DISSOLUTION OF TRIOCTAHEDRAL LAYER SILICATES BY AMMONIUM OXALATE, SODIUM DITHIONITE–CITRATE–BICARBONATE, AND POTASSIUM PYROPHOSPHATE

1972 ◽  
Vol 52 (1) ◽  
pp. 19-26 ◽  
Author(s):  
M. A. ARSHAD ◽  
R. J. ST. ARNAUD ◽  
P. M. HUANG
Keyword(s):  
Particle Size ◽  
Organic Matter ◽  
Size Range ◽  
Ammonium Oxalate ◽  
Size Fraction ◽  
Sodium Dithionite ◽  
Particle Sizes ◽  
Particle Size Range ◽  
Layer Silicates ◽  
Chemical Extractants

The effects of NH4-oxalate (pH 3), Na–dithionite–citrate–bicarbonate (pH 7.3), and K-pyrophosphate (pH 10) on various size fractions of biotite, chlorite, muscovite, and illite minerals were investigated. The data showed that the release of mineral cations by the three chemical extractants increased with decreasing particle sizes. The dissolution of layer silicates was slight and gradual in the particle size range of 100–5 μ, increased considerably for 5–2 μ and markedly below 2 μ. In general, NH4-oxalate dissolved the maximum percentage of Fe, Mg, and Al, and K-pyrophosphate extracted the least amount. Approximately 18.8% of original Fe, 15.5% of Mg, and 11.3% of Al were extracted from 0.2–0.08 μ-size biotite by the oxalate procedure. The corresponding values for the same size fraction of chlorite were: 23.2% Fe, 18.5% Mg, and 13.5% Al. In view of the data obtained it is suggested that the use of NH4-oxalate as an extractant for amorphous Fe and Al may have limitations for soils containing trioctahedral minerals. Instead, K-pyrophosphate, which has little effect on crystalline minerals and also has the advantage of extracting organic matter-complexed Fe and Al, may be more suitable.

Application of mineral magnetism to describe profile development of toposequences of a sedimentary soil in south-eastern Australia

Soil Research ◽  
2001 ◽  
Vol 39 (5) ◽  
pp. 927 ◽  
Author(s):  
R. H. Crockford ◽  
I. R. Willett
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Magnetic Susceptibility ◽  
Magnetic Particles ◽  
Size Range ◽  
The Other ◽  
Particle Sizes ◽  
Mineral Magnetism ◽  
Particle Size Range ◽  
Eastern Australia

Mineral magnetism and chemical properties of soil profiles across a valley with an erosion gully in a Yellow Dermosol sedimentary soil suggest that the magnetic profile resulted from a combination of alluviation and pedogenesis. The concentration of soil magnetic minerals in a range of particle sizes (3.36–2 mm to <2 μm) diminished from the surface downwards to a minimum (referred to as layer P), then increased to high values (layer H), after which it decreased to bed rock level at the base layer. It is proposed that the H layer was the surface of a buried soil, and that the ferrimagnetic mineral through the profiles was dominantly maghemite, formed by fire enhancement. The magnetic pattern of the profiles compressed as the soil became shallower up-slope, from 3 m in depth at the lowest site to 0.7 m at a site 40 m up-slope. Above this site the high susceptibility H layer was absent, which is consistent with the H layer being an earlier soil surface. Except for the profile at the very top of the slope (depth of 0.63 m), the magnetic grain size did not vary with depth. In the P layers, there was a greater proportion of paramagnetic minerals than in the other layers. The changes in magnetic susceptibility through the profiles were influenced by ferrimagnetic, paramagnetic, and canted anti-ferromagnetic material. For all depths in all profiles the magnetic susceptibility changed consistently through the particle size range, decreasing from the larger sizes to the 10–20 m size then increasing slightly to the smallest size (<2 μm). The mean magnetic grain size also decreased through the particle size range. Magnetic particles of 3 concentration levels were extracted by a hand magnet from the 4 largest particle sizes and showed the same magnetic-particle size relationships, for both mass susceptibility and magnetic grain size, as the other particle sizes. This showed that the proportion of highly magnetic particles effectively determined the susceptibility and magnetic grain size features of the bulk samples of each particle size class. The particle size/magnetic susceptibility pattern described in this paper occurs in all sedimentary soils and derived river sediments studied in this part of Australia. However, soils and sediments of granitic origin have an inverse pattern. These differences are attributed to pedogenic and geomorphological process. The difficulties in using mineral magnetic properties as a means of sourcing mobile sediments in catchments are discussed.

381. Sampling Efficiencies of Three Personal Aerosol Samplers within and Beyond the Inhalable Particle Size Range

2001 ◽  
Author(s):  
V. Aizenberg ◽  
P. Baron ◽  
K. Choe ◽  
S. Grinshpun ◽  
K. Willeke
Keyword(s):  
Particle Size ◽  
Size Range ◽  
Particle Size Range

Particle Size Effects on Concentration of Metals in Lake Erie Bottom Sediments

1984 ◽  
Vol 19 (1) ◽  
pp. 27-36 ◽  
Author(s):  
Alena Mudroch
Keyword(s):  
Particle Size ◽  
Organic Matter ◽  
Clay Minerals ◽  
Surface Sediment ◽  
Size Effects ◽  
Lake Erie ◽  
Size Fraction ◽  
Mineralogical Composition ◽  
Major Elements ◽  
Sediment Samples

Abstract Surface sediment samples obtained at the offshore and nearshore area of Lake Erie were separated into eight different size fractions ranging from &lt;2 µm to 250 µm. The concentration of major elements (Si, Al, Ca, Mg, K, Na, Fe, Mn and P), metals (Zn, Cu, Cr, Ni, V, Co and Pb) and organic matter was determined together with the mineralogical composition and morphology of the particles in each size fraction. The distribution of the metals in the offshore sediment was bimodal with the majority of the metals divided between the 63 to 250 um size fraction which also contained the highest concentration of organic matter (about 20%) and the &lt;4 µm fraction containing up to 60% of clay minerals. However, the metals in the nearshore sediment were associated mainly with the clay minerals.

scholarly journals Long term trends in fertility of soils under continuous cultivation and cereal cropping in southern Queensland. III. Distribution and kinetics of soil organic carbon in particle size fractions

Soil Research ◽  
1986 ◽  
Vol 24 (2) ◽  
pp. 293 ◽  
Author(s):  
RC Dalal ◽  
RJ Mayer
Keyword(s):  
Particle Size ◽  
Organic Matter ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Size Fraction ◽  
Organic C ◽  
Size Fractions ◽  
Particle Size Fractions ◽  
Clay Size Fraction ◽  
Sand Size

Distribution of soil organic carbon in sand-, silt- and clay-size fractions during cultivation for periods ranging from 20 to 70 years was studied in six major soils used for cereal cropping in southern Queensland. Particle-size fractions were obtained by dispersion in water using cation exchange resin, sieving and sedimentation. In the soils' virgin state no single particle-size fraction was found to be consistently enriched as compared to the whole soil in organic C in all six soils, although the largest proportion (48%) of organic C was in the clay-size fraction; silt and sand-size fractions contained remaining organic C in equal amounts. Upon cultivation, the amounts of organic C declined from all particle-size fractions in most soils, although the loss rates differed considerably among different fractions and from the whole soil. The proportion of the sand-size fraction declined rapidly (from 26% to 12% overall), whereas that of the clay-size fraction increased from 48% to 61% overall. The proportion of silt-size organic C was least affected by cultivation in most soils. It was inferred, therefore, that the sand-size organic matter is rapidly lost from soil, through mineralization as well as disintegration into silt-size and clay-size fractions, and that the clay fraction provides protection for the soil organic matter against microbial and enzymic degradation.

X-ray diffraction measurement of the quartz content of clay and silt fractions in soils

Clay Minerals ◽  
1992 ◽  
Vol 27 (1) ◽  
pp. 47-55 ◽  
Author(s):  
M. Hardy
Keyword(s):  
Particle Size ◽  
Size Fraction ◽  
Internal Standard ◽  
Diffraction Measurement ◽  
Particle Sizes ◽  
Quartz Content ◽  
Size Fractions ◽  
Particle Size Fractions ◽  
Calibration Curves ◽  
Fine Quartz

AbstractAn XRD method for measurement of quartz content using ZnO as the internal standard was tested on different particle sizes between 0 and 20 µm. Calibration curves showed a good correlation coefficient for particle-size fractions up to 20 µm; the slope increased for the fractions from 0·7 to 5 µm and was relatively constant for coarser particle sizes. Fine quartz fractions were etched with hydrofluoric acid to remove the surface layer damaged during dry grinding. The use of such etched quartz increased the slopes of the calibration curves for small particle-size fractions and approximated the natural fine quartz fraction much better than the original dry-ground material. The mean of six measurements gave good accuracy provided that the slope of the calibration curve was adjusted for the particular particle-size fraction. This method was used on 0–2 µm, 0–0·2µm and 0·2–2 µm fractions of French silty soils and the results are in agreement with the data from chemical analysis and with the mineralogical interpretation.

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