Al2O3 Mass Research Articles

Microstructure, corrosive wear and electrochemical properties of Al2O3 reinforced FeAl coatings by laser cladding

PurposeThis study aims to investigate the influences of Al2O3 mass fraction on the corrosive wear and electrochemical behaviors of FeAl–xAl2O3 coatings.Design/methodology/approachFeAl–xAl2O3 coatings were prepared on S355 steel by laser cladding to improve its corrosive wear and electrochemical properties.FindingsThe average coefficients of friction and wear rates of FeAl–xAl2O3 coatings are decreased with the Al2O3 mass fraction, and the Al2O3 plays a positive role in the corrosion wear resistance. Moreover, the charge transfer resistance of FeAl–xAl2O3 coatings is increased with the Al2O3 mass fraction, showing the FeAl–15%Al2O3 coating has the best corrosion resistance. The findings show the corrosion resistance of FeAl–15%Al2O3 coating is the highest among the three kinds of coatings.Originality/valueAl2O3 was first added into FeAl coatings to further improve its corrosive wear and electrochemical properties by laser cladding.

Microstructure, corrosive-wear and electrochemical performance of laser cladded NiTi–xAl2O3 coatings in 3.5%NaCl solution

PurposeThe aim of this study is to investigate the effects of Al2O3 mass fraction on the corrosive-wear and electrochemical performance of NiTi coating in 3.5% NaCl solution.Design/methodology/approachThe NiTi–xAl2O3 coatings were fabricated on S355 steel by laser cladding, and their corrosive-wear and electrochemical performance were investigated using a wear tester and electrochemical workstation, respectively.FindingsThe wear rates of NiTi–5%Al2O3, –10%Al2O3 and –15%Al2O3 coatings are 82.33, 54.23 and 30.10 µm3 mm−1 N−1, respectively, showing that the wear resistance of NiTi–15%Al2O3 coating is the best. The wear mechanism is abrasive wear, which is attributed to the increase of coating hardness by the Al2O3 addition. The polarization resistance of NiTi–5%Al2O3, –10%Al2O3 and –15%Al2O3 coatings is 3,639, 5,125 and 10,024 O cm2, respectively, exhibiting that the NiTi–15% Al2O3 coating has the best corrosion resistance.Originality/valueThe roles of Al2O3 in the corrosive-wear and electrochemical performance of NiTi–xAl2O3 coating were revealed through the experimental investigation.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-02-2024-0044/

Research on the adsorption mechanism of As by Fe-bearing minerals in coal during high-temperature combustion

As can be retained by Fe components in coal during high-temperature combustion, which is beneficial for reducing As emissions. In this study, high-temperature As adsorption experiments were carried out in a fixed-bed experimental system with As model compound and minerals. The adsorption amount of As was much higher when Fe2O3, SiO2, and Al2O3 acted together than when they acted alone. As was mainly distributed in the Fe-Si-Al minerals generated by the reaction of the three oxides, for which the Fe2O3:SiO2:Al2O3 mass ratio of 1:1:1 was the most favorable, and the maximum adsorption amount of As was 18.2 mg·g−1. Density functional theory calculations were carried out for the adsorption of As2O3 by Fe2O3, SiO2, Al2O3, and Fe2Al4Si5O18. Fe2Al4Si5O18 had the highest adsorption energy for As2O3, indicating the most stable adsorption. As2O3 was adsorbed on the Fe and Si sites. The adsorption ability of the Fe site was strengthened in Fe2Al4Si5O18 relative to that in Fe2O3. The formation of Fe-O-Si and Fe-O-Al in the mineral promoted electron transfer from the adsorbent to As2O3 molecule, thereby strengthening adsorption. These results can guide the optimization of coal blending methods and the modification of adsorbents to control As emissions in coal-fired systems.

The Effects of MgO and Al2O3 Content in Sinter on the Softening-Melting Properties of Mixed Ferrous Burden.

The softening-melting properties of mixed ferrous burden made from high-basicity sinter with increased MgO and Al2O3 content and acid pellets was investigated for optimization. The influences of MgO and Al2O3 are discussed with the aid of phase analysis. The results showed that, with decreasing MgO mass%/Al2O3 mass% in mixed burden, all the softening-melting characteristic temperatures decreased, which can be attributed to the low melting temperature and viscosity of the slag caused by MgO and Al2O3. The permeability of the melting zone deteriorated again when MgO mass%/Al2O3 mass% decreased to a certain content. The softening interval widened slightly at first and then narrowed, while the melting interval first increased slightly and then increased greatly later. It can be deduced that the softening properties were improved, but the melting properties were worsened. Under comprehensive consideration of its softening-melting properties, permeability, iron ore reduction and the thermal state of the blast furnace hearth, the optimal softening-melting properties of a mixed ferrous burden with MgO mass%/Al2O3 mass% of 0.82 is optimal.

LOW-TEMPERATURE ELECTROLYTIC PRODUCTION OF Al-REM ALLOYS IN CRYOLITE MELTS

The process of electrolytic production of Al–Y and Al–Sc alloys in an electrolyte based on potassium cryolite KF–NaF(10 wt %)–AlF3 with a cryolite ratio (CR) of 1.5, containing Al2O3, Sc2O3, or Y2O3 oxides, in a cell with vertical electrodes has been studied. The Fe–Ni–Cu alloy served as an inert anode. The wetted cathode was a graphite plate coated with the aluminum diboride. The electrolysis was carried out at a cathode current density of 0.2 A/cm2 and a temperature of 830°C. The Al2O3 mass was calculated based on the value of the current efficiency of 60%. The Sc2O3 additive was introduced into the melt in an amount of 1 wt %. The mass of the Y2O3 additive was chosen based on its solubility in the melt under study. For this, the influence of Y2O3 additives on the liquidus temperature of the quasi-binary mixture [KF–NaF(10 wt %)–AlF3 (KO = 1.5)]–Y2O3 was determined and it was found that, in contrast to Sc2O3 additives, which lower the liquidus temperature of the cryolite melt, small additions of Y2O3 lead to its sharp increase. It has been found that the efficiency of the electrolytic reduction of Y2O3 is 10 times higher than that of the aluminothermic reduction. Other things being equal, the efficiency of the electrolytic reduction of Y2O3 is higher than that of Sc2O3. Alloys Al–Y and Al–Sc with a REM content of 0.6 wt % have been obtained. However, the time to reach the maximum recovery of yttrium significantly exceeds the time to recover scandium. Metallographic studies of the obtained alloys indicated the presence of Al3Sc and Al2Y intermetallic compounds. A conclusion is made about the fundamental possibility of low-temperature electrolytic production of Al-REM alloys in cryolite melts based on potassium cryolite in vertical cells with an inert metal anode and a wettable cathode.

Influence of Slag Chemistry on the Dissolution of FeCr<sub>2</sub>O<sub>4</sub> in CaO–SiO<sub>2</sub>–Al<sub>2</sub>O<sub>3</sub>–MgO Slag with Graphite Crucible

The effect of Al2O3 and SiO2 content and basicity (w(CaO) + w(MgO)/w(SiO2) + w(Al2O3)) on the chromite ore dissolution in CaO–SiO2–Al2O3–MgO slag system was studied under the condition of 1550°C. The results show that the increase of basicity (R = 0.54, 0.67, 0.82) results in the reduction of the dissolved amount and dissolution rate of chromite ore in the slag. The dissolved amount of Cr in lower basicity slag (R = 0.54) is about 1.5 to 2 times higher than that in higher basicity slag (R = 0.67, R = 0.82). The dissolved amount of Cr tends to increase when the Al2O3 mass content decreases from 20% to 15%. While as the Al2O3 mass fraction continues to decrease from 15% to 10%, the dissolved amount begins to decrease. This may be related to the viscosity of the slag. The spinel phase tends to form on the surface of the unreacted FeCr2O4, thus hindering the further dissolution of FeCr2O4. After starting to dissolve, the FeCr2O4 decomposes into FeO and Cr2O3 dissolving in the slag. The FeO in the slag is preferentially reduced to metal iron attached to the surface of the FeCr2O4. The main forms of Cr element in the slag are CrO and Cr2O3, and the proportion of these two depends on the composition of the slag and the experimental environment. The proportion of CrO in the slag with lower basicity is larger. In the experiment, the maximum solubility of FeCr2O4 in 60 min was obtained in the slag system with 45% SiO2, 15% CaO, 20% Al2O3 and 20% MgO.

Sequential Infiltration Synthesis of Al2O3 in Biodegradable Polybutylene Succinate: Characterization of the Infiltration Mechanism.

The introduction of inorganic materials into biopolymers has been envisioned as a viable option to modify the optical and structural properties of these polymers and promote their exploitation in different application fields. In this work, the growth of Al2O3 in freestanding ∼30-μm-thick poly(butylene succinate) (PBS) films by sequential infiltration (SIS) at 70 °C via trimethylaluminum (TMA) and H2O precursors was investigated for the first time. The incorporation of Al2O3 into the PBS matrix was clearly demonstrated by XPS analysis and SEM-EDX cross-sectional images showing a homogeneous Al2O3 distribution inside the PBS films. Raman measurements on infiltrated freestanding PBS show a reduction of the signal related to the ester carbonyl group as compared to pristine freestanding PBS films. Accordingly, FTIR and NMR characterization highlighted that the ester group is involved in polymer–precursor interaction, leading to the formation of an aliphatic group and the concomitant rupture of the main polymeric chain. Al2O3 mass uptake as a function of the number of SIS cycles was studied by infiltration in thin PBS films spin-coated on Si substrates ranging from 30 to 70 nm. Mass uptake in the PBS films was found to be much higher than in standard poly(methyl methacrylate) (PMMA) films, under the same process conditions. Considering that the density of reactive sites in the two polymers is roughly the same, the observed difference in Al2O3 mass uptake is explained based on the different free volume of these polymers and the specific reaction mechanism proposed for PBS. These results assessed the possibility to use SIS as a tool for the growth of metal oxides into biopolymers, paving the way to the synthesis of organic–inorganic hybrid materials with tailored characteristics.

Deep Understanding of the Mechanism and Thermophysical Properties of Prepared Nanofluids Lube Oil Stock-60 with Al2O3 NPs

Iraqi petroleum refineries produce large quantities of base lubricating oils (lube oils). Managing the influence of nano-additives on the lube oil nanofluids is required deep understanding to explain the resulting new specifications of produced nano-lubricants. The present study investigated the effect of Al2O3 NPs addition on the thermal properties of lube oil stock-60. Different mass additions of 0.25, 0.65, 1.05, 1.45, and 1.85 wt.% of Al2O3 NPs at operating temperatures of 20-50°C were evaluated. Also, the thermal conductivity coefficient of the prepared nanofluid was studied at the full range of the experimental temperatures (20-50°C). It was noted that the addition of Al2O3 NPs improved the thermal properties of the prepared nano-lubricant due to the high thermal conductivity of the added Al2O3 NPs. Moreover, the greatest improvement in the thermal conductivity of modified nano-lubricating oil was 13.02% at added Al2O3 mass fraction of 1.85%. The results indicated that the viscosity index of the prepared nano-lubricant was improved dramatically with Al2O3 NPs addition increase at measured standard temperatures of 40 and 100°C. The viscosity index of lubricant nanofluid is increased up to 2.46% at a weight fraction of 1.85%. The flashpoint increased by 1.33, 3.54, 5.75, 7.52, and 9.73% for mass fraction of 0.25, 0.65, 1.05, 1.45, and 1.85 wt.%, respectively. Furthermore, the highest flashpoint value was 248oC of prepared nanofluid lube oil with 1.85 wt.% of Al2O3 NPs. Finally, the produced nano-lubricating oil has high operating quality with economic feasibility. Furthermore, an accurate correlation for predicting the viscosity of both types of nano-lubricants was provided.

Fine-tuned fabrication parameters of CaO catalyst pellets for transesterification of palm oil to biodiesel

In recent years, the use of heterogeneous catalysts has gained increasing attention for biodiesel production. Among metal oxide catalysts, CaO powder is widely explored and considered to be a promising catalyst. However, the powder catalyst is inappropriate for continuous biodiesel production. Therefore, the catalyst pellet fabrication parameters related to its properties and biodiesel yield were investigated. Key results included the observation that catalysts produced using an Al2O3 binder possessed the highest catalytic activity compared to kaolin and diatomite supported catalysts, for calcination temperatures of 800 °C, possessing a comparable catalytic activity to the CaO powder. The CaO to Al2O3 mass ratio exhibited a significant effect on the surface area and total basicity. The highest biodiesel yield was obtained using the CaO-A(800)-3.5:1 catalyst due to the presence of several active crystal phases including CaO, Ca(OH)2 and CaSiO3 phases to accelerate the transesterification rate. These fabricated CaO catalyst pellets can be utilized as a catalyst for the continuous biodiesel production process.

Effects of Al2O3 mass fraction on microstructure and friction–wear performance of laser cladded Fe90 alloy coating

Purpose This paper aims to improve the friction reduction and wear resistance of Fe90 alloy coating by the addition of Al2O3. Design/methodology/approach Fe90 alloy coatings with the different Al2O3 mass fractions were prepared on Q235 steel by laser cladding (LC). The morphologies, phases and hardness of Fe90 alloy coating were analyzed using a scanning electron microscope (SEM), X-ray diffraction (XRD) and microhardness tester, respectively. The effects of Al2O3 mass fraction on the coefficient of friction (COF) and wear rates of Fe90 alloy coating were investigated using a friction tester, and the wear model was built to discuss the wear mechanism of Al2O3-reinforced Fe90 alloy coating. Findings The results show that the large number of Fe carbides is generated on the Fe90–Al2O3 coatings by the effect of laser high energy, and the hardness of Fe90–coating is 806 HV0.5, which is 4.48 times of substrate. The average COFs of Fe90–Al2O3 alloy coatings decrease from 0.73 to 0.55, and the wear rates are also reduced from 447.78 to 274.63 µm3•s–1•N–1 by the addition of Al2O3. The Fe90–6% Al2O3 coating presents the highest wear resistance among the three kinds of coatings, and the wear mechanism is abrasive wear and micro-cutting wear. Originality/value The Al2O3-reinforced Fe90 alloy coating was first fabricated by laser cladding, and the effect of Al2O3 on the friction-wear performance of Fe90 alloy coating was investigated.

Effects on Al2O3 and La2O3 additions on electrochemical performances of laser‐cladded WC10Co4Cr coatings

AbstractAl2O3 and La2O3‐reinforced WC10Co4Cr coatings were fabricated on Cr12MoV steel by laser cladding (LC). The microstructure and phases of obtained coatings were analyzed using a digital microscopic system (DMS) and X‐ray diffraction (XRD), respectively. The effects of Al2O3 and La2O3 mass fractions on the electrochemical corrosion performances of WC10Co4Cr coatings in 3.5% NaCl solution were investigated on an electrochemical workstation. The results show that the WC10Co4Cr with the different Al2O3 mass fractions are composed of Co4W2C, WC, Al2O3, W2C, and Fe‐Cr phases, and the La2O3‐reinforced WC10Co4Cr‐Al2O3 coatings are composed of WC, W2C, Al2O3, La2O3, LaAlO3, and Fe‐Cr phases. The corrosion current density icorrof the substrate, WC10Co4Cr‐Al2O3, and WC10Co4Cr‐Al2O3‐La2O3 coatings decreases from 2.424 × 10−5 to 6.840 × 10−7 A•cm−2; and the corresponding polarization resistance Rp and charge transfer resistance Rct increase from 1371 to 64 536 Ω•cm2 and from 1568 to 14 020 Ω•cm2, respectively. The La2O3‐reinforced WC10Co4Cr‐Al2O3 coatings have higher electrochemical corrosion resistance than the Al2O3‐reinforced WC10Co4Cr coatings, and the WC10Co4Cr‐6%Al2O3‐9%La2O3 coating presents the highest electrochemical corrosion resistance among all the experimental coatings.

Highly Efficient CO2 Hydrogenation to Methanol over the Mesostructured Cu/AlZnO Catalyst

AbstractIn this work, the mesostructured Cu/AlZnO catalysts were prepared for the CO2 hydrogenation to methanol. Experimental results showed that the weight ratio of Al2O3 and ZnO affected the morphology of the mesoporous AlZnO supports and surface properties of the mesostructured Cu/AlZnO catalysts. The AlZnO‐9 (the Al2O3 mass within the AlZnO support was 90 wt%) with loose spongy porous structure and high surface area facilitated the Cu nanoparticle dispersion. Thus, the Cu/AlZnO‐9 catalyst showed higher exposed Cu surface area (SCu) and more exposed CO2 adsorption sites, which accelerated the CO2 conversion. Meanwhile, the ZnO added into catalysts increased the strength of surface basicity and the surface concentration of Zn species, which promoted the catalytic activity of CO2 hydrogenation to methanol. In addition, the well mesostructure heightened the stability of supported Cu catalyst due to the high dispersion of Cu nanoparticles.

Thermal conductivity enhancement and shape stabilization of phase change thermal storage material reinforced by combustion synthesized porous Al2O3

The utilization of paraffin in latent heat storage system is limited by its leakage and low thermal conductivity. To address such challenges, we prepare composite phase change materials (PCMs) with enhanced thermal conductivity and shape stability. Paraffin is supported by porous Al2O3 which is synthesized by solution combustion synthesis (SCS). The porous structure of Al2O3 is quite influenced by the fuel species in SCS reactions. The glycine-induced Al2O3 shows highly hierarchical porous structure, which can improve the anti-leakage performance of the composites. The thermal conductivity of Al2O3/PW reaches 1.27 W/m•K with an Al2O3 mass ratio of 50 wt%, which is 5 times of pure paraffin. The composite also presents acceptable latent heat capacity of higher than 100 J/g and very good thermal cycling stability. These characteristics assure the promising application of Al2O3/PW composites for thermal energy storage.

Microstructures and properties of Cu-10Sn oil bearings reinforced by Al2O3 nanoparticles

Using Sn and Cu-Al powders as raw materials, three oxide dispersion-strengthened (ODS) Cu-10Sn alloy powders with different Al2O3 mass content (0.42%, 0.85% and 1.68%, respectively) were prepared by mechanochemical synthesis combined with diffusion alloying method. The oil bearings were then fabricated by pressing and sintering. The effects of Al2O3 on microstructures and properties of the powders and the oil bearings were investigated. The results show that Al2O3 nanoparticles with sizes of about 5 nm are uniformly distributed in the ODS Cu powders. The content of Al2O3 nanoparticles has no effect on the distribution uniformity of tin during the diffusion process. And three ODS Cu-10Sn alloy powders with homogeneous tin distribution are prepared. However, the temperatures of forming liquid phases in the ODS Cu-10Sn alloys decrease with increasing Al2O3 content. This affects the sintering behaviors and mechanical properties of oil bearings. Increasing Al2O3 content also has a significant promoting effect on the precipitation of Sn-rich particles. In order to synergize the solid solution strengthening of tin and the dispersion strengthening of Al2O3 nanoparticles, the content of Al2O3 in the ODS Cu-10Sn alloys will not exceed 0.85%. The ODS Cu-10Sn oil bearings with 0.42% Al2O3 sintered at 900 °C have the best comprehensive properties, with uniform radial and axial shrinkage, oil content of 19.1%, radial crushing strength of 284 MPa and micro-hardness of 142 HV.

Microstructure, dry sliding friction performances and wear mechanism of laser cladded WC–10Co4Cr coating with different Al2O3 mass fractions

To enhance the hardness and wear resistance of cold work mold, Al2O3 reinforced WC–10Co4Cr coatings were fabricated on Cr12MoV steel using a laser cladding (LC). The morphologies, chemical elements and phase compositions of obtained coatings were analyzed using a scanning electron microscope (SEM), energy disperse spectroscopy (EDS), and X–ray diffraction (XRD), respectively. The results show that the Al2O3 reinforced WC–10Co4Cr coatings are composed of Co4W2C, WC and C–depleted W2C phases, and the chemical elements of Al2O3 reinforced WC–10Co4Cr coatings are diffused to the substrate, which form the metallurgical bonding at the coating interfaces. The hardness of WC–10Co4Cr coatings with the 2, 4 and 6% Al2O3 mass fractions increases from 538% to 640% than that of substrate. The average coefficients of friction (COFs) of WC–10Co4Cr–2%Al2O3, –4%Al2O3 and –6%Al2O3 coatings decrease from 71% to 56% than the substrate; and the corresponding wear rates also decrease from 12.4% to 4.2% than the substrate. The average COF and wear rate of WC–10Co4Cr–6%Al2O3 coating are the lowest among the three kinds of coatings, showing that the addition of Al2O3 is the main factor to reduce the COFs and increase the wear resistance of WC–10Co4Cr coatings.

Thermal-hydraulic analysis of Al2O3 nanofluid as a coolant in Canadian supercritical water reactor by porous media approach

In this study, thermal-hydraulic analysis of Canadian Supercritical Water Reactor (Canadian SCWR) with nanofluid coolant has been done by porous media approach. In the applied analysis the derived conservation equations of mass, momentum and energy for coolant and conduction heat transfer equation for fuel and clad were discretised by finite volume method and solved numerically using C# program. Nanofluid coolant with various concentration of Al2O3 (Alumina) nanoparticle (up to 40% mass fraction) was selected for this study. Since in Canadian SCWR coolant and moderator are separated, higher mass fraction of nanofluid can be applied in this concept. The achieved results show that by increasing Al2O3 mass fraction, coolant heat transfer coefficient and average coolant temperature grow up in the middle of the core and pressure drop will be raised. Average clad and fuel temperature in the core was calculated. The results show that by using Alumina nanofluid with 40% nanoparticle mass fraction, maximum clad wall and fuel temperatures decrease about 20 °C and 30 °C respectively.

High-efficiency and ultra-thin electromagnetic wave absorption xAl2O3–(1 − x)Sr0.85Gd0.15TiO3 ceramics in X-band

xAl2O3–(1 − x)Sr0.85Gd0.15TiO3(x = 0.2, 0.3, 0.4, 0.5) ceramics were fabricated by hot-press sintering. Their phase composition, morphology, element compositions, conductivity, dielectric properties as well as microwave absorption performance were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), multifunction digital four-probe meter and vector network analysis, respectively. The microwave absorption of the as-prepared xAl2O3–(1 − x)Sr0.85Gd0.15TiO3 ceramics demonstrates excellent microwave absorbability. It is unexpectedly found that with a thickness of only 0.346 mm, xAl2O3–(1 − x)Sr0.85Gd0.15TiO3 (x = 0.2) ceramic exhibits an absorption bandwidth of 3.7 GHz (8.7–12.4 GHz), being consequential to reflection loss less than − 10 dB (over 90% of microwave absorption). It is as well discovered that the minimum reflection loss and absorption peak frequency of xAl2O3–(1 − x)Sr0.85Gd0.15TiO3 (x = 0.3) with a thickness of 0.436 mm were − 45.43 dB and 11.3 GHz, respectively. The prominent microwave absorption performance of the ceramic with such a thin thickness can be attributed to strong interfacial polarization, dielectric frequency dispersion, and good electromagnetic impedance matching. It indicates that the xAl2O3–(1 − x)Sr0.85Gd0.15TiO3 ceramics with appropriate Al2O3 mass fraction and thickness showing good potential for effective microwave absorbing materials.

Influence of Al2O3 mass fractions on microstructure, oxidation resistance and friction–wear behaviors of CoCrAlYTaSi coatings

CoCrAlYTaSi coatings with different Al2O3 mass fractions were fabricated on Ti–6Al–4V alloy using a laser cladding (LC). The effects of Al2O3 mass fractions on the microstructure, oxidation resistance and friction–wear performance of obtained coatings were investigated, and the wear mechanisms were also discussed. The results show that the hardness of CoCrAlYTaSi coating increases with the increase of Al2O3 mass fractions, the dendritic structure with the Al2O3 mass fraction of 15% is compactly refined. The diffusion barrier layer of Al2O3 contains Y oxide precipitate, which reduces the oxidation rate and the movement of Ta. The total mass gain per unit area of CoCrAlYTaSi coating with the Al2O3 mass fractions of 15, 30 and 45% is 33.96, 29.82, and 26.27 mg •cm−2, respectively, the oxidation resistance with the Al2O3 mass fraction of 15% is the best among the three kinds of coatings. The average coefficients of friction (COFs) of CoCrAlYTaSi coatings with the Al2O3 mass fractions of 0, 15, 30 and 45% are 1.12, 0.17, 0.23, and 0.35, respectively, and the corresponding wear rates of are 1.59 × 10−4, 1.02 × 10−4, 0.54 × 10−4, and 0.3 × 10−4 mm3 N−1•m−1, respectively, the wear mechanism is abrasive wear and micro–cutting.

Determination method of high-temperature characteristics of iron-ore sintering based on n(Fe2O3)/n(CaO)

The high-temperature characteristics of iron ores play important roles in optimizing ore proportion of sintering, which are tested by using iron-ore fines and analytical reagent CaO as raw materials. Two calculation methods of CaO addition amount based on binary basicity (basicity method) and n(Fe2O3)/n(CaO) (mole ratio method), respectively, were employed to evaluate the liquid phase fluidity (LPF) and the capability of calcium ferrite formation (CCFF) of iron ores. The results show that the rule of LPF of iron ores under the mole ratio method is different from that with basicity method. The LPF measured by basicity method has a linear positive correlation with the SiO2 content, and there is no linear relationship between LPF and Al2O3 content or mass loss on ignition, which are inconsistent with the results of the previous study. And the results of CCFF with low SiO2 content ( 7 wt.%) based on basicity method cannot reflect the true CCFF. The mole ratio method could successfully solve this problem by reducing the effect of CaO addition amount changes caused by SiO2 content of iron ores.

Appropriate titanium slag composition during smelting of vanadium titanomagnetite metallized pellets

The suitable titanium slag composition with high titanium content for electric furnace smelting of vanadium titanomagnetite was investigated through thermodynamics and related phase diagram analysis. According to the thermodynamic results, low-melting-point regions and MgTi2O5 primary phase area in the phase diagrams, the suggested titanium slag composition for the present vanadium titanomagnetite metallized pellets should consist of 50% TiO2, 8%–12% MgO and 13% Al2O3 (mass fraction) with a binary basicity of 0.8–1.2. Finally, the verified smelting experiments were conducted and successful separation of the molten iron from the titanium slag is obtained. The obtained vanadium-containing molten iron contains 0.681% V and 0.267% Ti, and the obtained titanium slag contains 52.21% TiO2 (mass fraction), in which MgTi2O5 is the primary phase. The titanium resource in the final titanium slag production could be used to produce TiO2 pigment by acid leaching methods.