Relatedness between catalytic effect of activated carbon and passivation phenomenon during chalcopyrite bioleaching by mixed thermophilic Archaea culture at 65°C

混合嗜热古菌在65°C生物浸出黄铜矿过程中活性炭的催化作用和钝化现象的相关性（英文）

The relatedness between catalytic effect of activated carbon and passivation phenomenon during chalcopyrite bioleachingby mixed thermophilic Archaea culture(Acidianus brierleyi,Metallosphaera sedula,Acidianus manzaensis and Sulfolobusmetallicus)at65°C was studied.Leaching experiments showed that the addition of activated carbon could significantly promote thedissolution of chalcopyrite for both bioleaching and chemical leaching.The results of synchrotron-based X-ray diffraction,ironL-edge and sulfur K-edge X-ray absorption near edge structure spectroscopy indicated that activated carbon could change thetransition path of electrons through galvanic interactions to form more readily dissolved secondary mineral chalcocite at a low redoxpotential(?400mV)and then enhanced the copper dissolution.Jarosite accumulated immediately in the initial stage of bioleachingwith activated carbon but copper dissolution was not hindered.However,much jarosite precipitated on the surface of chalcopyrite inthe late stage of bioleaching,which might account for the decrease of copper dissolution rate.More elemental sulfur(S0)was alsodetected with additional activated carbon but the mixed thermophilic Archaea culture had a great sulfur oxidation activity,thus S0waseliminated and seemed to have no significant influence on the dissolution of chalcopyrite.

研究活性炭对四株典型嗜热古菌混合培养物(Acidianus brierleyi,Metallosphaera sedula,Acidianus manzaensis和Sulfolobus metallicus)在65°C时浸出纯黄铜矿过程中活性炭的催化作用和钝化现象的相关性。浸出实验表明,活性炭能够有效地促进黄铜矿的生物浸出和化学浸出。基于同步辐射技术的X射线衍射、铁的L-边和硫的K-边X射线吸收近边结构光谱学分析表明,在生物浸出过程中当氧化还原电位较低((27)400 mV)时,活性炭能通过原电池反应改变电子传递途径,生成更易溶解的次生矿物辉铜矿,从而增强黄铜矿的浸出。在添加活性炭的生物浸出过程的前期,黄钾铁矾迅速累积但铜离子的浸出速率未受到抑制,然而在生物浸出的后期,大量黄钾铁矾沉淀在矿物表面,从而抑制黄铜矿的进一步溶解。在添加活性炭时检测到了更多的单质硫,但由于嗜热古菌混合培养物具有很强的硫氧化活性,所以生成的单质硫被其消解,因此,未检测到其对黄铜矿浸出有显著影响。