【作者】 刘树根；

【导师】 田学达；

【作者基本信息】 湘潭大学 ， 环境工程， 2006， 硕士

【摘要】 砷华生产废渣中Fe、S、As含量较高,同时含有一定量的Zn、Pb、Ag等金属元素,是一种很有综合利用价值的工业废渣。长期以来这类废渣大多采用就地掩埋或囤积贮存的方法处理,不仅对周围环境造成污染,而且大量有价元素得不到充分利用。本文综述了从固体废渣中回收利用S、Fe、Zn的大量研究成果,同时考虑到原料来源、处理技术、经济效益等因素,采用氧化焙烧-软锰矿浆吸收、磁化焙烧-磁选、酸浸的方案实现砷华生产废渣的综合利用,并通过进一步的试验探索了设计方案的各项优化工艺参数。研究试验表明:(1)高温焙烧后废渣中的砷转化为高价态的化合物,利用传统固砷技术,砷以难溶的砷酸盐形式得以沉淀;(2)利用中低品位的软锰矿制浆吸收氧化焙烧产生的烟气,可回收废渣中的硫。氧化焙烧的适宜条件为,焙烧温度650℃,焙烧时间60min,废渣粒度-97μm。采用主副双槽二段循环吸收,在提高Mn浸出率的同时,能确保较高的SO2脱除率;(3)废渣脱硫后,利用磁化焙烧-磁选方法回收其中的铁。磁化焙烧的适宜条件为,焙烧温度550℃,焙烧时间30min,废渣粒度-97μm。选用适宜的磁场强度进行磁选,铁的回收率达84.86%;(4)废渣经氧化焙烧、磁化焙烧处理后,采用高温高酸浸出可回收其中的锌。适宜的浸出条件为,浸出温度90℃,硫酸质量浓度20%,液固质量比5:1,浸出时间120min。在上述优化的工艺条件下进行了氧化焙烧、磁化焙烧-磁选、酸浸的全流程试验。结果表明:硫以硫酸锰形式得以有效回收,总铁回收率为86.83%,锌的回收率为83.42%,最终处理渣中银含量高达246g/t。设计的综合利用工艺流程中副产硫酸锰、铁精矿以及硫酸锌,处理渣中银含量较高,可用来提取银等贵金属。方案的设计为含砷固体废物的无害化、资源化处理相结合开辟了一条新途径,同时也为工业固体废弃物的综合利用提供了重要的借鉴作用。更多还原

【Abstract】 Containing higher contents of Fe, S and As, as well as some minerals of Zn, Pb and Ag, the cinder in arsenite preparation is a valuable residue. In conventional technique of producing arsenite, however, this cinder was disposed by burying on the spot or stockpiling, resulting in a serious environmental pollution and a waste of valuable minerals.Based on a great deal of researches for recovery of S, Fe and Zn from solid waste, a comprehensive utilization technique, including oxidation roasting-absorption with pyrolusite pulp, deoxidization roasting-magnetic separation and acid leaching, was investigated in this paper.Test results showed that (1) Arsenic was transformed into arsenate compounds after a high temperature roasting, and precipitated. (2) The flue gas generated in the process of oxidation roasting was absorbed by a lower pyrolusite pulp, and sulfur was recovered. The optimum condition of oxidation roasting was roasting temperature 650℃, roasting time 60min, and the cinder fineness was less than 97μm. Two troughs of absorption were used to improve the leaching rate of Mn and the desulfurization rate. (3)Fe in the arsenic cinder was recovered by deoxidization roasting-magnetic separation after desulfurization. The optimum condition of deoxidization roasting was roasting temperature 550℃, roasting time 30min and less than 97μm of the cinder fineness. At a certain magnetic intensity, the recovery of Fe was up to 84.86%. (4) Zinc was recovered by acid leaching under high temperature after the cinder was treated by oxidation roasting and subsequent deoxidization roasting. The optimum condition of acid leaching was as following: leaching temperature 90℃, 20% of the mass fraction of sulfuric acid , 5:1 of the L/S and 120min of the leaching time.On the base of conditional tests, a flow-sheet for recovery of Fe, S and Zn was developed. In this flow-sheet, S was recovered in the form of manganese sulfate, Fe and Zn was separated from the cinder with a recovery of 86.83% and 83.43% respectively. The grade of Ag in the final residue was 246g/t.更多还原