钒云母氧化焙烧机理研究

Study on Oxidizing Roasting Mechanism of Roscoelite

通过TG-DSC、XRD、SEM分析以及化学浸出试验,研究了氧化焙烧过程中钒云母晶体结构和钒赋存状态的变化情况,以及这些变化对钒浸出效果的影响,探讨了钒云母的氧化焙烧机理。结果表明:1在升温过程中,钒云母依次失去层间吸附水、结晶水和羟基水。2钒云母晶体结构非常稳固,焙烧温度小于850℃时,钒云母仅发生晶体结构调整。焙烧温度低于600℃,主要发生V^(3+)的氧化反应;焙烧温度为600~850℃,V^(3+)和V^(4+)的氧化反应同时存在,但主要发生V^(4+)的氧化反应;焙烧温度大于850℃,羟基的脱除导致云母层间结合力减弱,矿物结构失去原有的稳定性,出现松散解体趋势,V^(3+)和V^(4+)的氧化反应均达到平衡;焙烧温度大于1 000℃,钒云母的晶体结构遭到破坏,原有的矿物形态逐渐消失,向非晶态玻璃相转化。

Research was carried out with the assistance of TG-DSC,XRD,SEM analysis and chemical leaching tests,in order to figure out the changes of crystal structure of roscoelite and occurrence of vanadium during oxidizing roasting process,also effect of which on vanadium leaching,and discuss oxidizing roasting mechanism of roscoelite. Results were as follows:1during temperature rising,the adsorbed water,crystal water and hydroxyl water existed in roscoelite were removed in turn. 2Roscoelite has steady structure,when roasting temperature was below 850 ℃,crystal structural adjustment happened,and V^(3+)existed in the lattice was oxidated to V^(4+)when was below 600 ℃; at the range of 600 to 850 ℃,oxidizing reaction of V^(3+)and V^(4+)occurred at the same time,while V^(4+)oxidated reaction was dominant; when above 850 ℃,removal of hydroxyl weakened the bonding force between interlayer,the steady crystal structure began loose gradually,tended to loose and disintegration,while the oxidizing reaction of V^(3+)and V^(4+)both reached an equilibrium; When above 1 000 ℃,crystal structure of roscoelite has been destroyed severely,original mineral was fade away and transformed to amorphous glass phase.