磁化焙烧-磁选含铁氟碳铈粗精矿研究

Study on Magnetization Roasting-Magnetic Separation Process for Iron Containing Bastnaesite Crude Concentrates

某氟碳铈型稀土粗精矿中铁含量较高(全铁3%~10%)、稀土氧化物(REO)含量偏低,约占50%~60%,水分为6.5%;经工艺矿物学分析表明,粗精矿中铁元素主要以弱磁性的赤(褐)铁矿的形式存在,且部分铁矿物与氟碳铈矿解离不彻底,难以直接采用磁选方法与氟碳铈矿分离,因此采用磁化焙烧-磁选工艺提高REO品位。磁化焙烧热力学分析表明,在磁化焙烧过程中,氟碳铈矿发生分解反应,不会与铁氧化物发生反应;当温度高于626.85℃时,水会与碳发生水煤气反应产生CO和H_(2),即水分的存在有利于铁氧化物的还原。含水的稀土粗精矿在还原温度为650℃、还原时间为30 min和还原剂用量为2%的条件下,磁化焙烧的还原度为41.59%;经过一次粗选、再磨再选的工艺,精矿REO品位和回收率分别为68.53%、96.59%,铁粉的铁品位和回收率分别为68.56%、80.38%。该工艺的应用既提高了精矿REO和铁精矿品位,又省去了干燥作业。

The bastnaesite rare earth crude concentrates contains 3%~10%iron,50%~60%REO,and 6.5%moisture.Mineralogy analysis indicated that iron element was mainly occurred in the form of low magnetic hematite or limonite,a part of hematite and bastnaesite were not liberated completely,so it’s difficult to separate iron from bastnaesite by magnetic selection method.Method of magnetization roasting-magnetic separation was adopted to improve REO grade.Thermodynamics analysis of the magnetization roasting indicated that bastnaesite was decomposed during the roasting process,and didn’t react with the iron oxides.When temperature was higher than 626.85℃,water would react with carbon to produce CO and H_(2),which means the presence of water could promote the reduction of iron oxide.When the wet raw rare earth coarse concentrate was roasted at 650℃for 30min,and the reductant dosage was 2%,the reduction degree was 41.59%.The roasted ore was treated by the process of magnetic separation-milling-magnetic separation.The REO grade and recovery of iron power were 68.53%and 96.59%respectively.The grade and recovery rate of iron concentrate were 68.56%and 80.83%,respectively.The process not only improved REO grade and obtained iron concentrates,but also omitted drying process.