MnO对低镁含钛炉渣流动性及热力学性质的影响

Effect of MnO on the Fluidity and Thermodynamic Behavior s of Low Magnesium Titaniferous Slag

为分析钛矿护炉及锰矿洗炉条件下MnO对炉渣黏度的影响,以低镁含钛炉渣为基础渣系,通过试验和Factsage计算分别研究了不同温度下MnO含量与炉渣黏度、熔化温度、活度等的变化关系。结果表明,在本试验条件下,炉渣黏度、开始熔化温度和完全熔化温度随MnO含量增大而降低,当MnO含量大于1.5%时,其对炉渣黏度降低的作用减弱。在炉渣冷却过程中,黄长石是最主要的析出相,并最先从渣中析出,增大炉渣中MnO含量利于增加液相含量,抑制熔点相对较高的物相形成,从而改善炉渣流动性。同时,随着MnO含量的增加,炉渣热焓增大,渣中固相含量和比热容以及液相炉渣结构等是影响炉渣热焓的主要因素。另外,液相炉渣中MnO和TiO2的活度随MnO含量的增加呈现相反的变化趋势,MnO活度的增大与TiO2活度的减小,也进一步反映出MnO具有简化炉渣结构的作用。

In order to analyze the effect of MnO on viscosity of slags under the conditions of titanium ore retaining furnace and manganese ore washing furnace,the low magnesium titaniferous slags had been used as basic slag system.The relationship between MnO content and slags viscosity,melting temperature,activity and so on under different temperatures were studied through experiments and Factsage calculations,respectively.The results show that viscosity,initial melting temperature and complete melting temperature decrease with the increase of MnO content under the experimental conditions.When the content of MnO is more than 1.5%,its effect of reducing viscosity of slags is weakened.In the process of slags cooling,the melilite is the main precipitated phase and the first precipitation from slags.Increasing MnO content helps to increase the fraction of liquid phase and inhibit the formation of phase having a relatively high melting point,thereby improving slags fluidity.At the same time,the enthalpy of slags increases with the increase of MnO content.The fraction of solid phase and specific heat capacity as well as the structure of liquid slags are the main factors affecting the enthalpy changing.In addition,the activity of MnO and TiO2 in liquid slags showed the opposite trend with the increase of MnO content.The increase of MnO activity and the decrease of TiO2 activity further reflect that MnO can simplify the structure of the slags.