Basic characteristics of Australian iron ore concentrate and its effects on sinter properties during the high-limonite sintering process

The basic characteristics of Australian iron ore concentrate (Ore-A) and its effects on sinter properties during a high-limonite sintering process were studied using micro-sinter and sinter pot methods. The results show that the Ore-A exhibits good granulation properties, strong liquid flow capability, high bonding phase strength and crystal strength, but poor assimilability. With increasing Ore-A ratio, the tumbler index and the reduction index (RI) of the sinter first increase and then decrease, whereas the softening interval (Delta T) and the softening start temperature (T (10%)) of the sinter exhibit the opposite behavior; the reduction degradation index (RDI+3.15) of the sinter increases linearly, but the sinter yield exhibits no obvious effects. With increasing Ore-A ratio, the distribution and crystallization of the minerals are improved, the main bonding phase first changes from silico-ferrite of calcium and aluminum (SFCA) to kirschsteinite, silicate, and SFCA and then transforms to 2CaO center dot SiO2 and SFCA. Given the utilization of Ore-A and the improvement of the sinter properties, the Ore-A ratio in the high-limonite sintering process is suggested to be controlled at approximately 6wt%.

Detection of the assimilation characteristics of iron ores: Dynamic resistance measurements

Resistance in iron ore undergoes a sharp change of up to several orders of magnitude when the sintered solid phase changes to liquid phase.In view of the insufficiency of existing assimilation detection methods,a timing-of-assimilation reaction is proposed,which was judged by continuously detecting the changes in resistance at the reaction interface.Effects of pole position and additional amounts of iron ore on assimilation reaction timing were investigated.The results showed that the suitable depth of pole groove was about 2 mm,and there was no obvious impact when the distance of the poles changed from 4 to 6 mm,or the amount of iron ore changed from 0.4 to 0.6 g.The temperature of sudden change of resistance in the temperature-resistant image was considered to be the lowest assimilation temperature of iron ore.The accuracy of this resistance method was clarified by X-ray diffraction,optical microscope,and scanning electron microscope/energy dispersive spectrometer(SEM/EDS)analyses.

Mineralogical properties and co-sintering characteristics of fluxed iron ore with magnetite concentrates

To investigate the feasibility of co-sintering of fluxed iron ore with magnetite concentrates, the mineralogical properties of a novel fluxed iron ore were studied using particle size analysis, microscopic morphology characterization, and X-ray diffraction Rietveld analysis. Following that, the experiments for granulation performance and basic sintering characteristics were designed under seven different fluxed iron ore ratios, and the integrated ranking of different fluxed iron ore ratios was determined using gray relation analysis. Finally, the results of the industrial trails were combined with the feasibility analysis. Test and experimental results show that the fraction of the fluxed iron ore particles larger than 0.5 mm can account for more than 48%, and the particles have two morphologies: spherical-rough and flaky-smooth. Ca elements are found in the form of calcite (CaCO3) and dolomite (CaMg(CO3)2). The average particle size of granules and powder removal rate can be improved from 2.50 to 3.16 mm and 39.60% to 24.20%, respectively, with the increase in the fluxed iron ore ratio. Furthermore, the fluxed iron ore can improve assimilability and liquid fluidity of magnetite concentrates. In terms of overall granulation performance and sintering characteristics, the fluxed iron ore ratios are graded from best to worst as follows: 12%, 15%, 9%, 18%, 21%, 6% and 3%. The industrial trails show that when the fluxed iron ore ratio is increased, the beneficial effect of the superior sintering characteristics of the fluxed iron ore itself is ideally balanced with the negative effect of the lower amount of additional CaO at 12% ratio, and thus, it is feasible to bring the fluxed iron ore into production at a level of roughly 12%.

Melting Characteristics of Iron Ore Fine During Sintering Process

The whole melting curve of iron ore during sintering process was obtained,and the melting characteristics of iron ore were defined and explained. The whole melting process of mixture,mixed by iron ore and CaO reagent at basicity of 2.0 and 4.0,respectively,was observed using a SiC heating furnace with camcorder unit,and the melting curves of mixture that were relative height vs temperature curves were obtained. Besides,the melting characteristics of iron ore during sintering were introduced through defining some points in the melting curves,such as liquid forming temperature,inflexion temperature and flowing temperature,and the meaning of different shapes of the melting curves was clarified.

Comprehensive evaluation of sintering basic characteristics of iron ore based on grey relational analysis

Sintering basic characteristics of fourteen iron ores were comprehensively evaluated using micro-sinter and grey relational analysis methods. The results show that magnetite has a low assimilability, high bonding phase strength, and high crystal strength. Hematite presents a good assimilability, while limonite exhibits a strong assimilability, but the bonding phase strength and crystal strength of these two kinds of iron ores are comparatively low. Great difference in liquid flowability exists for the same kind of iron ores. When the assimilation temperature of the sinter mixture is too high, limonite can be added;when the bonding phase strength or crystal strength of the sinter mixture is too low, magnetite can be added. The liquid fluidity of the sinter mixture can be adjusted according to the ratios of corresponding iron ores. Grey relational analysis is an effective method to evaluate the comprehensive sintering characteristics of iron ores, which can provide theoretical basis for the purchasing department of the steel enterprises.

司家营精粉烧结特性试验研究

基于唐钢原料条件,进行了司家营精粉烧结特性的试验研究。主要研究了司家营精粉配比(50%～100%)变化对烧结矿品位、强度及冶金性能的影响规律。