基于硫酸铵+硫酸混合助剂的石煤焙烧─酸浸提钒

为了了解含钒石煤焙烧过程助剂硫酸铵+浓硫酸对焙烧—酸浸提钒效果的影响,以四川广元某V2O5含量为0.82%的含钒石煤试样为研究对象(33.03%的钒赋存在有机质中,59.45%的钒赋存在硅酸盐矿物中),在混合助剂硫酸铵与浓硫酸的物质的量之比为1∶1的情况下,考察了焙烧温度、混合助剂添加量、试样的粒度和浸出温度对钒提取率的影响。结果表明,在添加硫酸铵+浓硫酸助剂的情况下,250℃焙烧导致试样中的云母相消失,伴随着硫酸铁铵、硬石膏新相的生成;焙烧温度上升到400℃,硫酸铁铵的衍射峰强度达到最强;继续提高焙烧温度至500℃,硫酸铁铵的衍射峰强度减弱;在320℃的焙烧熟料中有新相硫酸铝铵生成,至350℃处于增强阶段,至400℃硫酸铝铵相又全部消失。细度为-120目的试样按SO2-4与Al2O3+Fe2O3的物质的量之比3.5添加硫酸铵+浓硫酸,350℃下的焙烧熟料在90℃下进行硫酸酸浸,钒浸出率可达95.67%。

Extraction of Vanadium from Stone Coal by Roasting Acid Leaching based on Ammonium Sulfate and Sulfuric Acid as Additives

In order to understand the influence of ammonium sulfate and concentrated sulfuric acid additives on extraction of vanadium in the process of roasting-acid leaching of vanadium-containing stone coal,taking the vanadium-containing stone coal from Guangyuan,Sichuan as the research object (33.03% of vanadium occurs in organic matter,and 59.45% of vanadium occurs in silicate minerals),the influences of roasting temperature,the dosage of mixed auxiliary additives,particle size of the sample and leaching temperature on the leaching rate of vanadium were investigated under the mole ratio of mixed auxiliary ammonium sulfate and concentrated sulfuric acid 1∶1.The results showed that under the conditions of the ammonium sulfate + concentrated sulfuric acid as additives,mica phase disappeared at roasting temperature 250 ℃with new phases NH₄Fe(SO₄)₂ and CaSO₄ generated.With the roasting temperature gradually raising to 500 ℃,the diffraction peak intensity of NH₄Fe (SO₄) is weakened.A new phase NH₄Al(SO₄)₂ among roasting clinker was generated at 320 ℃,raised at 350 ℃ and totally disappeared at 400 ℃；For the samples with fineness of -120 mesh,adding ammonium sulfate + concentrated sulfuric acid with the mole ratio of SO^2-₄ and Al₂O₃+Fe₂O₃ 3.5,the roasting clinker with temperature of 350 ℃ was treated by sulfuric acid leaching at 90 ℃,and then the leaching rate of vanadium reached 95.67%.