机械活化攀枝花钛铁矿精矿中主要矿物的结构与性质变化规律研究

【作者】 韦亮平；

【导师】 胡慧萍；

【作者基本信息】 中南大学 ， 冶金物理化学， 2010， 硕士

【摘要】 本文综述了国内外钛铁矿精矿生产富钛料的研究现状和机械活化在强化矿物浸出方面的应用现状。针对我国攀枝花钛铁矿精矿的结构及矿物组成特点、及其机械活化研究现状,本工作系统探索了攀枝花钛铁矿精矿中的钛铁矿、钛辉石和斜长石等单矿物的机械活化效果与其结构变化之间的规律。采用QM-1 SP型行星式球磨机对攀枝花钛铁矿精矿中的钛铁矿、钛辉石和斜长石等单矿物进行机械活化,并采用XRD、粒度分析、SEM等分析手段对机械活化前后各单矿物进行表征,考察机械活化时间对各单矿物结构的影响。研究发现,随着机械活化时间的增加,钛铁矿的晶格畸变率逐渐增大,而晶粒尺寸和粒度不断下降；钛辉石的晶格畸变随着机械活化时间的延长不断增大,而其晶粒尺寸和粒度则都先减小后增大；而斜长石在机械活化过程中,其晶格畸变先增大后减小,而晶粒尺寸先减小后增大,粒度则不断变小。采用热重分析法(TGA)研究了机械活化前后钛铁矿、钛辉石和斜长石等单矿物的热重行为。在氧气气氛下的TGA分析发现,机械活化前后的钛铁矿在303～1273 K之间发生了氧化,导致其质量增加。随机械活化时间的延长,钛铁矿的起始增重温度不断降低,而最大增重率不断减小。这表明钛铁矿的晶格畸变是导致机械活化钛铁矿的起始增重温度提前、最大增重率减小的主要原因。在氮气气氛下的TGA分析发现,机械活化前后钛辉石和斜长石在303～1473 K间均发生热失重,且它们的最大失重率都是随机械活化时间的延长先增大后减小。这说明机械活化前后的钛钛辉石和斜长石的热重行为差异是由机械活化导致的晶格畸变和粒径变化共同引起的。系统研究了机械活化前后的钛铁矿、钛辉石和斜长石的盐酸浸出行为。结果表明,钛铁矿和钛辉石的浸出效果的提高主要与机械活化导致的晶格畸变增大有关,而机械活化前后斜长石的盐酸浸出行为差异是机械活化作用导致晶格畸变变化和粒度下降共同作用的结果。首次将钛铁矿与钛辉石,或与斜长石以一定比例混合,并对这些混合样品进行机械活化,研究了盐酸浸出过程中这些混合样品的浸出行为。结果表明,在盐酸浸出过程中,钛辉石或斜长石等杂质矿物的存在会对钛铁矿的盐酸浸出起抑制作用,而且此时机械活化对钛铁矿浸出的强化效果也会受到抑制,且杂质含量越高,抑制作用越明显；这是因为钛辉石或斜长石在浸出过程中生成的硅胶覆盖在未反应的钛铁矿的表面,从而阻止了钛铁矿内部钙、镁和铁等元素的浸出。更多还原

【Abstract】 In this paper, the researches on the manufactures of high-grade titanium-rich materials from ilmenite concentrates and on the effects of mechanical activation on the accelerating the dissolution rate of different minerals were reviewed. In the face of the structural and mineralogical properties of Panzhihua ilmenite concentrate of China and the disadvantage of its mechanical activation researches, this work focused on the effects of structural changes of ilmenite, plagioclase and titanaugite single minerals in the Panzhihua ilmenite concentrate on the reactivities resulted by mechanical activation.The structural changes of unactivated and mechanically activated ilmenite, titanaugite and plagioclase were investigated using XRD, particle size analysis, and SEM, etc. The results show that with the increase of mechanically activation time, the lattice strain of ilmenite increased gradually, and its crystallite size and particle size decreased constantly; and the lattice strain of titanaugite increased gradually, its crystallite size and particle size first decreased then increased; while the lattice strain of plagioclase first increased then decreased, its crystallite size first decreased then increased, and the particle size reduced regularly.The thermal behaviours of unactivated and mechanically activated ilmenite, titanaugite and plagioclase were studied by thermogravimetry method (TGA). Unactivated and mechanically activated ilmenite underwent thermal oxidation, resulting to a mass increase, from 303 to 1273 K under oxygen atmosphere. With the increase of mechanically activation time, the initial oxidation temperature of ilmenite decreased gradually, and the maximum mass gain ratio in the TGA curve reduced regularly. The results indicate that these phenomena mostly are attributed to the increase of the lattice strain of ilmenite. Unactivated and mechanically activated titanaugite and plagioclase underwent mass losses from 303 to 1473 K under nitrogen atmosphere. And the maximum mass loss ratio of titanaugite and plagioclase both first increase and then decrease which imply that the differences of thermal behaviors between the mechanically activated and unactivated titanaugites or plagioclases were the mutual effects of the change of lattice disorder and the decrease of particle size during the mechanical activation.Effects of mechanical activation on the hydrochloric acid leaching behaviors of ilmenite, titanaugite and plagioclase were investigated. The results show that mechanical activation improved the leaching reactivity of these three minerals. The results indicate that the accelerating leaching capability of ilmenite and titanaugite mostly ascribe to the lattice disorder of the minerals after mechanical activation, while the leaching differences between unactivated and mechanically activated plagioclases are attributed to both the change of lattice disorder and the decrease of particle size.Hydrochloric acid leaching behavior of unactivated and 4 h mechanically activated of mixture samples of ilmenite and titanaugite/ plagioclases were studied. The results show that the leaching of ilmenite was inhibited when titanaugite/plagioclase was present in the sample due to silica gel produced from the titanaugite/plagioclase covering the surface of unleached ilmenite, then impeding the iron, magnesium and calcium of ilmenite being leached.更多还原