w(MgO)对本地高硅铁精粉球团强度影响

采用铁矿粉基础特性测定系统和偏光显微镜，对本地高硅铁精粉M、Y以及低硅精粉进行基础特性实验并通过矿相分析研究了w(MgO)对球团强度的影响。铁矿粉基础特性实验结果表明：M粉同化性温度较高且连晶强度较高，适宜用作造球的主要原料；混合料的合理配比为M粉∶Y粉∶低硅精粉=5∶3∶2，在此配比下的w(SiO2）约为55%~56%。然后进行压块焙烧实验，研究结果表明：随着w(MgO)的提高，压块抗压强度呈先升高后降低的趋势，在w(MgO)=18%时达到最高，为3531N/个；当w(MgO)=18%时，矿相主要为赤铁矿相，赤铁矿结晶最好并连接成片，硅酸钙相较少，粘结相和铁酸钙相一定程度上稳定了整体的结构，强度达到最高；而随着w(MgO)继续增多，铁酸镁相增多，抑制了赤铁矿的结晶，连接晶发育差，晶粒细小分散，强度降低。

Effect of w(MgO)on strength of pellets made of local high silicon iron powder

The basic characteristics of local high silicon iron concentrate M, Y and low silicon iron concentrate were tested by using the basic characteristics measurement system of iron ore powder. And the effect of w(MgO) on the strength of pellets was studied by mineral phase analysis using polarizing microscope. The experimental results show that M powder has high assimilation temperature and high crystalline strength, which is suitable to be used as the main raw material for pelletizing. And the reasonable ratio of the mixture is M∶Y∶low silicon iron concentrate =5∶3∶2, under the w(SiO2) was about 55%-56%. Then the roasting briquette experiment was carried out. The results show that with the increase of w(MgO), the compressive strength of the briquette increases first and then decreases, reaching the highest value of 3531N/pcs when w(MgO)=18%. When w(MgO)=18%, the ore phase is mainly hematite phase, hematite is crystallized and connected into pieces, and calcium silicate phase is less, bonding phase and calcium ferrite phase stabilize the overall structure to a certain extent, and the strength reaches the highest. However, as w(MgO) continues to increase, the increase of magnesium ferrite phase inhibits the crystallization of hematite, the connection crystal growth is poor, the grain is fine and dispersed, and the strength decreases.