A glass-bonded ceramic material from chrysotile (white asbestos)

MacKenzie, Kenneth J.D.; Meinhold, R. H.

doi:10.1007/bf00356832

Cited by 18 publications

(20 citation statements)

References 8 publications

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“…The decrease of intensity of the Mg-OH infrared bands, which begins earlier and is faster than for the Si-O bands also indicate that the octahedral layer in lizardite is affected first and that most likely the recombination of OH groups and the formation of water molecules are dominant in the onset of the dehydroxylation reaction. According to McKelvy et al (2006), the survival of the tetrahedral layer at the beginning of the reaction also explains the appearance of the 7.4 2Â XRD peak, which is an indicator for an intermediate phase similar to that observed during the thermal transformation of chrysotile (MacKenzie & Meinhold, 1994). Assuming that the waterforming reaction is the initial rate-determining step, there are six nearest hydroxyl group pairs (Fig.…”

Section: Discussionmentioning

confidence: 74%

Dehydroxylation kinetics of lizardite

Trittschack¹,

Grobéty²

2012

ejm

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Abstract:The thermally induced dehydroxylation of lizardite and its phase transformation to forsterite were studied by hightemperature X-ray diffraction (HT-XRD), thermogravimetry (TGA) and Fourier-transformed infrared spectroscopy (FTIR). Primary sample characteristics like chemical composition and crystallographical structure were determined by combined (HR)TEM-EDX, electron-microprobe analyses (EMPA) as well as conventional X-ray diffraction (XRD). Isothermal HT-XRD and non-isothermal TGA data were treated with the classical Avrami-Erofe'ev method and more advanced isoconversional methods in order to obtain kinetic data of a multi-step decomposition reaction. A highly precise activation energy E a versus reaction progress (a) dependency based on non-isothermal TGA data of lizardite is provided and associated mechanisms are discussed. Here, the main focus is on recently published ab initio calculations from the phase transformation of other phyllosilicates. Moreover, the calculated overall apparent activation energy is compared with discrepant data from the literature and discussed. Especially, the usability of overall activation energies of multi-step decomposition reactions is critically discussed. The presented and discussed reaction steps of water formation from different hydroxyl species in lizardite can be used to improve ab initio calculations, especially the pre-selection of reacting hydroxyl species in hydrous sheet like minerals.

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Section: Discussionmentioning

confidence: 74%

Dehydroxylation kinetics of lizardite

Trittschack¹,

Grobéty²

2012

ejm

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“…where Fe is the fraction of Cs + adsorbed at equilibrium and is obtained by the expression: (9) where C0 and Ce are the initial and equilibrium concentrations of Cs + in solution (mmol/L).…”

Section: Cs(i) Adsorptionmentioning

confidence: 99%

“…Kc for the adsorption of Cs + on the product was calculated at different temperatures and at equilibrium using Equations (8) and (9). The variation of Kc with temperature, as summarized in Table 5, showed that Kc decreased with increase in adsorption temperature, implying a strengthening of adsorbate-adsorbent interactions at lower temperature.…”

Section: Cs(i) Adsorptionmentioning

confidence: 99%

“…Nevertheless, challenges remain in the disposal of asbestos-contaminated waste materials, presenting a serious industrial and social concern. Mechanical milling [4,5], plasma [6], fusion [7] and various other treatments [8][9][10] have been used to transform asbestos-contaminated materials into nonhazardous wastes. Anastasiadou et al converted chrysotile asbestos into non-fibrous, nonhazardous materials such as forsterite using hydrothermal treatments at 300 -700 oC and 1.75 -5.80 MPa [4].…”

Section: Introductionmentioning

confidence: 99%

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Synthesis of Tobermorite from the Ash after Treatment of Asbesto-Containing Disaster Waste, and Its Removal Ability of Cs(I) from Aqueous Solution

Wajima

2016

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Abstract. Tobermorite was synthesized successfully from the ash, which was produced and detoxified from asbesto-containing disaster waste in great east Japan earth quake, by alkali hydrothermal treatment. Tobermorite synthesis was examined as a function of reaction temperature and NaOH concentration. The formation of tobermorite was identified in the product treated with 1-4 M NaOH solution at 130 and 180 o C, while no product phases was identified at 80 o C. With increasing reaction temperature, intensity of tobermorite phase in the product and Cs + removal ability of the product increase. The product, which was treated with 4 M NaOH at 180 o C for 20 h, revealed the high selective uptake for Cs + in saline water. The Cs + uptake of the product was extrapolated using Langmuir and Freundlich isotherm models, experimental data are found to fit Langmuir than Freundlich, and the calculated uptake amount was 0.51 mmol/g. The kinetics for Cs + uptake was tested for pseudo-second order reactions, and the rate constants of uptake were calculated. With increasing temperature of aqueous solution, the kinetics of uptake is almost same and the uptake amount of Cs + decreases. The product is expected to be used for Cs + removal from wastewater.

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“…With a brittle matrix, the mechanical properties are highly affected by the fibre types and fibre/matrix interfacial properties 2,3 , which are a reflection of the formulation, moulding conditions and post curing, etc. The properties of the composite system were found depending on a number of materials and processing variables 3,7 . Some other matrix systems could be found in applications when specific properties are required from the composite that cannot be provided by a polymeric system.…”

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confidence: 99%

Low cost ceramic moulding composites: materials and manufacturing technology

Ren

Hogg²,

Woolstencroft

2008

Advances in Applied Ceramics

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Low cost ceramic moulding compound/composites are composed of inorganic metal silicates, fillers and different types of chopped fibre reinforcements, such as glass fibres. This research investigated manufacturing process of a series of ceramic moulding compounds that could be moulded at modest temperature(~ 150 °C) and pressure. The process replicates the polymer dough moulding compounds as fibre reinforced polymeric moulding composites(FRP). The conventional polymeric matrix of the DMC has been replaced by a soluble metal silicates based on an inorganic system which can be compounded with fibres, minerals or synthetic fillers and hardening additives to produce a thick paste or a doughy substance(ceramic DMC/CDMC). The CDMC compounds demonstrated a good handle-ability and can be adjusted by the viscosity of the matrix through the use of amount of fillers and additives. The mechanical properties of the compounds have been tested and additional formulation changes have been introduced to maintain desirable processing characteristics... Low cost ceramic moulding composites: -Materials and manufacturing technology G Ren*, P J Hogg* and D H Woolstencroft** Low cost ceramic moulding compounds/composites (CMC) are composed of inorganic metal silicates, fillers and different types of chopped fibre reinforcements, such as glass fibres. This research investigated manufacturing process of a series of ceramic moulding compounds that could be moulded at modest temperature (~ 150 °C) and pressure (0~8 MPa). This manufacturing process replicated the polymer dough moulding compounds as fibre reinforced polymeric moulding composites or Dough Moulding Compounds (DMC). The conventional polymeric matrix of DMC has been replaced by a soluble metal silicates based on an inorganic system which can be compounded with fibres, minerals or synthetic fillers and hardening additives, to produce a thick paste or a doughy substance -so called Ceramic Dough Moulding Compounds (CDMC). The CDMC demonstrated a good handle-ability and can be adjusted by the viscosity of the matrix through the use of various amounts of fillers and additives. The mechanical properties of the compounds have been tested and additional formulation changes have been introduced to maintain desirable processing characteristics.Dr Ren (g.ren@qmul.ac.uk) was in the Department of Materials, Queen Mary, University of London. He is now in the University of Hertfordshire, Hatfield AL10 9AB, UK. Professor P J Hogg is now in the University of Manchester, Manchester M60 1QD. Dr Woolstencroft is with Matrice Technology, Poulton, Lancs. FY6 8GD, UK.Keywords: ceramic silicates, moulding, composites, compounding, processing, glass fibre, fillers, viscosity. IntroductionIt is well known that ceramic materials can provide good fire resistance and thermal stability at elevated temperature. However, due to their nature of the bonding within the composition and molecular structures, they are very brittle and considered as unreliable or inappropriate in many engineering applicatio...

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A glass-bonded ceramic material from chrysotile (white asbestos)

Cited by 18 publications

References 8 publications

Dehydroxylation kinetics of lizardite

Dehydroxylation kinetics of lizardite

Synthesis of Tobermorite from the Ash after Treatment of Asbesto-Containing Disaster Waste, and Its Removal Ability of Cs(I) from Aqueous Solution

Low cost ceramic moulding composites: materials and manufacturing technology

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