K-rich rectorite from kaolinized micaschist of the Sesia-Lanzo Zone, Italy

Benincasa, Emanuele; Brigatti, Maria Franca; Medici, Luca; Poppi, Luciano

doi:10.1180/000985501750539508

Cited by 8 publications

(3 citation statements)

References 37 publications

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“…Contours (interval 0.1) denote correlations between the NAO winter index and average winter (December to March) temperature from 12 weather stations (blue dots) over the period 1967 to 1995. Correlative contours were constructed as described 29 using linear interpolation 30 . Red and green circles show the location of the respective musk oxen and caribou populations used in our analyses.…”

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confidence: 99%

First-principles study of illite–smectite and implications for clay mineral systems

Stixrude

Peacor

2002

Nature

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Illite-smectite interstratified clay minerals are ubiquitous in sedimentary basins and they have been linked to the maturation, migration and trapping of hydrocarbons, rock cementation, evolution of porewater chemistry during diagenesis and the development of pore pressure. But, despite the importance of these clays, their structures are controversial. Two competing models exist, each with profoundly different consequences for the understanding of diagenetic processes: model A views such interstratified clays as a stacking of layers identical to endmember illite and smectite layers, implying discrete and independently formed units (fundamental particles), whereas model B views the clays as composed of crystallites with a unique structure that maintains coherency over much greater distances, in line with local charge balance about interlayers. Here we use first-principles density-functional theory to explore the energetics and structures of these two models for an illite-smectite interstratified clay mineral with a ratio of 1:1 and a Reichweite parameter of 1. We find that the total energy of model B is 2.3 kJ atom(-1) mol(-1) lower than that of model A, and that this energy difference can be traced to structural distortions in model A due to local charge imbalance. The greater stability of model B requires re-evaluation of the evolution of the smectite-to-illite sequence of clay minerals, including the nature of coexisting species, stability relations, growth mechanisms and the model of fundamental particles.

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confidence: 99%

First-principles study of illite–smectite and implications for clay mineral systems

Stixrude

Peacor

2002

Nature

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“…The crystalline structure of natural clay minerals and the corresponding hybrid pigments (Clay-IORs) were studied by XRD analyses (see Figure 1 ). The main crystal phase information of natural clay minerals, including IS [ 25 ], REC [ 26 ], KAO [ 27 ], MMT [ 28 ], VMT [ 29 , 30 ], SEP [ 9 ], HYS [ 31 ] and ILL was listed in Table S1 (see Supplementary Materials ). As can be seen from Figure 1 and Table S1 , the associated minerals, such as quartz (at 2 θ = 20.86°, 26.67°, 36.55°, 42.45°, 50.12°, 59.94° and 68.15°) [ 32 ], muscovite (at 2 θ = 8.81°, 17.78°, and 27.96°) [ 33 ], talc (at 2 θ = 9.49°, 18.66° and 28.65°) [ 30 ], biotite (at 2 θ = 10.56°) [ 29 ], dolomite (at 2 θ = 30.94°, 33.54°, 41.13°, 44.95°, and 50.53°), and calcite (at 2 θ = 23.05°, 29.39°, 35.98°, 39.42°, 47.50°, 48.50°, 56.58°, 57.42°and 60.99°) are present in the natural clay minerals.…”

Section: Resultsmentioning

confidence: 99%

Optimal Synthesis of Environment-Friendly Iron Red Pigment from Natural Nanostructured Clay Minerals

Dong

Wang

et al. 2018

Nanomaterials

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A series of environment-friendly clay minerals—α-Fe2O3 iron-red hybrid pigments—were prepared by a simple one-step hydrothermal reaction process using natural nanostructured silicate clay minerals as starting materials. The influence of structure, morphology and composition of different clay minerals on the structure, color properties, and stability of the pigments was studied comparatively by systematic structure characterizations with X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmittance electron microscope (TEM), X-ray fluorescence spectroscopy (XRF), X-ray photoelectron spectroscopy (XPS) and CIE-L*a*b* Colorimetric analyses. The results showed that the clay minerals act as green precipitants during the hydrothermal reaction to induce in-situ transformation of Fe(III) ions into Fe2O3 crystals. Meanwhile, they also act as the “micro-reactor” for forming Fe2O3 crystals and the supporter for inhibiting the aggregation of Fe2O3 nanoparticles. The color properties of iron-red hybrid pigments are closely related to the surface charges, surface silanol groups, and solid acid sites of clay minerals. The clay minerals with higher surface activity are more suitable to prepare iron-red pigments with better performance. The iron-red hybrid pigment derived from illite (ILL) clay showed the best red color performance with the color values of L* = 31.8, a* = 35.2, b* = 27.1, C* = 44.4 and h° = 37.6, and exhibited excellent stability in different chemical environments such as acid, alkaline, and also in high-temperature conditions.

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“…Figure 2 shows the TG‐DSC curves of the rectorite and kaolin minerals. From Figure 2A, it can be seen that the TG‐DSC curves of the rectorite can be divided into the following three regions: (1) the region below 400°C, in which the two endothermic peaks at 100°C and 160°C on the DSC curve can be assigned to the losses of adsorbed and inter‐layer water, respectively, and the weight loss in this region was estimated about 6 wt % from the corresponding TG curve; (2) the region between 400°C and 1000°C, in which there are two endothermic peaks at 580°C and 700°C, attributed to the dehydroxylation of smectite‐type layers and mica‐like layers of the rectorite, respectively,29 and the weight loss of the rectorite is about 5 wt %; (3) the region above 1000°C, in which the endothermic peak at 1020°C and the followed exothermal peak at 1060°C reflect the destruction of the rectorite and the formation of new phases, respectively. For the kaolin mineral, the TG‐DSC curves in Figure 2B can also be divided into three different regions: (1) the region below 400°C, in which the endothermic peak at 100°C is assigned to the removal of adsorbed water; (2) the region between 400°C and 900°C, in which the dehydroxylation of kaolinite occurs, with a 14.8 wt % weight loss as shown by the TG curve; (3) the region above 900°C, in which the characteristic exothermal peak at 980°C indicates the decomposition of kaolinite structure and the formation of more stable phases.…”

Section: Resultsmentioning

confidence: 99%

Natural rectorite mineral: A promising substitute of kaolin for in‐situ synthesis of fluid catalytic cracking catalysts

Wei¹,

Liu²,

Li³

et al. 2010

AIChE Journal

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Fabrication of high-performance fluid catalytic cracking (FCC) catalysts is suffering from the shortage of high-quality kaolin that has long been used as matrix or starting material for synthesizing FCC catalysts. This work aimed at exploring the potential of rectorite, a natural aluminosilicate mineral, to substitute kaolin for preparing FCC catalysts through in-situ synthesis technique. The physicochemical properties of a rectorite mineral, including its chemical composition, structure, thermal behavior, and chemical reactivity, were systemically investigated and compared with those of commercial kaolin. The results showed that the rectorite mineral suitably treated could substitute kaolin for synthesizing FCC catalysts. Moreover, we had shown that a hydrothermally stable ZSM-5/rectorite composite in which ZSM-5 crystals of ca. 2 lm in size were overgrown on preformed rectorite substrate could be synthesized using the rectorite mineral calcined at 800 C as raw material. When used as FCC additive, the obtained ZSM-5/rectorite composite demonstrated enhanced light olefin (ethylene and propylene) yields.

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K-rich rectorite from kaolinized micaschist of the Sesia-Lanzo Zone, Italy

Cited by 8 publications

References 37 publications

First-principles study of illite–smectite and implications for clay mineral systems

First-principles study of illite–smectite and implications for clay mineral systems

Optimal Synthesis of Environment-Friendly Iron Red Pigment from Natural Nanostructured Clay Minerals

Natural rectorite mineral: A promising substitute of kaolin for in‐situ synthesis of fluid catalytic cracking catalysts

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