硼铁精矿钠盐焙烧及冷却方式对硼活性的影响

以硼铁精矿团块为原料进行煤基直接还原试验,考察了钠盐添加剂及不同冷却方式对还原焙烧矿中硼活性的影响。结果表明,Na₂CO₃的添加使硼主要以玻璃体形式存在于还原焙烧矿中,硼活性显著降低,且不利于铁矿物的还原;另外,Na₂CO₃与硼镁石的热解产物遂安石反应形成低熔点硼酸钠盐,造成硼的挥发损失。硼铁精矿无钠盐还原焙烧时,无液相形成。以水淬方式冷却硼活性最高,为80.76%。

Effects of Roasting with Sodium Salt and Cooling Methods on Boron Reactivity of Boron-Bearing Iron Concentrate

An experiment on coal-based direct reduction of boron-bearing iron concentrate was carried out under laboratory conditions, and effects of additive sodium salt and different cooling methods on the boron reactivity of roasted ore were investigated. Results showed that after adding Na₂CO₃, boron mainly existed in the reduction roasting product with the form of vitreous body with reactivity significantly reduced, which was not conductive to the reduction of iron minerals. Meanwhile, Na₂CO₃ reacted with suanite, the thermal decomposition product of ascharite, to form low melting point sodium borate salts, resulting in a loss of boron by means of volatilization. It is found that there was no liquid phase generated during the reduction roasting of boron-bearing iron concentrate without sodium carbonate. The roasted ore cooled by water quenching led to the highest boron reactivity of 80.76%.