氯化挥发法综合处理含金高铁硫酸烧渣的研究
文献类型：学位论文
| 作者 | 丁剑 |
| 学位类别 | 硕士 |
| 答辩日期 | 2012-06-06 |
| 授予单位 | 中国科学院研究生院 |
| 导师 | 叶树峰 |
| 关键词 | 硫酸烧渣 氯化挥发 金 挥发率 氧化球团 |
| 其他题名 | Study on Comprehensive Treatment of Gold Bearing and High Iron Content Pyrite Cinder by Chlorination Volatilization Process |
| 学位专业 | 化学工程 |
| 中文摘要 | 含金高铁硫酸烧渣由氰化尾渣富集硫铁焙烧制取硫酸后所得，其铁品位63.53%，达到了炼铁用铁精粉的标准，通常用于掺配烧结，该法虽然实现了铁资源的利用，但是其中的金（2.12g/t）却被浪费。烧渣独特的理化性能会对烧结产生不利影响，其中的少量的铜、铅、锌也会影响烧结产品的质量。烧渣中的金品位低，直接氰化收益难以弥补成本，铜、铅、锌的常规湿法回收也存在同样的问题。本文采用氯化挥发法以实现铁金分离、炼铁杂质（铜、铅、锌）的脱除以及铁资源的高效利用，提金的同时生产高品质的氧化球团。论文主要研究内容和结果包括：（1）探讨了反应的过程。采用HSC热力学软件计算不同温度下反应的吉布斯自由能变化来推断氯化挥发过程中可能的反应。计算结果表明，直接氯化反应只有当CaCl2呈气态或液态时才能进行。相比较而言，两步反应更容易进行：氯化剂的分解反应在有SO2参与的情况下，当CaCl2为固态时就能发生；分解产生的Cl2与金属氧化物的诸反应中，除与Fe2O3难以进行外，其它都能自发进行。过量CaCl2焙烧，氯元素大部分被挥发，证明氯化挥发以两步反应为主。（2）确定了挥发的最佳条件。不同条件下的直接焙烧结果表明：金、银、铜、铅、锌分别在CaCl2含量2%、4%、9%、3%、9%左右达到最大值；CaCl2加入量在9%以内都不会对铁的品位产生影响；在CaCl2含量较高的情况下，超过一定的温度时，铜、铅、锌挥发率反而会下降；烧渣中加入9% CaCl2在1100℃下焙烧时，有色金属挥发需20min，氯化剂的分解需60min；加入6% CaCl2，在1100℃下焙烧60min，金、银品位分别降到了0.11g/t、6.92g/t，回收率分别为88.7%、73.67%，铜、铅、锌含量较低，符合铁精粉的要求。（3）确定了球团固结的条件。高温焙烧时，球团的固结主要在1150℃以上发生。少量CaCl2（3%）的加入在1175℃以上会提高球团的强度，但是加入量过多会降低球团的强度，在1150~1300℃范围内，同样的温度，氯化剂含量升高会导致球团强度下降500N。在加入6% CaCl2的情况下，焙烧温度在1230℃以上达到一级球团的强度（2000N），焙烧温度在1206℃以上达到二级球团的强度（1500N）。在焙烧时间短时，磨矿有助于提高焙烧球的抗压强度。（4）进行了中试工艺选择与设计。为便于根据反应的需要随时改变载流气的性质，采用间接加热的方式。根据氯化挥发的条件以及防腐的要求，选用密封性能好、投资少、热效率高的竖炉作为主要的焙烧设备。两种常见的耐火材料中只有Al2O3材料在耐火性、耐腐蚀性方面能满足要求。为保证物料的透气性，防止烧渣被载流气带出进入收尘系统影响分离效果，采用造球后焙烧的工艺流程。磨矿9min，加入2%膨润土造球的条件下能获得合格的生球。本文还制定了中试的方案与路线。 |
| 英文摘要 | Gold bearing pyrite cinder with high iron content is produced by flotation-roasting of cyanide tailing. The iron content of the material has met the criteria of iron concentrate fines production, which is as high as 63.53%. It is now added to conventional iron concentrate fines to produce sinter. Iron resource has been made full use of, however gold (2.12g/t) in the material is wasted. The unique physical and chemical properties of the pyrite cinder have a negative effect on the production of sinter. The content of gold is so low that hydrometallurgical process for recovery is not profitable. The same problems happened to copper, lead and zinc. In this article, chlorination volatilization process was adopted for the separation of gold from iron, removal of copper, lead and zinc, as well as full use of iron resource. Gold was recovered at the same time of the production of high quality oxidized pellet. The main content and the result are as follows: (1) The process of the reaction was confirmed. Free enthalpy (ΔGr) of reaction is calculated by HSC software to deduce the possible reaction. The results demonstrate that direct chlorination reaction occurs only when CaCl2 exists in the form of gas or liquid. Two-step reaction is more likely to occur. Decomposition of CaCl2(s) occurs when there is SO2. Reactions between metallic oxide and Cl2 decomposed from CaCl2 occur except Fe2O3. Experiments proved that decomposition-chlorination two-step reaction is more likely to occur. (2) The conditions for volatilization were fixed. Direct roasting experiments demonstrate that the volatile ratios of elements approached maximum when CaCl2 contents were 2%, 4%, 9%, 3%, 9% for gold, silver, copper, lead and zinc separately. The addition of CaCl2 hasn’t decreased iron content because of decomposition. High temperature may have a negative effect on the volatile process when added excessive CaCl2. The process of volatile took 20min when 9% CaCl2 added and roasted in 1100 ℃. However, the decomposition of CaCl2 took 60min. Gold and silver content and volatilization ratios of roasted pyrite under the optimum conditions of 9% calcium chloride content at 1100℃ for 60min are 0.17g/t, 91.26% and 6.24g/t, 80.05% respectively. The content of other elements also conformed to the requirements. (3) The conditions for the consolidation of the pellets were fixed. Roasting experiments demonstrates that the strengthening temperature is mainly above 1150℃. Addition of CaCl2 may increase the compressive strength, but too much may have negative effects on compressive strength. In 1150℃~1300℃,3% more added, the strength lowered by 500N. 6% CaCl2 added, 1230℃ is required for the compressive strength up to the first-rate demand of oxidized pellet, while 1206℃ to second-rate demand. Grinding process may increase the compressive strength of the roasted pellet when the roasting time is limited. (4) The pilot process was selected and designed. Indirect heating method was adopted because the nature of loading current may be changed as required easily when heated indirectly. Sealing good and thermal efficient shaft furnace with less investment was adopted as main roasting equipment according to the requirements for chlorination volatilization and corrosion prevention. SiC material corroded when roasted with CaCl2, so it could not be used as furnace pipe. However, thermostability and corrosion resistance of Al2O3 material could meet the requirements. Pelletizing before roasting process was adopted to keep gas permeability and prevent pyrite cinder being brought by the current. Qualified green pellets were produced if 2% bentonite was added and the pyrite cinder was grinded for 9min. The pilot scheme and routes were selected. |
| 语种 | 中文 |
| 公开日期 | 2013-09-25 |
| 源URL | [http://ir.ipe.ac.cn/handle/122111/1784]  |
| 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 | 丁剑. 氯化挥发法综合处理含金高铁硫酸烧渣的研究[D]. 中国科学院研究生院. 2012. |
入库方式： OAI收割
来源：过程工程研究所
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