A multitechnique, quantitative characterization of the pore space of fired bricks made of five clayey raw materials used in European brick industry

Büchner, Thomas; Kiefer, Thomas; Zelaya-Lainez, Luis; Gaggl, Wolfgang; Konegger, Thomas; Füssl, Josef

doi:10.1016/j.clay.2020.105884

Cited by 20 publications

(9 citation statements)

References 63 publications

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“…However, it is likely that other clay compounds promote the CO 2 diffusion. Clays typically contain substantial amounts of alumina (Al 2 O 3 ) with portions around 15–25 m-% ( Table 2 and [ 23 ]). Rivarola and Smith tested CO 2 diffusing in alumina pellets at room temperature, reporting that besides gas-phase diffusion (molecular and/or Knudsen), surface transport can substantially contribute to diffusion fluxes, [ 21 ].…”

Section: Resultsmentioning

confidence: 99%

“…Hg porosity ( Hg ε ), obtained by mercury intrusion porosimetry (Pascal 140 and 440, Thermo Fisher Scientific, Waltham, Massachusetts, USA), was evaluated for a selection of specimens from sample A. Calculated and Hg porosity are quite close to each other, showing both methods to be appropriate for evaluating the porosity of clay mixtures [ 23 ]. The values reveal that, for both samples, raw mixture porosity is already substantial and increases by burnout by ~5–15 v-%.…”

Section: Methodsmentioning

confidence: 99%

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Considerations on Temperature Dependent Effective Diffusion and Permeability of Natural Clays

et al. 2021

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A series of porous clay samples prepared at different pretreatment temperatures have been tested in a diffusion chamber. Diffusivity and permeability were examined in a temperature range from ambient to 900 °C. Gaseous mixtures of O2, CO2, and N2 have been applied, as these species are the relevant gases in the context of clay brick firing and similar thermochemical processes. Diffusive transport characteristics have been determined by means of the mean transport-pore model, and permeability has been evaluated by Darcy’s law. CO2 diffusivity increased strongly with temperature, whereas O2 diffusion was limited to a certain level. It is proposed that one should consider CO2 surface diffusion in order to explain this phenomenon. The diffusion model was expanded and surface diffusion was included in the model equation. The results of the model fit reflected the important role of incorporated carbonates of the clay foundation in gas-phase (molecular or Knudsen) diffusivity. CO2 surface diffusion was observed to exhibit similar coefficients for two different investigated clays, and is therefore indicated as a property of natural clays. Permeability showed a progressive rise with temperature, in line with related literature.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Considerations on Temperature Dependent Effective Diffusion and Permeability of Natural Clays

et al. 2021

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“…The average content of clay minerals is the highest with 34.7 wt%. The clay minerals are mainly composed of illite and chlorite, in which illite is the main component and has a strong water-shale reaction and expansion characteristics [3]. This provides a material basis for the follow-up experiment to observe the variation of shale specimens during the water-shale reaction.…”

Section: Testing Of Shale Mineral Components Based On Xrd Scanningmentioning

confidence: 99%

“…Jiang et al found that the water-shale reaction rate is gradually accelerated, that is, the soluble mineral solution will accelerate the water-shale reaction [17]. The study of Buchner et al confirmed the increase in reaction speed and found that the reason for the increase in reaction speed was the formation of sulfate after the dissolution of pyrite, which placed the shale specimen in an acidic solution, and prolonged water-shale reaction time could reduce the liquid pH value [3,4].…”

Section: Introductionmentioning

confidence: 99%

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Strategies for Optimizing Shut-In Time: New Insights from Shale Long-Term Hydration Experiments

Zeng,

Dong,

Yao

et al. 2024

Processes

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In the process of hydraulic fracturing, fracturing fluid invades the formation and reacts with shale. Water-sensitive clay minerals swell when exposed to water. This results in a change in the mechanical properties of shale. However, the influences of a long-term water–shale reaction on mechanical properties are still unclear, and an optimization strategy of the shut-in time is required. In this paper, an optimization strategy for the shut-in time based on a shale long-term hydration experiment is proposed. In this paper, the water–shale reaction is simulated by laboratory experiments under normal temperature and pressure. The experiments are performed based on specimens from a shale outcrop. Clay and mineral composition, Young’s modulus, surface hardness, and tensile strength parameters are measured at 30-day intervals for 90 days. A CT scan was performed for 180 days. The experimental results show that the mass fraction of clay increased by 14.719%. In addition, significant argillaceous shedding occurs during the water–shale reaction period of 3–4 months. By testing the tensile strength, uniaxial compression decreases by 90.481% in three months. The Young’s modulus of mineral points decreases to 40% after reaction for three months. The shale has softened. The softening process is nonlinear and there are inflection points. The diffusion behavior of clay minerals and the expansion behavior of new fractures are observed by CT during 3–4 months of water–shale reaction. The results show that the shale softening and pore fracture structure changes are non-linear and heterogeneous, resulting in critical water–shale reaction time. According to the experimental results, the critical water–shale reaction time can be summarized. In this time, the fracture volume increases significantly, which is conducive to increasing oil and gas production. However, the fracture volume is not significantly increased by prolonging the shut-in time. The experimental results can guide the design of hydraulic fracturing shut-in time of shale reservoirs.

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Non-clay bricks with high compressive strength made from secondary aluminum dross and waste glass

Guo,

Li,

Zhang

et al. 2024

J Mater Cycles Waste Manag

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A multitechnique, quantitative characterization of the pore space of fired bricks made of five clayey raw materials used in European brick industry

Cited by 20 publications

References 63 publications

Considerations on Temperature Dependent Effective Diffusion and Permeability of Natural Clays

Considerations on Temperature Dependent Effective Diffusion and Permeability of Natural Clays

Strategies for Optimizing Shut-In Time: New Insights from Shale Long-Term Hydration Experiments

Non-clay bricks with high compressive strength made from secondary aluminum dross and waste glass

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