碳热还原法制备铁尾矿多孔陶瓷的结构与性能

Structure and Properties of Iron Tailing Porous Ceramics Prepared by Carbothermal Reduction Method

以泥状细颗粒铁尾矿和石墨粉为原料,采用碳热还原法制备了铁尾矿多孔陶瓷,将尾矿中低热导率的氧化物和矿物相转变成高热导率的碳化物,克服高孔隙率多孔陶瓷热导率低的问题。采用控制变量法分析了铁尾矿多孔陶瓷的结构与性能及其影响因素。结果表明:铁尾矿多孔陶瓷的结构与性能受烧结温度和石墨含量影响较大,保温时间影响较小。通过改变试验条件,可以调控铁尾矿多孔陶瓷的性能指标,其显气孔率的变化范围是39.30%~82.30%,热导率变化范围是0.53~1.52 W/(m·K),抗压强度变化范围是0.78~15.02 MPa。热导率受孔隙率的影响远大于SiC生成量的影响,力学性能受孔隙率的影响较大。当石墨含量为25%、烧结温度为1600℃、保温时间为2 h时,铁尾矿多孔陶瓷的综合性能最优,其显气孔率为81.07%,热导率为0.58 W/(m·K),与相同孔隙率的普通铁尾矿多孔陶瓷相比,热导率提高了6.6倍。本研究为铁尾矿的高效利用提供了一种新思路。

Iron tailing porous ceramics were prepared by carbothermal reduction method using argillaceous fine-grained iron tailings and graphite as the raw materials.The oxides and mineral phases with low thermal conductivity in tailings were transformed into carbides with high thermal conductivity to overcome the limitation of low thermal conductivity with high porosity.The influence factors on the structure and performance of iron tailings porous ceramics were analyzed by using control variable method.The results showed that the structure and properties of iron tailing porous ceramics were greatly affected by the sintering temperature and graphite content,and less affected by the holding time,and the performance index of iron tailings porous ceramics can be regulated by changing the experimental conditions.The range of the apparent porosity,the thermal conductivity and the compressive strength was 39.30%~82.30%,0.53 W/(m·K)~1.52 W/(m·K)and 0.78 MPa^15.02 MPa,respectively.The influence of porosity was much greater than that of the generation of SiC in thermal conductivity.The mechanical properties were greatly affected by the porosity.The properties of iron tailing porous ceramics were the best with the apparent porosity and the thermal conductivity are 81.07%and 0.58 W/(m·K)when the graphite content,the sintering temperature and the holding time were 25%,1600℃and 2 h,respectively.Compared with ordinary iron tailing porous ceramics with the same porosity,the thermal conductivity was increased by 6.6 times,which provides a new idea for the research and utilization of iron tailings.