高砷含铜硫铁矿烧渣的综合利用研究

发布时间：2018-02-23 06:56

  本文关键词： 硫铁矿烧渣 SEM形貌分析 硫酸浸出 除砷 动力学　出处：《昆明理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：硫铁矿烧渣是在使用硫铁矿为主要原料煅烧硫酸时产生的固体废渣,目前对硫铁矿烧渣的处理主要是堆放或者简单的填埋处置,既占用大量土地,还会对大气、水体、土壤等造成严重的污染。硫铁矿烧渣中主要成分为铁的氧化物,含量一般为30%～60%,部分硫铁矿烧渣还含有少量的Cu等有价值的元素,是一种宝贵的二次资源,但由于硫铁矿烧渣中的杂质含量普遍偏高,特别是烧渣中有砷的存在,直接影响其作为铁精矿的回收利用,铁精矿含有砷将导致铸铁热力学性能降低,还会造成一系列的工艺和环境问题,脱除硫铁矿烧渣中的有害杂质是十分有必要的。对于含有有价金属的硫铁矿烧渣能在回收铁资源的同时回收其他有价金属,既能消除其对环境的影响,还可获得一定的经济价值。本论文在充分查阅和参考硫铁矿烧渣综合利用、含砷物料的脱砷研究等相关文献资料的基础上,对高砷含铜硫铁矿烧渣进行了研究。该烧渣含铁51.15%、As含量为3.35%,Cu含量为1.02%；硫铁矿中的铁主要以赤铁矿(Fe2O3)和磁铁矿(Fe3O4)形式存在,As主要以砷化物(As2O3)存在,Cu主要以CuFe2O4存在；高砷含铜硫铁矿烧渣呈浸染状、蜂窝状等结构,表面结构疏松；部分脉石矿物与铁矿物相互包裹,或者附着在铁矿物表面,杂质元素在烧渣表面均匀分布,这种复杂连生结构导致其物理或机械处理方法分离变得困难。实验的研究是根据烧渣的矿物学性质,采用硫酸溶液浸出硫铁矿烧渣,可达到脱砷和铜等其他杂质的目的,同时提高铁的品位。实验进行了硫酸浓度、固液比、温度、反应时间和清水洗涤的影响实验,最后确定最佳实验条件：初始硫酸浓度(质量浓度)为15%,固液比1：3,浸出温度60℃,在机械搅拌下浸出3.0h,搅拌洗涤两次。高砷含铜硫铁矿烧渣在最佳实验条件下浸出,可使高砷含铜硫铁矿烧渣中As的含量降至0.20%、Cu含量降至0.39%、Fe的品位提高到57.66%,达到铁矿烧结厂对铁矿中Fe的品位和对As、Cu杂质含量的要求。由于浸出液中含有大量的铁、砷和铜,因此实验采用中和沉淀去除砷和铁的方法,使铜存留于滤液,便于后序的回收利用。鉴于滤液中主要是三价砷,而三价砷比五价砷毒性大,且五价砷更易于与三价铁形成砷酸铁盐,所以在中和沉淀前采用双氧水氧化三价砷,实验得出在常温下中和沉淀除砷和铁的最佳工艺条件为：中和沉淀终点pH值为3,反应时间为10min,最大除砷率为99.89%,除铁率为99.77%,而铜的损失率仅为3.35%,溶液中的铜的含量达到了1.4g/L,具有萃取回收利用的价值。采用热力学对中和沉淀铁和砷进行理论分析,论证中和沉淀终点pH值的正确性。通过对高砷含铜硫铁矿烧渣中砷的浸出动力学机理研究,为硫酸浸出高砷硫铁矿烧渣提供理论依据,对硫酸法处理高砷含铜硫铁矿烧渣具有重要的指导意义,并可以为其他高砷物料的无害化处理提供理论参考。
[Abstract]:Pyrite cinder is a solid waste produced when pyrite is used as the main raw material to calcinate sulfuric acid. At present, pyrite cinder is treated mainly by stacking or simple landfill disposal, which not only takes up a large amount of land, but also affects the atmosphere and water body. The main component of pyrite cinder is iron oxide, the content of which is generally 300.Some pyrite cinders also contain a small amount of valuable elements, such as Cu, which is a valuable secondary resource. However, the content of impurities in pyrite cinder is generally high, especially the presence of arsenic in slag, which directly affects the recovery and utilization of iron concentrate, which will lead to the reduction of thermodynamic properties of cast iron. It can also cause a series of technological and environmental problems, and it is necessary to remove harmful impurities from pyrite cinders. For pyrite cinders containing valuable metals, pyrite cinders can recover other valuable metals while recovering iron resources. It can not only eliminate its influence on the environment, but also obtain certain economic value. This paper makes full reference to the comprehensive utilization of pyrite cinder and the study of arsenic removal from arsenic-bearing materials. The iron content of pyrite cinder with high arsenic and copper content is 51.15% and 3.35% and Cu content is 1.02.The iron in pyrite is mainly in the form of hematite Fe2O3) and magnetite Fe3O4). The pyrite cinder with high arsenic and copper content is impregnated, honeycomb structure and loose surface structure. Some gangue minerals and iron minerals are wrapped in each other, or attached to iron mineral surface, and impurity elements distribute uniformly on the surface of slag. This complex conjunctive structure makes it difficult to separate its physical or mechanical treatment methods. According to the mineralogical properties of cinder, pyrite cinder can be leached by sulfuric acid solution, so as to remove arsenic and other impurities such as copper. The effects of sulfuric acid concentration, solid-liquid ratio, temperature, reaction time and clean water washing were studied. The optimum experimental conditions were as follows: the initial sulfuric acid concentration (mass concentration) was 15, the solid-liquid ratio was 1: 3, and the leaching temperature was 60 鈩，

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