摘要
对白云鄂博铌精矿氢还原前后铌、稀土、钛等关键元素的赋存状态进行了表征,研究了氢还原条件对铁金属化率的影响.结果表明,氢气流量 300 mL/min、还原时间 90 min条件下,还原温度 800℃、850℃、900℃、950℃、1000℃、1050℃时的金属化率分别为 89.22%、85.79%、82.50%、80.52%、72.15%、70.64%.氢还原过程中,大部分铁矿物会被还原成金属铁,但随着还原温度升高,受矿粉黏结影响,铁矿物还原率降低;主要含铌矿相铌铁矿易被还原,易解石和铌铁金红石难被还原;主要含稀土矿相氟碳铈矿未发生变化,独居石在 1050℃下可发生热分解反应;主要含钛物相钛铁矿、铌铁金红石和易解石难被还原.
Abstract
The occurrence state of key elements of niobium,rare earths,and titanium in Bayan Obo niobium concentrate samples was characterized before and after hydrogen reduction,and effect of hydrogen reduction condition on iron metallization rate was also explored.After 90 min reduction with flow rate of hydrogen at 300 mL/min,and reduction temperatures of 800℃,850℃,900℃,950℃,1000℃,and 1050℃respectively,the corresponding metallization rates are 89.22%,85.79%,82.50%,80.52%,72.15%,and 70.64%.It is found that during hydrogen reduction process,most of iron minerals can be reduced to metallic iron,but with temperature rise,the reduction rate of iron minerals decreases due to effect of mineral powder bonding.Niobite,as the main niobium-containing phase,is easily reduced,while aeschynite and niobium-iron rutile are difficult to be reduced;bastnasite,the main rare earth-containing phase,doesn't change,while monazite can undergo thermal decomposition at 1 050℃;ilmenite,niobium-iron rutile and aeschynite,as the main titanium-containing phases,are difficult to be reduced.
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