细磨海砂矿烧结特性及其对烧结矿质量影响机理

Sintering characteristics of titanium sands after grinding and its influence mechanism on the quality of sinter

  • 摘要: 通过细磨海砂矿研究其粒级分布、微观结构和烧结高温特性的变化,结合烧结杯试验、扫描电镜能谱分析等研究方法考察海砂矿粒级分布对烧结矿质量的作用机理.经细磨后海砂矿颗粒不规则程度增大,制粒性能得到改善.随着海砂矿粒度变细,其烧结高温特性呈现出与普通铁矿粉相反规律,其中海砂矿3(细磨25 min的海砂矿)与海砂矿1(未经细磨的海砂矿)相比,同化温度升高21℃,1280℃时液相流动性指数减小0.35,细磨后海砂矿与Ca O反应生成钙钛矿增多,阻碍同化反应进行,生成的液相黏度增大.配加8%海砂矿3的烧结矿与配加相同比例海砂矿1相比,还原性提高3.8%,细磨后海砂矿在混合料中分布更加均匀,造成烧结矿中含钛物相质点增多,还原中产生众多微细裂纹,利于还原气体扩散.

     

    Abstract: The size distribution,microstructure and high temperature properties of titanium sands after grinding were studied in the paper. The influence and mechanism of titanium sands on the sinter quality were identified by sinter pot test and scanning electron microscopy and energy dispersive spectrometry(SEM-EDS) test. It is found that the micromorphology of titanium sands becomes more irregular after grinding,and the granulation gets strengthened. Meanwhile,the high temperature characteristics of sintering are different with the common iron ore fines: when titanium sands become finer,the assimilation temperature improves by 21 ℃,and the liquid phase fluidity index decreases by 0.35 at 1280 ℃. The reason for these differences is that titanium sands after grinding react with Ca O to produce more perovskite,which can hinder the assimilation reaction and get the liquid phase stickier. In comparison with unground titanium sands,the reduction index(RI) of sinters produced with 8% of ground titanium sands in blends improves by 3.8%. The reasons are that titanium sands are distributed more uniformly in blends after grinding,resulting in the increase of phase particles containing titanium in sintered ores,and many microcracks emerge in the reduction reaction,which is in favor of reducing gas diffusion.

     

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