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IRON OXIDE REMOVAL FROM SOILS AND CLAYS BY A

2019.2.27  Sodium dithionite in acid system (comparison method).-Deb (1950) proposed three methods for the removal of free iron oxide: ammonium oxalate and oxalic

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Iron Oxide Removal from Soils and Clays by a Dithionite

1958.2.1  It was found that the bicarbonate-buffered Na 2 S 2 O 4 -citrate system was the most effective in removal of free iron oxides from latosolic soils, and the least

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DCB dissolution of iron oxides in aeolian dust deposits

2022.2.18  DCB treatment removes iron oxides in samples through the following reactions: reducing ferric iron with sodium dithionite, chelating the reduced iron with

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Biological beneficiation of kaolin: A review on iron removal

2015.4.1  Similarly, iron ores such as hematite may contain clays like kaolin as contamination which cause problems in the operation of blast furnaces. Therefore, the

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Iron Removal from Kaolin Waste Dumps by Chemical (Oxalic

2022.7.7  Introduction The term kaolin applies to ores composed mainly of kaolinite and, therefore, it could be defined as any massive rock, with a variable percentage of

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Iron Removal from Kaolin Waste Dumps by Chemical

2022.8.25  inorganic acids and reducing agents, such as sodium dithionite (Na 2S 2O 4) with aluminum sulfate (Al 2(SO 4) 3), sulfur dioxide with aluminum powder, and sulfur

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On the Possibility of Removal of Non-Structural Iron from Kaolinite ...

The efficiency of removal of the free iron from kaolinite-group minerals by means of acid leaching was followed by chemical, AES, XRD and ESR analyses. Structural Fe

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Effect of organic acids on ferric iron removal from iron-stained kaolinite

2000.3.1  Abstract. The effect of various organic acids viz. acetic, formic, citric, ascorbic, succinic, tartaric and oxalic acids, on the iron removal and the resulting

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Iron oxide removal from soils and clays by a dithionite citrate ...

Iron oxide removal from soils and clays by a dithionite citrate system buffered with sodium bicarbonate. A series of methods for the extraction of iron oxides from soils and clays

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Iron oxides and aluminous clays selectively control soil ... - Nature

2021.3.3  For that purpose, five to six grams of bulk soil, pre-treated with 30% H 2 O 2 to remove OM, were extracted with 30 g sodium dithionite (Na 2 S 2 O 4) and 1.35 L buffer solution (0.27 M trisodium ...

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The reductive dissolution of synthetic goethite and hematite in dithionite

2018.7.9  The reductive dissolution of synthetic goethite and hematite in dithionite - Volume 22 Issue 3. ... Iron oxide removal from soils and clays by dithionite-citrate systems buffered with sodium ... stability of Al-goethite, Al-hematite, and Fe 3+ - kaolinite in bauxites and ferricretes: an approach to the mechanism of concretion formation. Am. J. ...

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Refinement of industrial kaolin by microbial removal of iron

2013.12.1  The reductive leaching of Fe from kaolins with sodium hydrosulfite (Na 2 S 2 O 4), alternatively known as sodium dithionite, is particularly efficient and is currently employed by the kaolin industry, in some cases giving very low iron concentrations (below 0.3% Fe 2 O 3) and very high brightness values (above 94%) required for high ...

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Iron removal from kaolin by oxalic acid using a novel pre

2023.5.24  Iron removal from kaolin by oxalic acid using a novel pre-agitating and high-pressure washing technique - Volume 58 Issue 2 ... Effect of organic acids on ferric iron removal from iron-stained kaolinite. Applied Clay Science, ... Iron oxide removal from soils and clays by a dithionite–citrate system buffered with sodium bicarbonate.

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EXTRACTION OF IRON OXIDES FROM SEDIMENTS

2023.12.8  The heated dithionite method dissolved 3-6 times more A1 from kaolinite and nontronite standard clays than room temperature dithionite, and 4-6 times more A1 than the Ti(III)-citrate-EDTA-

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Removal of arsenic from contaminated soils by combining

2023.6.1  Dithionite dissolved iron oxides by a reductive effect such that most of the stably bound arsenic was released, enabling the reduction of other heavy metals. The TA could form Fe-TA complexes with Fe 2+ through complexation, reducing the formation of new iron oxides and preventing arsenic from being readsorbed or precipitated onto the

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Effect of organic acids on ferric iron removal from iron-stained kaolinite

2000.3.1  The corresponding iron oxide removal was of the order of ∼80%. ... . 1-Hydroxyethane-1, 1-diphosphonic acid (HEDPA), l-ascorbic acid, oxalic acid, sodium dithionite, sodium formaldehydesulphoxylate (SFS) are potential reagents for ferric iron dissolution (Conley and Lloyd, 1970; Chiarizia and Horwitz, 1991). The kinetics of

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CSIRO PUBLISHING Soil Research

2013.6.18  Iron (Fe) oxides and organic matter (OM) play important roles in maintaining the fertility of highly weathered soils. The main objective of this study was to investigate the interactive effects of variable surface charge minerals, particularly Fe oxide minerals, and OM on the charge properties of red soils from Thailand. We also evaluated

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Chromate Adsorption by Kaolinite SpringerLink

Chromate (CrO42−) adsorption was investigated on kaolinite (0.2–2 μm) saturated with NaClO4 over a range of pH. Adsorption increased with decreasing pH because of protonation of chromate and/or variable charge sites on kaolinite. Chemical pretreatment to remove noncrystalline and crystalline oxide contaminants affected the magnitude of

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Iron removal from waterlogged wood: Extraction by

2013.1.21  TEA is a strong chelant for iron and did remove part of iron at pH 10. The effect of chemical reduction simultaneously with EDTA was studied by using sodium borohydride, sodium dithionite, and ...

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The Estimation of Free Iron Oxydes in Soils and Clays and their Removal ...

2006.8.1  Deb was among the first to use sodium dithionite to measure the free iron oxide content of soils [3]. More recently, a series of modified procedures were presented and reported in the past decade ...

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Iron removal from kaolin using thiourea assisted by

2011.5.19  Xia et al. (2012) studied the US removal of iron from kaolin using thiourea. They performed US leaching at different US frequencies of 20, 40, 60, 80, 100 and 120 kHz using US power at 500 W ...

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EXTRACTION OF IRON OXIDES FROM SEDIMENTS

The heated dithionite method dissolved 3-6 times more A1 from kaolinite and nontronite standard clays than room temperature dithionite, and 4-6 times more A1 than the Ti(III)-citrate-EDTA-

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The influence of organic matter, cation bridges and Fe and Al-oxides ...

1993.1.1  The selective removal of cation bridges or dithionite-extractable Fe- and Al-oxides and hydroxides had no effect on particle size distribution but caused a considerable decrease in surface area.

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Iron Removal from Kaolin Waste Dumps by Chemical (Oxalic

2022.7.7  The term kaolin applies to ores composed mainly of kaolinite and, therefore, it could be defined as any massive rock, with a variable percentage of clay minerals, of a composition equal to or close to kaolinite (Bartolomé, 1997).Kaolinite is an aluminum silicate hydrate, with an approximate composition of 2H 2 OAl 2 O 3 2SiO 2.Structurally, it

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Quantitative determination of goethite and hematite in

2018.7.9  First, Fe-oxides are still quite often considered X-ray amorphous, although numerous results, e.g. a low ratio of oxalate- to dithionite-soluble Fe, have indicated the opposite. Second, even if crystalline, the cocentration of Fe-oxides in many soils is low, thereby complicating their identification by XRD.

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Changes in the CEC of a soil smectite–kaolinite clay fraction as ...

2006.10.1  The treatment with sodium dithionite which presumably caused the removal of iron oxide and hydroxide coatings from the surfaces of clay mineral particles, thereby increasing the net negative ...

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SOIL - Aluminous clay and pedogenic Fe oxides modulate aggregation

2021.7.6  Abstract. Aggregation affects a wide range of physical and biogeochemical soil properties with positive effects on soil carbon storage. For weathered tropical soils, aluminous clays (kaolinite and gibbsite) and pedogenic Fe (oxyhydr)oxides (goethite and hematite; termed “Fe oxides”) have been suggested as important building units for

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Biological beneficiation of kaolin: A review on iron removal

2015.4.1  Therefore, the first beneficiation step to make these raw materials commercially valuable is to effectively eliminate iron oxides from kaolinite clays and vice versa (Poorni and Natarajan, 2013). The iron removal processes can be categorized as physical, chemical, or a combination of both (Prasad et al., 1991, de Mesquita et al., 1996).

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DCB dissolution of iron oxides in aeolian dust deposits

2022.2.18  Dithionite-citrate-bicarbonate (DCB) treatment is a classical method for removing iron oxides from soil. The DCB-induced dissolution effects on iron oxides are controversial. In this paper ...

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