球团矿中MgO含量对炉料熔滴性能的影响

球团矿带入适宜的MgO可以提高炉渣的冶金性能,有利于高炉冶炼。为了探究球团矿MgO含量对高炉炉料性能的影响,在全球团冶炼的条件下,以高炉终渣成分为依据进行配料,利用高温熔滴炉检测球团矿不同w(MgO)时高炉初渣性质、炉料软熔滴落性能的变化情况。试验结果表明,随球团矿w(MgO)升高,初渣中未矿化的MgO明显增多,软化结束温度升高,软化温度区间变宽,炉料软化性能变差。当球团矿w(MgO)大于1.01%后初渣熔点升高,导致熔化特征温度升高,熔化带位置向高温区移动,熔化温度区间变窄,熔化带透气性提高;炉料的软熔带温度区间由229 ℃升高至269 ℃,软熔带增厚,炉料整体透气性变差。由于初渣中w((MgO))随之增加,初渣黏度升高,炉料最大压差和熔滴性能特征值增大。因此,在试验范围内,随球团矿w(MgO)升高,高炉炉料的软熔滴落性能恶化,渣铁分离变差,不利于高炉顺行。

Effect of MgO content in pellets on softening-dripping properties of burden in BF

The appropriate MgO content in pellets can improve the metallurgical properties of slag, which is beneficial to the smelting of blast furnace. In order to explore the influence of MgO content in pellet on the performance of burden, based on the composition of final slag in on-site blast furnace (BF), the effects of different MgO contents in pellets on the initial slag and softening dripping properties of burden in BF under the condition of whole pellet smelting were studied by the high-temperature droplet furnace. It is shown that with increase of w(MgO), amount of unmineralized MgO in primary slag increases obviously, the softening finishing temperature increases, and the softening temperature zone widens, as a result, the softening performance of burden becomes worse. The melting point of initial slag increases obviously when the w(MgO) is more than 1.01%, which results in the increasing of melting characteristic temperature, therefore, the position of melting zone moves to the high temperature zone, the melting temperature zone narrows, and the permeability of melting zone is improved. With higher MgO content in the pellets, the cohesive zone temperature increases from 229 ℃ to 269 ℃, the cohesive zone thickens, as a result the permeability of burden becomes poor. Due to the increasing of w(MgO) in the primary slag with the increase of w(MgO) in the pellet, the viscosity of initial slag increases, as a result, the maximum pressure difference of burden and the characteristic values of droplet properties increase as well. Therefore, within the test conditions, with increase of w(MgO) in the pellets, the softening-dripping performance of burden in BF becomes bad and the slag-iron separation deteriorates, which is not conducive to the operation of BF.