硫酸酸浸铌钽矿的浸出机理研究

Study on Leaching Mechanism of Columbite by Sulfuric Acid

目前国内外普遍采用HF-H2SO4混合酸体系分解法从矿中提取铌和钽。为提高铌、钽浸出率以及减少含氟渣的排放,针对我国铌钽矿的赋存特性,以富含锡石的铌钽铁锰矿为原料,通过XRD和SEM观察酸浸前、后的铌钽铁锰矿的矿相结构及形貌,并用EDS对微区元素含量进行分析,获得矿物在酸浸前后表面宏观结构的变化以及表面元素含量的变化。利用XPS分析酸浸前后铌钽矿物表面各元素化学价态及其化学键合状态的变化,以及各元素组分含量的变化,并结合ICP检测结果,研究不同酸浸条件下的铌钽矿表面结构变化以及结构变化导致的溶解机制。结果表明,锡石与硫酸不发生反应,留在尾渣中。矿物中的Nb比Ta更容易溶解。

At present,HF-H2SO4 mixed acid system is widely used to extract niobium and tantalum from ores in order to improve leaching rate of niobium and tantalum and reduce discharge of fluoride slag.Based on columbite ore occurrence characteristics of China and applying columbite ore rich in cassiterite as raw material,phase,structure and morphology of columbite were detected through XRD and SEM observation before and after acid leaching.EDS analysis were used to analyze micro zone elements for minerals and change of surface macrostructure and surface element content before and after acid leaching.XPS was used to analyze changes of chemical valence and bond state of each element on surface of columbite before and after acid leaching,as well as changes of component content of each element.Combined with ICP results,surface structure changes of columbite under different acid leaching conditions and dissolution mechanism caused by structural changes were studied.The results show that cassiterite does not react with sulfuric acid and remains in tailings.Niobium is more soluble in minerals than tantalum.