Knowledge Management System Of Guangzhou Institute of Energy Conversion, CAS
| 回转窑热解处理废锌锰电池试验研究 | |
| Alternative Title | Research on pyrolysis of Spent Zinc Manganese Dioxide Batteries in a Ratory kiln |
| 瞿兆舟 | |
| Thesis Advisor | 李海滨 |
| 2007-06-08 | |
| Degree Grantor | 中国科学院研究生院 |
| Place of Conferral | 北京 |
| Degree Name | 硕士 |
| Degree Discipline | 热能工程 |
| Keyword | 废锌锰电池 热解 回转窑 Spent Zinc Manganese Dioxide Batteries Pyrolysis Rotary Kiln |
| Abstract | The battery production of China was 20.9 billions in 2003. It has been the first place in the world for a long time. Most of them are zinc-manganese batteries. If they are improperly disposed, the heavy metal substances in them will infiltrate into the soil and pollute the soil and water. The heavy metals will enrich in the human bodies and cause illness. In another aspect, there are a lot of useful things in them: Zn, MnO2 and so on. They should be recovered. This paper retrospects the techniques and research status of recovering the used zinc-manganese batteries. The purpose of these techniques usually contain the aspects as follows: recover Zn, Mn and Hg；recover alloy；recover Zn and MnO2；prepare trace fertilizer；prepare manganese-zinc ferrite；prepare ZnSO4 and MnCO3. The merits and drawbacks of these methods are analyzed in five aspects: effect of the innocent treatment，recycling degree，rank of the product，complexity of the technology and secondary pollution. A method which is fit for industrialization is put forward: firstly, remove Hg from the spent zinc manganese dioxide batteries by pyrogenic process, secondly, remove the other heavy metal contamination from it by hydrometallurgical method and then prepare trace fertilizer. The dimension of the rotary kiln is devised based on the experiential formula of the residence time. The power of the resistance coil and the thickness of the heat preservation material are calculated based on the heat transfer formulae. The pontes of the rotary kiln are airproofed by the united use of heat preservation material and lube. The residence time of the cracked used batteries is adjusted by changing the rotate speed of the rotary kiln and the height difference of it’s two ends. The pyrolyzing temperature is changed by the servomechanism which can regulate the power of the resistance coil. The pyrolyzing of the used batteries is studied in the rotary kiln. The tail gas and granules are absorbed by a series of absorbing liquid. The orthogonality pyrolyzing experiments are carried out by changing the temperature, the residence time and the flowrate of the carrier gas. The effects of temperature, residence time and flowrate of carrier gas on Hg removal ratio were investigated. Research was conducted on the Hg absorption by ICP apparatus. The content of the tail gas is mensurated by gas chromatography. The substantial form transformation of the spent zinc manganese dioxide batteries are tested by X-ray. The result indicates: The most efficient condition is in the following: temperature 690℃，residence time 100min，flowrate of carrier gas 0.06m3/h.The most influential factor is residence time. The less influential factor is temperature. Flowrate of carrier gas has little impact on Hg removal ratio. The absorbing solution absorbs almost all the Hg in the tail gas. Approximately 95% of the Hg absorbed in the absorbing solution is simple substance. The unabsorbed Hg remains in the pipelines. The organic impurities largely decompose after pyrolyzed. The productions are C2H4、CH4 and H2, etc. There are redox reactions between graphite C and high oxide of metals. A lot of CO generates and the metal oxide is deoxidized to low chemical valences. It can be concluded from the X-ray diffraction analysis that, when the temperature is 350℃, unconspicuous peaks appear near the 2θ value 35°.These peaks evidently swell when the temperature become 500℃, it is the crystal of ZnO and FeO. At the same time, new peaks appear at the 2θ value 41°.It owes to the redox reaction between graphite C and high oxide of Mn. The low oxide of Mn forms crystals. The peaks become steady when the temperature is 650℃. After the pyrolytic reation, the relative content of the high valenced Mn oxide changes from 32.2% to 4.6%. The relative content of MnO changes from 6.4% to 38.6%. The metallic elements are mostly in crystal forms. The pyrolysis residue is suitable for preparing organic chelated microelement fertilizer. |
| Other Abstract | 我国电池生产量已经达到209亿节（2003年），多年来一直占据世界第一大电池生产国的地位，其中锌锰电池占大多数。废锌锰电池丢弃后，其中的重金属物质会逐渐渗透到地下，污染土壤和水体。重金属在生物体内富集，会使生物体致畸或致变。但同时，废锌锰电池中也含有大量有用的资源如锌、二氧化锰等。应对其进行回收利用，变废为宝。本文介绍了废锌锰电池回收处理的主要技术及研究进展，不同的处理技术回收废锌锰电池时的目标产物各不相同，但一般可分为以下几种：以单质形式回收锌、锰和汞；以合金的形式回收锌和锰；回收锌和二氧化锰；回收各金属元素制备复合微量元素肥料；回收锌、锰元素制备锰锌铁氧体；回收锌、锰元素制备硫酸锌和碳酸锰等。本文对一些废锌锰电池回收处理技术的优缺点从无害化程度、资源化程度、产品等级、工艺要求以及二次污染五个方面进行了分析和比较。在对国内外废锌锰电池回收处理技术进行分析比较的基础上提出了一种成本较低、可操作性较强的处理技术：先以干法除去废锌锰电池中的汞，然后以湿法除去其它的有害重金属并进一步加工制备有机螯合微量元素肥料。 本文以回转窑中物料停留时间的经验公式和传热学的知识设计和计算了回转窑的长度和内径尺寸、电热丝的功率以及外围的保温材料厚度等参数。用保温材料和润滑油相结合的方式对回转窑的连接部分实行密封。通过调整回转窑的转速和回转窑支架两端高度差的方式控制物料在回转窑中的停留时间，从而调节热解时间的长短。利用自动控制设备调节电热丝的功率从而调节试验中的热解温度。利用该回转窑在不同条件下对热解处理废锌锰电池进行了试验研究，热解过程中产生的尾气和颗粒物用一系列吸收液进行吸收和固定。 在热解试验中改变影响热解过程的三种因素：热解温度、热解时间和载气流速并按三因素四水平的正交方法安排试验。改变废锌锰电池热解过程中的热解温度、热解时间和载气流速三种因素进行正交试验并利用正交统计学的方法分析了这三种因素对热解除汞率的影响。利用ICP检测仪测定了各吸收液中汞的含量，并分析热解气体产物经过系列吸收液时汞被吸收的情况以及汞的形态分布。利用气相色谱仪对尾气成分进行了测定，并对热解过程中产气的过程和规律进行了分析。用X射线衍射测试的方法研究了热解前后锌锰电池的物质形态变化情况。对除汞率的正交统计分析表明，合适的热解条件为：热解温度690℃，热解时间100min，载气流速0.06m3/h，在这种试验条件下热解处理废锌锰电池的除汞率达到100%。同时还得到：热解时间对除汞效果影响最大，热解温度次之，载气流速的影响较小。ICP测试的结果表明：热解尾气在经过试验中设置的吸收瓶后，其中的汞被完全吸收，尾气中95%以上的汞以单质的形式存在。气相色谱分析的结果表明，热解开始后，废锌锰电池中的有机质迅速分解，其产物为C2H4、CH4和H2等。一段时间后，有机质的分解量大幅度减少，同时废电池中的石墨碳和高价金属氧化物发生氧化还原反应，生成CO气体。对废锌锰电池原料以及热解残渣的X射线衍射分析表明，当热解温度为350℃时，X射线衍射图谱上2θ值为35°附近的区域有新峰出现，但不明显，说明有结晶体形成但量不大。500℃时上述峰明显增强，这是由于ZnO和FeO形成了结晶体，同时在2θ值为41°附近有新峰出现，这是高价锰氧化物与石墨碳发生氧化还原反应生成了MnO并形成了结晶体。650℃时，2θ值在41°附近的峰显著增强，且热解过程中形成的峰稳定下来，基本上不再有新的结晶体生成。热解后，高价锰氧化物的相对含量从32.2%下降到4.6%，而MnO的相对含量则从6.4%上升到38.6%。热解后的残渣中晶体物质含量大，金属元素大多以低价态存在，适合于制备有机螯合微量元素肥料。 |
| Subject Area | 热能工程 |
| Pages | 共64页 |
| Document Type | 学位论文 |
| Identifier | http://ir.giec.ac.cn/handle/344007/1547 |
| Collection | 中国科学院广州能源研究所 |
| Recommended Citation GB/T 7714 | 瞿兆舟. 回转窑热解处理废锌锰电池试验研究[D]. 北京. 中国科学院研究生院,2007. |
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