烧结用生石灰所含杂质对其消化性能的影响

Effects of impurities in lime used for iron ore sintering on its hydration characteristics

采用恒温量热法,针对实验室煅烧的各种生石灰试样,研究其所含SiO_2、Al_2O_3、MgO等杂质对消化性能的影响规律,并选用烧结现场使用的五种生石灰对研究结果进行验证.研究发现:生石灰的消化放热量与其CaO含量呈正相关关系,并随SiO_2、Al_2O_3和MgO含量的增加而下降;SiO_2、Al_2O_3和MgO杂质对生石灰消化速率有重要影响,当SiO_2质量分数增加至1%水平时,生石灰消化速率的降幅较大,之后则缓慢降低;少量的Al_2O_3对生石灰消化速率影响较小,但当Al_2O_3质量分数超过2%时生石灰消化速率急剧下降;随着MgO含量的增加,生石灰消化速率显著降低.

The effects of SiO2 , A12 03 and MgO on the hydration of lime were investigated by isothermal calorimetry, and the results were validated by 5 types of lime used in the sintering plant. It is found that the total hydrating heat of lime has positive relationship with CaO content, and decreases with increasing SiO2 , Al2O3 and MgO contents. The contents of SiO2 , Al2O3 and MgO also have important effect on the hydrating speed of lime. When the mass fraction of SiO2 increases to 1% , the hydrating speed of lime dramatically decreases, and then slowly drops with increasing SiO2 content. A small amount of Al2O3 has no significant effect on the hydrating speed of lime, but when the mass fraction of Al2O3 is more than 2% , the hydrating speed of lime sharply decreases. With the increase of MgO content, the hydrating speed of lime significantly decreases.