微波加热提高有机粘结剂铁矿球团的强度

Improving strength of iron ore pellet containing organic binder by microwave heating

对微波功率、加热时间、反应温度对预热球团强度的影响进行研究,并将微波加热与传统管炉加热进行对比。研究结果表明:有机粘结剂铁矿球团对微波具有良好的吸收性能,当微波功率为2.5kW,球团质量为0.4kg时,球团平均升温速率为76.1℃/min;微波加热能明显提高预热球团抗压强度;在微波功率为2.5kW,加热时间为8min,球团终点温度为830℃时,预热球团抗压强度为454N/个;当加热时间为11min,球团终点温度上升至1000℃时,预热球团抗压强度为1038N/个;采用微波加热,预热球团内部矿物结构较均匀、紧密,细粒磁铁矿氧化成赤铁矿,并在大颗粒之间连接成片,球团强度明显提高。

Effects of microwave output power, heating time and temperature on pellet strength were investigated and the comparison to conventional heating was made. The results show that the pellets have wonderful microwave absorbability and the rate of temperature change is 76.1℃/min by microwave heating with power of 2.5 kW and the material mass of 0.4 kg. The preheating pellets obtained have greater compression strength than conventional ones. The pellets strength is 454 N per pellet with the microwave power of 2.5 kW, heating time of 8 rain, last temperature of 830℃ and 1038 N per pellet at 1 000℃ and heating for 11 min. The crystal form of preheating pellets interlink well and the structure is well-proportioned and compact, fine magnetites are oxidized to form hematite which are connected with each other.