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以冶炼厂废锌灰为原料,经硫酸浸取,考察了不同工艺条件对锌的浸出率的影响。实验结果表明:锌灰在50℃下浸取,pH值为1.5时,可使锌灰中锌的溶出率达93.5%。碱式碳酸锌最佳水解温度为40℃,水解时间为2 h,pH值为7.5时,溶液中锌含量为12 g/L,得到96%以上的水解率。 相似文献
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以炼锌厂废锌灰为原料,经硫酸浸取,考察了不同工艺条件对锌的浸出率的影响.实验结果表明:锌灰在50℃下浸取,pH值为1.5时,可使锌灰中锌的溶出率达92.9%.碱式碳酸锌最佳水解温度为40℃,水解时间为2h,pH值为7.5时,溶液中锌含量为10g/L,得到96%以上的水解率. 相似文献
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研究了以含锌废催化剂为原料,经酸浸、除杂、锌粉置换、合成等工艺制得碱式碳酸锌,再经过滤、洗涤、干燥、煅烧制备纳米氧化锌。考察了酸浸工艺硫酸溶液质量分数和液固比(硫酸与含锌废催化剂的质量比)对锌浸出率的影响,以及煅烧温度对纳米氧化锌质量的影响。实验结果表明,含锌废催化剂酸浸工艺的最佳实验条件为:硫酸质量分数30%,液固比5,在此工艺条件下,锌浸出率为92%。纳米氧化锌的最佳煅烧温度为400℃,在此条件下,氧化锌质量分数大于95%,比表面积大于50 m2/g。纳米氧化锌颗粒大小均匀,平均粒径小于50 nm,应用该工艺建成了一套3000 t/a的生产装置。 相似文献
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以碳酸氢铵和氨水浸出锌灰,然后经除杂净化得到高纯锌氨溶液,以高纯锌氨溶液为原料,采用加热水解沉淀法合成超细碱式碳酸锌,碱式碳酸锌经煅烧得到超细氧化锌。研究了加热水解沉淀工艺条件对碱式碳酸锌的粒径分布的影响。结果表明,最佳工艺条件为:搅拌速度为300 r/min、蒸氨温度为90 ℃、锌氨溶液中锌质量浓度为75 g/L、负压为-2 kPa。最佳工艺条件下得到的碱式碳酸锌的D50为0.77 μm,颗粒近似球形;煅烧后的氧化锌为六方晶系纤锌矿结构,D50为0.69 μm。 相似文献
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回收含锌催化剂废料中的锌来制备氧化锌粉体。先用氯化铵浸取含锌催化剂,经过滤得到氯化锌溶液;滤液中加入碳酸氢铵反应得到白色沉淀,经过滤煅烧滤饼得到氧化锌粉体。单因素实验确定了制备氧化锌粉体的适宜工艺条件:浸出反应温度60℃,反应时间2 h,原料配比n(Zn2+)∶n(NH4+)=1∶2.2。滤液中加入的碳酸氢铵配料比n(Zn2+)∶n(NH4HCO3)=1∶2.3,反应时间1 h,抽滤得中间产物。中间产物煅烧温度为300℃,煅烧时间1 h。样品进行XRD表征,杂质峰比较少,与标准卡片参数基本一致,晶体结构较好。 相似文献
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选择性催化还原反应(SCR)的废催化剂中含有钒、钨和钛等有价值的金属,为最大限度回收其中的钒和钨资源,采用草酸分级浸取废SCR催化剂中的钒和钨,系统考察了草酸浓度、浸取温度、液固比和浸取时间对钒和钨浸出率的影响,并通过X射线衍射(XRD)和X射线光电子能谱(XPS)等表征手段分析浸出机理。废SCR催化剂直接用草酸浸取,钒浸出率为76.95%,钨和钛浸出率仅为5.31%和0.22%,钒被浸出。滤渣经焙烧后用草酸浸取,钨浸出率为56.70%,钒和钛浸出率仅为16.36%和0.12%,钨被浸出,最后滤渣主要成分为锐钛矿型TiO2。该流程实现了废SCR催化剂的分级浸取,钒和钨在不同步骤中浸出,避免了钒和钨分离困难的问题,简化了后续处理工作,降低了二次污染。 相似文献
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锌冶金渣尘作为一种重要的锌二次资源,来源广、储量大、具有较高的综合回收利用价值。以NH3-CH3COONH4-H2O为浸出体系,考察粒度、反应时间、搅拌速度、液固比、总氨浓度、NH3与NH4+物质的量比和温度对锌浸出率的影响,结果表明:控制浸出温度为25 ℃、总氨浓度为5 mol/L、液固体积质量比为5 mL/g、n(NH3)/n(NH4+)=1:1、搅拌速度为300 r/min、浸出时间为60 min,在此条件下锌的浸出率可达84%。含锌冶金渣尘浸出动力学分析显示,浸出反应表观活化能为22.66 kJ/mol,锌浸出过程的浸出速率受固体膜层扩散及界面化学反应共同控制,并获得了浸出锌的动力学速率方程。 相似文献
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钒铅锌矿含有多种有价金属,V品位高,具有较高的经济价值。本工作采用硫酸浸出法从该矿中提取钒锌,对浸出过程热力学进行分析,通过条件实验研究硫酸浓度、液固比、浸出时间、搅拌速率、浸出温度等条件对钒、铅、锌等主要有价金属浸出率的影响。结果表明,在较高pH值及较高温度下,浸出液中V会出现水解,含V的水解产物留在浸出渣中影响V浸出率。得到最优浸出条件为:硫酸浓度200 g/L,液固比3:1,浸出时间30 min,搅拌速率200 r/min,浸出温度为30℃。最优条件下V浸出率可达97.90%,Zn浸出率为97.11%,Fe浸出率<1%,Pb浸出率<0.01%。动力学分析结果表明,浸出过程的反应速率受扩散过程控制。酸浸过程使V和Zn进入浸出液,Pb和Fe留在浸出渣中,所得浸出液可使用离子交换或萃取法分离V和Zn。浸出渣中含钒0.41wt%、锌0.61wt%、铁15.50wt%、铅47.70wt%,主要成分为PbSO4和FeO(OH),可返回火法炼铅系统。 相似文献
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Deep purification of zinc ammoniacal leaching solution by cementation using zinc dust was studied.The effects of relative amount of metallic impurities,dosage of zinc dust,purification time,temperature,pH value and total ammonia concentration in the solution on the purification of the solution were investigated.The results indicate that total ammonia concentration in the solution had no effect on the purification,but relative amount of metallic impurities,dosage of zinc dust,purification time,temperature and pH value of the solution were the main factors influencing the purification.Keeping appropriate molar ratio of copper to cadmium or nickel to cadmium was beneficial to the cementation of cadmium.Nevertheless,the presence of cobalt went against the cementation of cadmium and cobalt.All metallic impurities could be decreased to acceptable levels under the optimized conditions of 2 g/L of zinc dust dosage,1 h of purification time,35℃,pH value 9.03 of zinc ammoniacal leaching solution.The deeply purified zinc ammoniacal solution obtained by one-stage purification meets the requirements of zinc electrowinning. 相似文献
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Deep Purification of Zinc Ammoniacal Leaching Solution 总被引:1,自引:0,他引:1
Deep purification of zinc ammoniacal leaching solution by cementation using zinc dust was studied. The effects of relative amount of metallic impurities, dosage of zinc dust, purification time, temperature, pH value and total ammonia concentration in the solution on the purification of the solution were investigated. The results indicate that total ammonia concentration in the solution had no effect on the purification, but relative amount of metallic impurities, dosage of zinc dust, purification time, temperature and pH value of the solution were the main factors influencing the purification. Keeping appropriate molar ratio of copper to cadmium or nickel to cadmium was beneficial to the cementation of cadmium. Nevertheless, the presence of cobalt went against the cementation of cadmium and cobalt. All metallic impurities could be decreased to acceptable levels under the optimized conditions of 2 g/L of zinc dust dosage, 1 h of purification time, 35℃, pH value 9.03 of zinc ammoniacal leaching solution. The deeply purified zinc ammoniacal solution obtained by one-stage purification meets the requirements of zinc electrowinning. 相似文献
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T.Y. Yan 《Chemical Engineering Communications》1985,33(1):219-230
The technical feasibility of in situ uranium leaching using dilute sulfuric acid and molecular oxygen has been assessed and the important process parameters examined by use of laboratory high pressure leaching columns.
The dilute H2SO4/O2 lixiviant was effective in leaching uranium from the ore samples tested. The leaching process was chemical reaction rate limited and can be represented using pseudo first-order kinetics. The leaching rate constant is proportional to the proton concentration of the lixiviant.
Much of the uranium was leached from the ore before decomposition of carbonate minerals by the acid was complete. Acid consumption per pound of U3O8 increased sharply as the uranium recovery level exceeded 70%. There appears to be a minimum oxygen pressure for effective uranium leaching. A pressure of 2758 KPa was adequate for the ore samples tested 相似文献
The dilute H2SO4/O2 lixiviant was effective in leaching uranium from the ore samples tested. The leaching process was chemical reaction rate limited and can be represented using pseudo first-order kinetics. The leaching rate constant is proportional to the proton concentration of the lixiviant.
Much of the uranium was leached from the ore before decomposition of carbonate minerals by the acid was complete. Acid consumption per pound of U3O8 increased sharply as the uranium recovery level exceeded 70%. There appears to be a minimum oxygen pressure for effective uranium leaching. A pressure of 2758 KPa was adequate for the ore samples tested 相似文献
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低品位氧化锌矿氨-碳酸氢铵浸出制备氧化锌工艺的研究 总被引:2,自引:0,他引:2
采用氨-碳酸氢铵溶液从低品位氧化锌矿中浸出制备氧化锌。研究结果表明,在氨水浓度7mol/L、碳酸氢铵浓度0.62mol/L、浸出温度50℃、氧化锌矿粉粒度为177μm、液固比5:1、浸出时间3h的条件下,锌一段浸出率为87.2%,经过二段浸出,锌总收率可提高至95.9%;浸出液采用足量锌粉还原除杂后,净化液中铜为0.51mg/L,铬为0.18mg/L,铅可降至0.10mg/L以下;净化液经过蒸氨和焙烧制得的氧化锌含量为99.53%(以氧化锌计)。该方法具有工艺简单、能耗低、浸出率较高、浸出过程对环境较友好等优点。 相似文献