粗铌精矿氢氧化钾介质水热溶出试验研究

Experimental study on the extraction of niobium from crude niobium ore by KOH hydrothermal

本文针对粗铌精矿难以利用的难题,通过对粗铌精矿成分及物相的分析,采用氢氧化钾(KOH)介质水热法进行粗铌精矿溶出试验研究,探索了KOH浓度和温度对粗铌精矿溶出的影响。结果表明:在KOH浓度为30%、温度为200℃时,铌的溶出率达到90%;随着KOH浓度和温度的升高,铌的溶出率呈现先增加后降低的趋势;在整个溶出过程中,碱性组分铁(Fe)、锰(Mg)、镁(Mn)的溶出率较低。XRD和SEM等检测结果表明:KOH浓度和温度的增加促进(Fe,Mn)(Nb,Ta)_2O_6的分解,当KOH浓度超过30%、温度超过200℃时,进一步增加温度或碱浓度,(Fe,Mn)(Nb,Ta)_2O_6分解生成的可溶性六铌酸钾(K_8Nb_6O_(19))发生向不溶性偏铌酸钾(KNb O_3)的转化,铌的溶出率显著降低。

Because the crude niobium ore is difficult to be used,according to the composition analysis and phase analysis of crude niobium ore,the KOH hydrothermal method was used to research the dissolution of crude niobium ore and the dissolution of crude niobium under hydrothermal system was researched by changing the temperature and the KOH concentration. The results show that the dissolution of niobium from crude niobium ore could reach 90%,at 30% of KOH concentration,and 200 ℃; the dissolution of niobium increased first and then decreased with the increasings of KOH concentration and temperature; in the whole process of the dissolution,the alkaline components Fe,Mn,Mg kept a low dissolution yields. XRD and SEM's results show that the increasings of KOH concentration and temperature accelerated the decomposition of( Fe,Mn)( Nb,Ta)_2O_6. When the KOH concentration was 30 %,and the temperature was 200 ℃,continuing to strengthen the reaction conditions,the dissolution of Nb decreased significantly owing to the transformation from soluble K_8Nb_6O_(19) to insoluble KNb O_3.