准化学平衡条件下MgO对多元铁酸钙生成的影响

 研究了不同碱度、不同SiO2与Al2O3含量条件下MgO对铁酸钙生成的影响以及Fe2O3 SiO2 CaO Al2O3 MgO系内烧结矿的成矿过程，通过模拟高碱度烧结矿配料在空气气氛、1220 ℃准化学平衡条件下进行烧结实验，利用XRD QAMS法进行矿物定量、显微镜下观察矿相结构等方法进行分析。实验结果表明：R=2.0、不含Al2O3时增加MgO含量铁酸钙生成量明显增多，加入质量分数为25%的Al2O3后，MgO促进铁酸钙生成的作用减弱，Al2O3改变了MgO对铁酸钙生成的影响规律；随着碱度从1.8增加到2.3，铁酸钙生成量呈上升趋势，但是MgO对铁酸钙生成的促进作用减弱；实验还发现，随着MgO含量增加，不含Al2O3时铁酸钙晶形有“柱状”向“针状”变化趋势；加入质量分数为2.5%的Al2O3后，MgO含量增加对铁酸钙晶形影响减小。

Effect of Magnesia on Formation of Calcium Ferrites Under the Quasi-Chemical Equilibrium

The chemical composition of high basicity sinter was simulated to investigate the effects of magnesia content on calcium ferrite formation in Fe2O3 SiO2 CaO Al2O3 MgO system in air atmosphere at 1220 ℃ by determining the amount of calcium ferrite formation from XRD QAMS method, by observing the microstructure from optical microscopy, and so on. The experimental results show that the amount of calcium ferrite formation for samples with R=2.0 and no alumina increases markedly with increase of magnesia content, however the amount of calcium ferrite formation for samples at 2.5% alumina and R=2.0 increases smaller with increase of magnesia content, which is considered that effect of magnesia on calcium ferrite formation was changed after adding alumina into the samples. Secondly, with increase of basicity from 1.8 to 2.3 ，the amount of calcium ferrite formation in samples increase, but the effect of magnesia on calcium ferrite formation become smaller. The columnar type transfers to acicular type for the shape of calcium ferrite with increase of magnesia content before addition of alumina, however the effect of magnesia content become smaller after added 2.5% alumina.