A novel coating technique was developed for controlling Pyrite oxidation. The technique invo1ved leachingpyrite particles with a solution containing low concentrations of phosphate and hydrogen peroxide. Duringthe lea...A novel coating technique was developed for controlling Pyrite oxidation. The technique invo1ved leachingpyrite particles with a solution containing low concentrations of phosphate and hydrogen peroxide. Duringthe leaching process, the iron released from pyrite by hydrogen proxide was precipitated by phosphate as aferric phosphate coating. This coating was shown to be able to effectively prevent Pyrite from oxidation and itcould be established at the expense of only surface portions of Pyrite. The emergence of this technique couldprovide a unique potential route for abating acid mine drainage and reclaiming sulfide-containing degradedmining land.展开更多
The exposure of pyrite (FeS2) to atmospheric conditions during mining activity causes a series of complex oxidation reactions, resulting to acid generation and the subsequent release of toxic heavy metals in the surro...The exposure of pyrite (FeS2) to atmospheric conditions during mining activity causes a series of complex oxidation reactions, resulting to acid generation and the subsequent release of toxic heavy metals in the surrounding aquatic and terrestrial ecosystems. The produced acidic mine waters, known as acid mine drainage (AMD), constitute one the major environmental problems of both operating and abandoned mixed sulphide, coal and other mine sites where sulphidic minerals are encountered. A sustainable approach to the environmentally safe pyrite-bearing extractive waste management is related to the prevention of oxidation by developing artificial coatings on the pyrite surfaces. In this study, experiments performed to study the conditions of the silica coating formation on the FeS2 particles contained in a pyrite concentrate are presented. Batch tests involving the treatment of pyrite samples with a coating solution, consisting of Na2SiO3, H2O2 and buffered pH, were performed under a liquid to solid ratio (L/S) 100 l/kg. The effect of parameters including SiO2 concentration (5 - 50 mM), pH values (5.0 - 8.0) and contact time up to 24 hours, was investigated. Parameters examined to monitor the silica coating formation process include analysis of Fe, Si, ?and H2O2 in the aqueous phase. Scanning electron microscopy with energy dispersive spectrometry (SEM/EDS) was used for the examination of the chemically modified surfaces of silica-treated pyrite samples.展开更多
Acid mine drainage (AMD)and toxic metal release generated by oxidation of sulphide minerals, particularly pyrite, in mine wastes,are a critical environmental issue worldwide.Currently, there are many options to dimini...Acid mine drainage (AMD)and toxic metal release generated by oxidation of sulphide minerals, particularly pyrite, in mine wastes,are a critical environmental issue worldwide.Currently, there are many options to diminish sulphide oxidation including barrier methods that isolate pyrite from oxygen or water, chemical additives and inhibition of iron-oxidizing bacteria. This study focuses on understanding the rolethatsilicate and pH conditions play in the formation and stabilisation ofpyrite surface passivation layers found in lab and field studies.The results from pyrite dissolution tests under various conditions showed that the pyrite oxidation rate has been reduced by up to 60% under neutral pH with additional soluble silicate. Solution speciation calculation predicted that crystalline goethite is formed in the experiment without silicate additionbutan amorphous iron hydroxide surface layer is stabilizedby the addition of the silicate, inhibiting goethite formation and continuing pyrite oxidation.This coherent, continuous amorphous layer has been verified in SEM.展开更多
硫铁矿烧渣是硫铁矿生产硫酸过程中产生的固体废弃物,其大量堆积带来了严重的生态环境问题。经适当处理的硫铁矿烧渣中较高价的铁含量高,若能提取利用,不仅可以解决生态环境问题,还可以带来一定的经济效益。本文通过添加固体还原剂高温...硫铁矿烧渣是硫铁矿生产硫酸过程中产生的固体废弃物,其大量堆积带来了严重的生态环境问题。经适当处理的硫铁矿烧渣中较高价的铁含量高,若能提取利用,不仅可以解决生态环境问题,还可以带来一定的经济效益。本文通过添加固体还原剂高温焙烧,成功将硫铁矿烧渣中较高价的铁(Fe 2 O 3)还原为较低价的铁(Fe 3 O 4)。通过单因素试验,得到了较优的还原焙烧条件:在850~900℃下焙烧45~60 min,还原剂化学计量比为1.4~1.7;较优的酸浸条件:硫酸质量分数为30%~40%,硫酸化学计量比为1.2~1.4,浸取时间在30 min以上。在上述条件下,铁的浸出率高达98%。对酸浸液进行除杂处理,利用除杂后的硫酸亚铁净化液制备了磷酸铁产品,经检测,产品质量达到了HG/T 4701-2021《电池用磷酸铁》的技术指标要求。研究成果为硫铁矿烧渣的高值利用提供了一条新途径。展开更多
文摘A novel coating technique was developed for controlling Pyrite oxidation. The technique invo1ved leachingpyrite particles with a solution containing low concentrations of phosphate and hydrogen peroxide. Duringthe leaching process, the iron released from pyrite by hydrogen proxide was precipitated by phosphate as aferric phosphate coating. This coating was shown to be able to effectively prevent Pyrite from oxidation and itcould be established at the expense of only surface portions of Pyrite. The emergence of this technique couldprovide a unique potential route for abating acid mine drainage and reclaiming sulfide-containing degradedmining land.
文摘The exposure of pyrite (FeS2) to atmospheric conditions during mining activity causes a series of complex oxidation reactions, resulting to acid generation and the subsequent release of toxic heavy metals in the surrounding aquatic and terrestrial ecosystems. The produced acidic mine waters, known as acid mine drainage (AMD), constitute one the major environmental problems of both operating and abandoned mixed sulphide, coal and other mine sites where sulphidic minerals are encountered. A sustainable approach to the environmentally safe pyrite-bearing extractive waste management is related to the prevention of oxidation by developing artificial coatings on the pyrite surfaces. In this study, experiments performed to study the conditions of the silica coating formation on the FeS2 particles contained in a pyrite concentrate are presented. Batch tests involving the treatment of pyrite samples with a coating solution, consisting of Na2SiO3, H2O2 and buffered pH, were performed under a liquid to solid ratio (L/S) 100 l/kg. The effect of parameters including SiO2 concentration (5 - 50 mM), pH values (5.0 - 8.0) and contact time up to 24 hours, was investigated. Parameters examined to monitor the silica coating formation process include analysis of Fe, Si, ?and H2O2 in the aqueous phase. Scanning electron microscopy with energy dispersive spectrometry (SEM/EDS) was used for the examination of the chemically modified surfaces of silica-treated pyrite samples.
文摘Acid mine drainage (AMD)and toxic metal release generated by oxidation of sulphide minerals, particularly pyrite, in mine wastes,are a critical environmental issue worldwide.Currently, there are many options to diminish sulphide oxidation including barrier methods that isolate pyrite from oxygen or water, chemical additives and inhibition of iron-oxidizing bacteria. This study focuses on understanding the rolethatsilicate and pH conditions play in the formation and stabilisation ofpyrite surface passivation layers found in lab and field studies.The results from pyrite dissolution tests under various conditions showed that the pyrite oxidation rate has been reduced by up to 60% under neutral pH with additional soluble silicate. Solution speciation calculation predicted that crystalline goethite is formed in the experiment without silicate additionbutan amorphous iron hydroxide surface layer is stabilizedby the addition of the silicate, inhibiting goethite formation and continuing pyrite oxidation.This coherent, continuous amorphous layer has been verified in SEM.
文摘硫铁矿烧渣是硫铁矿生产硫酸过程中产生的固体废弃物,其大量堆积带来了严重的生态环境问题。经适当处理的硫铁矿烧渣中较高价的铁含量高,若能提取利用,不仅可以解决生态环境问题,还可以带来一定的经济效益。本文通过添加固体还原剂高温焙烧,成功将硫铁矿烧渣中较高价的铁(Fe 2 O 3)还原为较低价的铁(Fe 3 O 4)。通过单因素试验,得到了较优的还原焙烧条件:在850~900℃下焙烧45~60 min,还原剂化学计量比为1.4~1.7;较优的酸浸条件:硫酸质量分数为30%~40%,硫酸化学计量比为1.2~1.4,浸取时间在30 min以上。在上述条件下,铁的浸出率高达98%。对酸浸液进行除杂处理,利用除杂后的硫酸亚铁净化液制备了磷酸铁产品,经检测,产品质量达到了HG/T 4701-2021《电池用磷酸铁》的技术指标要求。研究成果为硫铁矿烧渣的高值利用提供了一条新途径。
