材料期刊网

铁酸钙作为高碱度烧结矿黏结相的主要组成，其形成受SiO2的影响，但到目前为止，其影响机理尚不是十分明确。通过XRD和矿相显微镜观察，并结合Rietveld法定量分析，研究了SiO2对二元铁酸钙形成过程的影响。结果表明：Fe2O3与CaO反应，700℃时形成Ca2Fe2O5，在800℃时出现CaFe2O4，随着温度升高，Ca2Fe2O5逐渐向CaFe2O4转变。SiO2存在时，在铁酸钙形成过程中有Ca2SiO4生成，温度低于900℃时，受动力学条件的影响，反应速率较低， Ca2SiO4的量相对较少，另外，SiO2的阻碍作用随其质量分数的增加而增强，进而导致已形成的Ca2Fe2O5与Fe2O3未能继续反应形成CaFe2O4而使其质量分数逐渐增多；高于900℃时，随着温度的升高，动力学条件改善，离子扩散能力增强，其中，Fe3+通过CaFe2O4层比Ca2+通过Ca2Fe2O5层更容易，进而促进了CaFe2O4形成反应的进行，Ca2Fe2O5向CaFe2O4转变，但随着SiO2质量分数增加，Ca2SiO4的生成量增多，CaO与Fe2O3的接触面积减小，抑制了CaFe2O4的生成。

The effect of SiO2 on the formation process of calcium ferrite which is the main composition of bonding phase in high basicity sinter is not very clear at present. So,X-ray diffraction(XRD),ore microscope (OM),and quantitative Ri-etveld analysis were used to analyze the effect of SiO2 on the formation process of binary calcium ferrite. Experimental re-sults show that the initial reaction products of Fe2O3 with CaO is Ca2Fe2O5 at 700℃,then,Ca2Fe2O5 transforms to Ca-Fe2O4 gradually with increasing temperature and CaFe2O4 appears when the temperature reached 800℃. Ca2SiO4 appears at the formation process of binary calcium ferrite when containing SiO2,and the amount of Ca2SiO4 is relatively less be-fore 900℃due to the influence of the dynamic conditions. In addition,a large amount of Ca2Fe2O5 appears due to it fails to transform to CaFe2O4 because of the hindrance of SiO2 with increasing content of SiO2. At last,Ca2Fe2O5 transforms to CaFe2O4 quickly because the formation reaction of CaFe2O4 is enhanced when the dynamic conditions improve with in-creasing temperature after 900℃and Fe3+through the CaFe2O4 layer is easier than Ca2+through the Ca2Fe2O5 layer,how-ever,the formation of CaFe2O4 is inhibited resulting from the production of Ca2SiO4 increased with increasing content of SiO2 and the contact area of CaO and Fe2O3 decreases.