SiO2、Na2CO3对预还原烧结过程中气化脱磷的影响

Effect of SiO2 and Na2CO3 addition on gasification dephosphorization during pre-reduction and sintering of iron concentrate

白云鄂博铁精矿磷含量较高为0.08%(质量分数),且磷元素主要以氟磷灰石的形式存在。基于前期白云鄂博矿磷的赋存状态及白云鄂博矿预还原烧结工艺对脱磷影响的研究,同时为了开发利用其他中、高磷铁矿,研究了白云鄂博铁精矿预还原烧结过程中磷的气化脱除机制。利用FactSage热力学软件、XRD、SEM-EDS对比分析不同SiO2、Na2CO3添加量对预还原烧结过程中气化脱磷率、金属化率以及物相转变的影响。结果表明:最佳的SiO2、Na2CO3添加量(质量分数)分别为3%、1%,对应的脱磷率为31%,金属化率为96%,实现了预还原烧结过程中磷的有效脱除,进一步明确预还原烧结脱磷机制,为以后中、高磷铁矿脱磷的研究指明了方向。

The phosphorus content of Baiyunebo iron concentrate reaches 0.08 mass% and the phosphorus element mainly exists in the form of fluorapatite. To develop and utilize other medium and high-phosphorus iron ores, the mechanism of phosphorus removal by gasification during pre-reduction sintering of Baiyunebo iron concentrate was studied based on previous study on the occurrence of phosphorus in Baiyunebo iron ore and the influence of pre-reduction sintering process on dephosphorization. FactSage thermodynamic software, XRD and SEM-EDS were leveraged to compare and analyze the effects of different SiO2 and Na2CO3 additions on the dephosphorization rate, metallization rate and phase transformation during pre-reduction sintering process. The results show that the optimum addition of SiO2 and Na2CO3 is 3 mass% and 1 mass% respectively, and the corresponding dephosphorization rate is 31% and the metallization rate is 96%. The effective dephosphorization of phosphorus in a pre-reduction sintering process is achieved. The mechanism of dephosphorization in pre-reduction sintering is further clarified, which points out the direction for future research on dephosphorization of medium and high phosphorus iron ores.