硼铁矿碳热还原过程中MgO的挥发

在热力学分析的基础上,研究了碳热还原硼铁矿过程中MgO的还原挥发过程.结果表明,试样的总失重率随着温度的升高而增大,1 400~1 450℃时很快达到最大值,最大失重率为61.8%.MgO以镁蒸气的形式挥发而造成失重,试样中MgO最大失重率达到98.0%.挥发过程中又被重新氧化,一部分在炉管底部形成羽毛状的白色晶体,另一部分和硼、硅的挥发物一起在炉管口形成白色粉末,附着在炉管壁上.证明了碳热还原硼铁矿过程中MgO有挥发现象.

Volatilization of MgO from Ludwigite in Carbothermal Reduction Process

Thermodynamic analysis was made to study the reduction volatilization of MgO in ludwigite by way of carbothermal reduction. The experimental results showed that the total mass loss rate of samples increases with rising temperature, of which the maximum is 61.8 wt% in the range from 1400°C to 1450°C. Magnesia in ludwigite was reduced and volatilized as gaseous magnesium vapour in the process of carbothermal reduction, and its mass loss rate went up to 98.0%. Magnesium was reoxidated into magnesia in the process of volatilization, where part of the volatilized matter formed the white feather-like crystal deposited on the bottom of furnace tube and the rest formed white powder deposited at the opening of furnace tube and adhered to tube wall together with boride/silicon volatilized. It was proved that there is volatilization of MgO from ludwigite in the process of carbothermal reduction.