Azza Ahmed

Parameters Affecting Energy Consumption for Producing High Carbon Ferromanganese in a Closed Submerged Arc Furnace

The power consumption is considered to be the most important factor affecting the production cost of ferromanganese alloy. Different parameters affecting the energy consumption for industrial production of high carbon ferromanganese HCFcMn were investigated in a closed submerged arc furnace. The analysis of industrial data revealed that the most energy-consumed factorswcre the direct reduction by solid carbon, Boudouard reaction, metal and slag formation, and dccompositionof fluxing materials (limestone and dolomite). To reduce the energy consumption and minimize the energy losses in the production process of HCFcMn, it was recommended to use Mn blend with minimum Mn to Fc ratio of 6 and lower SiO2 content or higher basicity. The added cokcmust be adjusted according to the material balance to prevent the over-coke and to minimize the highly endothermic “Boudouard reaction”. In addition, it was recommended towork at basic slags with the ratio of (CaO + MgO) to SiO2 equal to 1. 0–1. 2 instead ofmuch higher slag basicity. Furthermore, the mass losses had to be minimized through adjusting the handling and charging process and to take care of all metal produced.

Influence of Partial Replacement of Nickel by Nitrogen on Microstructure and Mechanical Properties of Austenitic Stainless Steel

A new modified austenitic stainless steel has been developed through partial replacement of nickel by nitrogen. Nitrogen stainless steel was produced in 10 kg induction furnace under nitrogen pressure, while reference one, AISI 316 steel grade, was produced in open-induction furnace. Both were cast and hot forged, and the total nitrogen was determined. Furthermore, the produced forged steels were subjected to solution treatment at different temperatures. The microstructure of produced stainless steels was observed. The X-ray diffractmeter and Mossbauer effect spectroscopy were used to follow the phase change in reference and modified steels after different heat treatment temperatures. The influence of grain-size, soluble, and insoluble nitrogen on tensile strength and hardness was investigated. The major phase in the modified steel has a fcc structure similar to the reference one, but with finer grains and more expanded lattice. The yield strength and hardness of the nitrogen-modified stainless steel are higher than the reference steel. On the other hand, the increase of nitrogen content deteriorates the steel ductility.

Conversion of Mill Scale Waste into Valuable Products via Carbothermic Reduction

Mill scale is one of waste materials which is produced as a result of hot rolling of steel in all steel companies. On the other hand, mill scale is considered a rich iron source with minimum impurities. This work aims at conversion of mill scale by adjusting smelting processes to produce different valuable products. The smelting processes were carried out using carbothermic reduction in a submerged arc furnace. Two carbonaceous reducing agents and different fluxing materials have been used to adapt optimum smelting process condition. A maximum iron recovery of 83% was obtained by using graphite compared with 76% obtained by using coke. Low sulphur content (≤0.02 wt% S) can be attained by using graphite as a reducing agent in amount that equals or exceeds the stoichiometric molar ratio. By using coke, the highest degree of desulfurization of 97.8% and much lower content of sulphur in the castable metal (0.0028 wt% S) were obtained by controlling the type and quantity of the flux. The results reveal that mill scale waste can be converted into valuable products such as high purity iron as alternative to Sorelmetal used in ductile iron production, low carbon steel, and free cutting steel.