Book•
The x-ray identification and crystal structures of clay minerals
01 Jan 1961-
About: The article was published on 1961-01-01 and is currently open access. It has received 966 citations till now. The article focuses on the topics: Clay minerals.
Citations
More filters
TL;DR: In this article, the micromorphology and mineralogy of the clay and sand fractions from the Bt horizon, among other characteristics, were investigated, and indices of pedogenic evolution, including relative redness index, relative development index of color and the relative development indices of color + structure, clay illuviation index, anisotropy index for clay content, iron release index and kaolinite/smectite ratio, were calculated.
Abstract: Eight xeralfs from the province of Jae´n in the region of Andalusia (southern Spain) were studied. The micromorphology and mineralogy of the clay and sand fractions from the Bt horizon, among other characteristics, were investigated, and indices of pedogenic evolution, including relative redness index, relative development index of color and the relative development index of color + structure, clay illuviation index, anisotropy index for clay content, iron release index and kaolinite/smectite ratio, were calculated. These findings were supported by the results of factorial analysis (R mode) and correlation between variables. We found micromorphological evidence of clay illuviation (even in calcareous soils), alterations leading to clay formation, argillopedoturbation, coating disruption by carbonates, and polycyclicity. The clay fraction was essentially illitic, with smaller amounts of kaolinite, smectite and interstratified phases. Alterations were therefore moderate. Numerical estimators of evolution were informative of some specific pedogenic processes, and confirmed the influence of certain soil formation factors and the relative degree of evolution of different soils. The soil system comprising the xeralfs can be defined in terms of four factors that grouped the soil variables, and accounted for more than 90% of the variance: Factor 1, pedological development of the Bt horizon; Factor 2, a mineralogical factor; Factor 3, clay translocation in the profile; and Factor 4, a mineralogenetic feature of the Bt horizon.
16 citations
TL;DR: In this paper, a calcarenite of the Sardinian Miocene (Cagliari pietra cantone) has been selected as a model material for the investigation.
Abstract: Certain kinds of stone used in buildings of archaeological, historic and architectural significance resemble aggregate of micrometre size, of weakly cemented, essentially calcite particles, containing numerous voids. Below the results are presented of an experimental investigation conducted for the purpose of determining the water-induced weakening effects on such stone. A calcarenite of the Sardinian Miocene (Cagliari pietra cantone) has been selected as model material for the investigation. Its microstructure is characterized by means of XRD, ESEM and MIP techniques. Compression strength, ultrasound propagation velocity and elongation provide an indication of the role played by various fluids (water, aqueous sodium chloride solution, kerosene) in weakening the interparticle bonding forces of the calcite grains. Permeability, pH and calcium ions concentration in the permeating water, on the other hand, point to the dissolution behaviour and hence weakening effects of water permeating through this type of microstructure.
16 citations
Cites background from "The x-ray identification and crysta..."
...It is well known that when wet, montmorillonite expands to many times its volume [10]....
[...]
TL;DR: The relationship between the ratio of component layers and basal spacings in two component systems is discussed in this paper, where it is observed that adjacent pairs of expanded and unexpanded layers form non-expansible units.
Abstract: Interstratifled layer structures were studied by electron microscopy and electron diffraction In order to distinguish between expansible and non-expansible layers, interstratifled mica-smectite was treated with laurylamine hydrochloride solution Electron micrographs of the layers at the curled edges of the crystals show expanded basal spacings of 24 A and unexpanded spacings of 10 A It was observed that adjacent pairs of expanded and unexpanded layers in the micrographs form non-expansible units Arrangement of the expanded and unexpanded layers shows that the layers expanded by sorption of laurylammonium ions have expansible and non-expansible surface characteristics on opposite sides of the layer The relationships between the ratio of component layers and basal spacings in two component systems are discussed
16 citations
TL;DR: In this paper, the correlation between the mineralogy of a raw material and its physical characteristics is reasonably good; the presence of montmorillonite, in particular, can have a marked effect; however, the importance of the degree of compaction of the raw material (largely a function of geological age) is emphasized.
Abstract: A B S T RA C T: Ten raw materials, typical of those used by the majority of British manufacturers of structural clayware, are shown to cover a wide range of mineralogical composition. Kaolin, mica minerals and quartz are always present, though their relative percentages vary widely. Other minerals which may be present in more than trace amounts, are montmorillonite, dolomite, calcite, sepiolite and chlorite. The correlation between the mineralogy of a raw material and its physical characteristics is reasonably good; the presence of montmorillonite, in particular, can have a marked effect. The importance, however, of the degree of compaction of the raw material (largely a function of geological age) is emphasized. Variations in clay mineralogy appear to affect firing behaviour less than variations in the content of alkaline earths, where present.
16 citations
TL;DR: In this article, the authors investigated the dehydroxylation of three soil minerals and their rehydration under wet conditions, and they found that the specific surface area of all three de-hydroxylated minerals was increased substantially by wet incubation.
16 citations