Earth Recovery Research Articles

Ultra-Fine Centrifugal Concentration of Bastnaesite Ore

Historically, the ability to effectively separate carbonate gangue from bastnaesite via flotation has frequently proven to be challenging without sacrificing significant rare earth oxide (REO) grade or recovery. However, in light of the fact that the rare earth bearing minerals often exhibit higher specific gravities than the carbonate gangue, the possibility exists that the use of gravity separation could be used to achieve such a selective separation. This however is complicated by the fact that, in cases such as this study when the liberation size is finer than 50 µm, most traditional gravity separation methods become increasingly challenging. The purposes of this study is to determine the applicability of gravity concentrators to beneficiate bastnaesite from deleterious calcite bearing flotation feed material. Via the use of a UF Falcon, it was possible to achieve rougher gravity REO recoveries approaching the upper 80% range while rejecting on the order of 30% of the total calcium. In terms of purely REO recovery, this represents a significant improvement over results obtained via a traditional Falcon in previously reported studies.

Recovery of Rare Earth Oxides from Flotation Concentrates of Bastnaesite Ore by Ultra-Fine Centrifugal Concentration

Historically, the ability to effectively separate carbonate gangue from bastnaesite via flotation has frequently proven to be challenging without sacrificing significant rare earth oxide (REO) grade or recovery. However, in light of the fact that the rare earth bearing minerals often exhibit higher specific gravities than the carbonate gangue, the possibility exists that the use of gravity separation could be used to achieve such a selective separation. This however is complicated by the fact that, in cases such as this study when the liberation size is finer than 50 microns, most traditional gravity separation methods become increasingly challenging. The aim of this study is to determine the applicability of centrifugal concentrators to beneficiate ultra-fine (UF) bastnaesite and calcite bearing flotation concentrates. By using a UF Falcon, it was possible to achieve initial gravity REO recoveries exceeding 90% while rejecting on the order of 25% to 35% of the total calcium from an assortment of rougher and cleaner flotation concentrates. Additionally, when additional stages of cleaner UF Falcon gravity separation were operated in an open circuit configuration, it was possible, from an original fine feed of 35 microns containing 50.5% REO and 5.5% Ca, to upgrade up to approximately 59% REO and 2.0% calcium. While not the goal of this study, these results also support previous limited data to suggest that UF Falcons are potentially capable of treating a wider range of materials than they were originally designed for, including feeds rich in heavy mineral content.

Possibilities of recovery and separation of rare earth elements

Rare earth metals are a group of elements widely used in high technology products. They are included in the group of critical mineral resources for the EU economy. Rare earth elements are found in computers and mobile phones, as well as in low-emission energy technologies. They are also applied in chemical processes as catalysts in the oil refining. Some of them occur even in considerable quantities in the earth's crust but not very often in the concentrations justifying the profitability of their extraction. Additionally, the constantly growing demand and the current market situation cause that alternative resources of rare earth elements recovery are sought after. Therefore, the recovery and separation methods as well as recovery from the secondary sources are becoming more and more important. The following paper presents the possibilities of recovery and separation of rare earth elements from primary and secondary sources.

TPE and RE Extraction during Long-lived Radionuclide Partitioning in Combination with PUREX-process Using a Single TBP-Based Solvent

ABSTRACTExtraction of 241Am and 154Eu by 50% tributyl phosphate (TBP) in C13 fraction from nitric acid solutions containing 6 mol L−1 nitrate-ion of ammonium, aluminum, and iron salts has been investigated. Rig trials with transplutonium elements (TPE) and fission rare earth (RE) recovery from the evaporated raffinate of reprocessed WWER-1000 spent fuel were carried out in hot cells using mixer-settlers. The HLW feed acidity was adjusted by dissolving metallic iron up to 1 mol L−1 Fe(NO3)3. TPE and RE were recovered by 99.98% with DF from 137Cs > 7500. The combined extraction-partitioning cycle of a Modified Purex-process is proposed using 50% TBP as the single solvent.

Negative Effects of Long-duration Spaceflight on Paraspinal Muscle Morphology

Prospective case series. Determine the extent of paraspinal muscle cross-sectional area (CSA) and attenuation change after long-duration spaceflight and recovery on Earth. Determine association between in-flight exercise and muscle atrophy. Long-duration spaceflight leads to marked muscle atrophy. However, another negative consequence of disuse is intramuscular fatty infiltration. Notably, few studies have investigated the effects of spaceflight on intramuscular fatty infiltration, or how muscle atrophy is associated with in-flight exercise. We analyzed computed tomography scans of the lumbar spine (L1/L2) from 17 long-duration astronauts and cosmonauts to determine paraspinal muscle CSA and attenuation. Computed tomography scans were collected preflight, postflight, 1-year postflight, and, in a subset, 2 to 4 years postflight. We measured CSA (mm) and attenuation (Hounsfield Units) of the erector spinae (ES), multifidus (MF), psoas (PS), and quadratus lumborum (QL) muscles. We used paired t tests to compare muscle morphology at each postflight time point to preflight values and Pearson correlation coefficients to determine the association between muscle changes and in-flight exercise. ES, MF, and QL CSA and attenuation were significantly decreased postflight compared with preflight (-4.6% to -8.4% and -5.9% to -8.8%, respectively, p < 0.05 for all). CSA of these muscles equaled or exceeded preflight values upon Earth recovery, however QL and PS attenuation remained below preflight values at 2 to 4 years postflight. More resistance exercise was associated with less decline in ES and MF CSA, but greater decline in PS CSA. Increased cycle ergometer exercise was associated with less decline of QL CSA. There were no associations between in-flight exercise and muscle attenuation. Both CSA and attenuation of paraspinal muscles decline after long-duration spaceflight, but while CSA returns to preflight values within 1 year of recovery, PS and QL muscle attenuation remain reduced even 2 to 4 years postflight. Spaceflight-induced changes in paraspinal muscle morphology may contribute to back pain commonly reported in astronauts. 4.

Brown coals of Far East – natural resource for multipurpose industrial processing

The analysis of the potential economic value of brown coals of the Far East of Russia is carried out when to use them as a complex chemical mineral resource. It was conducted assessment of industrial attractiveness to use coal combustion or coal chemical processing wastes as an additional source of gold, rare metals and rare earth elements. The Sergeevskoye brown coal deposit of the Zeya-Bureya Sedimentary Basin in the Amur Region was proposed as a potential standard facility for the construction of a coal-chemical processing plant to produce resin, montan wax, complex hydrocarbons with associated gold, rare metals and rare earth elements recovery.

Extraction of rare earth elements with 2-[2'-(methoxydiphenylphosphoryl)phenyldiazenyl]-4-tert-butylphenol in the presence of 1-butyl-3-methylimidazolium and trioctylmethylammonium picrates

Extraction of micro amounts of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y with solutions of 2-[2'-(methoxydiphenylphosphoryl)phenyldiazenyl]-4-tert-butylphenol in 1,2-dichloroethane in the presence of 1-butyl-3-methylimidazolium and trioctylmethylammonium picrates has been studied. The stoichiometry of extracted complexes has been determined, the effect of HNO3 concentration in aqueous phase on the efficiency of rare earth elements recovery into organic phase has been considered.

Hydrometallurgical process for rare earth elements recovery from spent Ni-HM batteries

Rare earth elements (REE) have been widely used in various sectors, from the aerospace and steel industries, to electronic applications, particularly in displays and batteries for portable devices. The high demand for newer and better equipment has increased the consumption of the REE and at the same time the need for its recovery from electronic wastes. For that reason, recycling of batteries is important, principally the Ni-HM batteries, owing to their elevated content of rare earths elements. In the present work, electrodes from spent Ni-HM batteries were leached using H2SO4, in the presence of ozone as the oxidant, where recoveries of 96% for La, Ce and Nd were obtained at room temperature. The separation of Ni and Co from the leach solutions was performed using an electrochemical reactor, after which REE were precipitated, obtaining a mixture of its hydroxides with impurities below 1%, according to EDS analysis.

Separation and Recovery of Rare Earths in Reciprocating Extraction Columns

Multi‐component rare earth (RE) separation (Nd group/Sm group) and recovery (Nd group) in sulfuric acid solution by di(2‐ethyl‐hexyl) phosphoric acid (D2EHPA) dissolved in kerosene were investigated using two 3.7 cm inner diameter reciprocating extraction columns (RPCs) (height: 5.0–5.6 m) connected in sequence. The height equivalent to a theoretical stage (HETS) for Nd group/Sm group separation was in the range of 0.80–0.90 m and 0.66 m for extraction and scrubbing process, respectively. Under testing conditions, the concentration of Sm2O3 left in the raffinate (Nd group) was less than 0.1 wt% and the concentration of Eu2O3 in concentrated Sm Eu Gd oxides in the scrubbed organic phase was larger than 8.0 wt% (commercial grade). In the concentrating process of Nd group elements, the total RE concentration left in the raffinate was less than 0.1 g/L with a recovering efficiency more than 99%. The concentrated RE concentration was more than 250 g/L in the stripping raffinate and more than 14 times the feed concentration (17 g/L). The results show that the RPC has a great promise as an alternative of mixer‐settlers for saving space, solvent input, and operating (energy) cost in rare earth extraction and separation using the D2EHPA/RE2(SO4)3 system.

Observations of postglacial uplift at Churchill, Manitoba

Churchill, Manitoba, is located near the centre of postglacial uplift caused by the Earth's recovery from the melting of the Laurentide Ice Sheet. The value of present-day uplift at Churchill has important implications in the study of postglacial uplift in that it can aid in constraining the thickness of the ice sheet and the rheology of the Earth. The tide-gauge record at Churchill since 1940 is examined, along with nearby Holocene relative sea-level data, geodetic measurements, and recent absolute gravimetry measurements, and a present-day rate of uplift of 8–9 mm/a is estimated. Glacial isostatic adjustment models yield similar estimates for the rate of uplift at Churchill. The effects of the tide-gauge record of the diversion of the Churchill River during the mid-1970's are discussed.

Unique Charts for Space Missions

A flight to the moon and return requires an array of unique aerospace charts. The USAF Aeronautical Chart and Information Center has supported the charting requirements of NASA's Manned Space Program commencing with the first Mercury flight, followed by Gemini and finally the Apollo mission of landing astronauts on the moon. The various charts used for liftoff, earth orbit, lunar orbit, lunar landing, lunar departure and earth recovery are discussed.