Production and Characterization Of Electroless Ni Coated Fe-Co Composite Using Powder Metallurgy In Microwave Furnace

The specimens, magnetic properties materials, and microwave characteristics of Ni coated Fe and Co composites were researched by specimens produced by microwave furnace sintering at 1100°C temperature. A uniform nickel deposit on Fe-Co particles was coated previously to sintering by electroless coating deposition procedure. A composite consisting of quaternary additions, a metallic phase, Fe-Co inside of Ni matrix has been prepared under in a neutral atmosphere environment then microwave sintered. X-Ray Diffraction, SEM(Scanning-Electron-Microscope), Empedans Phase Analyzer were utilized to obtain structural data and to determine magnetic and electrical features such as dielectric and conductivity at the temperature range of 25-400C. The ferromagnetic resonance varied from 10 Hz to 1GHz and measurements were employed to characterize the features of the specimens. Empirical of findings obtained for the composition (Fe-%25Co)50Ni at 1100°C recommend that the best conductivity and hardness were obtained with 50Ni addition at a sintering temperature of 1100°C.

Design and optimisation of a laboratory scale microwave furnace for heating titanomagnetite ironsand

<p><b>TTM (Titanomagnetite) ironsand is an abundant source of iron oxide on the western beaches of the Waikato and Auckland regions in New Zealand, with chemical formula TixFe3-xO4 (x=0.27). This ironsand has been used for the last four decades to produce steel in New Zealand, but the reduction process releases large amounts of carbon dioxide. This is because coal is used as the primary reducing agent. Using hydrogen gas instead as a reducing agent, it is possible to reduce ironsand while avoiding the excessive production of carbon dioxide. In addition, standard electrical heating methods are generally limited by low power transfer rates to the steelmaking reactants. Microwave heating is an alternative heating method, shown to be good candidate for ironsand heating via direct power transfer to the NZ ironsand itself due to its excellent microwave absorbing features. This research focuses on modelling the dynamics of microwave power transfer in a resonant microwave cavity, and refines a computational model to improve the modelling capability of such a process.</b></p> <p>Microwave heating is known to demonstrate high direct power transfer rates to microwave absorbing materials, such as TTM ironsand. The microwave heating of ironsand as a candidate heating method is shown in this work by the optimisation of the resonant performance of a custom-built laboratory scale microwave cavity to heat ironsand to over 1000 C. The microwave furnace developed in this work was specifically designed to mimic the contemporary steelmaking standards (i.e., a continuous throughput furnace). A microwave furnace was designed with a computational model, then built and tested in a laboratory. Measurements tracking various energy fluxes throughout the furnace refined an initial transient microwave heating simulation of the computational model with a simple experimental procedure, which exploits the significant variation of the real permittivity (εr) of the ironsand at T = 430 C. </p> <p>From that experimental procedure, a significant variation in microwave absorption was observed as the ironsand passed through its Curie temperature. This effect was reproduced in an initial transient microwave heating simulation. Experimental results were then used to improve simulation accuracy. This encourages further refinement of the computational model as an avenue for future work in this field.</p> <p>In summary, this research demonstrates the feasibility of designing a microwave furnace for efficiently heating TTM ironsand. It also exhibits the feasibility of simulating microwave heating of TTM ironsand with a computational model. The results from this thesis show promise for further study on the hydrogen reduction of TTM ironsand within a microwave furnace. The findings therein present results which ‘set the scene’ for for larger-scale zero-CO2 production of techno-economically essential materials via microwave heating.</p>

Design and optimisation of a laboratory scale microwave furnace for heating titanomagnetite ironsand

<p><b>TTM (Titanomagnetite) ironsand is an abundant source of iron oxide on the western beaches of the Waikato and Auckland regions in New Zealand, with chemical formula TixFe3-xO4 (x=0.27). This ironsand has been used for the last four decades to produce steel in New Zealand, but the reduction process releases large amounts of carbon dioxide. This is because coal is used as the primary reducing agent. Using hydrogen gas instead as a reducing agent, it is possible to reduce ironsand while avoiding the excessive production of carbon dioxide. In addition, standard electrical heating methods are generally limited by low power transfer rates to the steelmaking reactants. Microwave heating is an alternative heating method, shown to be good candidate for ironsand heating via direct power transfer to the NZ ironsand itself due to its excellent microwave absorbing features. This research focuses on modelling the dynamics of microwave power transfer in a resonant microwave cavity, and refines a computational model to improve the modelling capability of such a process.</b></p> <p>Microwave heating is known to demonstrate high direct power transfer rates to microwave absorbing materials, such as TTM ironsand. The microwave heating of ironsand as a candidate heating method is shown in this work by the optimisation of the resonant performance of a custom-built laboratory scale microwave cavity to heat ironsand to over 1000 C. The microwave furnace developed in this work was specifically designed to mimic the contemporary steelmaking standards (i.e., a continuous throughput furnace). A microwave furnace was designed with a computational model, then built and tested in a laboratory. Measurements tracking various energy fluxes throughout the furnace refined an initial transient microwave heating simulation of the computational model with a simple experimental procedure, which exploits the significant variation of the real permittivity (εr) of the ironsand at T = 430 C. </p> <p>From that experimental procedure, a significant variation in microwave absorption was observed as the ironsand passed through its Curie temperature. This effect was reproduced in an initial transient microwave heating simulation. Experimental results were then used to improve simulation accuracy. This encourages further refinement of the computational model as an avenue for future work in this field.</p> <p>In summary, this research demonstrates the feasibility of designing a microwave furnace for efficiently heating TTM ironsand. It also exhibits the feasibility of simulating microwave heating of TTM ironsand with a computational model. The results from this thesis show promise for further study on the hydrogen reduction of TTM ironsand within a microwave furnace. The findings therein present results which ‘set the scene’ for for larger-scale zero-CO2 production of techno-economically essential materials via microwave heating.</p>

Improving the efficiency of the carbothermal reduction of red mud by microwave treatment

In this work, we studied the effect of microwave treatment of red mud briquettes containting more than 48% of Fe on the process of iron reduction under various conditions of heat treatment. Research samples were collected from red mud formed during the production of alumina from bauxite at the Ural Aluminum Smelter. The chemical composition of mud samples was examined by X-ray fluorescence analysis. The composition of initial mud and that of agglomerates obtained after treatment in microwave and muffle furnaces was studied using the X-ray diffraction method. Phase transitions and structural changes occurring under the effect of heating were studied by scanning electron microscopy. The experimental briquettes comprising red mud and charcoal were treated at 850°C and 1000°C in a microwave furnace (under the frequency of 2.45 GHz and the power of 900 W). For reference, briquettes of analogous composition were heat-treated in a muffle furnace under the same conditions. It was found that, under the conditions of microwave heating to 1000°C for 10 min, hematite is completely reduced to metallic iron after the addition of wustite. An analysis of the m i-crostructure of the samples after microwave treatment showed that the particles of metallic iron in the as-obtained pellet-agglomerates have a larger size than in those after conventional thermal heating in a muffle furnace. The metallized phases of reduced iron at the end of heat treatment in a microwave furnace create a stable durable body of agglomerates. The evidence-based parameters of the process can become a basis for designing a technology for recycling such an industrial material as red mud. The obtained high-strength pellets from red mud with a high content of reduced iron (up to 85%) may be used as an alternative charge material for ferrous metallurgy. The proposed technology for recycling red mud into pellet-agglomerates can be applied in various industries to reduce environmental impact on the production areas of alumina plants.

A Combined Soda Sintering and Microwave Reductive Roasting Process of Bauxite Residue for Iron Recovery

In this study an integrated process is presented as a suitable method to transform Fe3+ oxides present in bauxite residue into magnetic oxides and metallic iron through a microwave roasting reduction, avoiding the formation of hercynite (FeAl2O4). In the first step, all the alumina phases were transformed into sodium aluminates by adding sodium carbonate as a flux to BR and then leached out through alkali-leaching to recover alumina. Subsequently, the leaching residue was mixed with carbon and roasted by using a microwave furnace at the optimum conditions. The iron oxide present in the sinter was converted into metallic iron (98%). In addition, hercynite was not detected. The produced cinder was subjected to a wet high intensity magnetic separation process to separate iron from the other elements.

FEATURES OF UTILITARIAN STONEWARE FIRED WITH MICROWAVE RADIATION

The energy dependence on fossil resources and the increasing competitiveness of the stoneware industry, which is a relevant natural gas consumer, leads to new and more environmentally friendly firing methods. Microwave radiation is herein presented as an alternative heating technology for stoneware firing. The samples were fired in a multimode furnace with 6 magnetrons in its core, each one operating at a nominal power of 900 W and frequency of 2.45 GHz. A pyrometer and a thermocouple were installed in the microwave furnace for temperature measuring, control and monitoring. Pyrometer was calibrated in an electric furnace for accurate temperature measurements. During calibration, the thermocouple used in the microwave furnace was installed in the electric furnace, giving a temperature difference from the control (electric furnace) of 2 to 5 ºC, from room temperature up to 1450 ºC. To help the stoneware firing, a silicon carbide (SiC) plate was used as microwave susceptor, also working as a support base for the stoneware samples (mugs). The microstructure of the microwave fired stoneware shows features similar to those of conventionally fired samples (gas and electric heating), with the microwave requiring lower firing temperature to reach an equal structure. X-Ray diffraction and scanning electron micrograph show the relevant transformations taking place for lower temperatures when using microwave heating.