Mechanism of phosphorus removal in beneficiation of high phosphorous oolitic hematite by direct reduction roasting with dephosphorization agent  

高磷鲕状赤铁矿添加脱磷剂还原焙烧脱磷机理(英文)

作　　者：徐承焱[1] 孙体昌[1] 寇珏[1] 李永利[1] 莫晓兰[1] 唐利刚[1] 

机构地区：[1]北京科技大学金属矿山高效开采与安全教育部重点实验室,北京100083

出　　处：《Transactions of Nonferrous Metals Society of China》2012年第11期2806-2812,共7页中国有色金属学报（英文版）

基　　金：Project (51074016) support by the National Natural Science Foundation of China

摘　　要：High phosphorous oolitic hematite ore is one of typical intractable iron ores in China, and the conventional beneficiation methods are found to be impracticable to , remove phosphorus from the ore effectively. Better beneficiation index were gotten by direct reduction roasting with dephosphorization agent followed by two stages of grinding and magnetic separation. P content decreases from 0.82% in the raw ore to 0.06% in the magnetic concentrate, and the total iron grade increases from 43.65% to 90.23%, the recovery of iron can reach 87%. Mechanisms of phosphorus removal in the beneficiation of high phosphorous oolitic hematite ore by direct reduction roasting with dephosphorization agent were studied using XRD, SEM and EPMA. The results showed that about 20% of the apatite in the raw ore transferred into phosphorus and volatilized with the gas in the process of reduction roasting, while the rest 80% apatite was not involved in the reaction of generation of phosphorus, and remained as apatite in the roasted products, which was removed to tailings by grinding and magnetic separation. A small amount of phosphorus existed in the magnetic concentrate as apatite. The oolitic texture of raw ore was partly changed during roasting, resulting in the formation of nepheline in the reaction between the dephosphorization agent, SiO2 and Al2O3 in the raw ore, which greatly improved the liberation degree of minerals in the roasted products, and it was beneficial to the subsequent grinding and magnetic separation.高磷鲕状赤铁矿是一种典型的难处理铁矿石,采用常规的选矿方法难以得到较好的提铁降磷指标。采用添加脱磷剂还原焙烧,然后对焙烧产物进行两段磨矿磁选来处理此类矿石,获得了较好的选别指标。实验结果表明,铁的品位从43.65%(原矿)提高到90.23%(磁选精矿),磷含量从0.82%(原矿)降低到0.06%(磁选精矿),铁的回收率达到87%。采用XRD、SEM、EPMA等分析方法对焙烧产物进行脱磷机理研究。结果表明,在还原焙烧过程中,原矿中有20%的磷灰石生成单质磷随气体挥发,80%的磷灰石没有参与生成单质磷的反应,仍以磷灰石的物相存在于焙烧产物中,而通过磨矿磁选被脱除到尾矿中。磁选精矿中少量的磷以磷灰石的形态存在。在焙烧过程中,加入的脱磷剂与原矿中的脉石矿物(SiO2、Al2O3)反应生成铝硅酸钠,此反应部分破坏原矿的鲕状结构,充分改善焙烧产物中矿物的单体解离程度,有利于后续的磨矿磁选。

关 键 词：high phosphorous oolitic hematite direct reduction roasting phosphorus removal -dephosphorization agent GRINDING magnetic separation 

分 类 号：TD951[矿业工程—选矿]