Catalytic conversions of chloroolefins over iron oxide nanoparticles 1. Isomerization of dichlorobutenes in the presence of iron oxide nanopaticles immobilized on silicas with different structures

Rostovshchikova, T. N.; Смирнов, В. В.; Цодиков, М. В.; Bukhtenko, O. V.; Maksimov, Yu. V.; Kiseleva, Olga Igorevna; Pankratov, D. А.

doi:10.1007/s11172-005-0421-2

Cited by 14 publications

(8 citation statements)

References 11 publications

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“…The relatively narrow and asymmetric resonance lines of the high-temperature spectrum, representing a distinctly broadened sextet, can be described by a superposition of four sextets, which differ mainly in the magnitude of the magnetic splitting and line width (#1-4, Table 2). The parameters of the external sextet of this group (#1, Table 2) are in very good agreement with the parameters of hematite-α-Fe 2 O 3 [42,43]. Internal sextets, which differ mainly in larger line widths, their lower intensity, and lower magnitude of magnetic splitting, obviously belong to defective forms of hematite, differing in various degrees of substitution of iron atoms by atoms of another nature (#2-4, Table 2).…”

Section: Composition Of the Neutralized Red Mudsupporting

confidence: 63%

Reductive Smelting of Neutralized Red Mud for Iron Recovery and Produced Pig Iron for Heat-Resistant Castings

Valeev

Zinoveev

Kondratiev

et al. 2019

Metals

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The chemical and mineral composition of the red mud from the Ural Aluminum Plant were studied by XRF, XRD, and Mössbauer spectroscopy. Experiments on reductive smelting of red mud were carried out in a range of temperatures (1650–1750 °C) to recover iron from the aluminum production waste with maximum efficiency. It was found that it is possible to obtain pig iron with a high content of titanium, phosphorus, and vanadium, and low sulfur content. The efficiency of iron recovery at 1750 °C was found to be around 98%. Thermodynamic calculations were carried out to assist in finding the optimal conditions for the process (e.g., carbon content, furnace temperature, slag liquidus temperature). It was also found that the pig iron phase obtained at 1650 to 1700 °C is not separated from the slag phase into ingot compared with the sample obtained at 1750 °C. Pig iron obtained at 1750 °C can be used to produce molds for the steel-casting equipment.

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Section: Composition Of the Neutralized Red Mudsupporting

confidence: 63%

Reductive Smelting of Neutralized Red Mud for Iron Recovery and Produced Pig Iron for Heat-Resistant Castings

Valeev

Zinoveev

Kondratiev

et al. 2019

Metals

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“…Three sextets correspond to Fe +3 atoms in an octahedral oxygen environment, but belong to different phases. The parameters of sextet #1 is similar to the sextet detected in the sample of the original ZPR ( Figure 14 and Table 8 ) and corresponds to α-Fe 2 O 3 [ 75 ]. Evidently, two other sextets (##3–4, Table 8 ) are related to γ-Fe 2 O 3 [ 76 , 77 , 78 ].…”

Section: Resultssupporting

confidence: 60%

Comprehensive Study on the Mechanism of Sulfating Roasting of Zinc Plant Residue with Iron Sulfates

et al. 2021

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Zinc plant residue (ZPR) is a secondary material generated during hydrometallurgical zinc production that contains considerable contents of valuable elements such as Zn, Cu, Fe, Pb, Cd, Ag, In, Ga, Tl. Zinc, copper and accompanying elements in ZPR are in different minerals, mainly in the ferrites. A promising approach for recycling ZPR is the sulfating roasting using iron sulfates followed by water leaching. In this study, the composition of ZPR and the obtained products were thoroughly investigated by various methods including X-ray diffraction analysis (XRD), chemical phase analysis and Mössbauer spectroscopy. The effect of temperature, amount of iron sulfates and roasting time on the conversion of valuable metals into a water-soluble form was thermodynamically and experimentally studied both using pure ferrites and ZPR. Based on the results of time-resolved XRD analysis and synchronous thermal analysis (STA), a mechanism of the sulfation roasting was elucidated. The rate-controlling step of zinc and copper sulfation process during the ZPR roasting was estimated. The sulfating roasting at 600 °C during 180 min with the optimal Fe2(SO4)3∙9H2O addition followed by water leaching enables to recover 99% Zn and 80.3% Cu, while Fe, Pb, Ag, In, Ga retained almost fully in the residue.

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“…The maximum activity of the 2.5% Fe/ASM catalyst at 100 °C is more than an order of magnitude as high as the activity achieved for the most active catalyst based on α Fe 2 O 3 with a high (15%) Fe content. 2 The apparent activation energies calculated from the temperature plots of the rate constants of the forward and backward reactions were 65 and 78 kJ mol -1 for the AGM catalyst and 128 and 140 kJ mol -1 for the ASM based samples. These values are higher than those found previously for larger iron oxide particles in similar catalytic systems.…”

Section: Resultsmentioning

confidence: 97%

Catalytic conversions of chloroolefines over iron oxide nanoparticles 3. Electronic and magnetic properties of γ-Fe2O3 nanoparticles immobilized on different silicas

et al. 2006

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Catalytic properties of superparamagnetic γ ferric oxide nanoclusters, which are uniform in terms of size and magnetic properties were studied. The catalysts were supported on the activated silica gel matrix (AGM) prepared from the KSK 2 silica gel of globular structure and on the activated silica matrix (ASM) prepared from layered natural vermiculite. The clusters are active in some reactions of chloroolefin conversions: isomerization of dichlorobutenes and alkylation of benzene with allyl chloride. Their activity in these reactions is many times higher that of usual suppоrted catalysts based on α ferric oxide. Analysis of the Mössbauer spectra of the 2.5 wt.% Fe/AGM and 2.5 wt.%Fe/ASM samples before and after the reaction at Т = 3-300 К shows that during the reaction some Fe III ions arranged in ∼2-3 nm γ Fe 2 O 3 nanoclusters magnetically ordered at 6 K are reduced to form a high spin Fe II complex in the paramagnetic state. According to the macroscopic magnetization data (SQUID) of the initial clusters, curves with hysteresis are observed at 2 K in the plots of forward and backward magnetization, while the 2.5 wt.%Fe/ASM catalyst after the reaction at Т = 2 К demonstrates a linear field dependence of the magnetization passing through the coordinate origin. Analysis of the Mössbauer spectra and magnetic properties suggests that during the catalytic reaction the Fe III ions in the γ Fe 2 O 3 nanoclusters interact with chloroolefin with the allylic structure to be partially reduced to the Fe II ions that are bound in a complex containing chloride ions and O II ion(s) of the silicate matrix as ligands. This is a reason, probably, for the high catalytic activity of γ Fe 2 O 3 nanoparticles.

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Catalytic conversions of chloroolefins over iron oxide nanoparticles 1. Isomerization of dichlorobutenes in the presence of iron oxide nanopaticles immobilized on silicas with different structures

Cited by 14 publications

References 11 publications

Reductive Smelting of Neutralized Red Mud for Iron Recovery and Produced Pig Iron for Heat-Resistant Castings

Reductive Smelting of Neutralized Red Mud for Iron Recovery and Produced Pig Iron for Heat-Resistant Castings

Comprehensive Study on the Mechanism of Sulfating Roasting of Zinc Plant Residue with Iron Sulfates

Catalytic conversions of chloroolefines over iron oxide nanoparticles 3. Electronic and magnetic properties of γ-Fe2O3 nanoparticles immobilized on different silicas

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