富氧侧吹熔炼烟气干法收砷工艺技术难点研究

以含砷金铜精矿富氧侧吹熔炼烟气干法收砷为研究对象,分析了烟气中三氧化硫含量、骤冷塔喷枪布局、骤冷塔有效高度、布袋收砷器入口温度等因素对干法收砷效果的影响,并就相关技术控制难点作了研究。通过控制氧气含量可控制烟气中的三氧化硫含量;取消骤冷塔顶部喷枪,在塔体再增加2支喷枪,可使烟气有效降温;通过增加骤冷塔的高度可延长吸收剂在骤冷塔中的停留时间,使其完全汽化;通过控制骤冷塔喷枪吸收剂的喷洒量,可控制布袋收砷器入口温度维持在150~170℃。上述措施成功应用于生产实践。目前系统投矿量1 900 t/d,投矿砷品位1.5%,收砷量23 t/d,制酸工段净化稀酸含砷量由18 000 mg/L下降至4 000 mg/L;净化工序一级高效洗涤器阻力下降2 000 Pa左右,稀酸压滤渣产量大幅下降;系统运行稳定。

Study on Technical Difficulties of Dry Arsenic Collection Process for Off-gas from Oxygen-enriched Side-blowing Smelting

Taking the dry arsenic collection technology of oxygen-enriched side-blown smelting flue gas of As-bearing gold-copper concentrate as the research object, the effects of sulfur trioxide content in flue gas, spray gun layout of quench tower, effective height of quench tower and inlet temperature of bag collector on dry arsenic recovery were analyzed, and the related technical control difficulties were studied. Sulfur trioxide content in flue gas can be controlled by controlling oxygen content;cancelling the top spray gun of the quench tower, and increasing two spray guns in the tower body can effectively cool the flue gas;by increasing the height of the quench tower, the residence time of the absorbent in the quench tower can be prolonged to make it completely vaporized. By controlling the spraying amount of the absorbent of the spray gun in the quench tower, the inlet temperature of the bag filter can be maintained at 150-170 ℃. The above measures have been successfully applied to production practice. At present, this system under stable operation treats 1 900 t/d ore feed with As grade of 1.5% and collects 23 t/d As. The As content in purified dilute acid from acid-making section drops from 18 000 mg/L to 4 000 mg/L. Resistance of primary high-efficiency scrubber used in purification procedure decreases by around 2 000 Pa and the filter press residue of dilute acid dramatically declines.