PVC废塑料与石煤混合焙烧—酸浸提钒试验

石煤提钒过程中,为提高钒浸出率,往往会在焙烧阶段添加添加剂,而PVC废塑料则是没有得到很好回收利用的大宗废弃物。针对这一状况,以PVC废塑料为添加剂,进行了石煤提钒工艺条件研究。结果表明:(1)在焙烧过程中加入与石煤质量比为10%的PVC废塑料,在升温速率为10℃/min,焙烧温度为800℃,焙烧时间为60 min,焙砂酸浸的硫酸体积浓度为15%,液固比为1.5 mL/g,浸出温度为95℃,浸出时间为4 h情况下,钒浸出率可达92.60%,与空白焙烧—酸浸工艺相比,钒浸出率提高了6.50个百分点。(2)石煤焙烧阶段加入10%的PVC废塑料后,石煤中各主要元素的浸出率有不同程度的提高,说明PVC的加入有助于破坏石煤的矿物结构,促进后续酸浸过程中钒的浸出,但并不给后续富集钒和沉钒工艺带来不利影响。因此,在石煤提钒焙烧过程中添加PVC废塑料,可改善钒的浸出效果,降低钒的浸出成本,实现PVC废塑料的综合利用,经济效益和环境效益显著。

Study on Vanadium Extraction from Stone Coal by Roasting with PVC Waste and Acid Leaching Technology

A large amount of additive is consumed to improve the leaching rate of vanadium in the process of extracting va-nadium from stone coal,while substantial Polyvinyl chloride(PVC) waste is not recycled well. In response to this situation,PVC wastes were adopted as stone coal roasting additive to study the process conditions of vanadium extraction from stone coal. The re-sults showed that:①Adding 10% PVC waste of stone coal quality in the roasting process,under the roasting conditions of heating rate 10 ℃/min,roasting temperature 800 ℃,roasting time for 60min and the leaching conditions of ratio of liquid to solid 1. 5 mL/g,concentration of sulfuric 15%,leaching temperature 95 ℃ for 4 h,the leaching rate of vanadium could reach 92. 60%, which is increased by 6. 50% percentage points compared with blank roasting and acid leaching process.②The leaching rate of major element in stone coal are significantly enhanced by adding 10%PVC in the stone coal roasting stage,which shows that the addition of PVC can effectively destroy the mineral structure and promote the leaching of vanadium during acid leaching while it does not have an adverse effect on subsequent enrichment of vanadium and vanadium precipitation. Therefore,adding PVC waste in the process of vanadium extraction from stone coal can improve the effect and reduce the cost of vanadium leaching and realize the comprehensive utilization of PVC waste with the economic performance and environment benefit remarkable improved.