ZnO对烧结矿矿相和结构的影响

 ZnO在烧结矿中的分布和存在形态,对烧结矿的矿相、结构和冶金性能有重要影响。在实验室条件下采用含ZnO的分析试剂,进行1 300 ℃、纯氮气条件下准平衡相烧结试验,研究不同ZnO含量对烧结矿矿相和结构的影响规律。结果表明,添加ZnO的烧结矿中主要矿相为磁铁矿、复合铁酸钙(SFCA)、硅酸盐相和铁酸锌相,ZnO与Fe₂O₃结合生成铁酸锌,铁酸锌在烧结矿中与磁铁矿固溶,且随着ZnO含量的增加,烧结矿中铁酸锌含量逐渐增加。烧结矿中ZnO质量分数由0到4%逐渐增加时,SFCA相的形貌由块状逐渐向条状、针状甚至更细密的网络状转变,且分布由分散到集中。烧结矿中添加ZnO对其液相生成有促进作用,从而对孔结构和孔隙率有较大的影响,ZnO含量增加使微孔减少,大孔数量逐渐增加,且大孔形状较规则;烧结矿的总孔隙率在ZnO质量分数从0到1.6%增加时变化不明显,而随着ZnO含量继续增加,其总孔隙率呈现逐渐增加的现象。

Effect of ZnO on phase and structure of sinter

The distribution and morphology of ZnO have an important effect on the mineral phase, structure, and metallurgical properties of sinter. Therefore, quasi-equilibrium phase sinter experiments were performed under 1 300 ℃, pure N₂ conditions using analytical reagents with different ratios of ZnO under laboratory conditions to study effect of different ZnO content on phase and structure of sinter. The result showed that the main mineral phases in sinter with ZnO are magnetite, silico-ferrite of calcium and aluminum (SFCA), silicate, and zinc ferrite. ZnO combined with Fe₂O₃ to form zinc ferrite,which was solid-dissolved with magnetite in the sinter. With the increase of ZnO, the content of zinc ferrite in the sinter mineral phase increased. The morphology of the SFCA phase changed gradually from block to strip and acicular or even finer network structure, and its distribution changed from scattered to concentrated when the mass percent of ZnO increased from 0 to 4% in sinter. The addition of ZnO to the sinter promoted the formation of its liquid phase, which had an impact on pore structure and porosity. The micropores decreased and the number of large pores increased with the increase of ZnO content, the shape of large pores was regular.As the mass percent of ZnO increased from 0 to 1.6%, the total porosity of the sinter was not changed obviously, and its total porosity showed a gradual increase when the ZnO content continued to increase.