燃煤电厂废弃SCR催化剂中回收有价金属的研究

发布时间：2018-03-16 12:06

  本文选题：废弃SCR催化剂　切入点：碱浸法　出处：《华北电力大学》2016年硕士论文　论文类型：学位论文

【摘要】：废弃SCR催化剂中含有V、W和Ti等多种有价金属,直接废弃不仅会造成环境污染,且造成资源的浪费,因此回收其中的有价金属具有重大意义。论文首先采用湿法冶金的方法,通过Na OH碱性浸出法浸出废弃催化剂中的V和W,然后对浸出液进行钙化沉淀,通过甲酸选择性浸出混合沉淀物中的钒,经过除杂和加入氨水,钒将以偏钒酸铵的形式沉淀出来;甲酸浸出后沉淀物中的钨,加入盐酸转化为钨酸,经过灼烧,最终生成三氧化钨。通过实验确定了Na OH碱性浸出法最佳工艺条件和甲酸选择性浸出最佳反应条件。结果表明:最佳条件为NaOH浓度为25%,固液比1:7,催化剂粒径125~180μm,温度60℃,浸出时间60min。随后采用钠化焙烧工艺从浸取后的滤渣中回收二氧化钛。研究了碳酸钠投加量、硫酸投加量、浸出热水量、浸出时间、浸出温度、焙烧时间、焙烧温度对二氧化钛回收率的影响。最佳条件:焙烧温度700℃,Na2CO3与原料比为3.8,焙烧时间3.5h,80℃去离子水80mL,充分搅拌后静置2h,5%的稀硫酸125mL。本文创新性的对废弃SCR催化剂中的主要金属元素Ti、V和W都提供了较好的回收途径和较高的回收率,分别达到了92.15%、85.21%和75.42%。工艺过程更为清洁环保,对目前较为流行废催化剂处理方法进行了总结和创新,最大程度的减少二次污染和二次排放。碱性浸取过程中的滤液和滤渣分别用来回来V、W和Ti,同时在工艺过程中所产生的碱液以及酸液均可以进行二次回收和处理。进行了经济可行性分析,具有一定的经济效益,为废弃催化剂的回收处理及其工业化应用提供理论支持和工艺参考。
[Abstract]:There are many valuable metals in the waste SCR catalyst, such as VN W and Ti, which not only cause environmental pollution and waste of resources, but also cause waste of resources. Therefore, it is of great significance to recover the valuable metal from the catalyst. Firstly, hydrometallurgical method is adopted in this paper. The V and W in the waste catalyst were leached by NaOH alkaline leaching method, then the leaching solution was calcified and precipitated. The vanadium in the mixed precipitate was selectively leached by formic acid. After removing impurities and adding ammonia water, the vanadium would be precipitated in the form of ammonium metavanadate. After leaching with formic acid, the tungsten in the precipitate is converted into tungstic acid by adding hydrochloric acid. Finally, tungsten trioxide was formed. The optimum technological conditions of alkaline leaching of NaOH and selective leaching of formic acid were determined by experiments. The results showed that the optimum conditions were as follows: the concentration of NaOH was 25%, the ratio of solid to liquid was 1: 7, the particle size of catalyst was 125 ~ 180 渭 m, and the temperature was 60 鈩，

本文编号：1619836