低品位钒矿硫酸化焙烧—浸出提钒工艺试验研究

为实现某低品位钒矿中钒的有效提取,采用低温硫酸化焙烧预处理技术,强化含钒矿物伊利石在焙烧过程中晶体结构破坏和物相转变,为焙砂水浸提取钒创造有利条件。重点考察了焙烧温度、焙烧时间、原矿粒度、硫酸用量等因素对钒浸出率的影响及焙烧过程中的物相演变规律。 结果表明:在焙烧温度为 250 ℃ 、焙烧时间为 2 h,原矿 粒度为-0. 096 mm、硫酸用量为 40%的最佳焙烧条件下,钒浸出率可达 83. 64%。 原矿、焙砂及浸出渣的 XRD 分析结果表明:在硫酸和升温的协同作用下,原矿中铝硅酸盐矿物晶格被有效破坏,伊利石与硫酸反应生成了重钾矾和易于浸出的水钒钠矿,脉石矿物方解石则反应生成石膏,为水浸提取钒创造了有利条件。焙烧过程的热力学计算进一步验证了低温硫酸化焙烧—水浸提钒工艺的可行性。

Expermental Research on Sulphated Roasting and Leaching Process for Vanadium Extraction from a Low-grade Vanadium Ore

In order to achieve the effective extraction for the vanadium from a low-grade vanadium ore,low-temperature sulphated roasting pretreatment technology was adopted for strengthening crystal structure destroying and phase transformation of vanadium-bearing mineral illite during roasting process,which created favorable conditions for the extraction of vanadium from calcine during water leaching. The influence of roasting temperature,roasting time,particle size of raw ore and sulfuric acid dosage on vanadium leaching rate and phase evolution during roasting were investigated. The results showed that the vanadium leaching rate could reach 83. 64% under the optimal roasting conditions of the roasting temperature of 250 ℃ for 2 h, -0. 096 mm of raw ore and 40% sulfuric acid dosage. XRD analysis of the raw ore,roasted products and leached slag showed that under the synergistic effect of sulfuric acid and temperature rising,the aluminosilicate mineral lattice in the raw ore is effectively destroyed,the illite reacts with sulfuric acid to form misenite and easily leached munirite,and the gangue mineral calcite is transformed into gypsum in the roasting process,which creates favorable conditions for the extraction of vanadium by water leaching. The thermodynamic calculation of roasting process further verified the feasibility of low temperature sulfated roasting and water leaching process for vanadium extraction.