三种石煤钒矿浸出行为的对比研究

Comparison for Vanadium Leaching Behaviors of Three Kinds of Carbonaceous Shale

以江西省修水县、江西省彭泽县和湖北省通山县的三种石煤钒矿为对象,研究了直接酸浸工艺和空白焙烧-酸浸工艺对三种石煤钒矿中钒浸出行为的影响。结果表明:在温度95℃、浸出时间4h、液固比1∶1、H2SO4体积分数15%和CaF2质量分数5%的浸出条件下,三种石煤钒矿在直接酸浸工艺中的钒浸出率分别为92.39%、74.10%和40.53%,而在空白焙烧-酸浸工艺中的钒浸出率则分别为85.53%、90.78%和41.59%。石煤钒矿中钒、铁的赋存形式以及方解石等耗酸物质的含量均对钒浸出率有很大影响。空白焙烧能使炭质钒转变为较易溶出的游离钒氧化物,并能破坏云母类含钒矿物而促进钒的浸出,但同时也可能使黄铁矿等非耗酸矿物转变成赤铁矿等耗酸矿物而阻碍钒的浸出。上述三种石煤中的钒均主要赋存于云母类铝硅酸盐矿物中,根据原矿的不同特性需采用不同的提钒工艺:江西修水石煤钒矿宜采用直接浸出工艺,江西彭泽石煤钒矿宜采用空白焙烧-酸浸工艺,湖北通山石煤钒矿需采用其他提钒工艺。

Study is made on the influences of direct acid leaching and black roasting-acid leaching on vanadium leaching behaviors of three kinds of carbonaceous shale from Xiushui or Pengzhe in Jiangxi province and Tongshan in Hubei province,respectively. The results show that under the conditions of leaching temperature 95 ℃ ,leaching time 4 h,mass ratio of liquid to solid 1 ： 1 ,volume fraction of H2SO4 15% ,mass fraction of CaF2 5 %,the vanadium leaching rates of three kinds of carbonaceous shale treated with direct acid leaching are 92. 39%, 74. 10%and 40. 53%, respectively, while the above leaching rates with black roasting-acid leaching are 85. 53%,90. 78% and 41.59%,respectively. It is found that both the existing forms of vanadium and iron in carbonaceous shale and the contents of acid-consumable minerals have great effects on vanadium leaching. By blank roasting, vanadium in organics can be transformed into free and soluble vanadium oxide, and mica-contained vanadium can be disintegrated to accelerate vanadium leaching. However,the acid-nonconsumable mineral of pyrite could be transformed into the acid-consumable mineral of hematite to hinder vanadium leaching. It is reasonable for the three kinds of carbonaceous shale in which vanadium exists mainly in the form of aluminosilicate including mica to adopt correspondingly different vanadium leaching processes. Direct acid leaching process is suitable for carbonaceous shale from Xiushui inJiangxi Province,blank roasting-acid leaching process is suitable for carbonaceous shale from Pengzhe in Jiangxi Province,and another vanadium extracting process should be adopted for carbonaceous shale from Tongshan in Hubei Province.