Papers by Keyword: Iron Reduction

Abstract: The simplified model of biochar-bearing iron ore with binder was studied. It was considered a mixture of two types of core-shell particles, ‘iron ore – binder’ particles and ‘biochar – binder’ particles. The expressions to calculate complex effective permittivity and permeability was derived by effective medium approximation (EMA). The corresponding dependencies on volume fraction of iron ore in the mixture are provided.

Abstract: Limitation of iron ore reserve having high quality ore and of energy has enhanced development in iron and steel producing technology and method. The ITmk3 process is one of iron making technology that can cope with the problems. It uses composite pellet as feeding material. In this process the ratio between iron and carbon are very important. Carbon holds an important role in the reduction process of iron. The transformation from iron oxides to iron metal will complete if composite pellet contains enough carbon. This paper discusses the influence of carbon ratio in iron reduction process. Nickel saprolite and coal are used as iron and carbon source. They are grinded, crushed, sieved, mixed and formed in cylinders. The weight ratios of ores to coal are 1:1 and 2:1. The reduction held in a furnace at 1100^OC for 60 minutes and 1250^OC for 120 minutes. The results show that the reduction could not complete. Weak peak of FeNi is due to reduction process do not immediately follow the dehydroxylation process.

Abstract: Iron oxidizing bacteria Acidithiobacillus ferrooxidans, iron reducing bacteria Acidiphilium spp. and their mixture were applied for leaching of iron impurities from quartz sand. The bacterial leaching was carried out in order to decrease the amount of colouring iron oxides and to improve the technological properties of the raw material. Mineralogical analysis confirmed the presence of siderite, iron-bearing muscovite and various amorphous and crystalline forms of iron oxides occurring both free and coating siderite and quartz particles. Mössbauer spectroscopy revealed various oxidation and magnetic states of iron ions, with the prevalence of reduced ionic species. Highest extraction of iron was achieved with pure culture of iron-reducing bacteria with ferrous iron as dominant species in the leaching liquor. Surprisingly, iron oxidizing bacteria caused passivation of the surface of iron-bearing minerals, resulting in the depression of iron leaching in comparison with abiotic control. Ferric iron was major species in the leaching solution containing the mixed culture of iron-oxidizing and iron-reducing bacteria. The mixture was far less efficient in iron extraction than pure culture of iron-reducing bacteria.

Abstract: Purification fluxes JDMR-1 containing B2O3 and JDMR-2 containing Na2B4O7 were developed for magnesium alloy. Density, viscosity and melting points of the two fluxes were measured. In the magnesium alloy iron concentration decreased from 0.024% to 0.004% and 0.001%, and average volume fraction of nonmetallic inclusions from 2.06% to 0.86% and 0.23% after JDMR-1 and JDMR-2 processing, respectively. Corrosion resistance and tensile properties of the magnesium alloy were greatly improved. Iron reduction mechanism was studied thermodynamically.