【作者】 王宁；

【导师】 沈峰满；

【作者基本信息】 东北大学 ， 冶金工程（专业学位）， 2018， 硕士

【摘要】 烧结矿作为高炉炼铁的主要原料,其冶金性能直接影响高炉炼铁生产的技术经济指标。近年来,在钢铁行业经济效益逐渐减少的市场条件下,各钢铁企业为了改善经济效益指标,不断压缩原料成本,使得矿石来源复杂化。改善烧结矿质量,有利于提高高炉煤气利用率,减少CO2排放量,符合当今社会的CO2减排的绿色发展方向。为此,本文研究了一定范围内的Fe2O3-CaO-SiO2铁酸钙系粘结相的流动性。以此可结合相图(熔点、液相比例)来预测铁酸钙粘结相流动性和强度,进而为不同原料(SiO2)合理制定配料参数提供理论指导。本文首先研究了 Fe2O3-CaO二元系的流动性指数与液相组成、液相线温度(即熔点)及液相比例之间的变化关系。在此基础上,针对Fe2O3-CaO-SiO2三元系流动性展开研究,检测了一定Fe2O3含量、一定CaO含量、一定碱度条件下的流动性指数,并结合三元相图的等温截面图对其进行机理分析。最后针对本文的基础理论研究结果进行了验证。采用实际的铁矿石模拟烧结过程,比较铁矿石的流动性和强度与化学试剂的试验结果,以此来验证基础理论研究的正确性。本文的研究内容主要得到如下结论:(1)液相组成对流动性的影响最大。当液相组成相同时,可以通过液相比例和液相线温度来判断流动性的强弱,即流动性与液相比例成正比,与液相线温度成反比。Fe2O3-CaO二元系中,随Fe2O3含量增加,液相流动性呈减弱趋势。液相中Fe2O3含量由72.4%增加到83.6%,流动性指数由7.9降低至5.9。(2)在Fe2O3含量为70%的液相区内,随着SiO2含量由0升高到10%,Fe2O3-CaO-SiO2三元系的流动性指数由9.29降低至7.33。(3)无论是化学试剂还是铁矿石,在CaO含量为8%,SiO2含量由0升高到10%,各试样虽经焙烧之后未熔化,但是通过显微观察能看到一定数量的液相存在,经过对能谱分析的成分点比例换算,得到的结果与通过相图绘制得到的液相成分所在区域相同。各试样焙烧后未体现出流动性(流动性指数=1)的原因是:(a)液相较少;(b)反应未达平衡。在全部液相区内,CaO含量为25%时,随SiO2含量的提高,Fe2O3-CaO-SiO2三元系的流动性表现出减弱的趋势,由7.71下降到6.21。主要是由于硅酸根离子团的数量增加,导致黏度增大,流动性减弱。(4)无论是R=1.0还是R=4.0,随着Fe2O3含量的升高,SiO2含量的降低,Fe2O3-CaO-SiO2三元系的流动性变弱,而且差距很大。R=1.0时,流动性指数由11.97降低至1,R=4.0时,流动性指数由5.9降低至1。将铁矿石的碱度设定为4.0时,流动性指数基本随着矿石中SiO2含量的增加而增强。高硅的SiO2含量最高,流动性指数也最高,为6.55,巴卡的SiO2含量最低,流动性指数也最低,为1.86。更多还原

【Abstract】 As the main raw materials of blast furnace(BF),the metallurgical properties of sinter have important effects on the technical indices of BF ironmaking process.Recently,in order to decrease the cost of raw materials,more kinds of ores have been used in sintering plant,and the chemical compositions of sinter change in a wider range.The improvement in the qualities of sinter has advantages in increasing the utilization of gas and reducing CO2 emission.Therefore,the fluidity of calcium ferrite bonding phase in a wider range was investigated based on Fe2O3-CaO-SiO2 phase diagram.Then,the fluidity of bonding phase may be predicted based on the liquidus temperature and percentage of liquid.Consequently the research results can give guidance for sintering mixing raw materials.First the relation between fluidity index and composition of liquid phase,liquidus temperature,and percentage of liquid was investigated based on the binary Fe2O3-CaO phase diagram.Then,the fluidity indexes of certain content of Fe2O3,CaO and certain basicity have been detected in Fe2O3-CaO-SiO2 ternary phase diagram.Finally,mechanism can be analyzed combined with isothermal section of tertiary phase diagram.The goal of the fifth chapter is to verify the results of basic research in the former chapters.The experimental results between the actual iron ores and chemical reagents are consistent.The main findings in this thesis could be summarized as follows:(1)The composition of liquid phase has the greatest influence on the fluidity.The fluidity can be predicted by the amount of liquids and liquidus temperature if the two points have the same composition of liquid phase.The fluidity is proportional to the amount of liquid phase,and is inversely proportional to the temperature of melting temperature.With the increase of the content of Fe2O3,the fluidity index of liquid shows a decreasing trend.When the contents of Fe2O3 increase from 72.4%to 83.6%,the indexes of fluidity decrease from 7.9 to 5.9.(2)In Fe2O3-CaO-SiO2 ternary system,in case of Fe2O3=70%,when the SiO2 content increases from 0 to 10%,the fluidity decreases from 9.29 to 7.33.(3)Whether the materials are chemical reagent or iron ores,although the samples that the content of CaO is 8%and the content of SiO2 increase from 0 to 10%have not been melted after roasted,a certain amount of liquid phase can be observed by microscopic observation.The region where the liquid phase located drawn by the phase diagram is the same as the result by the conversion of the component point ratio of the energy spectrum analysis.The reasons why the samples after melted don’t reflect fluidity are as follows:a)amounts of liquids are not enough;b)reaction is not balanced.In the region which is full of liquids with the content of CaO is 25%,with the increase of SiO2 content,the fluidity of the Fe2O3-CaO-SiO2 shows a decreasing trend from 7.71 to 6.21.The increase of the ionic group of silica acid leads to the increase of viscosity and the weakening of the fluidity.(4)With the increase of the content of Fe2O3 and the decrease of the content of SiO2,the fluidity of Fe2O3-CaO-SiO2 becomes worse.There is a large range between the maximum and the minimum.At R=1.0,the fluidity index decreased from 11.97 to 1,and at R=4.0,the fluidity index decreased from 5.9 to 1.When the basicity of the iron ore is set to 4,the fluidity becomes better with the increase of content of SiO2 in the ore.The fluidity index of Gaohui is highest(6.55)due to its highest SiO2 content.Similarly,the fluidity index of Baka is lowest(1.86)due to its lowest SiO2 content.更多还原