球团预制-硅热还原炼镁的球团传热性研究

摘要 针对皮江法炼镁存在的问题，提出将白云石粉、硅铁、萤石及黏结剂混合造球，然后煅烧，煅烧后的热球团直接用于还原的炼镁新技术.采用稳态平板法测定了预制球团的导热系数，并通过数值方法研究预制球团的传热规律.结果表明:导热系数随着平均温度提高而增加，随着球团密度和硅铁添加量的增加而降低.当密度为1.1g/cm3、硅铁为理论添加量时，预制球团的导热系数与温度的关系:λ=1.04×10-4T+0.11;球形球团的传热情况优于圆柱形球团，球团具有较小的密度和热容以及较大的导热系数有助于热量由表面向中心传递.预制球团与皮江法球团的传热情况基本相同.
Abstract：A novel method of feed preparation for silicothermic process was proposed to overcome the shortages in Pidgeon process. In this method， dolomite， ferrosilicon， fluorite and binder are mixed to produce pellets and then calcined. Thereafter， the pre-prepared pellets are charged into the retorts immediately. Heat transfer of the pellets was investigated by the steady-state-flat method and numerical method. The results show that thermal conductivity of the pellets increases with the increasing temperature， conversely with the pellet density and the amount of Si-Fe addition. For the sample pellet with the density of 1.1g/cm3 and the theoretical amount of Si-Fe， the relationship between thermal conductivity and temperature can be expressed as λ=1.04×10-4T+0.11. Heat transfer of a spherical pellet is better than a cylindrical one. The better heat transfer from pellet surface to pellet center can be obtained for a pellet with less density， less specific heat capacity and larger thermal conductivity. The mode/mechanism/principle of heat transfer of the pre-prepared pellets is similar to the pellets used in Pidgeon process.