Exfoliation of vermiculites with chemical treatment using …

In all the tests the exfoliation of the samples was higher when the reaction was carried out with H 2 O 2 solution at 50% than at 30%, which agreed with that observed by Obut and Girgin (2002) for vermiculite. The exfoliation speed (thickness or volume/ time) of the samples Santa Olalla, Libby and Goiás increased with the concentration of H 2 ...

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Continuous energy efficient exfoliation of vermiculite through

Microwave exfoliation of vermiculite showed that power densities of greater than 2 × 10 8 W/m3 in the heated phase (interlayer water) were required to successfully exfoliate all size classifications of vermiculite, though it depends on the bed thickness (Dodds, et al. 2010). This knowledge together with electromagnetic modelling was used to ...

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OPEN ACCESS Onthemechanismofexfoliationof Vermiculite

Onthemechanismofexfoliationof Vermiculite S.HILLIEo1,2,*,E.M.M.MARWA3,4a C.M.oICEP 1TheJamesHuttonInstitute,Craigiebuckler,Aberdeen,AB158QH,UK ...

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Vermiculite composition with improved chemical exfoliation

A vermiculite composition comprising a vermiculite ore concentrate material having at least 85% of at least one vermiculite mineral specie or mixture thereof having a specific density in the range of from 2.3 g/cm 3 to 2.7 g/cm 3 and at least 30 meq/100 gm of the vermiculite mineral specie of intercalated cations selected from the group ...

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On the mechanism of exfoliation of 'Vermiculite'

Lateral phase boundaries between vermiculite and mica layers, or vermiculite and chlorite layers are postulated to prevent or impede the escape of gas from a particle, resulting in exfoliation ...

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"Vermiculite" – what a mixture!

Vermiculite definitions • Vermiculite as a traded commodity • Often use same mineralogical definition, although the property of exfoliation is emphasised. Potassium contents are frequently high, and mineralogically many are predominately composed of hydrobiotite i.e. interstratified mica/vermiculite.

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Preparation and application of expanded and exfoliated …

Nitrogen-defect g-C 3 N 4 /vermiculite composites (gCVx, x = 0.1, 1, 3, 4) with high efficient photocatalytic performance were constructed by a wet chemical method cooperating …

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Preparation and characterization of micron and submicron …

Micron and submicron-sized vermiculite lamellar particles with nanometric thickness (< 10 nm) were prepared by ultrasonic treatments (< 12 h) of aqueous and hydrogen peroxide suspensions of thermally exfoliated vermiculite.Laser granulometry characterizations showed that the particles size distribution was dependent on the treatment time and that the use of H 2 O 2 …

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MICROWAVE EXFOLIATION OF VERMICULITE AND …

microwave energy, and the exfoliation and weight loss valuesfor variousexposuretimes at this power are given in Figures 5 and 6 which show that samples PV, KP and PP have 28-, 10.1- …

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On the mechanism of exfoliation of 'Vermiculite'

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Hydrogen peroxide exfoliation of vermiculite and …

In many applications, notably fire retardants, it is desirable that exfoliation of vermiculite should occur at temperatures in the range of 200 °C to 350 °C. For this purpose, South African Palabora vermiculite was modified by ion exchange with ammonium and selected alkali metal and alkaline earth metal ions. These experiments were performed ...

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Microwave Exfoliation of Vermiculite and Phlogopite

It was observed that the water molecules in the interlayers of the individual flakes were driven off quickly by microwave treatment causing layer separation in the samples. The vermiculite sample showed 2.8 and 5.6 times, respectively, the exfoliation ratio of the phlogopite samples, in accord with their water contents.

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Ultrasonic exfoliation of NiFe LDH/CB nanosheets for …

Specifically, ultrasonic exfoliation (UIP500hd, 20 kHz, 500 W) in pure water has been applied to boost the activity of NiFe LDH/CB towards OER. The exfoliated NiFe LDH/CB nanosheets display significantly higher OER activity than their corresponding bulk NiFe LDH/CB in an alkaline solution, with an overpotential of 220 mV at a current density of ...

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Production of exfoliated vermiculite by ultrasound …

Since the first case of vermiculite exfoliation was reported in 1960s, practice has repeatedly proved the feasibility of nanofluidic proton channels derived from ultrathin vermiculite sheets (VS ...

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Vermiculite: Structural Properties and Examples of the Use

2. Obtaining vermiculite small particles . Natural vermiculite flakes are characterized by high values of aspect ratio. In clay science, exfoliation involves a degree of separation of the layers of a host structure where units, either individual layers or stacking of several layers, are dispersed (freely oriented and independent) in a solvent or polymer matrix [].

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Premium Vermiculite Supplier & Wholesaler Australia

Premium Vermiculite Australia Manufacturers. Exfoliators are the leading manufacturer of Premium Vermiculite Australia and currently source from two major areas: Southern Africa and Northern Australia. It is an extremely unique product that is Sterile and pH Neutral, which allows its use in many applications including Vermiculite insulation & Vermiculite Horticulture.

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Preparation and application of expanded and exfoliated vermiculite…

Vermiculite exfoliation is based on the principle when water between the layers evaporate, and the crystal layers spread out pressured by the steam. As a result, elongated, curved particles are ...

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On the mechanism of exfoliation of 'Vermiculite'

KEYWORDS: vermiculite, hydrobiotite, phlogopite, exfoliation, hydrogen peroxide. As a traded commodity, the term 'Vermiculite' is used to describe commercially exploited deposits of

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Exfoliation mechanism scheme of a commercial vermiculite …

Vermiculite is a low-cost phyllosilicate, which, due to its characteristics of stability, safety, abundant reserves, easy exfoliation, high porosity and specific surface area (Midgley and Midgley ...

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Continuous energy efficient exfoliation of vermiculite …

A continuous microwave system operating at 2.45 GHz for industrial exfoliation of vermiculite was designed and tested. Microwave energy causes rapid removal of interlayer water which brings about its exfoliation and product with a low density. The designed system allows improved product yield over conventional systems and negates the ...

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Stabilization of heavy metals in solid waste and sludge …

Vermiculite, which has important applications in the energy storage (Deng et al., 2016) ... Comparative study on intercalation-exfoliation and thermal activation modified kaolin for heavy metals immobilization during high-organic solid waste pyrolysis. Chemosphere, 280 (2021)

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Green and scalable narrow-gap exfoliation of high-quality …

Currently, require high-quality VMT nanosheets that are free of basal-plane defects are required for several applications [[18], [19], [20]].Although, compared to chemical exfoliation [21, 22], ion-exchange exfoliation of layered compounds in certain stabilizing ionic solvents or aqueous surfactant solutions can yield defect-free nanosheets, and the scalability of such …

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Configuration modulation of vermiculite by exfoliation …

In recent, the exfoliation strategy to construct a two-dimensional (2D) structure (e.g., MoS 2, graphene, MXene) is a research hotspot in the layered materials science field [20], [21], [22].Especially in the adsorption and photocatalytic realm, the exfoliation method is able to enlarge the specific surface area as well as shorten the migration path of photogenerated …

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VERMICULITE Indian Minerals Yearbook 2020

process termed 'exfoliation'. Vermiculite is chemically inert, fireproof, non-conductor of electricity and a good insulator against heat (both radiant and Table – 3 : Pr oduction of Vermiculite, 2017-18 to 2019-20 (By S tates) (Qty in tonnes; Value in `'000) 2017-18 2018-19 2019-20 (P)

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OPEN ACCESS Onthemechanismofexfoliationof …

Onthemechanismofexfoliationof Vermiculite S.HILLIEo1,2,*,E.M.M.MARWA3,4a C.M.oICEP 1TheJamesHuttonInstitute,Craigiebuckler,Aberdeen,AB158QH,UK ...

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Understanding the performance of a pilot vermiculite exfoliation …

When heated rapidly to between 870 and 1100 °C, the interlayer water is turned to steam and the pressure generated within the structure disrupts the vermiculite silicate layer by a process known as exfoliation (Marcos and Rodríguez, 2010, Obut and Girgin, 2002).Resulting from this process, its volume expands to several times that of the unprocessed material (Hillier …

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Community Exposure to Asbestos from a Vermiculite …

• Children playing in or adults handling vermiculite pro-cessing wastes dumped in piles outside the plant for community use (Table 4). • Exposure to asbestos fibers from the disturbance of waste materials used at residential properties for a va-riety of purposes (Table 4). • Disturbance of vermiculite insulation (Table 4). TABLE 2

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MICROWAVE EXFOLIATION OF VERMICULITE AND …

MICROWAVE EXFOLIATION OF VERMICULITE AND PHLOGOPITE ABDULLAH OBUT 1,IÇ SMAILGIÇRGIÇN 1,* ANDABDU¨ LKERIÇM YO¨ RU¨ KOG´ LU 2 1 Hacettepe University, Mining Engineering Department, 06532, Beytepe, Ankara, Turkey 2 Mineral Research and Exploration General Directorate, 06520 Ankara, Turkey Abstract—Vermiculites and phlogopites can be …

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Stabilization of heavy metals in solid waste and sludge …

Mg 2+ impregnation, intercalation–exfoliation, and thermal activation methods were employed to create various types of modified vermiculite (MV), with their combination creating linked-modified vermiculite (LMV). Copyrolysis of MV with municipal sludge (MS)/aged refuse (AF) in a fluidized bed improved heavy metal (HM) stability compared to ...

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Hydrogen peroxide exfoliation of vermiculite and phlogopite

The exfoliation characteristics of Karakoç phlogopite (KP), Phalaborwa phlogopite (PP) and Phalaborwa vermiculite (PV) with hydrogen peroxide were investigated. A series of swelling tests were done to obtain comparative data in order to determine the effects of hydrogen peroxide concentration (1–50 wt.%) and reaction time (1–30 h) that ...

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