Electrical conductivity of anthracites as a function of heat treatment temperature

Celzard, Alain; Marêché, J.F.; Payot, F.; Bégin, Dominique; Furdin, G.

doi:10.1016/s0008-6223(99)00246-8

Cited by 26 publications

(13 citation statements)

References 17 publications

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“…• C can affect the structure of partially aromatized amorphous carbon (Jäger et al 1998;Celzard et al 2000;Chhowalla et al 2000). Higher temperatures affect both structural and optical properties.…”

Section: Carbon Black and Other Controlled Flame Generationmentioning

confidence: 99%

Light Absorption by Carbonaceous Particles: An Investigative Review

Bond

Bergström

2006

Aerosol Science and Technology

2,548

135

2,375

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The optical properties of the light-absorbing, carbonaceous substance often called "soot," "black carbon," or "carbon black" have been the subject of some debate. These properties are necessary to model how aerosols affect climate, and our review is targeted specifically for that application. We recommend the term light-absorbing carbon to avoid conflict with operationally based definitions. Absorptive properties depend on molecular form, particularly the size of sp 2 -bonded clusters. Freshly-generated particles should be represented as aggregates, and their absorption is like that of particles small relative to the wavelength. Previous compendia have yielded a wide range of values for both refractive indices and absorption cross section. The absorptive properties of light-absorbing carbon are not as variable as is commonly believed. Our tabulation suggests a mass-normalized absorption cross section of 7.5 ± 1.2 m 2 /g at 550 nm for uncoated particles. We recommend a narrow range of refractive indices for strongly-absorbing carbon particles, of which the highest is 1.

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Section: Carbon Black and Other Controlled Flame Generationmentioning

confidence: 99%

Light Absorption by Carbonaceous Particles: An Investigative Review

Bond

Bergström

2006

Aerosol Science and Technology

2,548

135

2,375

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“…[19] Different physical properties of anthracite have recently been studied. This includes the following: structural analysis, [20][21][22] DC conductivity of the order 10 1 -10 À4 S m À1 for different anthracite samples [23][24][25] (our sample 10 À4 to 100 S m À1 ; Table 1), and CESR analysis. [26][27][28][29][30][31] The CESR measurements were performed on cubic-shaped samples prepared by abrasion with high grit sandpaper.…”

Section: Samplesmentioning

confidence: 99%

“…Different physical properties of anthracite have recently been studied. This includes the following: structural analysis, DC conductivity of the order 10 1 –10 −4 S m −1 for different anthracite samples(our sample 10 −4 to 100 S m −1 ; Table ), and CESR analysis …”

Section: Introductionmentioning

confidence: 99%

Size effects in the conduction electron spin resonance of anthracite and higher anthraxolite

Tadyszak

Strzelczyk

Coy

et al. 2015

Magnetic Reson in Chemistry

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Electron paramagnetic resonance spectroscopy of conduction electrons, i.e. Conduction Electron Spin Resonance (CESR), is a powerful tool for studies of carbon samples. Conductive samples cause additional effects in CESR spectra that influence the shape and intensity of the signals. In cases where conduction electrons play a dominant role, whilst the influence of localized paramagnetic centres is small or negligible, the effects because of the spins on conduction electrons will dominate the spectra. It has been shown that for some ratios of the bulk sample sizes (d) to the skin depth (δ), which depend on the electrical conductivity, additional size effects become visible in the line asymmetry parameter A/|B|, which is the ratio of the maximum to the absolute, minimum value of the resonance signal. To study these effects the electrical direct current-conductivity and CESR measurements are carried out for two amorphous bulk coal samples of anthracite and a higher anthraxolite. The observed effects are described and discussed in terms of the Dyson theory. Copyright © 2015 John Wiley & Sons, Ltd.

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“…Indeed, when the temperature is increased, two antagonistic effects are expected: fast and efficient pore formation due to pyrolysis-induced gas evolution, and pore closure and pore collapse due to the structural reorganization of the carbonaceous matter at higher temperature (see [33], for example). 800-900 • C thus seem to be a good optimum for subsequent steam activation of particleboard waste chars at 800 • C. An influence of the first pyrolysis temperature may finally be seen in Table 2.…”

Section: Surface Area and Porositymentioning

confidence: 99%