机械活化强化难分解铌钽矿亚熔盐清洁工艺的基础研究
文献类型：学位论文
| 作者 | 王晓辉 |
| 学位类别 | 博士 |
| 答辩日期 | 2009-05-30 |
| 授予单位 | 中国科学院过程工程研究所 |
| 授予地点 | 过程工程研究所 |
| 导师 | 张懿 |
| 关键词 | 机械活化 亚熔盐 铌钽矿 动力学 清洁工艺 低碱矿比 |
| 其他题名 | Fundamental Research on the Mechanical Activation Enhanced Clean Process of Refractory Niobium-tantalum Ore with Sub-molten Salt of Potassium Hydroxide |
| 学位专业 | 化学工艺 |
| 中文摘要 | 铌、钽为重要的稀有金属，其金属和合金已被广泛应用于钢铁、电子等高新技术领域。铌钽矿石的分解为铌钽湿法冶金的关键技术。传统分解方法为氢氟酸分解法。但该法会造成严重的氟污染且对难分解矿的资源利用率较低。为此，中国科学院过程工程研究所开拓了亚熔盐法铌钽矿清洁生产新工艺，使难分解铌钽矿分解率较氢氟酸法提高10%以上，且从源头削减了氟污染，具有良好的工业前景。本研究在亚熔盐法铌钽矿清洁生产工艺的前期研究基础上，重点研究了铌钽矿在钾系亚熔盐介质中转化为可溶性六铌、钽酸盐的规律，在此基础上提出难分解铌钽矿的机械活化亚熔盐新工艺，并系统进行了相关的应用基础与工艺优化研究。论文取得如下创新性进展： (1) 首次系统研究了钾系亚熔盐介质中可溶性六铌酸钾向不溶性偏铌酸钾转化的规律，确定了六铌酸钾与偏铌酸钾的稳定区域，为在低温、低碱条件下实现铌钽矿浸出提供了理论依据。 (2) 研究了机械活化铌钽矿在KOH亚熔盐介质中的表观反应动力学，研究结果表明机械活化15min及30min后，表观活化能由未活化时的80.3KJ/mol下降到55.7KJ/mol和43.9KJ/mol，表观反应级数由2.43下降到1.24和0.96，浸出反应速率常数显著增大，从动力学角度阐明了机械活化强化分解机理；研究了机械活化铌钽矿的结构变化规律，结果表明，随着机械活化时间的延长，铌钽矿的粒径先急剧减少，而后由于团聚作用反而增大，相应的，比表面积则先增大后减小。而微观应变和矿物无定形程度则随机械活化时间的延长一直增大。在结构变化规律基础上，对机械活化机理进行了初步探讨，从结构变化的角度阐明了机械活化强化分解机理；机械活化时间越长，活化效果越显著，但活化效果存在极限状态。 (3) 对机械活化铌钽矿在氢氧化钾亚熔盐中的浸出工艺条件及总体工艺流程进行了优化，在优化条件下，矿石分解完全，铌、钽的浸出率均为95%以上，较传统氢氟酸法提高10%以上；新工艺过程得到的水合氧化铌、钽混合物纯度高达99.5%，可轻易溶于10%的稀氢氟酸中，并与后续铌、钽萃取分离工艺衔接。对铌钽矿亚熔盐浸出渣进行了综合利用研究，通过硫酸浸出-净化除杂-共沉淀工艺，制备了杂质含量低于国家标准的高附加值锰锌软磁铁氧体共沉淀粉料，实现了渣中铁、锰的深度利用。硫酸浸出后，渣中的铌、钽化合物得到富集，通过亚熔盐工艺再处理，铌、钽总回收率达99%以上。 (4) 探索了采用氢氧化钾亚熔盐法制备偏钽酸钾陶瓷粉末材料的新工艺。制得了粒度在50-300nm之间，形貌可控的偏钽酸钾晶体。与传统的碱熔融法相比，反应温度由1000℃下降到150℃，反应时间由10h下降到3h左右，从而可大幅度降低能耗。 (5) 研究了Ta2O5和Nb2O5在钾系熔盐中的溶解行为及相互作用机理。在此基础上，提出了配矿法强化铌、钽浸出新技术。该技术可在低碱矿比下实现铌钽矿的完全分解，且铌和钽的浸出率分别达到95%和93%。与传统碱熔融法相比，明显降低了反应温度，提高了铌、钽浸出率。 |
| 英文摘要 | Among the rare metals, niobium and tantalum have been applied widely in the fields of steel, electronic and other high-tech industries. The decomposition of niobium-tantalum ore is the key technology in niobium-tantalum hydrometallurgy. The traditional decomposition method of niobium-tantalm ore is the hydrofluoric acid method which brings serious environment pollution of fluorin. Moreover, it is hard to decompose the refractory niobium-tantalum ore with hydrofluoric acid. A new process for the leaching of low-grade niobium-tantalum ore with KOH sub-molten salt was proposed by the Institute of Process Engineering, Chinese Academy of Sciences. Through the new process, the decomposition rate of refractory niobium-tantalum ore was increased by 10% compared with the traditional hydrofluoric acid process and the pollution of fluorin was reduced from the source. Therefore, this new process showed industrial application prospect. Based on the previous research, the conversion behaviour of niobium-tantalum ore to soluble niobate and tantalate was mainly studied and a new process of mechanical activation enhanced clean process of refractory niobium-tantalum ore with sub-molten salt of KOH was proposed. And the applied fundamental research and process optimization on the new process were carried out. In this thesis, the following achievements and progress were exhibited: (1) The conversion behaviour of soluble potassium hexa-niobate to insoluble potassium niobate was firstly systematically researched and the stable region of hexa-niobate was found. This provided a theoretical basis for the leaching of refractory niobium-tantalum ore under mild reaction effects. (2) The apparent reaction kinetics of mechanically activated niobium-tantalum ore with KOH sub-molten salt was studied. The results showed that, after mechanical activation of 15min and 30min, the apparent activation energy for the leaching of niobium decreased from 80.3KJ/mol to 55.7KJ/mol and 43.9KJ/mol, and the apparent reaction order decreased from 2.43 to 1.24 and 0.96. The reaction rate constant increased significantly.These results explained the reason for the enhancd decomposition of mechanically activated niobium-tantalum ore; the rules for the changes of structures of mechanically activated niobium-tantalum ore were studied. The results showed that, the particle size of niobium-tantalum ore decreased sharply at beginning stage of mechanical activation, and then increased as the agglomeration of the fine particles. Correspondingly, the specific surface area increased firstly and then decreased. The crystal lattice distortion rate and the disordering of niobium-tantalum ore increased through the whole stage of mechanical activation. Based on the rules for the changes of structures, the mechanism of mechanical activation was investigeated. (3) The technical parameters of the leaching process and the general process were optimized. The results showed that niobium-tantalum ore can be decomposed completely, and the leaching rates of both niobium and tantalum are above 95%, which were 10% higher than those in the hydrofluoric acid process. Niobium and tantalum oxide with purity of 99.5% was obtained through the new process, and could be dissolved by hydrofluoric acid under the concentration of 10% and then be separated through extraction. Mn-Zn ferrite coprecipitation powders with high purity were obtained through sulphuric acid leaching-solvent purification-coprecipitation process from the niobium-tantalum ore residue. The total recovery rate of niobium and tantalum from the ore is above 99%. (4) A new process for preparing ceramic powder of potassium tantalate with KOH sub-molten salt was developed. Compared with the alkali fusion process, the reaction temperature was decreased from 1000℃ to 150℃, and the reaction time was decreased from 10h to 3h. Therefore, the energy consumption of this process was decreased remarkably. (5) The dissolution behavior of Ta2O5 and Nb2O5 and the interaction mechanism between them in KOH molten salt were studied. Based on the interaction mechanism, a new process for the enhancing of the leaching of niobium-tantalum ore through adjusting the niobium/tantalum ratio in the ore was proposed. The results showed that niobium-tantalum ore can be decomposed completely through this new process, and the leaching rates of niobium and tantalum are 95% and 93% separately. Compared with the traditional alkaline fusion method, the reaction temperature was decreased and the leaching rates of niobium and tantalum were increased significantly through this new method. |
| 语种 | 中文 |
| 公开日期 | 2013-09-13 |
| 页码 | 187 |
| 源URL | [http://ir.ipe.ac.cn/handle/122111/1252]  |
| 专题 | 过程工程研究所_研究所（批量导入） |
| 推荐引用方式 GB/T 7714 | 王晓辉. 机械活化强化难分解铌钽矿亚熔盐清洁工艺的基础研究[D]. 过程工程研究所. 中国科学院过程工程研究所. 2009. |
入库方式： OAI收割
来源：过程工程研究所
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