Sinter Behavior Of Blends With High Proportion Of Australian Ores In Chongqing Iron And Steel Company

With the development of modern steel industry, iron ore resource shortagebecomes more and more severe, which causes major fluctuations of domestic rawmaterial structure, and the production is very unstable. Obtaining qualified andeconomical ore proportioning scheme and corresponding technological parametersunder the condition of limited resources to stabilize sinter production under fluctuantraw materials condition becomes a key point of sintering and even iron making groups.Australia iron ore has excellent assimilation, strong bonding strength and good calciumferrite formation ability over low grade iron ore in domestic. It is beneficial to improvesinter grade, optimize the structure of blast furnace, boost smelting efficiency withincreasing the ratio of Australia iron ore in blends. Research on sintering behavior withhigh proportion of Australian ores has important guiding significance for the actualproduction. This paper studied the influence of basicity, carbon content and MgOcontent in blends on sinter behavior.(1)The change rule of iron ore sinter phase and liquid mass for different basictieswere studied by using Factsage theoretical calculation and compact sinteringexperiment. Combining with two methods it is obvious that Qijiang iron ore and highsilicon Brazilian iron ore have good ability to generate liquid, whereas the ability togenerate liquid of Australia iron ore and concentrate in Domestic is insufficient. Thephase change rule showed that hematite phase decrease, the SFCA phase increasedwith increasing basicity for all iron ores.(2)The sinter behavior and sinter quality for different basicity and different ratiosof Australia iron ore were studied by using sinter pot. The results showed that sinterproduct ratio and finished product efficiency of sinter decreased with increasingbasicity of sinter blends, while vertical sinter speed increased with increasing basicity.The variation of shatter strength have different tendency for low basicity range andhigh basicity range, the tumbler strength get better with increasing basicity. Thenegative pressure of bed decreased, the highest off-gas temperature increased withincreasing basicity. Sinter product ratio have no obvious trend for different ratios ofAustralia iron ore. The finished product efficiency decreased with increasing ratio ofAustralia iron ore in low basicties range and the changing trend of finished productefficiency showed in opposite direction in high basicity range. Shatter strength did not have significant tendency of variation for different ratios of Australia iron ore. Thetumbler strength and abrasion index get better with increasing Australia iron ore whenthe ratio of Australia iron ore is below50%in blends, while the the tumbler strengthand abrasion index get worse when the ratio of Australia iron ore is more than50%inblend. The negative pressure of bed decreased and the highest off-gas temperatureincreased with increasing ratio of Australia iron ore in blends.(3)Carbon content: The sinter product ratio decreased with increasing carboncontent in blends, while the finished product efficiency have opposite change tendency.The suitable carbon content in blends is3.4%when the basicity of blend is between1.6and1.7, for the other two basicity range(1.8-2.0,2.15-2.3), the suitable carboncontent respectively are3.6%and3.8%. Results showed that the carbon content andthe ratio of of Australia iron ore should be controlled at low degree when the lowbasicity sinter is produced, and it is beneficial to increase the ratio of of Australia ironore in blend when high basicity sinter is produced.(4)MgO content: the sinter product ratio and finished product efficiencydecreased with increasing MgO content in blends. Vertical sinter speed showed adecreasing trend with increasing MgO content. Shatter strength and tumbler strengthget worse with increasing MgO content. The negative pressure of bed decreased withincreasing MgO content in the initial stage of sinter process. The intensity ofdiffraction peaks of kirschsteinite, forsterite and pyroxene increased with increasingMgO content in blends. It is beneficial to increase carbon content in blends when theMgO content in blends increased.