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传统的湿法炼锌工艺在热酸浸出阶段,会产出大量的铅银渣,由于该工艺的特点,冶炼原料中的绝大部分的铅银金属会进入铅银渣中,由于其矿石性质的特殊性,目前对铅银渣中的有价金属尚无有效的回收方法,大部分的铅银渣都采取堆存的方法。由于铅银矿物被铁酸锌包裹,利用传统的浮选工艺难以达到理想的回收效果,针对上述问题,研究了“酸性焙烧-浮选”联合工艺从铅银渣中回收铅银的影响因素和机制。结果表明:将铅银渣在650℃,硫酸用量为25%的条件下进行酸性焙烧50 min后浮选的联合工艺流程可以获得含铅46.76%,铅回收率75.89%,含银2846.41 g·t~(-1),银回收率为84.06%的铅银精矿。利用X射线衍射(XRD)、扫描电子显微镜(SEM)和能谱仪(EDS),研究了酸性焙烧的机制,通过对比焙烧前后的矿物组成及微观结构的变化,发现酸性焙烧导致包裹铅银的铁酸锌包裹层被破坏,其中的有价铅银矿物得以释放,是提高浮选回收铅银渣中铅银的主要原因。
Due to the characteristics of the process, most of the lead and silver metals in the smelting raw materials will enter the lead-silver slag due to the nature of the ore Of the particularity of the current lead-silver slag in the valuable metals there is no effective recovery method, most of the lead and silver slag to take stockpiling methods. Due to the lead and silver minerals are wrapped by zinc ferrite, the traditional flotation process is difficult to achieve the ideal recovery effect. In response to the above problems, the effect of lead-silver recovery from lead-silver slag was studied in a combination of “acid roasting-flotation” Factors and mechanisms. The results showed that 46.76% of lead, lead of 75.89% of lead and 2846.41 g · t of silver were obtained when the lead-silver slag was flotation at 650 ℃ and sulfuric acid concentration of 25% for 50 min. ~ (-1), silver recovery rate of 84.06% of lead and silver concentrate. The mechanism of acid roasting was studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). By comparing the changes of mineral composition and microstructure before and after roasting, The destruction of zinc ferrite coating and the release of valuable lead and silver minerals are the main reasons for the recovery of lead and silver from lead-silver slag by flotation.