Structural features of the silicate networks of serpentines

Zulumyan, N. H.; Papakhchyan, L. R.; Terzyan, A. M.; Beglaryan, H. A.; Isahakyan, Anna

doi:10.1134/s0040579512040215

Cited by 6 publications

(3 citation statements)

References 7 publications

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“…Heat treatment of serpentine minerals led to the destruction of the mineral's crystal lattice and the formation of secondary mineral phases [6] recorded by X-ray phase analysis (Figure 1). As the temperature increased above 500 • C, a decrease in the intensity of the serpentine reflexed, and an increase in forsterite and enstatite was observed while roasting the MF samples in a muffle furnace.…”

Section: Xrd Analysismentioning

confidence: 99%

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In Situ Control of Thermal Activation Conditions by Color for Serpentines with a High Iron Content

et al. 2021

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Serpentine heat treatment at temperatures of 650–750 °C yields magnesium–silicate reagent with high chemical activity. Precise and express control of roasting conditions in laboratory kilns and industrial aggregates is needed to derive thermally activated serpentines on a large scale. Color change in serpentines with a high iron content during roasting might be used to indicate the changes in chemical activity in the technological process. This study gives a scientific basis for the express control of roasting of such serpentines by comparing the colors of the obtained material and the reference sample. Serpentines with different chemical activity were studied by X-ray diffraction, Mössbauer spectroscopy, and optical spectroscopy. The color parameters were determined using RGB (red, green, blue), CIELAB (International Commission on Illumination 1976 L*a*b), and HSB (hue, brightness, saturation) color models. The color of heat-treated samples was found to be affected by changes in the crystallochemical characteristics of iron included in the structure of the serpentine minerals. The color characteristics given by the CIELAB model were in good coherence with the acid-neutralizing ability and optical spectra of heat-treated serpentines. Thus, in contrast to the long-term analysis by these methods, the control by color palette provides an express assessment of the quality of the resulting product.

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Section: Xrd Analysismentioning

confidence: 99%

“…The series of studies carried out under the leadership of N.O. Zulumyan should be noted [5][6][7]. This research group developed a thermal-acid treatment method of serpentines based on their ability to form an active metastable magnesium silicate phase under heat treatment [7,8].…”

Section: Introductionmentioning

confidence: 99%

In Situ Control of Thermal Activation Conditions by Color for Serpentines with a High Iron Content

et al. 2021

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“…A detailed analysis of the thermal decomposition of serpentines has demonstrated that, during the thermal treatment, the dehydroxylation process of the mineral is accompanied by partition of the silicate layer into various anions [21,22] and other oligosilicate anions from the silicate layer and transfer these anions into solution in the form of silicic acids, together with iron(III) and magnesium compounds [23]. The remaining fragments of the silicate layer of serpentine, in which metasilicate chains predominate, are easily separated from solution and unreacted part by decantation and fi ltration [24].…”

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confidence: 99%

Synthesis of β-wollastonite on the basis of silica formed from silicate layers of serpentine

et al. 2015

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Two-stage method for synthesis of β-wollastonite via reaction of calcium hydroxide and silica formed from silicate layers of serpentine and calcination of the resulting compounds was examined. It was found that the specifi c structural features of the silica used for this purpose make it possible to avoid a many hours' autoclave treatment and obtain such amorphous calcium hydro-and hydroxo-silicates that are converted under annealing, beginning at 800-810°C, to β-wollastonite by mixing a suspension of Ca(OH) 2 , SiO 2 , and H 2 O heated to its boiling point under atmospheric pressure. The optimal synthesis parameters, molar ratio of the starting substances and agitation duration, are determined.

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