Swelling of clay minerals in ammonium leaching of weathered crust elution-deposited rare earth ores

Zhang, Zhenyue; He, Zhengyan; Zhou, Fang; Zhong, Chengbin; Sun, Ningjie; Chi, Ruan

doi:10.1007/s12598-017-0977-7

Cited by 40 publications

(10 citation statements)

References 17 publications

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“…43 When ζ = 0, this point on the Zeta-pH curve is called the isoelectric point, and the system is easily and rapidly coalesced. 44 Therefore, to ensure the stability of the slurry system used for freeze casting, the ζ of the ceramic slurry was tested, and the results are shown in Figure 2I. The original pH of the ceramic powder dissolved in DI water was 9.…”

Section: Resultsmentioning

confidence: 99%

Rheological, mechanical, and electrical properties of Sr_0.7Bi_0.2TiO₃ modified BaTiO₃ ceramic and its composites

et al. 2023

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Porous BaTiO3‐based relaxor ferroelectric ceramics with lamellar structure were achieved by ice templating method, and the rheological properties of ceramic slurry for freeze casting were deeply studied. Epoxy resin was then backfilled to generate ceramic–epoxy resin composites. Ceramic–epoxy composites with a lamellar structure were obtained when using a slurry with a ceramic content of 45 wt.%. The nanoindentation results showed that the introduction of ceramic materials into the epoxy resin can significantly improve the penetration resistance and hardness of the material. The dielectric and ferroelectric properties of the composites were also characterized. The interaction between the highly coupled dipoles in the polymers results in a decrease in the breakdown field strength of the composite. The dielectric constant reached up to ∼800. At 220 kV/cm, Wrec = 0.62 J/cm3, and η was ∼80%. At low frequencies, Wrec was ∼0.16 J/cm3, which indicated good stability.

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Section: Resultsmentioning

confidence: 99%

Rheological, mechanical, and electrical properties of Sr_0.7Bi_0.2TiO₃ modified BaTiO₃ ceramic and its composites

et al. 2023

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“…In +2 and +1 valence cationic electrolyte solutions, zeta potential on the clay mineral surface increased with the increase of electrolyte solution concentration. Different cations have a greater impact on zeta potential, and cations in the same valence state have different zeta potentials, which was mainly due to the difference in the ion radius leading to different zeta potentials (Zhang Z. Y. et al, 2018). According to Figure 7D, by comparing the zeta potential of clay minerals at the same concentration of each electrolyte cation, the NH + 4 absolute value of zeta potential was the largest, and the zeta potential value was negative.…”

Section: Effects Of Cations On Zeta Potential Of Clay Mineralsmentioning

confidence: 96%

Effects of Ion Characteristics on the Leaching of Weathered Crust Elution-Deposited Rare Earth Ore

et al. 2020

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To reveal the ion-exchange mechanism in the leaching process of weathered crust elution-deposited rare earth ores with different leaching agents, the effects of a variety of cations and anions at different concentrations on the leaching process were investigated, including Al3+, Fe3+, Ca2+, Mg2+, Na+, K+, NH4+ and Cl−, NO3-, and SO42-. Meanwhile, the relationships between different concentrations of cations and anions and leaching efficiency were investigated, as was the relationship between different concentrations of cations and anions and zeta potential. The effect of different ions on the swelling of clay minerals during leaching process was also investigated. The results shown that NH4+ was the most affected electrolyte cation in terms of rare earth leaching efficiency during the leaching process of weathered crust elution-deposited rare earth ore among three different cationic valence states, and the leaching efficiency was 86.93% at the optimal leaching concentration. The influence of the three anions on the leaching efficiency of rare earth was NO3->Cl->SO42-, and the leaching efficiency of rare earth were 83.21, 81.52, and 80.12% at the optimal leaching concentration, respectively. The NH4+ had the greatest effect on the zeta potential of weathered crust elution-deposited rare earth ore, and the zeta potential was −18.1 mV at the optimal leaching concentration. Additionally, the order of the effect of three anions on zeta potential was SO42->NO3->Cl-. Combined with the effect on the rare earth leaching process, anions and cations were considered separately, and NH4+ and Cl− were selected; the relationship between the rare earth leaching efficiency and zeta potential conforms to the follow equations: NH4+:Y = −0.48X2 – 13.51X – 1.58, R2 = 0.98133 and Cl−:Y= −1.22X2 – 17.64X + 23.29, R2 = 0.99010. It was also found in the swelling experiment of the weathered crust elution-deposited rare earth ore that the swelling ratio of clay minerals was the lowest when the cation and anion were NH4+ and Cl− and the swelling ratios were 1.874 and 2.015%, respectively.

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“…In addition, with the increase in the P/I ratio in the preparation process, the expansion degree of dickite layer gradually increased, and the absolute ζ -potential value of the obtained washed expanded dickite also increased gradually. The ζ -potential of clay minerals was usually affected by its structure and the pH of the solution [22]. Maqueda et al found that after the sepiolite was treated at 500°C for 24 h, the structure of sepiolite changed due to the shedding of the OH structural group, which increased the negative charge on the surface of the sepiolite and was more conducive to the adsorption of diuron in aqueous solution [23].…”

Section: ζ -Potentialmentioning

confidence: 99%

Regulation and characterisation of the expansion structure of dickite layers

Dang

Ding

et al. 2023

Materials Science and Technology

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A dickite with an expanded layer structure was prepared by the co-calcination of the dickite-urea intercalation complex, urea, and potassium chlorate at 450°C. The expansion degree of the dickite layer could be regulated by the mass ratio (P/I) of potassium chlorate to the intercalation complex. XRD and SEM results showed that with the increase of the P/I ratio, the (002) diffraction intensity of expanded dickite gradually weakened and the degree of layer expansion gradually increased. When the P/I ratio exceeded 0.375, the expanded dickite exhibited an accordion-like porous morphology. The layer expansion of dickite exposed more internal layer surfaces, which was conducive to increasing the specific surface area, mesopore volume, and absolute ζ-potential, thus enhancing the adsorption capacity of methylene blue.

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Swelling of clay minerals in ammonium leaching of weathered crust elution-deposited rare earth ores

Cited by 40 publications

References 17 publications

Rheological, mechanical, and electrical properties of Sr_0.7Bi_0.2TiO₃ modified BaTiO₃ ceramic and its composites

Rheological, mechanical, and electrical properties of Sr_0.7Bi_0.2TiO₃ modified BaTiO₃ ceramic and its composites

Effects of Ion Characteristics on the Leaching of Weathered Crust Elution-Deposited Rare Earth Ore

Regulation and characterisation of the expansion structure of dickite layers

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Swelling of clay minerals in ammonium leaching of weathered crust elution-deposited rare earth ores

Cited by 40 publications

References 17 publications

Rheological, mechanical, and electrical properties of Sr0.7Bi0.2TiO3 modified BaTiO3 ceramic and its composites

Rheological, mechanical, and electrical properties of Sr0.7Bi0.2TiO3 modified BaTiO3 ceramic and its composites

Effects of Ion Characteristics on the Leaching of Weathered Crust Elution-Deposited Rare Earth Ore

Regulation and characterisation of the expansion structure of dickite layers

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Product

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Rheological, mechanical, and electrical properties of Sr_0.7Bi_0.2TiO₃ modified BaTiO₃ ceramic and its composites

Rheological, mechanical, and electrical properties of Sr_0.7Bi_0.2TiO₃ modified BaTiO₃ ceramic and its composites