Journal ArticleDOI
Ferrous-Ferric Ratio and CEC Changes on Deferration of Weathered Micaceous Vermiculite
TLDR
Ferrous iron in the layers increased 2-fold or more on deferration of coarser fractions of micaceous vermiculite naturally weathered from biotite (Colorado and Transvaal sources) as discussed by the authors.Abstract:
Ferrous iron in the layers increased 2-fold or more on deferration of coarser fractions of micaceous vermiculite naturally weathered from biotite (Colorado and Transvaal sources) The ferric iron content of the layers was decreased by the deferration treatment but the original content was restored by subsequent H2O2 treatment Sesquioxide coatings on micaceous vermiculite from Colorado, examined electron microscopically, were composed predominantly of Fe2O3 (80 to 85 percent), along with Al2O2 and SiO2 The CEC increased from 64 to 95 meq per 100 g in the fraction coarser than 1000 microns and 50 to 64 meq per 100 g in the fraction 2–02, microns in diameter, as a result of removal by deferration of positively charged sesquioxide coating which had originally blocked a portion of the CEC Although treatment with H2O2 after deferration restored the Fe3+ content to approximately the original value, the CEC was not affected probably because of deprotonation OH− O2− + H+ occurring simultaneous with Fe2+ Fe3+read more
Citations
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Journal ArticleDOI
Improvements to the quantitative assay of nonrefractory minerals for Fe(II) and total Fe using 1,10-phenanthroline
TL;DR: In this article, a method using 1,10-phenanthroline (phen) to quantify Fe (II) and total Fe in nonrefractory minerals was modified to improve the accuracy and precision and to eliminate the inconvenience of performing much of the analysis under darkroom conditions.
Book ChapterDOI
Structural Iron in Smectites
TL;DR: In the words of Ross and Hendricks (1945), "Clay minerals... are the dominant materials of shales and surficial rocks and so are among the most important structural materials of the earth's surface" as mentioned in this paper.
Book ChapterDOI
Properties and Behaviour of Iron in Clay Minerals
TL;DR: In this paper, structural changes of smectites were characterized by a variety of chemical, instrumental, and spectroscopic methods, including the use of synchrotron X-ray sources, infrared, UV-visible, and scanning, environmental-sample, and high-resolution electron microscopy.
Journal ArticleDOI
Deferration Effect on Structural Ferrous-Ferric Iron Ratio and CEC of Vermiculites and Soils
TL;DR: In this paper, the deferration by reduction of free Fe2O3 with Na2S2O4 in the presence of Na citrate and NaHCO3 caused a change in valence state of 10 to 35 per cent of the total structural iron in micaceous vermiculites, soils, nontronite, and muscovite.
References
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Journal ArticleDOI
Simultaneous Spectrophotometric Determination of Iron(II) and Total Iron with 1,10-Phenanthroline
Journal ArticleDOI
Determination of Silica in Citrate-Bicarbonate-Dithionite Extracts of Soils
TL;DR: In this article, a procedure was developed for the determination of Si directly in citrate-dithionite extracts of soils, which provided for noninterference by citrate, dithionites, Fe, and P. The interference by citrates was prevented by an excess of molybdate; that by Fe and P by tartaric acid addition.
Journal ArticleDOI
Chemical changes during the alteration of micas
A. C. D. Newman,Giles A. Brown +1 more
TL;DR: In this paper, the authors show that loss of K is accompanied by an increased loss on ignition, oxidation of some Fe z+ to Fe :~+, loss of divalent octahedral cations, mainly Mg z− loss of OH- (or sorption of H+) and decrease in net negative charge.
Journal ArticleDOI
Ferrous Chamosite and Ferric Chamosite
TL;DR: In this paper, it was shown that many variations in X-ray powder diagrams of chamosites can be accounted for by the existence of two kaolin-type structures, one hexagonal and one monoclinic, with simply related ceil dimensions.
Journal ArticleDOI
Cation Exchange Capacity Variations with pH in Soil Clays1
J. M. de Villiers,M. L. Jackson +1 more
TL;DR: In this article, a soil clays containing pedogenically chloritized 2:1 layer silicates, after brief contact at 25C with 2% Na₂CO₃ (pH 11), developed a proportionately large increment of CEC which was retained after thorough washing with neutral salts (KCl, NaCl) to reduce the pH value below 7.