钒渣制备99.9%五氧化二钒清洁生产研究

发布时间：2018-03-23 17:38

  本文选题：高纯五氧化二钒　切入点：结晶　出处：《中国科学院大学(中国科学院过程工程研究所)》2017年硕士论文

【摘要】：高纯五氧化二钒是制备钒及钒化合物的基础原料,具有优良的物理和化学性能而成为研究热点,但制备高纯五氧化二钒过程产生废水、废气和废渣污染环境。为此,本文针对钒渣制备99.9%五氧化二钒过程产生的除硅渣、除铬渣、结晶偏钒酸铵上层液和洗液中的有价元素进行回收和利用,并对反萃结晶偏钒酸铵工艺进行优化,主要研究内容及结果如下:(1)使用H2SO4浸出除硅废渣并过滤,滤液中加入回收高纯偏钒酸铵上层液中的氨氮制备硫酸铵溶液(300～400g/l,PH=1.5～2.8),在温度40℃,PH=2.6～2.8,NH4+:Al3+(摩尔比)=1.2:1,结晶硫酸铝铵。结晶母液中残留少量A13+和V5+返回含钒浸出液,并补加硫酸铝继续除硅(铝硅摩尔比0.8:1),再调pH=8.0～8.5去除残留的A13+,含钒浸出液中的硅和A13+可降低到20mg/L以下。(2)使用焦亚硫酸钠还原处理后含铬萃余液,焦亚硫酸钠加入理论质量1.15～1.2倍,再加入碳酸钠中和产生含铬渣和废水,废水Cr6+0.5mg/L,COD300mg/L,铬渣再经水洗钠离子含量可由6.5%降至2.4%。将铬渣与氢氧化铬按1:1混合,放于马弗炉在1300-1350℃下煅烧得到为氧化铬,在单位炉料反应热为2.98×103KJ,配铝系数为0.97冶炼金属铬(Cr≥98.5%),杂质满足JCr-99A要求。(3)通过多种树脂对比筛选出PH值使用范围广,溶液温度适应性强的D296树脂作为吸附材料,对反萃结晶偏钒酸铵上层液和偏钒酸铵洗液中的钒进行回收。D296树脂吸附服从Freundlioh等温吸附曲线,n=4.6树脂对钒的吸附容易进行,PH=3.5时吸附钒最高为278mg/g。D296树脂吸附钒为吸热反应△H=7.44KJ/mol,吸附反应符合Boyd液膜公式,吸附钒历程以液膜扩散为主。料液初始pH值10.5、室温、D296树脂/料液比为1g/100mL时吸附效果最佳,负载树脂使用3mol/LNaOH解析,钒脱除率均在95%以上,且树脂重复使用性能稳定。(4)氨水与伯胺富钒有机相以1:4比例混合,反萃和结晶偏钒酸铵共同进行,搅拌桨转速200r/min,温度40℃,添加偏钒酸铵为总量的0.8%作为晶种,反应2.5小时,得到的偏钒酸铵的粒径最大为59.15μm。
[Abstract]:High purity vanadium pentoxide is the basic raw material for the preparation of vanadium and vanadium compounds. It has become a research hotspot because of its excellent physical and chemical properties. However, the process of preparing high purity vanadium pentoxide produces waste water, waste gas and waste residue to pollute the environment. In this paper, desilication slag, chromium removal slag, crystal ammonium metavanadate upper liquid and washing solution produced by the preparation of 99.9% vanadium pentoxide from vanadium slag were recovered and utilized. The process of stripping crystalline ammonium metavanadate was optimized. The main contents and results of this study are as follows: (1) H2SO4 is used to leach and filter the silicon residue. Ammonium sulfate solution was prepared by adding ammonia nitrogen from the upper liquid of high purity ammonium metavanadate to produce ammonium sulfate solution of 400 g / L PH1. 5 and 2. 8% NH 4: Al 3 at 40 鈩，

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