黄铁矿利用过程中铊的迁移特征

Migration characteristics of thallium in utilization of pyrite

以静态浸泡、动态模拟淋滤和逐级提取作基础,结合工艺过程,研究了黄铁矿利用过程中铊的迁移特征。结果表明,铊在焙烧时主要随飞灰和炉渣迁移,少量以TlF的气态形式迁移;铊从飞灰、炉渣和沉灰渣中的释放率与浸泡时间成正比,与pH值和粒径成反比(沉灰渣新样除外),且新样铊的释放率大于陈样,浸泡样品铊的释放率大于淋滤样品。当样品中可提取态铊含量较高,或飞灰中不可提取态铊含量较高,且飞灰含有HF、SO2和SO3时,铊容易迁移。当赋存在碳酸盐矿物中的铊含量较高时,铊在酸性条件下也容易迁移,而保持炉渣和沉灰渣的pH值中性或接近中性,可有效防止废渣中的铊淋滤进入环境。

Based on the experimental researches of soak, model leaching and sequential extraction, combined with technological process, the numerous experimental researches were carried out to study migration characteristics of thallium in furnace dust, slag and dreg in utilization of pyrite. The results show that most thallium is moved from ore to furnace dust and slag, and some thallium is moved to gas as TIF form when pyrite is roasted. Release rates of thallium from furnace dust, slag and dreg vary directly with soak time, and inversely with pH and size of sample （except fresh sample of dreg）. Release rates of thallium from fresh samples are more than those from old samples, and release rates of thallium from soak samples are more than those from leaching samples. When the thallium content in the extraction form of the samples is high, or that in the non-extraction form of the furnace dust is high and there are some hydrogen fluoride, sulfur dioxide and sulfur trioxide in the furnace dust, the thallium is migrated easily. When the thallium content contained in carbonate minerals is high, the thallium is migrated easily under acidic condition. Moreover, keeping slag and dreg under neutral or near neutral condition, the leaching of thallium in slag and dreg can be effectively prevented.