{"title":"Mechanism of pyrite depression by marine Fe(II)-oxidizing bacteria in seawater flotation","authors":"","doi":"10.1016/j.mineng.2024.109029","DOIUrl":null,"url":null,"abstract":"<div><div>Seawater flotation is a promising technique to reduce environmental and economic loads in mineral processing. This study attempted to depress pyrite, a common gangue sulfide mineral, using two marine iron (Fe) oxidizing bacteria (MFeOB), <em>Thalassospira</em> sp. TF-1 and <em>Mariprofundus</em> sp. E-4, in seawater flotation without pH control; the MFeOB could contribute to hydrophilization of the pyrite surface by oxidation and/or adhesion of bacterial cells. Pyrite or chalcopyrite samples were preconditioned in seawater containing MFeOB for different times (15 min or 30 min). As a result of flotation experiments, the recovery of pyrite preconditioned without MFeOB (i.e., control sample) decreased to 64.2 % after 30 min reaction. The same recovery was observed when pyrite was preconditioned with <em>Thalassospira</em> sp. TF-1, whereas the recovery was successfully decreased to 20.2 % after preconditioning with <em>Mariprofundus</em> sp. E-4 for 30 min. X-ray photoelectron spectroscopy analysis of preconditioned pyrite samples showed no significant difference of Fe-oxidizing compounds between with and without MFeOB reaction, suggesting that the formation of hydrophilic substances such as Fe(OH)<sub>3</sub> derived from pyrite oxidation by MFeOB is unlikely to be the main reason for the pyrite depression by <em>Mariprofundus</em> sp. E-4. The adhesion experiment revealed that MFeOB cells could cover the pyrite surface but not the chalcopyrite surface, showing that the hydrophilicity of <em>Mariprofundus</em> sp. E-4 cell caused the pyrite depression. This result suggests that the hydrophilic/hydrophobic properties of bacterial cells are a significant determining factor in pyrite recovery in seawater flotation in the case of MFeOB.</div></div>","PeriodicalId":18594,"journal":{"name":"Minerals Engineering","volume":null,"pages":null},"PeriodicalIF":4.9000,"publicationDate":"2024-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Minerals Engineering","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0892687524004588","RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENGINEERING, CHEMICAL","Score":null,"Total":0}
引用次数: 0
Abstract
Seawater flotation is a promising technique to reduce environmental and economic loads in mineral processing. This study attempted to depress pyrite, a common gangue sulfide mineral, using two marine iron (Fe) oxidizing bacteria (MFeOB), Thalassospira sp. TF-1 and Mariprofundus sp. E-4, in seawater flotation without pH control; the MFeOB could contribute to hydrophilization of the pyrite surface by oxidation and/or adhesion of bacterial cells. Pyrite or chalcopyrite samples were preconditioned in seawater containing MFeOB for different times (15 min or 30 min). As a result of flotation experiments, the recovery of pyrite preconditioned without MFeOB (i.e., control sample) decreased to 64.2 % after 30 min reaction. The same recovery was observed when pyrite was preconditioned with Thalassospira sp. TF-1, whereas the recovery was successfully decreased to 20.2 % after preconditioning with Mariprofundus sp. E-4 for 30 min. X-ray photoelectron spectroscopy analysis of preconditioned pyrite samples showed no significant difference of Fe-oxidizing compounds between with and without MFeOB reaction, suggesting that the formation of hydrophilic substances such as Fe(OH)3 derived from pyrite oxidation by MFeOB is unlikely to be the main reason for the pyrite depression by Mariprofundus sp. E-4. The adhesion experiment revealed that MFeOB cells could cover the pyrite surface but not the chalcopyrite surface, showing that the hydrophilicity of Mariprofundus sp. E-4 cell caused the pyrite depression. This result suggests that the hydrophilic/hydrophobic properties of bacterial cells are a significant determining factor in pyrite recovery in seawater flotation in the case of MFeOB.
期刊介绍:
The purpose of the journal is to provide for the rapid publication of topical papers featuring the latest developments in the allied fields of mineral processing and extractive metallurgy. Its wide ranging coverage of research and practical (operating) topics includes physical separation methods, such as comminution, flotation concentration and dewatering, chemical methods such as bio-, hydro-, and electro-metallurgy, analytical techniques, process control, simulation and instrumentation, and mineralogical aspects of processing. Environmental issues, particularly those pertaining to sustainable development, will also be strongly covered.