(1. 昆明理工大学 省部共建复杂有色金属资源清洁利用国家重点实验室，昆明 650093；
2. 昆明理工大学 冶金与能源工程学院，昆明 650093)
摘 要: 钢渣是一种冶金工业固体废弃物，具有强碱性并富含铁氧化物，对酸性重金属废水处置有着巨大潜力，改性钢渣有望进一步提高除砷效率并应用于污酸除砷。实验研究了酸、碱、盐和热改性对钢渣理化性质和除砷效率的影响，考察了强化氧化对改性钢渣除砷性能的影响规律，分析了除砷后钢渣浸出毒性特性。结果表明：与未改性钢渣相比，改性钢渣除砷性能有所提高，其中酸改性和盐改性钢渣的除砷性能显著提高。针对含砷浓度为4200 mg/L的污酸，按照固液比0.04 kg/L加入酸改性钢渣，在氧化剂作用下并在室温振荡反应120 min，处置后污酸残余砷浓度降至88.44 mg/L，砷去除效率达到97.89%，除砷后钢渣浸出毒性低于危险废弃物鉴别标准《GB 5085.3— 2007》限值5 mg/L，属于一般固体废弃物，可安全堆存。研究表明：酸改性钢渣能释放大量Ca、Fe离子，通过共沉淀和吸附的作用可将砷去除。钢渣预处理及除砷机制为钢渣两步法处置含砷污酸提供了一种思路。
关键字: 污酸；砷；改性钢渣；共沉淀；吸附
（1. State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming 650093, China;
2. Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China）
Abstract:Steel slag, a bulk solid waste in metallurgical industry, characterizes with high alkalinity and iron-laden composition. It shows the great potential for the heavy metal wastewater treatment, expecting to be used for the high-efficiency arsenic removal from waste acid after further modification. The effects of modifications including acid, alkali, salt, and thermal pretreatments on the physicochemical properties and arsenic removal efficiency were studied. The influence of oxidation on the arsenic removal performance of modified steel slag was investigated. The toxic characteristics of arsenic-laden steel slag obtained from arsenic removal were analyzed. The results show that the modified steel slag exhibits better arsenic removal performance compared to untreated one, of which the arsenic removal performances of acid and salt modified steel slag are significantly improved. For the waste acid with arsenic concentration of 4200 mg/L, the acid-modified steel slag is added to remove arsenic according to the solid-liquid ratio of 0.04 kg/L and the reaction is kept at room temperature for 120 min. After the reaction, the residual arsenic concentration in the waste acid decreases to 88.44 mg/L, following with an arsenic removal rate of 97.89%. In addition, the arsenic leaching concentration of arsenic-laden steel slag obtained from arsenic removal is lower than the limit value of the hazardous waste identification standard (GB 5085.3—2007) 5 mg/L, which belongs to general solid waste and can be safely stored. It is found that the acid-modified steel slag can release a large amount of Ca and Fe ions that enable to remove arsenic by coprecipitation and adsorption. The arsenic removal mechanism using modified steel slag provides a feasible solution for the arsenic-containing waste acid treatment using a stepwise process composed of pretreatment of steel slag and arsenic removal.
Key words: waste acid; arsenic; modified steel slag; coprecipitation; adsorption
