Two natural clays (kaolinite and montmorillonite) were deposited onto a platinum electrode surface using two deposition techniques and under different experimental variables. For both clays, the percentages of surface coverage (%y) were optimized in the 75 96% range. A greater surface coverage was observed at higher temperatures for both clays, which confirms the endothermic nature of the depos...

Recent solubility, electrokinetic, spectroscopic and flotation studies in our laboratory on apatite and calcite in aqueous electrolytes indicate complex mineral_olution interactions which can alter surface characteristics of these minerals markedly in the presence of each other. In the case of systems containing such sparingly soluble minerals, understanding of the mineral_olution chemical equi...

Thin clay coatings can be deposited from water dispersions for the purpose of improved gas barrier properties and fire retardancy polymeric materials. Mechanical are difficult to assess, since they very thin (≈1µm). In-situ tests using a micro tensile stage in scanning electron microscope reveal thickness-dependent microcracking mechanism, Weibull parameters coating fracture extracted. Complex ...

A previously published hydrothermal brine-river water mixing model driven by ocean crust production suggests that the molar Mg/Ca ratio of seawater (mMg/Ca(sw)) has varied significantly (approximately 1.0-5.2) over Precambrian time, resulting in six intervals of aragonite-favouring seas (mMg/Ca(sw) > 2) and five intervals of calcite-favouring seas (mMg/Ca(sw) < 2) since the Late Archaean. To ev...

This study investigates the influence of some chemical additives such as methanol, ethanol, sodium oleat, chloroform and sodium hexametaphosphate (SHMP) on the dry fine grinding of calcite (X50= 33 µm) using a stirred media mill. The experiments were carried out by a batch operation, and the change in colour properties (Ry, whiteness and yellowness) of calcite powder. The results showed that th...

Solutions equilibrated with soils under laboratory conditions often exhibit Ca and CO^~ activities that exceed calcite saturation. This supersaturation has been attributed to various possibilities, none of which have been fully able to explain the phenomenon. In this study we report on the attainment of calcite supersaturation in calcite + water + organic matter systems under controlled CO2 con...

Brittleness is important in the evaluation of fracturing ability shale reservoir and has a significant impact on gas exploration development. This paper discusses characteristics controlling factors brittleness continental Da’anzhai Member Ziliujing Formation Lower Jurassic age northeast Sichuan Basin. Continental lithofacies their associations were grouped into four main rock types: clayey sha...

was dissolved from the soil; Le., equilibrium was ap­ Soils in the laboratory were reacted with agricultural drainage­ and distilled waters at various carbon dioxide (COl) levels. The soil water solutions yielded different Ion activity product (lAP) values than that of calcite, depending on experimental technique and whether calcite "equilibrium" is approached from supersaturation or under­ sat...