Desulfation of rare-earth concentrates

Локшин, Э. П.; Tareeva, O. A.; Kashulina, T. G.

doi:10.1134/s1070427206040057

Cited by 5 publications

(3 citation statements)

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“…Being a recent area of interest, there is very limited information with regards to the processing details of rare earths on leaching of zirconosilicate minerals. Present literature are mainly commercial in nature and highlights only the generic process of treatment which either involves the use of sulphation baking 2 to convert rare earths in the zirconosilicate minerals into water soluble sulphates followed by water leaching or the use of weak sulphuric acid for direct leaching of Zr and RE values without the need for sulphation baking [13][14][15] . For example, pilot-plant recovery of rare earths from Greenland's Kvanefield eudialyte flotation concentrate involves leaching continuously for 5 h using weak sulphuric acid followed by strong acid leach for 4 h at 90-95⁰C with 354 kg/T (0.354g/g) acid and free acidity of 110 g/L with high RE recoveries but there is no details as to how the leaching factors affects RE dissolution [16] .…”

Section: Introductionmentioning

confidence: 99%

Leaching of rare earths from fine-grained zirconosilicate ore

Lim

Ibana

Eksteen

2016

Journal of Rare Earths

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In this study, leaching of rare earths Y,La and Ce by sulphuric acid from fine-grained zirconosilicate ore is investigated using Taguchi method of experimental design. An orthogonal array of L 8 ,2 7 which denotes 7 factors at 2 levels is chosen to consider the various factors relevant to the leaching process: baking time , baking temperature, acid dosage, leaching time, leaching temperature, grind size and dilution. Statistical analysis showed that sulphation baking is a significant step for the leaching of rare earths from the whole-of-ground ore leach and optimized leaching of rare earths involves the following condition: baking for 3 h at 320 °C at 3.2 g acid/g ore acid dosage followed by water leaching at 20°C for 1 h and dilution of 20 mL water/g ore using 300 um grind size. The effect of each leaching factor is also discussed.

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Section: Introductionmentioning

confidence: 99%

Leaching of rare earths from fine-grained zirconosilicate ore

Lim

Ibana

Eksteen

2016

Journal of Rare Earths

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“…10) If cerium oxide, therefore, is converted into sodium cerium sulfate in Na 2 SO 4 H 2 SO 4 H 2 O solutions during the leaching-REPPW process, it would be one of the simpler separation methods because sodium cerium sulfate is poorly soluble under acidic conditions. 11) This simple method, aimed at sodium cerium sulfate (NaCe(SO 4 ) 2 ·H 2 O), has been applied in various fields.…”

Section: +mentioning

confidence: 99%

Conversion Kinetics of Cerium Oxide into Sodium Cerium Sulfate in Na2SO4–H2SO4–H2O Solutions

Hirato

2012

Mater. Trans.

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The conversion of cerium oxide (CeO 2 ) into sodium cerium sulfate (NaCe(SO 4 ) 2 ·H 2 O) in Na 2 SO 4 H 2 SO 4 H 2 O solutions was studied at elevated temperatures using a batch-type glass reactor under atmospheric pressure. Sodium sulfate (Na 2 SO 4 ) concentration, sulfuric acid (H 2 SO 4 ) concentration and reaction temperature were chosen as dependent variables, and the effects of these three variables on the conversion of cerium oxide into sodium cerium sulfate in Na 2 SO 4 H 2 SO 4 H 2 O solutions were investigated. The conversion includes two chemical reactions: cerium oxide dissolution and sodium cerium sulfate synthesis. The experimental data showed that increases of sodium sulfate concentration and sulfuric acid concentration decreased the conversion rate, whereas the conversion rate increased with increasing reaction temperature. The conversion kinetics of cerium oxide into sodium cerium sulfate for these three variables was analyzed and the fitted equation to the experimental data was determined. The variations of rate constant in dissolution and synthesis with temperature obeyed the Arrhenius equation with activation energies of 120 and 200 kJ/mol, respectively. In addition, the rate constant of cerium oxide dissolution was a function of the sodium sulfate concentration and sulfuric acid concentration at N ¹0.3 and C 6.5, respectively, and for sodium cerium oxide synthesis at N ¹0.2 and C

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“…Knowledge on the composition of the equilibrium phases formed in multicomponent systems, containing rare-earth sulfates is crucial for the application and optimization of sulfuric acid processing of rare earth concentrates [4][5][6]. The behaviour of the systems and especially the solubility of the different sulfates at ambient temperature (25 • C) and around 64 under the latter conditions.…”

Section: Introductionmentioning

confidence: 99%