The impact of vermiculite residual fines in the rheological properties of cement pastes formulated with different waste contents

Rojas-Ramírez, Roberto Antonio; Maciel, Marcel Hark; Romano, Roberto; Pileggi, Rafael Giuliano; Coelho, A. C. Vieira

doi:10.1016/j.clay.2019.01.017

Cited by 8 publications

(9 citation statements)

References 16 publications

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“…In Fig. 5c, for EC, the lamellar structure of expanded vermiculite clay is observed with morphology showing the presence of plaques and exfoliations due to the vaporization of water from the layers during the expansion process (as noted in similar, expanded materials studied by Rojas-Ramires et al [29]). For OC (Figs.…”

Section: Resultssupporting

confidence: 64%

“…The main peak at 7.23º 2θ was consistent with the interstratified phase (biotite-vermiculite), called hydrobiotite. The presence of mica was also apparent at 8.04º 2θ (9.9 Å) according to the reference file JCPDS 74608 [28][29][30][31]. It was possible to observe peaks at 3.02º, 41.02º, and 43.96º 2θ, corresponding to basal distances of 29.23, 1.17, and 2.78 Å, respectively, which may be further illustrative of the mineral hydrobiotite, which is formed in the conversion process to vermiculite and is ascribed to the hydration of phlogopite/biotite by weathering water on the surface of weathered rocks [29].…”

Section: Resultsmentioning

confidence: 99%

“…The presence of mica was also apparent at 8.04º 2θ (9.9 Å) according to the reference file JCPDS 74608 [28][29][30][31]. It was possible to observe peaks at 3.02º, 41.02º, and 43.96º 2θ, corresponding to basal distances of 29.23, 1.17, and 2.78 Å, respectively, which may be further illustrative of the mineral hydrobiotite, which is formed in the conversion process to vermiculite and is ascribed to the hydration of phlogopite/biotite by weathering water on the surface of weathered rocks [29]. The presence of quartz was identified by peaks at 22.70° (3.4 Å) and 28.84º (3.0 Å), whose main peak is at 3.4 Å according to the reference file ICSD 01-079-1910, which confirmed other works [27,28,[31][32][33].…”

Section: Resultsmentioning

confidence: 99%

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Doxazosin adsorption in natural, expanded, and organophilized vermiculite-rich clays

et al. 2022

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Vermiculite clays are adsorbent materials that have good chemical adsorption capacity, which makes them applicable in the removal of drugs from aqueous solutions. Their lamellar structure can be easily expanded and organophilized. To assess the efficacy and environmentally-tolerant capacity of the adsorption method, the organophilized vermiculite clay was compared to both natural and expanded vermiculite clays. To prepare the organophilized clays, a natural clay sample was expanded at 900 °C. The expanded clay was thus treated by immersion in a 1.0 M NaCl solution and organophilized using a cetyltrimethylammonium bromide (CTMA-Br) surfactant, for 24 h at 50 °C. Natural, expanded, and organophilized samples were characterized using the techniques of XRD, FTIR, TG/DSC, and SEM to observe structural changes after expansion and organophilization. These characterizations indicated that there was an increase in the interlamellar space of the expanded and organophilized sample. In addition, a study of the point of zero charge was performed to determine the surface changes of the samples and the amount of doxazosin adsorption in the samples was determined by the time adsorption test. Further, the organophilized sample showed potential adsorption of the drug doxazosin and high performance in relation to the expanded and natural samples.

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Section: Resultssupporting

confidence: 64%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Doxazosin adsorption in natural, expanded, and organophilized vermiculite-rich clays

et al. 2022

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“…Furthermore, a small displacement of the peaks is observed after acid treatment with high concentrations of HNO 3 , as in the sample VN3. This occurred due to morphological changes in the crystalline structure of vermiculite-hydrobiotite, in the replacement of intercalating cations by hydronium ions (H 3 O + ), causing the displacement of the crystalline planes [16,29].…”

Section: Resultsmentioning

confidence: 99%

Acid matrix production from treated natural vermiculite-hydrobiotite

et al. 2021

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Given the potential of acid-activated clays in adsorptive and catalytic processes, several studies focusing on acid matrices have grown over the years, making it possible to study vermiculite, a mineral composed of a type 2:1 unit cell with tetrahedral and octahedral sheets. Therefore, this work aimed to study vermiculite treated with acids for the production of matrices. In this work, the treatment of natural vermiculite-hydrobiotite, with nitric acid in concentrations of 0.25, 0.50, 0.75, and 1 mol.L -1 , followed by the dealumination process with sulfuric acid 25% v/v, aiming the production of acid matrices for applications as support for biocatalysts, chemical adsorbents, among others. The produced materials were characterized using different techniques, including X-ray fluorescence spectroscopy, X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, and isotherm adsorption using the BET method. The results showed that after acid leaching the vermiculite showed a high SiO 2 content, high Brønsted and Lewis surface acidity, good adsorption/desorption performance, and significant growth of the specific surface area, qualifying the vermiculite as a promising material for future applications in catalytic and biocatalytic processes. The acid concentration had a considerable influence on the compositional and textural modification of vermiculite-hydrobiotite.

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“…The particle size distribution was measured on a laser granulometer, Helos (Sympatec) [25], the specific surface area was determined by N2 adsorption at 77K in a Belsorp Max equipment [12], the real density was determined by gas He pycnometry in Quantachrome equipment, MVP 5DC, while the pozzolanic index was defined by applying the method described in the NBR 15895/10 -Pozzolanic materials -Modified Chapelle method. The images of scanning electron microscopy (SEM) were obtained using a Quanta 600FEG instrument.…”

Section: Characterizationmentioning

confidence: 99%

Combined evaluation of oscillatory rheometry and isothermal calorimetry for the monitoring of hardening stage of Portland cement compositions blended with bauxite residue from Bayer process generated in different sites in Brazil

Romano

Mesquita

Bernardo

et al. 2021

Rev. IBRACON Estrut. Mater.

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Bauxite residue (BR), a by-product of alumina and aluminum production, consists of high aluminum, silica, and iron content, and sodium from the bauxite ore digestion during the Bayer process. This waste is still being disposal into the lakes of mud, causing some environmental problems. So, the search for its application has gained interest. Studies reported in literature point out that one of the most promising applications is in association with Portland cement, which can also help to reduce the environmental impact caused by the CO2-emissions in its production. In this work, a combined evaluation of oscillatory rheometry and isothermal calorimetry was performed for the monitoring of the hardening stage of Portland cement (PC) compositions blended with BR generated in different sites in Brazil. The time-sweep test was applied to obtain the consistency gain of suspensions over-time, allowing us to understand the physical parameters of consolidation, while the changes in the hydration reaction showed considerable differences in the chemical contribution. As a conclusion, it was clear the impact of each BR, mainly due to the aspects related to soluble aluminates, silicates, and sodium, which in association with the soluble ions from PC, affected the chemical reaction and agglomeration/flocculation forces of particles.

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The impact of vermiculite residual fines in the rheological properties of cement pastes formulated with different waste contents

Cited by 8 publications

References 16 publications

Doxazosin adsorption in natural, expanded, and organophilized vermiculite-rich clays

Doxazosin adsorption in natural, expanded, and organophilized vermiculite-rich clays

Acid matrix production from treated natural vermiculite-hydrobiotite

Combined evaluation of oscillatory rheometry and isothermal calorimetry for the monitoring of hardening stage of Portland cement compositions blended with bauxite residue from Bayer process generated in different sites in Brazil

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