Effect of thermal annealing on synthetic sodium oxalate crystals

García-Guinea, Javier; Correcher, V.; Lozano-Diz, Enrique; Bañares, Miguel Á.; López-Arce, Paula; García, Ana M. García; Moreno, Diego A.

doi:10.1016/j.jaap.2011.03.011

Cited by 7 publications

(2 citation statements)

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“…According to McAlexander et al, [19] the thermal decomposition of Na 2 C 2 O 4 occurs through its decomposition in Na 2 CO 3 and CO at about 500 C, and subsequently, the breakdown of the carbonate in Na 2 O and CO 2 occurs close to 830 C. In the same form, the TG curve of a sample with pure Na 2 C 2 O 4 had decomposition in a temperature range between 500-600 C and corresponded to a loss of mass of approximately 14% in a study by Garcia-Guinea et al [20] The result obtained (Figure 3) also shows these decompositions (between 425-575 C), and the loss of mass was 1.64%. To establish a relationship with a thermogravimetric curve to decompose the standard pure sodium oxalate, it is possible to configure the quantification of the compound in the analysis.…”

Section: Waste Characterizationmentioning

confidence: 78%

Sodium recovery from crystallization waste of Bayer liquor in alumina beneficiation

et al. 2021

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The residue generated in the crystallization stage of the Bayer process to obtain alumina may be used for sodium recovery. The addition of calcium hydroxide (Ca(OH) 2 ) to the residues of the Bayer process may become an alternative study for recovering the caustic soda (NaOH) inserted in the process, so the objective of this work is to utilize the causticization technique in a real residue obtained from the crystallization step of the Bayer liquor. The residue characterized presented 13% Al, so this indicated that there were losses of this element in the Bayer process. Also, the presence of Na 2 C 2 O 4 , Na 2 CO 3 , and NaAlO 2 were observed. The total sodium recovery was 87%, and the best condition for causticization to occur was in the use of a 1:1 molar ratio (Na 2 C 2 O 4 and Ca(OH) 2 ), during 6 h of reaction, and at 80 C, with the conversion of 96% of the organic carbons present in the solution. The causticization was effective in separating sodium from residue in the removal of oxalates, organics, and aluminium, and it provided a reaction that separated oxalates and carbonates that are harmful to the aluminium obtaining process.

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Section: Waste Characterizationmentioning

confidence: 78%

Sodium recovery from crystallization waste of Bayer liquor in alumina beneficiation

et al. 2021

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“…For the original sample N‐P0 without PTFE, the weight loss between 550 °C and 600 °C may be attributed to the conversion of Na 2 C 2 O 4 to Na 2 CO 3 . [ 45 ] The final mass retention of N‐P0, N‐P2, and N‐P2C2 are 54.97%, 48.54%, and 51.21%, respectively, indicating that the PTFE escapes in the form of gas. To further explore the category of gases released by PTFE and the supplementation mechanism of fluoride in pyrolysis for sample N‐P2, we have obtained the in‐situ infrared spectrometry (TG‐IR) 3D spectrum and 2D spectrum at 550 °C of precursor which are illustrated in Figure 2c and Figure S6 (Supporting Information).…”

Section: Resultsmentioning

confidence: 99%

Synergistic Effect, Structural and Morphology Evolution, and Doping Mechanism of Spherical Br‐Doped Na₃V₂(PO₄)₂F₃/C toward Enhanced Sodium Storage

Zhang

Fan

et al. 2022

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Recently, the spray drying technology has emerged as an effective approach in preparing battery materials due to its advantage of preparing spherical particles with excellent dispersion, [27][28][29] which typically includes atomizing the raw material slurry and dry it into spherical particles with the excellent dispersing ability through high-temperature heat flow. However, the obtained sphere typically exhibits hollow interior with low tap density and specific surface area. The inner surface is hard to contact the electrolyte effectively, resulting in the poor electrochemical performance of active material.There are several reports on the preparation of fluorine-containing cathode materials such as LiVPO 4 F and Na 3 V 2 (PO 4 ) 2 F 3 through the spray drying method. Ding et al. [30] and Sui et al. [31] prepared pure phase LiVPO 4 F with excellent electrochemical performance through a two-step spray drying method. However, it is difficult to accurately match the addition amount of LiF due to the loss of VPO 4 in the spray drying process, and the energy consuming is large. Eshraghi et al. [32] and Shen et al. [33] have successfully synthesized spherical particles of Na 3 V 2 (PO 4 ) 2 F 3 by adding excessive NaF in one-step spray drying method. However, the excessive introduction of sodium element results in the formation of inert sodium salt, which is detrimental to the electrochemical performance of Na 3 V 2 (PO 4 ) 2 F 3 /C cathode. The utilization of high-energy ball milling also destroys the spherical structure and increases the production costs.Both the two-step method and the excessive addition of NaF were used to inhibit the production of impurity. For Na 3 V 2 (PO 4 ) 2 F 3 , the loss of fluorine during the synthesis process leads to the formation of Na 3 V 2 (PO 4 ) 3 , which is also a sodium superionic conductor and possesses only one voltage plateau at 3.4 V with theoretical capacity of 117.6 mAh g −1 . However, low voltage plateau and theoretical capacity lead to low energy density. In comparison, Na 3 V 2 (PO 4 ) 2 F 3 with an average voltage of 3.9 V and theoretical capacity of 128.4 mAh g −1 exhibit a promising application value.In this work, we have successfully synthesized pure phase porous spherical Br-doped Na 3 V 2 (PO 4 ) 2 F 3 particles by a simple one-step spray drying method. The hard template fluoropolymer polytetrafluoroethylene (PTFE) and soft template surfactant cetyltrimethylammonium bromide (CTAB) were utilized as the supplement and regulative agent of fluorine in the synthesis process of Na 3 V 2 (PO 4 ) 2 F 3 /C, respectively. Their influences on the structure, morphology, and electrochemical performance of Na 3 V 2 (PO 4 ) 2 F 3 /C were also investigated systematically. The density functional theory (DFT) calculation was further used to analyze the doping effect of Br on the density of states (DOS) and the diffusion barriers of Na ions.

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Effects of electrolyte pHs, temperatures, potentials and oxalate ions on the electrocatalytic reduction of nitrates

Guo,

Ye,

Shen

2024

Journal of Electroanalytical Chemistry

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Effect of thermal annealing on synthetic sodium oxalate crystals

Cited by 7 publications

References 20 publications

Sodium recovery from crystallization waste of Bayer liquor in alumina beneficiation

Sodium recovery from crystallization waste of Bayer liquor in alumina beneficiation

Synergistic Effect, Structural and Morphology Evolution, and Doping Mechanism of Spherical Br‐Doped Na₃V₂(PO₄)₂F₃/C toward Enhanced Sodium Storage

Effects of electrolyte pHs, temperatures, potentials and oxalate ions on the electrocatalytic reduction of nitrates

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Effect of thermal annealing on synthetic sodium oxalate crystals

Cited by 7 publications

References 20 publications

Sodium recovery from crystallization waste of Bayer liquor in alumina beneficiation

Sodium recovery from crystallization waste of Bayer liquor in alumina beneficiation

Synergistic Effect, Structural and Morphology Evolution, and Doping Mechanism of Spherical Br‐Doped Na3V2(PO4)2F3/C toward Enhanced Sodium Storage

Effects of electrolyte pHs, temperatures, potentials and oxalate ions on the electrocatalytic reduction of nitrates

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Synergistic Effect, Structural and Morphology Evolution, and Doping Mechanism of Spherical Br‐Doped Na₃V₂(PO₄)₂F₃/C toward Enhanced Sodium Storage