两段焙烧强化含铼低品位钼精矿的氧化分离

来源期刊:中南大学学报(自然科学版)2019年第8期

论文作者:范晓慧 邓琼 甘敏 CHEN Xu-ling(陈许玲)

文章页码:1778 - 1787

关键词:低品位;含铼钼精矿;两段焙烧;气流;挥发率;可溶钼

Key words:low-grade; molybdenum with rhenium-bearing; two stage oxidation roasting; airflow; volatilization rate; soluble molybdenum

摘    要:针对氧化焙烧法处理低品位钼精矿中存在的钼氧化不完全、铼难挥发分离、有价元素(钼和铼)回收率较低等问题,采用焙烧试验、热重、物相和显微结构分析等研究两段焙烧强化氧化含铼低品位钼精矿中钼、铼的工艺及原理。研究结果表明:两段焙烧是实现钼、铼充分氧化的有效处理工艺。该工艺通过调节两段的温度和气流方向,改善气固对流条件,减小氧化焙烧过程的氧化差异,促进含钼和含铼矿物的深度氧化。在最佳工艺条件下(Ⅰ段焙烧温度675 ℃,焙烧时间1 h,气流由下至上;Ⅱ段焙烧温度625 ℃,焙烧时间2 h,气流由上至下),最终焙烧过程铼挥发率可达77.21%,焙烧产物中可溶钼质量分数提高到83.98 %。相较于一段焙烧,两段焙烧各层产物的物相组成及微观结构一致,不存在未氧化的辉钼矿(MoS2)和氧化不完全的低价钼氧化物(MoO2),钼主要以MoO3形式存在。

Abstract: There were some problems in the oxidation roasting process of low-grade molybdenum with rhenium-bearing, such as incomplete oxidation of molybdenum, difficult volatilization and separation of rhenium and low recovery of valuable elements (molybdenum and rhenium). Aiming at these problems, the process and principles of two-stage roasting and strengthening the oxidation of low-grade molybdenum with rhenium-bearing were investigated through roasting experiments, thermogravimetry, phase and microstructure analysis. The results show that the two-stage roasting is an effective method for the sufficient oxidation of molybdenum and rhenium. The process improves the gas-solid convection conditions, reduces the oxidation difference during roasting, and promotes the deep oxidation of molybdenum and rhenium-bearing minerals by adjusting the temperature and air flow direction of the two stages. Under the optimum technological conditions (the roasting temperature is 675 oC, the roasting time is 1 h and the air flow is from the bottom to the top in the first stage; the roasting temperature is 625 oC; the roasting time is 2 h, and the air flow is from the top to the bottom in the second stage), the volatilization rate of rhenium can reach 77.21% and the soluble molybdenum mass fraction can be improved to 83.98%. Compared with one stage roasting, the phase composition and microstructures of the products in each layer of the two stages roasting are identical. There is no unoxidized molybdenite (MoS2) and incompletely oxidized low-valent molybdenum oxide (MoO2) in the calcine. Molybdenum mainly exists in the form of MoO3.

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