熔剂特性对碱性球团性能影响的研究

Research on Influence of Flux Characteristics on Properties of Alkaline Pellets

通过添加白云石、石灰石、生石灰、消石灰和镁橄榄石熔剂进行造球试验,探究熔剂特性对碱性球团性能的影响。对比不同熔剂种类对球团的影响发现,生石灰本身的二元碱度值高,具有最佳的调碱度能力,对生球落下强度提升最明显,而配加石灰石对生球抗压强度提升较大,对生球爆裂温度影响较小,从生球指标综合来看,选择石灰石作熔剂更佳。固定石灰石用量为4%,探究熔剂粒度对球团性能的影响,发现当石灰石中-0.074 mm粒级占比由31.37%提高至94.25%时,生球落下强度平均提高了50%,生球抗压强度平均提高了22.5%,成品球抗压强度先明显提高后微弱下降。对照不同产地的石灰石,考查其化学组成对球团强度的影响,发现CaO/SiO_(2)的比值对成品球抗压强度影响较大,石灰石用量固定的条件下,CaO/SiO_(2)的比值较高时SiO_(2)含量偏低,产生的硅酸钙液相较少,不利于高温固结,成品球强度较低;比值较低时SiO_(2)含量偏高,表面低熔点物质增多,会阻碍固结反应的持续,降低成品球强度。

In this paper,dolomite,limestone,quicklime,slaked lime and forsterite are added to carry out pelletizing experiments to explore the influence of flux characteristics on the properties of alkaline pellets.By comparing the effects of different flux types on pellets,it is found that quicklime has high binary alkalinity value and the best ability to adjust alkalinity,which significantly improves the drop strength of the pellets.While the compressive strength of green pellets is improved greatly by adding limestone,and the impact on the bursting temperature of green pellets is small.From the comprehensive index of green pellets,limestone is better as the flux.The influence of flux particle size on pellet properties is studied with a fixed limestone dosage of 4%.It is found that when the proportion of-0.074mm particle size in limestone increases from 31.37% to 94.25%,the drop strength of green pellets increases by 50% on average,and the compressive strength of green pellets increases by 22.5% on average,and the compressive strength of finished pellets increases obviously at first and then decreases slightly.Compared with limestone from different producing areas,the influence of chemical composition on pellet strength is investigated.It is found that the ratio of CaO to SiO_(2) had a great influence on the compressive strength of finished pellets.Under the condition of fixed limestone dosage,when the ratio of CaO/SiO_(2) is high,the SiO_(2) content is low,the liquid of calcium silicate produced is less,which is not conducive to high-temperature conglomeration,and the strength of the finished pellets is low;When the ratio of CaO/SiO_(2) is low,the SiO_(2) content is high,and there is an increase in low melting point substances on the surface,which will hinder the continuous conglomeration reaction and reduce the strength of the finished pellets.