Investigation of Photon Radiation Attenuation Capability of Different Clay Materials

This work aims to experimentally report the radiation attenuation factors for four different clays (red, ball, kaolin and bentonite clays) at four selected energies (emitted from Am-241, Cs-137, and Co-60). The highest relative difference in the mass attenuation coefficient (MAC) is equal to −3.02%, but most of the other results are much smaller than this value, proving that the experimental and theoretical data greatly agree with each other. From the MAC results, the shielding abilities of the clay samples at 0.060 MeV follow the order of: bentonite > red > ball > kaolin. Thus, at low energies, the bentonite clay sample provides the most effective attenuation capability out of the tested clays. The half value layer (HVL) increases as energy increases, which suggests that, only a thin clay sample is needed to sufficiently absorb the radiation at low energies, while at higher energies a thicker sample is needed to shield the same amount of high energy radiated. Furthermore, bentonite clay has the lowest HVL, while the kaolin clay has the greatest HVL at all energies. The radiation protection efficiency (RPE) values at 0.060 MeV are equal to 97.982%, 97.137%, 94.242%, and 93.583% for bentonite clay, red clay, ball clay, and kaolin clay, respectively. This reveals that at this energy, the four clay samples can absorb almost all of the incoming photons, but the bentonite clay has the greatest attenuation capability at this energy, while kaolin clay has the lowest.

Beneficiation of Faya Clay for Drilling Mud Production Using Froth Floatation and Jig Gravity Concentration Techniques

The comparative study for upgrading Faya clay, in Faya Town of Plateau State, Nigeria to oil and Gas drilling mud grade was carried out. The clay was sourced from three veins A, B, and C. The samples were homogenized, crushed and ground. 5 kg of the homogenized sample was used for the experiment and laboratory work. Chemical and mineralogical characterization of the clay sample was carried out using; X-ray fluorescence (XRF) and X-ray diffractorneter (XRD). The clay sample was beneficiated using two methods: froth flotation and gravity concentration method (Jigging). The chemical composition of the crude clay revealed that it contains 16.6% Al2O3, 35.6% SiO2, 0.559% K2O, 0.084% CaO, 6.133% Fe2O3, 0.91 % TiO2 and 38.7 % BaO. The result of XRD analysis shows that quartz is predominant in the sample with 61.7% wt quartz (SiO2). Other minerals found in the sample include 28.59% wt of dickite (Al2 Si205 (0H)), 8.89% wt goethite (Fe0 (0H 4) and 0.83% wt muscovite (KO.92 NaO.08) (Al.86 FeO.07 TiO.02) (Si.3 O.3 AlO.97) O10 (OH)2 at 2 . Froth flotation method is more efficient for the beneficiation of Faya clay as it improves the BaO composition of the clay from 38.7% to 52.2%, with a recovery of 97.2%, an enrichment and ratio of concentration of 1.4 compared with the jigging method, which improved BaO composition from 38.7% in the crude clay to 47.5%, with a recovery of 90.96% and an enrichment ratio of 0.7; and ratio of concentration of 0.7. Froth floatation improved the specific gravity of the clay from 3.3 to 4.31; while jigging improved the specific gravity from 3.3 to 4. 05. Therefore, froth flotation method is more appropriate for the concentration of Faya clay ahead of jigging method of processing.Keywords: Upgrading, Characterization, Faya - clay, Drilling, Production

Micromechanisms leading to shear failure of Opalinus Clay in a triaxial test: a high-resolution BIB–SEM study

A microphysics-based understanding of mechanical and hydraulic processes in clay shales is required for developing advanced constitutive models, which can be extrapolated to long-term deformation. Although many geomechanical tests have been performed to characterise the bulk mechanical, hydro-mechanical, and failure behaviour of Opalinus Clay, important questions remain about micromechanisms: how do microstructural evolution and deformation mechanisms control the complex rheology? What is the in situ microstructural shear evolution, and can it be mimicked in the laboratory? In this contribution, scanning electron microscopy (SEM) was used to image microstructures in an Opalinus Clay sample deformed in an unconsolidated–undrained triaxial compression test at 4 MPa confining stress followed by argon broad ion beam (BIB) polishing. Axial load was applied (sub-)perpendicular to bedding until the sample failed. The test was terminated at an axial strain of 1.35 %. Volumetric strain measurements showed bulk compaction throughout the compression test. Observations on the centimetre to micrometre scale showed that the samples exhibited shear failure and that deformation localised by forming a network of micrometre-wide fractures, which are oriented with angles of 50∘ with respect to horizontal. In BIB–SEM at the grain scale, macroscale fractures are shown to be incipient shear bands, which show dilatant intergranular and intragranular microfracturing, granular flow, bending of phyllosilicate grains, and pore collapse in fossils. Outside these zones, no deformation microstructures were observed, indicating only localised permanent deformation. Thus, micromechanisms of deformation appear to be controlled by both brittle and ductile processes along preferred deformation bands. Anastomosing networks of fractures develop into the main deformation bands with widths up to tens of micrometres along which the sample fails. Microstructural observations and the stress–strain behaviour were integrated into a deformation model with three different stages of damage accumulation representative for the deformation of the compressed Opalinus Clay sample. Results on the microscale explain how the sample locally dilates, while bulk measurement shows compaction, with an inferred major effect on permeability by an increase in hydraulic conductivity within the deformation band. Comparison with the microstructure of highly strained Opalinus Clay in fault zones shows partial similarity and suggests that during long-term deformation additional solution–precipitation processes operate.

An Experimental Investigation of Expansive Soil Treated with Glass powder and Granite Dust

In urban areas, borrow earth is not easily available which has to be hauled from a long distance. Quite often, large areas are covered with highly plastic and expansive soil, which is not suitable for such purpose. This study involves the collection of clay sample and evaluation of its properties in natural state and after stabilization with Granite dust and Glass powder. In the first set of experimental work the BC soil is mixed with Glass powder in different proportion i.e. 2%,4%,6%,8% and 10% and the optimum quantity of Glass powder is determined. The optimum quantity of Glass powder is found as 8% of the dry weight of clay. In the second set of experimental work the BC soil is stabilized by Glass powder and Granite dust in combination. Granite dust used 10-20 % of the dry weight of clay with Glass powder additives. From the experimental study it can be concluded that the stabilization of BC soil with Granite dust and Glass powder is more effective as compared to the stabilization with Glass powder only.

Micro-cracking and incipient shear microstructures at low-strain deformation of Opalinus Clay: Insights from triaxial testing and broad-ion-beam scanning-electron-microscopy (BIB-SEM)

A microphysics-based understanding of mechanical and hydraulic processes in clay shales is required for developing advanced constitutive models, which can be extrapolated to long-term deformation. Although many geomechanical laboratory tests have been performed to characterize the bulk mechanical, hydro-mechanical and failure behaviour of Opalinus Clay, important questions remain about microphysics: How do microstructural evolution and deformation mechanisms control the 15 complex rheology over time scales not accessible in the laboratory. In this contribution, Scanning Electron Microscopy (SEM) was used to image microstructures in an Opalinus Clay sample deformed in an unconsolidated-undrained triaxial compression test at 4 MPa confining stress followed by Argon Broad Ion Beam (BIB) polishing. Axial load was applied (sub-) perpendicular to bedding until the specimen failed. The test was terminated at an axial strain of 1.35 %. Volumetric strain measurements showed bulk compaction throughout the compression test. Observations on the cm- to μm-scale showed that deformation 20 localized by forming a network of μm-thick fractures. In BIB-SEM at the grain scale, incipient deformation zones show dilatant inter- and intragranular micro-cracking, granular flow, plastic deformation and bending of phyllosilicate grains, and pore collapse in fossils. Outside these zones, no deformation microstructures were observed indicating localized damage. Thus, microphysics of deformation appear to be controlled by both brittle and ductile processes along preferred orientations. Anastomosing networks of deformation bands develop into the main deformation bands along which the sample fails. 25 Microstructural observations and the stress-strain behaviour were integrated into a deformation model with three different stages of damage accumulation representative for the deformation of the compressed Opalinus Clay sample. Results on the microscale explain how the sample locally dilates while bulk measurement shows compaction, with an inferred major effect on permeability evolution. Comparison with the microstructure of highly strained Opalinus Clay in fault zones shows minor similarity and suggest that during long-term deformation additional solution-precipitation processes operate.

X-Ray Diffraction (XRD), X-Ray Fluorescence (XRF) And Scanning Electron Microscopy (SEM) Analysis Of Potsherds, Sungai Batu Complex, Bujang Valley, Kedah Sungai Batu Complex, Bujang Valley, Kedah

Archaeological excavations at the Sungai Batu Archeological Complex have unearthed potsherds with monument structures. The discovery of the potsherds enables scientific studies of X-ray diffraction (XRD), X-ray fluorescence (XRF) and Scanning Electron Microscopy (SEM) analysis to be conducted and resolve related issues such as where the raw materials were obtained by the manufacturers. To solve the issue, potsherds were taken from around the ancient river, and scientific analyses was conducted for comparison purposes. Before the clay sample was subjected to the scientific analyses, the samples were cleaned and measured (for weight, thickness and width). Color sampling was also performed. Based on results of the analyses, it clearly shows that the potsherds was produced using raw materials from the ancient river in the Sungai Batu Complex itself and baked at a temperature between 550°C and 650°C.

Improvement of Filtration Properties of Treated Nigerian Bentonitic Clay Using Locally Sourced Bio-Materials

Exploitation of Nigerian bentonitic clay deposit will offer economic advantage in terms of utilization for drilling purpose and prevent money spent on importation. Clay used for this analysis was beneficiated using sodium Carbonate (Na2CO3) and the change in the elemental composition of the raw clay sample and treated clay with was estimated using X-ray fluorescence spectroscopy (XRF). The treated clay and locally sourced bio-materials were added to the formulation of drilling fluid using Reduced Central Composite Design (RCCD). The fluid loss and cake thickness of prepared drilling fluid were determined using filter loss test kit. The result of the investigation show that the maximum recorded fluid loss was 14.4 ml/30mins at 100 psi while cake thickness values improved with addition of the bio-materials to the drilling fluid formulation when compared with the standard values.

Cigarette butts and waste coffee grounds as additives to brick clay

The paper analyses the influence of cigarette butts and waste coffee grounds addition on the properties of the brick clay. The waste materials were added to the clay in amounts of 5 wt.% and 10 wt.%. Standard consistency, plasticity, drying and firing behaviour and refractoriness were tested on the clay sample and the samples with wastes additions. Apparent density, apparent porosity, water absorption, strength and thermal conductivity were investigated on the samples fired at 1173 K. Addition of the waste materials improved thermal insulation characteristics and drying shrinkage, while other properties remain within the required limits for brick industry