A solution chemistry approach to the study of rare earth element precipitation by oxalic acid

Abstract

A solution chemistry approach is developed to study oxalic acid efficiency (OAE) in recovering rare earth (RE) elements from the leachates of weathered clays. The optimal pH for precipitation (approximately 2) to obtain the highest RE recovery with the highest purity is identified experimentally and confirmed by solution chemistry calculations. Applying the solution chemistry approach to three case studies, the cause for a larger oxalic acid consumption than that calculated from stoichiometry of RE oxalate precipitation is identified. A typical OAE of approximately 60 pct was determined with 40 pct of excess oxalic acid consumed by precipitating and complexing non-RE elements while maintaining a low residual RE element concentration. Both solution chemistry calculations and experimental results showed that OAE can be improved by processing leachates of high initial RE concentrations.

Optimization of the process of obtaining RE 2 O 3 from xenotime using statistical design

“…For the regression to be statistically significant, the value of F calculated , or the MQ R /MQ r ratio should be at least 4 times the value of F tabuleted [16,21]. In this case, F calculated is approximately 10 times greater than the F tabulated , which shows that the model described by Eq.…”

“…The concentration of precipitant solution used for conversion of the oxalates to oxides of rare earths was 80 g/mL, thus obtaining a yield of 98.25%. Oxalic acid has great selectivity, allowing for the attainment of rare earth oxalates which are insoluble in the reaction medium used [21][22][23]. According to the statistical design, we obtained oxalate by calcination from XRD pattern in Fig.…”

“…The behavior of the mixed rare earth oxide observed in the XRD pattern suggested that the constituents of the same metals, as oxides, form a solid solution of yttrium matrix due to the similarity of the rare earths (atomic radius, ionic radius, electronegativity and valence). The peaks were slightly displaced with respect to the rare earth oxides with the highest concentration found in xenotime [22][23][24][25][26]. Chemical analysis by atomic emission spectroscopy by induced plasma (Table VIII) [8].…”

Room‐temperature synthesis and characterization of cross‐like Pr2(C2O4)3·10H2O micro‐particles

“…As an important lanthanide compounds, lanthanide oxalates were widely used in rare-earth purification industry [6], or as a precursor to prepare lanthanide oxides [7]. In the past decades, mixed lanthanide oxalates, such as dysprosium gadolinium oxalate [8], neodymium praseodymium oxalate [9], lanthanide alkali-metals oxalate [10], lanthanide calcium oxalate [11] and lanthanide metal-organic frameworks [12], have been studied widely.…”

Kinetics of manganese reduction leaching from weathered rare-earth mud with sodium sulfite

“…The kinetment phase highly disseminated in amorphous manganese ics and mechanism of manganese reduction leaching from and/or iron oxides. [6,7,8] Conventional physical processing the REWM are the focus of this study. methods, such as flotation, magnetic, gravity, and electrostatic separation were found to be ineffective in recovering II.…”