Effectiveness of selective chemical treatments on concentrating magnetic minerals of samples from a nickel-ore peridotite mantle

Lélis, Maria de Fátima Fontes; Gonçalves, C.M.; Fabris, José Domingos; Mussel, Wagner da Nova; Serrano, W. A. Pacheco

doi:10.1590/s0103-50532004000600015

Cited by 4 publications

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“…Two more peaks were identified as Fe 3+ with 13% and 71.3%. The doublet of Fe 2+ agreed with magnetite species with a δ = 0:63 mm/s [40], as well as the second signal of Fe 3+ that also coincided with magnetite (δ = 0:29 mm/s) [39][40][41]. The changes in Fe 3+ quantity may be due to (a) oxidation process from Fe 2+ to Fe 3+ caused by MNZ/Fe calcination or (b) heterogeneous nature of mineral that can vary its composition of both Fe and zeolite species.…”

Section: Xps Analysis X-ray Photoelectron Spectroscopy Analysismentioning

confidence: 64%

“…Based on the parameters of Mössbauer doublets, the Fe 2+ fraction was related to fayalite species (Fe 2+ ) 2 SiO 4 with a chemical isomer shift of 1.13 mm/s [38]. These species belonged to nesosilicates class commonly found in volcanic rocks, and Fe 3+ fraction were associated to magnetite species with a δ = 0:24 mm/s [39] as listed in Table 4. The spectrum showed in Figure 5(b) for the MNZ/Fe calcined sample at 700°C presented 15.7% of relative area which corresponded to Fe 2+ .…”

Section: Xps Analysis X-ray Photoelectron Spectroscopy Analysismentioning

confidence: 99%

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Photo-Fenton Degradation of RB5 Dye in Aqueous Solution Using Fe Supported on Mexican Natural Zeolite

Domenzain-Gonzalez

Castro-Arellano

Galicia‐Luna

et al. 2019

International Journal of Photoenergy

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A Mexican natural zeolite (MNZ) was impregnated with Fe at concentrations of 5 and 10 mg FeCl3/g MNZ (MNZ/Fe) in order to study the photo-Fenton degradation of Reactive Black 5 (RB5) dye. Two samples were prepared and calcined at 550 and 700°C for each concentration. These samples were also characterized by the following techniques: X-ray diffraction (XRD) to determine crystalline phases of mineral, X-ray photoelectron spectroscopy (XPS) to observe the elemental composition of the material where the main element was Fe as Fe2p, Mössbauer to establish the phases in the material which were magnetite (Fe3O4), fayalite, and chlorite, Raman to corroborate that magnetite clusters in natural material were presented, and transmission electron microscopy (TEM) by which magnetite nanoparticles were observe on zeolite surface. Afterwards, the catalytic degradation of RB5 dye was performed by photo-Fenton process using a 2.2 W lamp as a radiation source. Four initial concentrations of RB5 dye ((RB5)0) were evaluated which ranged from 40 to 100 mg/L. Then, the evaluation reaction was carried out by UV-Vis spectroscopy to know the change in RB5 concentration and chemical oxygen demand (COD) removal to determine the organic carbon. The best results on the photo-Fenton degradation was 91% discoloration and 68.5% chemical oxygen demand removal based on an initial concentration RB50=100 mg/L and 10 mg MNZ/Fe (700°C of calcined temperature) at MNZ/Fe=0.05 g/L catalyst dose in aqueous solution, H2O2=3 g/L, pH=2.5, and 180 minutes of reaction time. Subsequently, variations on (RB5)0, pH, (H2O2), and (MNZ/Fe) were assessed in order to optimize the process by keeping 10 MNZ/Fe. The optimal RB5 dye degradation was achieved at RB50=100 mg/L in the presence of MNZ/Fe=0.2 g/L, H2O2=3 g/L and pH=2.5 where the highest discoloration and chemical oxygen demand removal were 93 and 70.5 at 180 min. Finally, the kinetic reaction was evaluated as a pseudo-first-order kinetics with an apparent rate constant (kapp) of 0.0225 min-1 at latest conditions.

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Section: Xps Analysis X-ray Photoelectron Spectroscopy Analysismentioning

confidence: 64%

Section: Xps Analysis X-ray Photoelectron Spectroscopy Analysismentioning

confidence: 99%

Photo-Fenton Degradation of RB5 Dye in Aqueous Solution Using Fe Supported on Mexican Natural Zeolite

Domenzain-Gonzalez

Castro-Arellano

Galicia‐Luna

et al. 2019

International Journal of Photoenergy

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“…Physical extraction methods and selective chemical dissolution are useful laboratory procedures in the sample preparation that improve the mineralogical analysis of soil materials [3]. The oxalic acid-ammonium oxalate treatment is conventionally used to extract poorly crystalline Fe oxides.…”

Section: Introductionmentioning

confidence: 99%

Distribution of Fe-bearing compounds in an Ultisol as determined with selective chemical dissolution and Mössbauer spectroscopy

et al. 2007

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The distribution of Fe-bearing compounds in the silt and clay fractions from samples of a Chilean Ultisol developing on pyroclastic material was determined in this study. The mineralogical analysis was carried out mainly by Mössbauer spectroscopy at 298, 80 and 6 K, for samples before and after treatment with ammonium oxalate (OX). The 298 and 80 KMössbauer spectra reveal relatively complex mineral assemblages for all samples. An intense central doublet, due to (super)paramagnetic Fe 3+ is observed. The incipient broad-line sextet may be due to coexisting magnetically ordered forms of iron oxides. Goethite, hematite and maghemite were identified from the Mössbauer spectral analysis of patterns obtained at 6 K, which were numerically fitted with model-independent hyperfine field distributions. Some low hyperfine fields are identified for both, the silt and clay samples, being more intense in the last one. These species are likely due to poorly crystalline iron oxyhydroxides, which are more easily removed with the OX treatment; maghemite tends to remain in the coarse fraction, whereas poorly crystalline forms do occur mainly in the clay fraction.

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“…Locally, the CM peridotites are overlaid by a deep marine sedimentary succession (Castrillón, 2013). These sediments were interpreted to be part of the ultramafic weathering profile (López-Rendón, 1986;Gonçalves et al, 1999;Gleeson et al, 2004, Lelis et al, 2004. Recently, Castrillón (2019) suggested that fossils and black conglomeratic mudstone found at Pit-1 represent ocean floor sediments associated with hydrothermal systems hosted by ultramafic rocks.…”

Section: Regional Geological Settingmentioning

confidence: 99%

Listvenites: new insights of a hydrothermal system fossilized in Cerro Matoso peridotites, Montelíbano, Córdoba Department, Colombia

Castrillón

Guerrero

2020

boletingeo

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The products of metasomatic alteration (e.g., carbonation) of peridotites are called listvenites. Based on a description of the outcrops in the laterite deposit at Cerro Matoso located in the NW of Colombia, the mineralogical composition confirmed by petrography, and a chemical analysis performed with XRF and WDS/EDS, the previous unit called tachylite is redefined as listvenite. Two types of listvenites are described: listvenite A, with the mineralogical association of quartz + siderite + phyllosilicates + goethite +/- magnetite, and listvenite B, with the association of siderite + phyllosilicates + goethite. Cr-spinel relics accompanied by Mn-siderite and neoblastic textures, indicate their origin from peridotites, where Mn-Fe would have been deposited by hydrothermal fluids. Hydrothermal reducing environments with alkaline fluids and low temperatures should have favored the formation of listvenites that are observed along a fracture zone, oriented WNW-ESE at Pit-1 in Cerro Matoso. Due to exposure to climatic conditions since the Eocene, but definitively since the last Andean Orogeny, listvenites were affected, like all the rocks in the Cerro Matoso deposit, by intense supergene weathering and leaching processes, which could make their true origin unclear.

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Effectiveness of selective chemical treatments on concentrating magnetic minerals of samples from a nickel-ore peridotite mantle

Cited by 4 publications

References 0 publications

Photo-Fenton Degradation of RB5 Dye in Aqueous Solution Using Fe Supported on Mexican Natural Zeolite

Photo-Fenton Degradation of RB5 Dye in Aqueous Solution Using Fe Supported on Mexican Natural Zeolite

Distribution of Fe-bearing compounds in an Ultisol as determined with selective chemical dissolution and Mössbauer spectroscopy

Listvenites: new insights of a hydrothermal system fossilized in Cerro Matoso peridotites, Montelíbano, Córdoba Department, Colombia

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