The α-β inversion in submilligram particles of natural quartz

Moore, Guy S M

doi:10.1007/bf02546561

Cited by 4 publications

(3 citation statements)

References 7 publications

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“…In the second stage (300-750°C, a minimum at 516.6°C), the mass loss of 3.8% corresponds to the dehydroxylation of the clay and the thermal polymorph transition (a ? b) of quartz [42,43].…”

Section: Thermal Characterization Of Sorption Productsmentioning

confidence: 99%

“…6. The peaks originating from the -CH 3 radical (M/Z = 15), amines (43), -N(CH 3 ) 2-CH 2 (58), and CH 3 Br(58), appearing in the region between 200 and 450°C, provide evidence for the defragmentation of surfactant molecules [45][46][47] Ion Current/A HDTMA(0.01)-P(V)- (44), and NO 2 (46) represent surfactant oxidation, which proceeds in two steps, between 200 and 400°C and between 400 and 800°C. The first step regards the surfactant sorbed on the mineral surface via electrostatic and covalent forces, whereas the second one relates to the surfactant present in the interior of the mineral structure, bound by electrostatic forces.…”

Section: Thermal Characterization Of Sorption Productsmentioning

confidence: 99%

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Study of effect of phosphate and uranium ions on the thermal properties of surfactant-modified natural red clay using TG–FTIR–MS techniques

Sternik

Gładysz–Płaska

Grabias

et al. 2018

J Therm Anal Calorim

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Products of sorption of uranyl ions on HDTMA-red clay in the presence of phosphates were characterized by thermal analysis. It was established on the basis of DTG curves of the sorption products and FTIR spectra of the gaseous phase of sorption products decomposition that the thermal stability of the mineral increased when P(V) ions were sorbed along with U(VI) ions, i.e., the temperature of defragmentation/oxidation of surfactant increased when going from U(VI)-HDTMAclay to U(VI)-P(V)-HDTMA-clay to P(V)-HDTMA-clay. The DSC curves of the sorption products showed that defragmentation/oxidation was an exothermic process and dehydration and dehydroxylation had an endothermic character. The investigated sorption system has practical importance, since an evident increase in U(VI) sorption over the entire pH range is observed when going from U(VI)-HDTMA-clay to U(VI)-P(V)-HDTMA-clay.

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Section: Thermal Characterization Of Sorption Productsmentioning

confidence: 99%

Section: Thermal Characterization Of Sorption Productsmentioning

confidence: 99%

Study of effect of phosphate and uranium ions on the thermal properties of surfactant-modified natural red clay using TG–FTIR–MS techniques

Sternik

Gładysz–Płaska

Grabias

et al. 2018

J Therm Anal Calorim

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“…Quartz undergoes crystalline transition at 573 °C and 870 °C and both alters the volume of quartz. At 573 °C α-quartz form undergoes structural change to β-quartz with associated 5% volume expansion, whereas at 870 °C β-quartz form changes to β-squamous quartz with a 12 % volume expansion (Balitsky et al, 1996;Moore, 1993). Due to a difference of the expansion rate between impurity and quartz, the rapid change in temperature can cause a large number of cracks at the junction of impurity and quartz matrix.…”

Section: Advanced Purification Of Industrial Quartz Using Calcinationmentioning

confidence: 99%

Advanced purification of industrial quartz using calcination pretreatment combined with ultrasound-assisted leaching

Yang¹

2018

Acta Geodynamica Et Geomaterialia

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Purification of quartz using an environment-friendly method is important in the contaminants removal. This paper presents advanced method based on calcination pretreatment combined with ultrasound-assisted leaching, for removing iron impurities from industrial quartz. The solvent used is a mixture comprised by diluted hydrochloric acid and oxalic acid. The effects of experimental parameters were investigated and the purification mechanism was discussed using particle size analyzer, scanning electron microscope and polarized light microscope. SiO 2 content of concentrate could be increased from 99.6828 % to 99.9047 %, which achieved 3N level high purity quartz, and Fe 2 O 3 content reduced from 0.0857 % to 0.0223 %, under the optimal conditions, i.e., calcination temperature of 900 °C, holding time of 2 h, oxalic acid concentration of 10 g/L, hydrochloric acid concentration of 5%, liquid solid ratio of 5, leaching temperature of 60 °C, ultrasound power of 400 W and treatment time of 30 min. Compared to conventional method, the proposed method significantly accelerates the leaching process and increases the iron removal rate. At the same time, the method also can remove gas-liquid inclusions. ARTICLE INFO

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Aggregation and thermal properties of nanostructured montmorillonite covered with mixed adsorption layers of cationic polyacrylamide and hazardous lead(II) ions

2020

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The aim of the study was to investigate the influence of nanostructured montmorillonite surface modification by the cationic polyacrylamide and the lead(II) ions on the thermal and aggregation properties of solid particles covered with mixed adsorption layers. The effects of cationic groups content in the polymeric macromolecules, the order of individual adsorbates addition, and lead(II) ions concentration were determined. Using spectrophotometry, potentiometric titration, microelectrophoresis, turbidimetry, DCS (Differential Centrifugal Sedimentation) and thermal analysis methods, the adsorption, electrokinetic, aggregation properties, as well as the thermal stability of studied montmorillonite—CT PAM—Pb(II) systems were established. It was shown that applied polymeric substance (soil flocculant) causes accumulation of lead(II) ions, which are hazardous at very low concentrations. Nevertheless, the chemical nature of these interactions may limit the bioavailability of this heavy metal for plants.

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The α-β inversion in submilligram particles of natural quartz

Cited by 4 publications

References 7 publications

Study of effect of phosphate and uranium ions on the thermal properties of surfactant-modified natural red clay using TG–FTIR–MS techniques

Study of effect of phosphate and uranium ions on the thermal properties of surfactant-modified natural red clay using TG–FTIR–MS techniques

Advanced purification of industrial quartz using calcination pretreatment combined with ultrasound-assisted leaching

Aggregation and thermal properties of nanostructured montmorillonite covered with mixed adsorption layers of cationic polyacrylamide and hazardous lead(II) ions

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