微波碳热还原-磁选工艺自粗铌精矿中回收铁并富集铌

以粗铌精矿为研究对象进行了微波还原-弱磁选回收铁的试验研究。在700、750、800、850℃4种温度下进行还原,还原矿分别在0.6、0.8、1.0、1.2 A 4种电流下进行弱磁选试验,以考察磁选电流对选矿指标的影响。结果表明,在4种温度下,原矿中的赤铁矿均较好地被还原为磁铁矿。850℃时,部分磁铁矿进一步被还原成FeO。磁选电流增大,精矿产率和铁回收率随之升高,但品位有所下降。还原温度越高,品位下降越显著;尾矿Nb2O5回收率随磁选电流的增大而下降,而品位有所升高。还原温度越高,回收率下降越显著。综合考虑精矿和尾矿的选矿指标,750℃还原,1.2 A电流下进行磁选获得的指标为最佳,精矿铁回收率和品位分别为91.34%和54.66%;尾矿Nb2O5回收率和品位分别为70.63%和7.12%。

Iron Recovery and Niobium Enrichment from Rough Niobium Concentrate by Microwave Reduction-Magnetic Separation Process

A test was made on iron recovery from rough Nb concentrate by microwave reduction-weak magnetic separation process.The ore was reduced at 4 temperatures: 700,750,800 and 850 ℃.The reduced ore was tested by the way of weak magnetic separation at 4 different currents: 0.6,0.8,1.0 and 1.2 A to investigate the effect of magnetic current on the separation results.The results show that hematite in the crude ore can be well reduced to magnetite at these four temperatures.At the temperature of 850 ℃,part of magnetite can be further reduced to FeO.With the increase of magnetic current,the concentrate yield and iron recovery rise,while the grade decreases a little.The higher the temperature is,the more obviously the grade decreases.The recovery of tailing Nb2O5 decreases while the grade increases a little with the increase of magnetic current.The higher the temperature is,the more obviously the recovery decreases.Considering the dressing indexes of the concentrate and tailings,the best results of magnetic separation are those obtained at 1.2 A and 750 ℃.The concentrate recovery and grade are 91.34% and 54.66%,respectively.The recovery and grade of Nb2O5 are 70.63% and 7.12%,respectively.