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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.
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Journal ArticleDOI
TL;DR: In this paper, the Stafford Clay marker bed from the Middle Coal Measures of North Staffordshire and the Woolhope Bentonite from the Silurian, Wool-hop Limestone near Woolhop in Herefordshire are described.
Abstract: Two clay deposits, the Stafford Clay marker bed from the Middle Coal Measures of North Staffordshire and the Woolhope Bentonite from the Silurian, Woolhope Limestone near Woolhope in Herefordshire are described. These clays contain mixed-layer clay minerals which have been separated by sedimentation for mineralogical and chemical analysis. Both minerals are shown to be mica-montmorillonites with MacEwan stacking parameters PA = 0·59, PAA = 0·44 and PA = 0·56, PAA = 0·70 respectively. In both cases the average layer charge (1·22 and 1·46) is intermediate between that of montmorillonites and micas but the exchangeable cation layer charge (1·07 and 1·27/montmorillonite layer) and fixed cation layer charge (1·32 and 1·63/mica layer) of the component layers are higher and lower respectively than the normal range of montmorillonites and micas. Some chemical data are given for the raw material which yielded these minerals and for associated and related rocks. In particular K, U and Th determinations permit a discussion of the natural gamma-ray flux which is sufficiently more intense than that of the associ~.ted sediments to permit its detection by scintillation counter in the field.

6 citations

01 Jan 2007
TL;DR: In this paper, the best activation condition for Na-bentonite was at the H2SO4 at concentration of 1.5 -2.0 M for 24 hours, then was dried.
Abstract: Bentonite obtanained from Kecamatan Padang Tualang, Kabupaten Langkat was a Na–bentonite. This bentonite was saturated with 1 M NaCl solution for 1 day to enrich the Na–bentonite. Then the Na–bentonite was activated by (0.5 – 2.0) M H2SO4 for 24 hours, then was dried. In the end this material was intercalated and pillaried with 0.82 M Ti complex solution and calcinated at 350°C to produce TiO2–bentonite and analyzed using XRD, FTIR, Surface area (BET) and SEM. From the analysis data, it was known that the best activation condition for Na– bentonite was at the H2SO4 at concentration of 1,5 M. Etching TiO2–bentonite using (HNO3/ HF/ CH3COOH/ I2) and HF/ H2O/ NH4F solutions was made to increase the hole at the between the layer distances inside the silica, then heated at 400–500°C for 1 hour. The resulting etched TiO2– bentonite which was heated at 450°C produce the material with a wide surface area 92,01 m/g and the porous volum 0,044 cm/g and was scanned with SEM. The etched pillary TiO2–bentonite was used as a co-catalyst in the hydrolisis of H2O, and showed that the total hydrogen and oxygen gases produced was 78.5 % after 4 days, compared was only 60.4 % using non-etched TiO2– bentonite. x Minto Supeno: Bentonit Alam Terpilar Sebagai Material Katalis/ Co-Katalis Pembuatan Gas Hidrogen Dan Oksigen Dari Air, 2007. USU e-Repository © 2008

6 citations

Journal ArticleDOI
11 Jan 1971-Nature
TL;DR: In this paper, the authors pointed out an alternative explanation for the results published under this title by Low et al. They proposed that there is a solubility equilibrium between some component of the silicate layer (probably octahedral aluminium) and the interlayer water and that an increase in water content of the clay suspension favours further solution of this component.
Abstract: THE purpose of this letter is to point out an alternative explanation for the results published under this title by Low et al.1. Briefly, they found that when montmorillonite saturated in sodium is swollen in water, the lateral (b) dimension of the silicate layer increases as a function of water content, even at water thicknesses of 400 A or more. They ascribe these changes to strong (epitaxial) interaction between montmorillonite and water “which modifies their respective structures”. We propose that there is a solubility equilibrium between some component of the silicate layer (probably octahedral aluminium) and the interlayer water and that an increase in water content of the clay suspension favours further solution of this component. It is well known that substitution of octahedral Al3+ by lower-valent ions results in an increase in b (ref. 2) and also that such substitution occurs rapidly in the presence of hydrogen ion3,4. (Other possible mechanisms for changing the composition of the silicate layer have been considered in another context by Low himself3—slight hydrolysis of an Al-bentonite, or chemisorption of H+ into the silicate lattice.)

6 citations