反应器结构对生物氧化含砷难处理金矿效率的影响

Effect of Reactor Structure on the Rate of Biooxidation of Arsenic-bearing Refractory Gold Ore

含砷难处理金矿的细菌氧化预处理法具有投资成本较低、反应易控制及适合中小型金矿等优点,但此法空气利用率较低,造成通气量很大,通气动力成本过高。本研究提出了新型的导流式搅拌槽,通过改善通气和搅拌方式,降低通气成本和动力消耗,提高浸出效率。以含砷难处理金精矿为研究对象,采用嗜酸性氧化亚铁硫杆菌(At.f)对其进行生物预氧化搅拌浸出实验。实验对比研究了采用普通搅拌槽和导流式搅拌槽对含砷金精矿生物浸出过程中矿浆p H值、氧化还原电位(Eh)、总铁和总砷浸出率的差异,并对导流式搅拌槽中浸渣进行XRD和SEM分析。结果发现,反应第二天开始导流式搅拌槽中Eh值迅速升高,且最大值为497 m V,脱砷率达到34.86%,浸渣硫脲法提金率为58%。

Compared with other pretreatment methods of arsenic-bearing refractory gold ore,biooxidation has some advantages such as low capital cost and easily operating, which are appropriate for small and medium sized gold mines.But the relatively low aeration efficiency in the biooxidation lead to require lots of aeration and high power cost.In this study,a novel structure of the stirred reactor is proposed,which improves the aeration efficiency and the way of agitation, can reduce amount of aeration and cost of power consumption by increasing the efficiency of biooxidation.Acidithiobacillus ferrooxidans （Atf） is applied to leach the arsenic-bearing refractory floatation gold concentrate in a 100 L stirred tank reactor with and without draft tube.The pH and redox potential （Eh）, are monitored and sampled regularly for measurement of total amount of iron and total amount of arsenic.The treated concentrate is analyzed with XRD and SEM.The results show that in the biooxidation process of two weeks, at the second day of biooxidation Eh increases rapidly and the maximum value is 497 mV,the arsenic removal rate reaches 34.86%, and gold extraction rate reaches 58%.