碱法处理钛铁矿和含钛高炉渣制取TiO2及钛铁分离研究
文献类型：学位论文
| 作者 | 汪元博 |
| 学位类别 | 博士 |
| 答辩日期 | 2009-06-01 |
| 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 | 齐涛 |
| 关键词 | 钛铁矿 分离提取 高炉渣 熔融焙烧 钛白 |
| 其他题名 | Treatment of Ilmenite and Ti-bearing Blast Furnace Slag by Alkaline Method for the Production of TiO2 and the Separation of Iron from Titanium |
| 学位专业 | 化学工艺 |
| 中文摘要 | 为从源头上解决钛白粉生产行业的高污染问题，中国科学院过程工程研究所以亚熔盐法分解钛铁矿，成功地将钛铁矿分解率提高到96%。但是铁的分离一直是钛白粉生产中的难点，也是目前工业生产钛白产生环境污染的主要原因。因此，有必要对钛、铁分离技术进行全新的研究，以找到一条经济有效的钛铁分离方法。有鉴于此，本文进行了新的化学法浸出钛铁矿亚熔盐产物中铁杂质而富集TiO2的基础性研究。同时，为富集利用攀钢高炉渣中含有的22%-26%钛成分，本文提出了一种从含钛高炉渣中富集TiO2的新方法。本研究基于从源头上消除污染的理念，具有清洁、无污染的特色。主要取得了以下成果： (1) 研究表明，钛铁矿亚熔盐中氧化铁在硫酸中的浸出过程受界面化学控制，表观活化能81.7 kJ/mol, 反应速率与质子浓度成正比。在最佳工艺条件下，铁浸出率为70%，浸出固体中TiO2含量在未采用还原剂时达到83%；采用Fe粉还原剂时铁浸出率达到90%，浸出固体TiO2含量达到89%。 (2) 绘出了常温下溶液中[H2C2O4]、 [HC2O4-]、 [C2O42-]的摩尔百分含量随溶液pH的变化关系及草酸-H2O的E-pH图。并分别作出了Fe3+-oxalate-H2O体系和Fe2+-oxalate-H2O体系各络合离子中分布随-log[C2O42-]的变化。 (3) 对氧化铁在草酸溶液中的动力学研究表明，该浸出过程遵循收缩未反应核模型，反应初期浸出速率受界面化学反应控制(X<50%)，反应后期(X>60%)浸出速率受内扩散控制。最佳工艺条件下，铁浸出率达到95%，其余5%的铁主要存在于未反应的钛铁矿中，浸出后的固体中可溶性氧化铁只有1600 ppm左右。 (4) 考察了K4Ti3O8转变为Ti2O2(OH)2(C2O4)•H2O的形成历程。对Ti2O2(OH)2(C2O4)•H2O进行热处理的研究表明，该盐在190oC即开始分解而转变为无定形TiO2，随着温度的升高依次转变为锐钛型、金红石型TiO2。 (5) 采用光化学法和pH法回收浸出液中草酸根。光化学下，浸出液中的铁主要生成FeC2O4•2H2O晶体及少量FeOOH。在pH法回收草酸根时，铁主要生成FeOOH•nH2O沉淀，且草酸根回收率可达为100%。 (6) 对浸出固体Ti2O2(OH)2(C2O4)•H2O的水解研究发现，即使在弱酸性溶液中亦能得到金红石型TiO2，且草酸根回收率可达98%左右。 (7)考察了熔融碱焙烧法处理高炉渣的影响因素。在焙烧反应中，生成新物质相NaFeO2、NaTiO2、Ca(OH)2。最佳条件下酸浸出后，可得含TiO2 70%左右的富钛渣。 |
| 英文摘要 | To avoid the heavy acid pollution in the production of TiO2, Institute of Process Engineering, Chinese Academy of Sciences has proposed a route for the decomposition of ilmenite by sub-molten salt method (SMS), with a conversion of 96%. However, the separation of Fe from Ti present the main difficulty in TiO2 white industry, in addition, the heavy pollution posed by sulfate process or chlorination process is due to the removal of Fe. Therefore, it is imperative to explore a new process for the removal of Fe in the treatment of ilmenite by SMS method. The aim of this thesis is thus to leach of iron oxide from the decomposition of ilmenite. Meanwhile, alkaline roasting method was proposed to enrich TiO2 from Ti-bearing blast furnace slag. Both routes have the characteristics of clean or little pollution to the environment. The following work has been done: (1) Analysis was done on the leaching of iron oxide with dilute H2SO4 both in thermodynamics and in kinetics. The dissolution rate was controlled by surface reaction with apparent activation energy of 81.7 kJ/mol, and the dissolution rate is linear with the proton concentration. Under the optimum conditions, product with 83% TiO2 is obtained in the absence of reductant and 89% in the presence of Fe powder as a reductant. (2) The effect of solution pH on the fraction curves of [H2C2O4], [HC2O4-] and [C2O42-] at 25oC was analyzed, and the E-pH diagram for oxalate-H2O system was described. Additionally, the fractions of Fe3+ species and Fe2+ species with -log[C2O42-] were described in Fe3+-oxalate-H2O system and Fe2+-oxalate-H2O system, respectively. (3) The leaching of iron oxide in oxalate solution follows the unreacted shrinking core model. The leaching rate which was controlled by surface complex reaction in the initial stage(X<50%) was transformed to the diffusion controlled mechanism in the second stage(X>60%)。 Under the optimum conditions, only about 1600 ppm dissolvable iron was left in the product. (4) The formation of Ti2O2(OH)2(C2O4)•H2O proceeded through three stages. Calcining the oxalate leached product under various temperatures, it begins to decompose at 190oC and to form amorphous TiO2. Rising the temperature, TiO2 transformed from amorphous to anatase and then to rutile. (5) Photochemical method and pH method were proposed to recycle oxalate in the leaching solution. By photochemistry, the precipitate FeC2O4•2H2O and a minor amount of FeOOH were formed. By pH method, iron was precipitated as FeOOH•nH2O. (6) 98% oxalate can be recycled from Ti2O2(OH)2(C2O4)•H2O by pH method. (7) Some substances, such as NaFeO2, NaTiO2, Na2TiO3 and Ca(OH)2 were formed when Ti-bearing blast furnace was treated by alkaline roasting method. Subjecting the roasted material to acid leaching, 70% TiO2-rich slag can be obtained. |
| 语种 | 中文 |
| 公开日期 | 2013-09-13 |
| 页码 | 149 |
| 源URL | [http://ir.ipe.ac.cn/handle/122111/1263]  |
| 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 | 汪元博. 碱法处理钛铁矿和含钛高炉渣制取TiO2及钛铁分离研究[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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