Journal of Sustainable Metallurgy ( IF 2.5 ) Pub Date : 2022-01-21 , DOI: 10.1007/s40831-021-00481-w Neha Nagar 1 , Himanshi Garg 1 , Meenakshi Dhaka 1 , Chandra Sekhar Gahan 1, 2
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The study aims to evaluate bioleaching of zinc sulfide concentrate in controlled redox potential fed-batch mode to avoid passivation occurring in redox non-controlled bioleaching. The microorganisms used in the bioleaching study were a mixed culture of iron-oxidizing microorganisms dominated with Leptospirillum ferriphilum. The motivation for the study was to cut down the cost involved in oxygen consumption due to suppression of sulfur oxidation and activating iron oxidation activity. This innovative approach was possible by carrying out bioleaching on a fed-batch mode with redox potential-controlled bioleaching. The redox-controlled bioleaching was carried out by 100% (v/v) inoculum with high redox potential 650 mV in the reaction vessel with controlled addition of zinc sulfide concentrate maintaining the redox between 550 and 650 mV. The solid percentage of 1% (v/v) of feed material (ZnS concentrate) in the redox-controlled experiment was considered for a batch mode of redox non-controlled experiment for a potential comparative assessment of fed-batch and batch modes. The fed-batch experiment succeeded in restricting the sulfur passivation layer. The time taken by the fed-batch experiment was two times shorter than the batch experiment. The recovery percentage of Zn in redox-controlled batch mode experiment was 51.6%, while in redox-controlled fed-batch mode experiment was 69.4%, which resulted in 34.55% higher recovery in redox-controlled fed-batch bioleaching of ZnS concentrate. The fed-batch bioleaching using iron-oxidizing microorganisms with controlled redox potential restricted sulfur oxidation and was advantageous over the batch process.
Graphical Abstract
中文翻译：
氧化还原控制的分批补料过程中硫化锌精矿的生物浸出与氧化还原非控制的分批过程的比较
本研究旨在评估硫化锌精矿在受控氧化还原电位补料分批模式下的生物浸出，以避免在氧化还原非受控生物浸出中发生钝化。生物浸出研究中使用的微生物是一种以嗜铁钩端螺旋体为主的氧化铁微生物的混合培养物。. 该研究的动机是通过抑制硫氧化和激活铁氧化活性来降低耗氧成本。这种创新方法可以通过采用氧化还原电位控制的生物浸出的补料分批模式进行生物浸出。氧化还原控制的生物浸出通过在反应容器中具有 650 mV 的高氧化还原电位的 100% (v/v) 接种物进行，同时控制添加硫化锌浓缩物，将氧化还原保持在 550 和 650 mV 之间。氧化还原控制实验中 1% (v/v) 的进料（ZnS 浓缩物）的固体百分比被认为是氧化还原非控制实验的分批模式，用于对分批补料和分批模式进行潜在的比较评估。补料实验成功地限制了硫钝化层。分批补料实验所用的时间是分批实验的两倍。氧化还原控制分批试验中锌的回收率为 51.6%，而氧化还原控制补料分批试验为 69.4%，这导致氧化还原控制补料分批 ZnS 精矿生物浸出的回收率提高了 34.55%。使用具有受控氧化还原电位的铁氧化微生物的补料分批生物浸出限制了硫氧化，并且优于分批工艺。
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