scholarly journals Effect of Sulfuric Acid Baking and Caustic Digestion on Enhancing the Recovery of Rare Earth Elements from a Refractory Ore

Minerals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 532 ◽  
Author(s):  
Rina Kim ◽  
Heechan Cho ◽  
Jinan Jeong ◽  
Jihye Kim ◽  
Sugyeong Lee ◽  
...  
Keyword(s):  
Rare Earth ◽  
Sulfuric Acid ◽  
Rare Earth Elements ◽  
Rare Earth Oxide ◽  
Decomposition Methods ◽  
Major Constituent ◽  
Water Leaching ◽  
Solid Ratio ◽  
Crystallinity Changes ◽  
Leaching Efficiency

To improve the recovery of rare earth elements (REEs) from a refractory ore, this study investigated two different chemical decomposition methods, namely sulfuric acid baking and caustic digestion, with their respective leaching processes. The studied lateritic ore contained goethite (FeOOH) as a major constituent with REEs scattered around and forming submicron grains of phosphate minerals, such as apatite and monazite. Therefore, despite the substantially high content of REEs (3.4% total rare earth oxide), the normal acidic leaching efficiency of REEs reached only 60–70%. By introducing sulfuric acid baking and caustic digestion, the REE-leaching efficiency was significantly improved. After sulfuric acid baking at 2.0 acid/solid ratio and 200 °C for 2 h, the leaching efficiency reached 97–100% in the subsequent water-leaching. When the ore was digested with a solid/liquid ratio of 100 g/L in a 30 wt% NaOH solution at 115 °C and 300 rpm for 3 h, the REE-leaching efficiency of 99–100% was attained at 80 °C using a 3.0 M HCl solution. The correlation between the REE and the Fe-leaching was determined. The improvements in REE-leaching in both methods were mostly attributed to the mineral phase and crystallinity changes of Fe-bearing minerals due to the ore pretreatments. Such findings were also supported by X-ray diffraction and scanning electron microscopy analyses.

INFLUENCE OF ADDITION OF RARE EARTH ELEMENTS ON THERMAL BARRIER COATINGS MICRO STRUCTURAL EVOLUTION

2006 ◽  
Vol 20 (25n27) ◽  
pp. 4010-4015 ◽  
Author(s):  
XIAOJUAN JI ◽  
QIULI WEI ◽  
CHUNGEN ZHOU ◽  
SHENGKAI GONG ◽  
HUIBIN XU
Keyword(s):  
Rare Earth ◽  
Thermal Diffusivity ◽  
Rare Earth Elements ◽  
Lattice Distortion ◽  
Oscillation Amplitude ◽  
Structural Evolution ◽  
Rare Earth Oxide ◽  
Thermal Barrier ◽  
Barrier Effect ◽  
Lattice Oscillation

Decreasing thermal diffusivity of YSZ can increase the thermal barrier effect. Thermal diffusivity is in direct proportion to lattice oscillation amplitude and frequency. The addition of rare earth oxide into YSZ may induce the lattice distortion, which will result in the change of lattice oscillation frequency. In the present work, combined with the experiment, a theoretical study was proposed to investigate the effect of the rare earth elements on the thermal barrier effect of YSZ using first-principal calculations implemented CASTEP program. It has been found that the addition of the rear earth element can make larger lattice distortion and favorable to reduce the thermal conductivity. The calculation results are in agreement with our experimental results.

scholarly journals Rare Earth Occurrences in Streams of Processing a Phosphate Ore

Minerals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 262 ◽  
Author(s):  
Xiaosheng Yang ◽  
Hannu Tapani Makkonen ◽  
Lassi Pakkanen
Keyword(s):  
Rare Earth ◽  
Sulfuric Acid ◽  
Phosphoric Acid ◽  
Rare Earth Elements ◽  
Electron Probe Microanalysis ◽  
Electron Probe ◽  
Phosphate Ore ◽  
Mineral Liberation ◽  
Efficient Recovery ◽  
Liberation Analysis

Rare earth elements (REEs) are defined as lanthanides with Y and Sc. Rare earth occurrences including the REE-bearing phases and their distributions, measured by rare earth oxides (REOs), in the streams of processing a phosphate ore were determined by using MLA, the mineral liberation analysis and EPMA, the electron probe microanalysis. The process includes an apatite ore beneficiation by flotation and further processing of the beneficiation concentrate with sulfuric acid. Twenty-six, sixty-two and twelve percent of the total REOs (TREO) contents from the ore end up in the products of beneficiation tailings, phosphogypsum (PG) and phosphoric acid, respectively. Apatite, allanite, monazite and pyrochlore are identified as REE-bearing minerals in the beneficiation process. In the beneficiation tailings, the REEs are mainly distributed in monazite (10.3% TREO), apatite (5.9% TREO), allanite (5.4% TREO) and pyrochlore (4.3% TREO). Gypsum, monazite, apatite and other REE-bearing phases were found to host REEs in the PG and the REEs distributions are 44.9% TREO in gypsum, 15.8% TREO in monazite, 0.6% TREO in apatite and 0.6% TREO in other REE-bearing phases. Perspectives on the efficient recovery of REEs from the beneficiation tailings and the PG are discussed.

Study on Leaching Zinc Calcine with High Iron

2013 ◽  
Vol 826 ◽  
pp. 118-121
Author(s):  
Jin Lin Yang ◽  
Hong Mei Zhang ◽  
Xiu Juan Su ◽  
Shao Jian Ma
Keyword(s):  
Sulfuric Acid ◽  
Acid Concentration ◽  
Great Influence ◽  
Sulfuric Acid Concentration ◽  
Acid Leaching ◽  
Leaching Rate ◽  
Iron Extraction ◽  
High Iron ◽  
Solid Ratio ◽  
Leaching Efficiency

In recent years, recovering zinc from zinc calcine with high iron has been a matter of discussion. In this paper, sulfuric acid leaching was carried out to assess the effect of several parameters on zinc and iron extraction in zinc calcine with high iron in which the grade of zinc and iron is 53.90% and 19.38%, respectively. Parameters, such as stirring speed, sulfuric acid concentration, liquid to solid ratio and leaching time, were investigated. The results show that leaching time has done nothing to the leaching rate, but has great influence on leaching efficiency. Liquid to solid ratio and sulfuric acid concentration have significant influence on leaching results, and stirring rate has not obvious influence on leaching results. Under the condition of 120g/L sulfuric acid, 6:1 liquid to solid ratio, 55°C leaching temperature and 120min leaching time, the recovery of zinc and iron is 82.24% and 9.64%, respectively. It is obvious that ZnO in zinc calcine is easy to dissolve in acidity solution, which shown in two aspects: high leaching rate and high leaching speed. ZnO can be dissolved entirely in sufficient sulfuric acid in 10min.

scholarly journals Leaching Kinetics of Praseodymium in Sulfuric Acid of Rare Earth Elements (REE) Slag Concentrated by Pyrometallurgy from Magnetite Ore

2015 ◽  
Vol 53 (1) ◽  
pp. 46-52
Author(s):  
Chul-Joo Kim ◽  
Ho-Sung Yoon ◽  
Kyung Woo Chung ◽  
Jin-Young Lee ◽  
Sung-Don Kim ◽  
...  
Keyword(s):  
Rare Earth ◽  
Sulfuric Acid ◽  
Rare Earth Elements ◽  
Leaching Kinetics ◽  
Magnetite Ore ◽  
Kinetics Of

scholarly journals Sulfuric Acid Leaching of Heavy Rare Earth Elements (HREEs) from Indonesian Zircon Tailing

2020 ◽  
Vol 11 (4) ◽  
pp. 804
Author(s):  
Iga Trisnawati ◽  
Gyan Prameswara ◽  
Panut Mulyono ◽  
Agus Prasetya ◽  
Himawan Tri Bayu Murti Petrus
Keyword(s):  
Rare Earth ◽  
Sulfuric Acid ◽  
Rare Earth Elements ◽  
Acid Leaching ◽  
Sulfuric Acid Leaching ◽  
Heavy Rare Earth ◽  
Heavy Rare Earth Elements

scholarly journals A Study on the Leaching of Rare Earth Elements from Waste Phosphor Powder

2021 ◽  
Vol 59 (7) ◽  
pp. 459-468
Author(s):  
Gee Hun Lee ◽  
Chang Kwon Kim ◽  
Dong Hoon Lee ◽  
Young Jun Song
Keyword(s):  
Rare Earth ◽  
Sulfuric Acid ◽  
Nitric Acid ◽  
Hydrochloric Acid ◽  
Acid Solution ◽  
Rare Earth Elements ◽  
Nitric Acid Solution ◽  
Reaction Rate ◽  
Phosphor Powder ◽  
Leaching Reaction

This study was carried out to obtain data to design a process to recover rare earth elements, specifically Y(Yttrium), La(Lanthanum), Ce(Cerium), Eu(Europium), Tb(Terbium) from waste phosphor powder. For this purpose, we investigated the effect of temperature, concentration, time and acids on leaching of the rare earth elements. The effect of roasting temperature, roasting time, roasting agent and its dosage on the leaching of rare earth elements were also investigated. 92% of the Yttrium, 70% of the Europium and 8% of the Cerium contained in the waste phosphor powder was leached at the condition of 50 oC and 0.3N HCl solution for 3hours. However, Terbium and Lanthanum were never leached at this condition. The leaching ratio increased to 100% of Yttrium and Europium, 98% of Cerium, 92% of Terbium and 89% of Lanthanum by leaching after soda ash roasting. In the leaching experiment with unroasted phosphor at 80 oC, the initial leaching reaction rate of Yttrium was 0.035 mol/L·s in 0.3N sulfuric acid solution, 0.033 mol/L·s in nitric acid solution and 0.028 mol/L·s in 0.3N hydrochloric acid solution. And the initial leaching reaction rate of Europium was 0.0017 mol/L·s in 0.3N sulfuric acid solution, 0.00114 mol/L·s in nitric acid solution and 0.00113 mol/L·s in 0.3N hydrochloric acid solution. For Cerium, the initial leaching reaction rate was 0.00019 mol/L·s in 0.3N sulfuric acid solution, 0.00025 mol/L·s in nitric acid solution and 0.00014 mol/L·s in 0.3N hydrochloric acid solution.

Leaching behaviour of rare earth elements from low-grade weathered crust elution-deposited rare earth ore using magnesium sulfate

Clay Minerals ◽  
2018 ◽  
Vol 53 (3) ◽  
pp. 505-514
Author(s):  
Kaihua Chen ◽  
Jiannan Pei ◽  
Shaohua Yin ◽  
Shiwei Li ◽  
Jinhui Peng ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Magnesium Sulfate ◽  
Low Grade ◽  
Second Stage ◽  
Leaching Solution ◽  
Weathered Crust ◽  
Leaching Behaviour ◽  
N Pollution ◽  
Leaching Efficiency

ABSTRACTThe present study investigates the use of magnesium sulfate (MgSO4) instead of (NH4)2SO4 as a lixiviant in the recovery of rare earth elements (REEs) from clays. Experiments were carried out to investigate the influence of leaching conditions such as leaching time, lixiviant concentration and liquid:solid ratio on the leaching efficiency. The optimum leaching conditions, leading to 75.48% of total REE leaching efficiency, required a stirring speed of 500 rpm, a leaching time of 30 min, a lixiviant concentration of 3 wt.% and a liquid:solid ratio of 3:1. After extension of the leaching process by a second stage, the leaching efficiency may reach up to 96.19%, which is slightly higher than that obtained by (NH4)2SO4. Leaching varies from element to element, with Ce presenting the lowest leaching efficiency, and the partition in leaching solution is in agreement with that in raw ore other than for Ce. Based on these findings, MgSO4 lixiviant is an excellent alternative leaching agent for a sustainable REE industry because it reduces or eliminates NH4+–N pollution.

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