DITHIONITE- AND OXALATE-EXTRACTABLE Fe AND Al AS AIDS IN DIFFERENTIATING VARIOUS CLASSES OF SOILS

1966 ◽  
Vol 46 (1) ◽  
pp. 13-22 ◽  
Author(s):  
J. A. McKeague ◽  
J. H. Day
Keyword(s):  
Iron Oxides ◽  
Amorphous Materials ◽  
Ammonium Oxalate ◽  
Iron Accumulation ◽  
Parent Materials ◽  
Wide Range ◽  
Canadian Soils ◽  
Oxalate Extraction ◽  
Crystalline Oxides ◽  
Extractable Iron

Iron and aluminum were determined in acid ammonium oxalate extracts and in dithionite–citrate–bicarbonate extracts of a wide range of Canadian soils, several oxide and silicate minerals, and some amorphous preparations of iron or aluminum and silica. The oxalate extraction dissolved much of the iron and aluminum from the amorphous materials but very little from crystalline oxides, whereas the dithionite extraction dissolved a large proportion of the crystalline iron oxides as well as much of the amorphous materials. Oxalate-extractable iron and aluminum gave a useful indication of Bf horizon development in many soils, even if the parent materials were high in iron oxides. In one class of Gleysolic soils, however, the Bfg horizons were high in dithionite-extractable iron and low in oxalate-extractable iron. An accumulation of goethite was found in the Bfg horizon of some of these soils. In some other Gleysolic soils iron was depleted in the A horizon but there was no horizon of iron accumulation. Extraction of soils with oxalate as well as with dithionite is useful in differentiating certain classes of soils and in identifying horizons of accumulation of secondary sesquioxides.

scholarly journals Comparison of the Ammonium Oxalate Extraction of Fertilizer for K2O, Method 983.02, with the Ammonium Citrate/EDTA Extraction, Method 993.31

2003 ◽  
Vol 86 (4) ◽  
pp. 640-642 ◽  
Author(s):  
Natalie F Newlon
Keyword(s):  
Ethylenediaminetetraacetic Acid ◽  
Extraction Procedure ◽  
Ammonium Oxalate ◽  
T Test ◽  
Ammonium Citrate ◽  
Official Method ◽  
Wide Range ◽  
Significant Difference ◽  
Oxalate Extraction ◽  
Edta Extraction

Abstract The direct available method for phosphorus in fertilizers, Method 960.03, is an Official Method for extraction of both P2O5 and K2O. Because K2O is much more soluble and easier to extract than P2O5, the conditions of the extraction procedure are set for efficient extraction of P2O5, and the extraction of K2O is, in effect, a bonus. In 1993, a modified extraction procedure, using an extractant of ammonium citrate/ethylenediaminetetraacetic acid (EDTA) solution, was evaluated for P2O5 and then collaboratively studied. This now-modified extraction procedure for phosphorus is Official Method 993.31, which is used extensively as an alternative to Method 960.03 for phosphorus because it is less labor-intensive. Method 993.31 was also evaluated in our laboratory for K2O extraction, but it was never formally collaboratively studied for K2O. To demonstrate the suitability of Method 993.31 as an extraction procedure for K2O, as well as P2O5 in fertilizers, Method 993.31 extraction for K2O was compared with Method 983.02, the traditional ammonium oxalate extraction procedure for K2O. A wide range of fertilizer samples was extracted by using both procedures. The t-test for samples containing <30% K2O had a t-value of 1.23 and a probability of 0.22, which indicates there was no significant difference in the results obtained by the 2 extraction methods. The t-test for samples containing >30% K2O had a t-value of 0.30 and a probability of 0.77, also indicating no significant difference. It is recommended that Method 983.02 be modified to include the ammonium citrate/EDTA extraction procedure as an additional option for extraction of K2O from commercial fertilizers.

scholarly journals Pedogenic Forms of Iron in Soils Developed from Four Parent Materials

2020 ◽  
Vol 25 (1) ◽  
pp. 47
Author(s):  
Ayodele Owonubi
Keyword(s):  
Iron Oxides ◽  
Ammonium Oxalate ◽  
Granite Gneiss ◽  
Field Work ◽  
Biotite Granite ◽  
Total Iron ◽  
Basement Complex ◽  
Parent Materials ◽  
Basaltic Rocks ◽  
Forms Of Iron

Information on the distribution of various forms of iron in soils are valuable in the study of soil genesis. The objective of this study was to to evaluate the pedogenic forms of iron in soils developed over basement complex and basaltic parent materials of the study area. Geologic units considered in the basement complex area were granite gneiss, biotite granite and migmatite. Stratified random sampling formed the basis for field work. Soil sampling was carried out by digging at least two soil profile pits in each geologic unit. Organically bound, amourphous and total iron oxides were estimated using 0.1 M sodium pyrophosphate, acidified (pH 3) ammonium oxalate, and dithionite-citrate-bicarbonate method, respectively. The total Fe in the soil samples were determined after a mixed acid digestion. In general, total iron fractions were statistically similar among the soils of basement complex geologic units but significantly lower than those of soils derived from basaltic rocks. However, the distribution of iron oxide fractions was similar among the basement and basaltic geologic units. Furthermore, there were significant differences in the distribution of iron oxides in the B horizons of basement complex derived soils. Consequently, the quantity of iron oxides in the B horizon was in the order migmatite > biotite granite > granite gneiss. About 70% of total iron oxides in the soils over granite gneiss, biotite granite and basaltic rocks was amorphous in nature. Furthermore, total iron oxides constitute less than 20% of total clay both in the basement complex and basaltic soils.

The effects of rice growing on soil phosphorus immobilization

1978 ◽  
Vol 18 (91) ◽  
pp. 270 ◽  
Author(s):  
IR Willett ◽  
WA Muirhead ◽  
ML Higgins
Keyword(s):  
Iron Oxides ◽  
New South ◽  
Soil Phosphorus ◽  
Ammonium Oxalate ◽  
Rice Soils ◽  
P Sorption ◽  
South Wales ◽  
Before And After ◽  
Extractable Iron ◽  
Sorption Characteristics

Representative rice soils of the Murrumbidgee and Coleambally Irrigation Areas, New South Wales, were analysed for phosphate (P) sorption characteristics and active iron. Samples analysed were taken before and after flooding (in the field and glasshouse) and from rice bays, irrigation control banks and nearby, non-irrigated fencelines. Previously flooded soils showed greater P sorption capacities than their non-flooded soil counterparts. It was indicated that soils that had previously grown rice required more P for upland cropping than non-rice soils. P sorption was significantly positively correlated with active (acid ammonium oxalate extractable) iron. It was proposed that prolonged waterlogging mobilized iron from relatively well ordered iron oxides of low P sorption capacity but on oxidation formed disordered iron oxides with a large capacity to immobilize P.

Kean Miltos: The Well-Known Iron Oxides of Antiquity

1997 ◽  
Vol 92 ◽  
pp. 359-371 ◽  
Author(s):  
E. Photos-Jones ◽  
A. Cottier ◽  
A. J. Hall ◽  
L. G. Mendoni
Keyword(s):  
Iron Oxides ◽  
Analytical Techniques ◽  
Field Work ◽  
Archaeological Record ◽  
The North ◽  
Naturally Occurring ◽  
Physico Chemical ◽  
Wide Range ◽  
Industrial Mineral

The island of Kea in the North Cyclades was well known in antiquity for its miltos, a naturally occurring red iron oxide valued for its colour and wide range of applications. By combining geological field work, physico-chemical analytical techniques, simulation (heating) experiments as well as simple laboratory tests, this paper describes the study of Kean iron oxides in an attempt to characterize this material which is still largely elusive in the archaeological record. The present work corroborates previous observations about the superior quality of some Kean iron oxides. Furthermore, it puts forward the hypothesis that miltos may have been considered an industrial mineral, and as such may have been used as an umbrella term for a variety of materials including mineralogically distinct purple as well as red iron oxides.

scholarly journals Composition of iron oxides in Archean and Paleoproterozoic mafic-ultramafic hosted Ni-Cu-PGE deposits in northern Fennoscandia: application to mineral exploration

2020 ◽  
Vol 55 (8) ◽  
pp. 1515-1534
Author(s):  
M. Moilanen ◽  
E. Hanski ◽  
J. Konnunaho ◽  
T. Törmänen ◽  
S.-H. Yang ◽  
...  
Keyword(s):  
Trace Element ◽  
Iron Oxides ◽  
Oxide Phase ◽  
Massive Sulfide ◽  
Sulfide Liquid ◽  
Monosulfide Solid Solution ◽  
Sulfide Deposits ◽  
Northern Fennoscandia ◽  
Pge Mineralization ◽  
Wide Range

Abstract Using electron probe microanalyzer (EPMA) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), we analyzed major and trace element compositions of iron oxides from Ni-Cu-PGE sulfide deposits hosted by mafic-ultramafic rocks in northern Fennoscandia, mostly focusing on Finland. The main research targets were the Archean Ruossakero Ni-(Cu) deposit; Tulppio dunite and related Ni-PGE mineralization; Hietaharju, Vaara, and Tainiovaara Ni-(Cu-PGE) deposits; and Paleoproterozoic Lomalampi PGE-(Ni-Cu) deposit. In addition, some reference samples from the Pechenga (Russia), Jinchuan (China), and Kevitsa (Finland) Ni-Cu-PGE sulfide deposits, and a barren komatiite sequence in the Kovero area (Finland) were studied. Magnetite and Cr-magnetite show a wide range of trace element compositions as a result of the variation of silicate and sulfide melt compositions and their post-magmatic modification history. Most importantly, the Ni content in oxide shows a positive correlation with the Ni tenor of the sulfide phase in equilibrium with magnetite, regardless of whether the sulfide assemblage is magmatic or post-magmatic in origin. The massive sulfide samples contain an oxide phase varying in composition from Cr-magnetite to magnetite, indicating that Cr-magnetite can crystallize directly from sulfide liquid. The Mg concentration of magnetites in massive sulfide samples is lowest among the samples analyzed, and this can be regarded as a diagnostic feature of an oxide phase crystallized together with primitive Fe-rich MSS (monosulfide solid solution). Our results show that magnetite geochemistry, plotted in appropriate discrimination diagrams, together with petrographical observations could be used as an indicator of potential Ni-(Cu-PGE) mineralization.

The nature of soil particles particularly those reacting with arsenate in a series of chemically treated samples

Soil Research ◽  
1983 ◽  
Vol 21 (4) ◽  
pp. 455 ◽  
Author(s):  
AW Fordham ◽  
K Norrish
Keyword(s):  
Iron Oxides ◽  
Ammonium Oxalate ◽  
Titanium Oxides ◽  
Iron Oxide Particles ◽  
Chemical Treatments ◽  
Organic Complexes ◽  
Oxide Particles ◽  
Soil Components ◽  
Diffraction Patterns ◽  
High Degree

Arsenate uptake by a surface sample of a lateritic podzol was controlled mainly by iron oxide particles in a very finely divided state of about 50 A in diameter. Despite their size, these particles had some crystalline characteristics - they had semi-regular appearance; had limited solubility in ammonium oxalate (in darkness) and in sodium pyrophosphate; and sometimes gave ring-type electron diffraction patterns identifiable as goethite. The particles contained a high degree of substitution of aluminium for iron. They associated with other soil components, for example, forming surface deposits upon larger kaolin flakes or else microaggregates with smaller ones. They reacted with soil organic matter, which caused marked inhibition of arsenate uptake. Titanium oxides competed with iron oxides for arsenate, and were able to dominate uptake when iron oxides were removed chemically. The behaviour of other components towards arsenate was described, together with their appearance, composition and stability during a series of successive chemical treatments. No iron-organic complexes nor poorly crystalline aluminosilicates appeared to be present. Some reputedly selective reagents extracted excess aluminium, most of it coming from chloritized vermiculite. Small kaolin particles were also dissolved and, in some cases,. this caused fresh precipitation of iron oxides from iron previously held within the clay lattice.

scholarly journals Xenon iron oxides predicted as potential Xe hosts in Earth’s lower mantle

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Feng Peng ◽  
Xianqi Song ◽  
Chang Liu ◽  
Quan Li ◽  
Maosheng Miao ◽  
...  
Keyword(s):  
Iron Oxides ◽  
Lower Mantle ◽  
Search Algorithm ◽  
Mass Density ◽  
Mantle Minerals ◽  
Fe Oxides ◽  
Structure Search ◽  
Wide Range ◽  
Deep Earth ◽  
Calculated Mass

Abstract An enduring geological mystery concerns the missing xenon problem, referring to the abnormally low concentration of xenon compared to other noble gases in Earth’s atmosphere. Identifying mantle minerals that can capture and stabilize xenon has been a great challenge in materials physics and xenon chemistry. Here, using an advanced crystal structure search algorithm in conjunction with first-principles calculations we find reactions of xenon with recently discovered iron peroxide FeO2, forming robust xenon-iron oxides Xe2FeO2 and XeFe3O6 with significant Xe-O bonding in a wide range of pressure-temperature conditions corresponding to vast regions in Earth’s lower mantle. Calculated mass density and sound velocities validate Xe-Fe oxides as viable lower-mantle constituents. Meanwhile, Fe oxides do not react with Kr, Ar and Ne. It means that if Xe exists in the lower mantle at the same pressures as FeO2, xenon-iron oxides are predicted as potential Xe hosts in Earth’s lower mantle and could provide the repository for the atmosphere’s missing Xe. These findings establish robust materials basis, formation mechanism, and geological viability of these Xe-Fe oxides, which advance fundamental knowledge for understanding xenon chemistry and physics mechanisms for the possible deep-Earth Xe reservoir.

In Situ Studies of the Processing of Sol-Gel Produced Amorphous Materials Using Xanes, Saxs and Curved Image Plate XRD

1999 ◽  
Vol 590 ◽  
Author(s):  
DM Pickup ◽  
G Mountjoy ◽  
RJ Newport ◽  
ME Smith ◽  
GW Wallidge ◽  
...  
Keyword(s):  
Amorphous Materials ◽  
Sol Gel ◽  
Heat Treatments ◽  
Silica Gels ◽  
Ex Situ ◽  
High Count ◽  
X Ray ◽  
Image Plate ◽  
Wide Range

ABSTRACTSol-gel produced mixed oxide materials have been extensively studied using conventional, ex situ structural techniques. Because the structure of these materials is complex and dependent on preparation conditions, there is much to be gained from in situ techniques: the high brightness of synchrotron x-ray sources makes it possible to probe atomic structure on a short timescale, and hence in situ. Here we report recent results for mixed titania- (and some zirconia-) silica gels and xerogels. Titania contents were in the range 8–18 mol%, and heat treatments up to 500°C were applied. The results have been obtained from intrinsically rapid synchrotron x-ray experiments: i) time-resolved small angle scattering, using a quadrant detector, to follow the initial stages of aggregation between the sol and the gel; ii) the use of a curved image plate detector in diffraction, which allowed the simultaneous collection of data across a wide range of scattering at high count rate, to study heat treatments; and iii) x-ray absorption spectroscopy to explore the effects of ambient moisture on transition metal sites.

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