空白焙烧石煤物相及钒形态变化对细菌浸钒的影响

Effects of the Change of Mineral Phase and Vanadium Speciation on Bioleaching Vanadium from Stone Coal

以湖北郧西某石煤为原料,研究了石煤空白焙烧对石煤物相、钒形态及微生物浸出过程的影响,并采用XRF、XRD和FTIR等检测手段对石煤原矿及焙烧熟料进行了表征。结果表明:(1)石煤试样在900℃空白焙烧预处理2 h,在细菌作用下,钒浸出率达到92.62%,浸出体系中Si的最大浸出量为53.93 mg/L,浸出结束后,体系中Al的最大浸出量小于10 mg/L,Fe的最大浸出量小于2 mg/L。(2)石煤中88.62%的钒存在于残渣态中,900℃空白焙烧熟料中,存在于残渣态中的钒仅占9.28%,可交换态中的钒增至85.52%。(3)空白焙烧使钒云母的层间水分子发生了变化,羟基脱除,铝氧四面体的结构失稳,基本构成单元发生畸变和垮塌,晶格中钒与周围元素的化学键能降低,削弱了对钒的束缚,为细菌浸出钒创造了条件。

The stone coal from Yunxi, Hubei was selected as raw materials. The influence of additive-free roasting tech- nique on the mineral phase, vanadium speciation and bioleaching vanadium process was investigated. The detection methods of X-ray fluorescence （XRF） ,X-Ray Diffraction （XRD） and Fourier Transform Infrared Spectroscopy （FTIR） were used to analyze the ore stone coal and the roasted residue. The results showed that （1）the vanadium leaching rate could reach 92.62% and the highest concentration of Si was 53.93 mg/L, when the sample was roasted at 900 ℃ for 2 h. After leaching, the maximum of Al and Fe in the system was less than 10 mg/L and 2 mg/L,respectively. （2）The V was chiefly present in the residual fraction in the stone coal,which account for 88.62%. The content of V increased to 85.52% in the extractable fraction and it is only 9.28% in the residual fraction after additive-free roasting in 900 ℃. （3）the additive-free roasting caused the changes of the hydrogen bonding of interlayer water in muscovite and the disappearance of OH ; the unstable of structure of alumina tetrahedron; the distorted and collapsed of basic composition unit; the reduced of chemical bond energies of the vanadium and around elements,which weaken the bond of vanadium. It provided favorable conditions for bioleaching process.