烧结过程中MgO在赤铁矿中的扩散行为的研究

Diffusion Between MgO and Hematite During Sintering

烧结矿中MgO主要分布于铁相中与赤铁矿和富士体固溶形成镁质赤铁矿和镁质富士体,Mg2+在硅酸盐粘结相中的固溶量很低。试验采用白云石-Fe2O3扩散偶,并通过光学显微镜、电子探针等手段分析考察了白云石中MgO及CaO对赤铁矿的扩散行为及MgO的扩散速度。试验结果表明:CaO在Fe2O3中的扩散形成CaO.Fe2O3和CaO.2Fe2O3等低熔点物质促进了白云石与Fe2O3间扩散,CaO扩散量大于MgO的扩散量,并求得MgO在Fe2O3中的扩散速度为17.2μm/min。

In sinters, MgO mainly distributes in ferric phase and reacts with hematite and wustite generating magnesioferrite and MgO-bearing wustite. In addition, only a small amount of Mg^2＋ is soluted in silicate binding phase. The diffusion couple consisted of dolomite and hematite fines was used to study diffusion behavior betweem MgO , CaO of dolomite and hematite and the diffusion rate of MgO into hematite by means of optical microscopy observation and EPMA test. The results show that the low melting point substances like CaO·Fe2O3 and CaO· 2Fe2O3 promote the diffusion reaction between dolomite and Fe2O3 and the amount of diffused CaO is more than that of MgO. The diffusion rate of MgO into hematite is 17.2 μm/min.