Exfoliation of Vermiculite by Chemical Means | Nature
SPECIMENS of vermiculite from different localities have been examined in the laboratories of the Mineral Resources Department of the Imperial Institute in the course of an investigation into ...
Chemical Exfoliation of Vermiculite and the Production …
of vermiculite, swelling does not pro-ceed to complete dispersion of the silicate layers, and the swollen crystal remains coherent and jelly-like in con-sistency. The negative charge on the silicate layers in vermiculites from different localities varies over a range but tends Fig. 2. Dimensional changes in a water-swollen butylammonium ...
EXFOLIATED VERMICULITE
VERMICULITE is the name given to a group of hydrated laminar minerals which are aluminium-iron-magnesium silicates, resembling mica in appearance. CRUDE VERMICULITE consists of thin, flat flakes containing microscopic layers of water. EXFOLIATION On being subjected suddenly to high temperatures (700°C to 1000°C) …
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 …
Chemical Exfoliation of Vermiculite and the Production of …
Chemical treatments involving ion exchange cause gross one-dimensional swelling in water of single crystals of vermiculite minerals. A delicate balance of forces holds the individual silicate layers (10 angstroms thick) parallel to one another although separated by several hundred angstroms.
On the mechanism of exfoliation of 'Vermiculite'
Six samples of 'Vermiculite' have been studied to investigate the mechanism of its well known but poorly understood property to exfoliate. The sample ... This mechanism provides a common explanation for the exfoliation of 'Vermiculite' by thermal methods or by treatment with H2O2. Paradoxically, one sample which consists of pure vermiculite, in ...
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 ...
Electronic Supplementary Information vermiculite …
ultrasound-assisted exfoliation results to be a more vigorous process with smaller flakes being formed, while shear mixing is less effective but able to produce a more homogenous dispersion with larger particle
Thermal insulation with 2D materials: liquid phase …
Topics: Exfoliation joint, Vermiculite and Specific surface area Related papers: Exfoliated Layered Materials for Digital Fabrication Formation processes, size changes, and properties of nanosheets derived from exfoliation of soft layered inorganic─organic composites
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 ...
Synthesis of nano-layered vermiculite of low density by …
— 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, ... Abstract The effect of ultrasounds on natural macroscopic vermiculite flakes has been studied.
Ultrasound assisted preparation of chitosan–vermiculite
— Bionanocomposites based on chitosan and natural or organically modified vermiculite • Partial exfoliation of vermiculite by intercalation of chitosan with ultrasounds • Macroporous s with good mechanical and thermal properties, and water stability • High capacity for adsorption of Cd(II) ions from aqueous solution
Incidental Vermiculite Building Insulation Exposure Hazards
ASBESTOS IN YOUR HOME - U.S. EPA, Exposure Evaluation Division, Office of Toxic Substances, Office of Pesticides and Toxic Substances, U.S. Environmental Protection Agency, Washington,D.C. 20460> [1] Thanks to Gary Randolph, Ounce of Prevention Home Inspection, LLC Buffalo, NY, for attentive reading and editing suggestions. Mr. Randolph …
Microwave Exfoliation of Vermiculite and Phlogopite
— The vermiculite sample showed 2.8 and 5.6 times, respectively, the exfoliation ratio of the phlogopite samples, in accord with their water contents. Vermiculites and phlogopites can be exfoliated by chemical and thermal treatment methods to obtain chemically inert, adsorbent, fire-resistant, low-density
Vermiculite | Formula, Properties & Application
Exfoliation of Vermiculite. One of the defining features of vermiculite is its ability to expand or 'exfoliate' when heated. This occurs because the trapped water molecules within the mineral structure turn into steam, causing the vermiculite to puff up. This results in a significant volume increase, with vermiculite being able to expand up ...
Thermal insulation with 2D materials: liquid phase exfoliated
XRD analysis revealed that the use of ultrasound waves in an acidic environment results in the complete exfoliation of the vermiculite layer, whereas the use of shear forces under the same conditions results in the exfoliation of hydrobiotite and mica crystalline phases. Thermal conductivity measurements provided clear evidence on how the ...
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
Thermal insulation with 2D materials: liquid phase …
ultrasound-assisted exfoliation and shear-mixing of a multi-phasic vermiculite in mild acidic aqueous solutions were employed to successfully obtain dispersions of mono- and few-layer thick clay nanosheets.
OPEN ACCESS Onthemechanismofexfoliationof …
Onthemechanismofexfoliationof Vermiculite S.HILLIEo1,2,*,E.M.M.MARWA3,4a C.M.oICEP 1TheJamesHuttonInstitute,Craigiebuckler,Aberdeen,AB158QH,UK ...
(a) Representative AFM image of ultrasound …
In general, both lateral size and thickness decrease as a function of exfoliation time indicating a progressive fragmentation and delamination of vermiculite particles subjected to cavitation...
How vermiculite is made
This expansion process is called exfoliation. The name vermiculite is derived from a combination of the Latin word vermiculare meaning "to breed worms," and the English suffix-ite, meaning mineral or rock. In its expanded form, vermiculite has a very low density and thermal conductivity, which makes it attractive for use as a soil amendment ...
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.
Production of exfoliated vermiculite by …
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 ...
Preparation and characterization of micron and submicron …
— The vermiculite material was submitted to powerful low frequency ultrasounds in either pure water or in 35% H 2 O 2 aqueous solution from 1 to 12 ... Hydrogen peroxide exfoliation of vermiculite and phlogopite. Minerals Engineering (2002) J. Poyato et al. Sonication induced redox reactions of the Ojén (Andalucía, Spain) vermiculite.
W.R. Grace Exfoliation Facility
• The site was an exfoliation facility that processed more than 100,000 tons of vermiculite ore from the Libby mine. Exfoliation processing of vermiculite involves heating vermiculite at high temperatures to expand it; higher quantities of asbestos are released during exfoliation processing than in other processing methods.
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 …
Journal Name
exfoliation of vermiculite in aqueous solutions.33, 44-46 Ultrasound-assisted exfoliation has been found to be more robust in terms of energy saving and lower exfoliation ... ultrasounds and shear forces on the exfoliation of cheap, multiphasic vermiculite crystals into mono- and few-layer thick nanosheets. We compared the quality of the ...
Preparation and application of expanded and exfoliated …
— It is found that compared with ball milling, ultrasound can exfoliate VMT to nanosheets with smaller particle size distribution, which can better maintain the microstructure of VMT, but the efficiency of ultrasonic treatment is also low.
Vermiculite : Properties, Uses, Deposits » Geology Science
— Vermiculite is a naturally occurring mineral that has gained significant attention due to its unique properties and various applications. It is a hydrated, laminar, and micaceous mineral belonging to the phyllosilicate group. Vermiculite has a layered structure, similar to mica, and it can expand or exfoliate when heated, making it a valuable …
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 …
Vermiculite exfoliation | Independently verified asbestos …
Vermiculite is a naturally occurring mineral that is widely used in various industries due to its unique properties. During the exfoliation process the material expands to many times its original size. This expanded form of vermiculite is lightweight, highly absorbent, and has excellent insulation properties.
Preparation and characterization of micron and submicron …
— The long ultrasound irradiation of the vermiculite in hydrogen peroxide (> 5 h) generated the decrease of the surface charge, pointed out by pH and zeta potential modifications, allowing an aggregation of the submicron particles in the suspensions.