese and Russian coal ores. The global mining potential ratio (MPR) is applied and suggests scandium, hafnium, cesium, yttrium, germanium, gallium, thallium, strontium and rare-earth elements could be potential recovery from coal. A number of benefits are expected with the extraction of critical elements during coal utilization.

scholarly journals Mineralogical and Geochemical Characteristics of Lithium and Rare Earth Elements in High-Sulfur Coal from the Donggou Mine, Chongqing, Southwestern China

Minerals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 627
Author(s):  
Jianhua Zou ◽  
Longfei Cheng ◽  
Yuanchen Guo ◽  
Zhengcheng Wang ◽  
Heming Tian ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Raw Materials ◽  
Geochemical Characteristics ◽  
Critical Elements ◽  
Geological Factors ◽  
Potential Alternative ◽  
Geological Factor ◽  
Alternative Sources ◽  
Coal Measures

Coal and coal by-products are considered as the potential raw materials for critical elements (e.g., rare earth elements, Li, Ga, Ge, etc.), which have attracted much attention in recent years. The purpose of this study is to investigate the mineralogical and geochemical characteristics, and controlling geological factors of lithium and rare earth elements in the Lopingian (Wujiaping Formation) coal from the Donggou Mine, southeastern Chongqing Coalfield, China. Results indicate that lithium and rare earth elements are significantly enriched in the Donggou coals, which could be new potential alternative sources for critical elements. Concentrations of lithium and rare earth elements in the Donggou coals gradually increase from top to bottom. Lithium is mainly associated with kaolinite, while rhabdophane, florencite, goyazite, and xenotime are the main hosts of rare earth elements. The controlling geological factor is the groundwater leaching of underlying tuff, and to a lesser extent, the terrigenous clastic materials input from the top layer of the Kangdian Upland. This study provides mineralization information for lithium and rare earth elements exploration in coal measures.

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