Microbial solubilization of phosphorus from phosphate rock by iron-oxidizing Acidithiobacillus sp. B2

Procedures for solubilization of phosphorus from insoluble phosphates by acidophilic autotrophs and heterotrophs are considered to be research subjects of great importance in sustainable soil management, and could become, in the future, an alternative to current expensive methods of industrial fertilizer production. Furthermore, this biological production of fertilizer can be considered to be more environmentally friendly than current production methods.The object of this study was to investigate the possibility of phosphorus leaching from phosphate rock apatite using sulphuric acid generated from pyrite by iron-oxidizing Acidithiobacillus sp. B2, and to test the possible application of the mixture of these two minerals to produce a natural phosphate fertilizer.Iron-oxidizing Acidithiobacillus sp. B2 was isolated from copper sulphide mine wastewater (Lake Robule) in Bor, Serbia. The bacterium was identified by 16SrDNA oligonucleotide sequence and characterized using matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy (MALDI-TOF MS).The leaching experiment was carried out in laboratory conditions at 28 °C for a period of four weeks.The results showed that up to 34.5% of the inorganic phosphorus was leached from the test mixture when in suspension with iron-oxidizing Acidithiobacillus sp. B2, while at the same time, the degree of leaching from a control suspension (without iron-oxidizing Acidithiobacillus sp. B2) was only up to 3.8%.Due to its low cost and environmental acceptance, treatment of soil with phosphate minerals in combination with pyrite and acidophilic iron- and sulphur-oxidizing bacteria could become an attractive and alternative way to improve the quality of alkaline soils.     

云南大红山铜矿化学浸出研究

以云南大红山铜矿的铜精矿为研究对象,分别考查其在稀硫酸、硫酸高铁、硫酸亚铁三种介质中的溶解情况。通过试验研究发现,在pH1.0~2.0、常温常压条件下,该铜精矿基本不溶于稀硫酸溶液和硫酸高铁溶液,而在硫酸亚铁溶液中该铜精矿溶解速率明显加快,但浸出后期有明显的钝化现象。浸渣XRD和SEM分析表明,硫酸亚铁溶液浸出后浸出渣有单体硫物相存在,而且矿物表面有明显的"腐蚀坑",能谱分析也证实矿物表面有硫元素过量的情况。另外,硫酸亚铁溶液浸出过程中体系酸耗明显增加,这一方面是由于Fe2+离子氧化造成的,另一方面矿石的大量溶解也增加了酸耗量。     

微生物浸出磁黄铁矿的试验研究

采用矿驯化以及矿坑的嗜酸嗜铁混合菌(Acidthiobacillus ferrooxidans与Leptospirillum ferriphilum)进行了磁黄铁矿浸出试验,并探讨了混合菌浸出磁黄铁矿的机理。结果表明,与矿驯化菌相比,矿坑混合菌对磁黄铁矿具有更强的吸附能力;细菌吸附后,磁黄铁矿的等电点朝细菌的等电点方向偏移;由于矿坑混合菌对磁黄铁矿的作用更强,使其得到的矿物接触角下降幅度均大于矿驯化混合菌作用下的接触角;磁黄铁矿浸出初期是以酸溶为主,随着浸矿的进行,混合菌发挥作用,整个浸矿过程,体系中会发生铁离子的相对富集,致使矿物动电位值增大,而由于铁离子不能稳定性存在,易在体系中生成亲水性的铁沉淀覆盖于矿物表面,从而引起磁黄铁矿表面亲水性增强,接触角变小。在嗜酸嗜铁混合菌浸出磁黄铁矿过程中,磁黄铁矿主要是被溶液中的铁离子氧化。     

Visualization of initial attachment of bioleaching bacteria using combined atomic force and epifluorescence microscopy

Bioleaching is the dissolution of metal sulfides, such as pyrite and chalcopyrite, by bacterial oxidation processes. It has been found that attachment of leaching bacteria to the mineral surface enhances the metal sulfide dissolution. The interaction of mixed cultures with respect to initial attachment processes has not been investigated. Therefore in this study we quantified and visualized initial colonization on pyrite by pure and mixed cultures. Strains of the genera Acidithiobacillus and Leptospirillum were tested. Sessile and planktonic cells were visualized by fluorescence microscopy using DAPI, FISH, Syto? 9, lectin- and calcofluor-staining. Additionally, atomic force microscopy (AFM) was used for the investigations on cell morphology, spatial arrangement of cells on pyrite and mineral surface topography. The morphology of planktonic and sessile cells is different. Moreover, planktonic cells show differences in morphology due to the use of different substrata. By using different visualization methods it could be proven that colonization and biofilm formation on pyrite in mixed cultures is mostly dominated by Leptospirillum spp. Interactions of different species resulted in increased production of extracellular polymeric substances (EPS) or caused bacteria showing little tendency to attach when in monoculture to be incorporated into a biofilm by those that attach preferentially. Consequently, biofilm formation and metabolic diversity were furthered. One of the most important results is the finding that not all bioleaching bacteria are involved to the same extent in biofilm formation. Thus, further work shall allow us elucidate the important bacteria for biotechnological use, thereby leaching processes can be faster, more efficient and costs can be reduced.     

黄铁矿表面氧化机理及动力学影响因素研究进展

黄铁矿作为矿区环境中最为常见的金属硫化物尾矿,在表生环境下易被氧化形成酸性矿山废水(acid mine drainage,AMD),进而产生一系列环境污染问题.因此,黄铁矿表面氧化机理及其动力学影响因素研究一直是矿区污染环境治理领域的研究热点.首先概述了黄铁矿基本结构和物理化学性质,指出黄铁矿表面氧化机理及其规律研究对...     

嗜酸氧化亚铁硫杆菌APY的生长特性及其在黄铁矿表面的吸附

为了筛选嗜酸氧化亚铁硫杆菌并探明其在黄铁矿表面的吸附性能,从赣州某矿山酸性矿坑水中分离得到APY菌,对该菌形态、生长特性和16S r DNA序列进行了分析,并对该菌在黄铁矿表面的吸附特性进行了研究。结果表明,APY菌与嗜酸氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans CK和BGL-2)处在系统发育树的同一分支,覆盖度和相似度均超过98%,判断APY菌为嗜酸氧化亚铁硫杆菌;APY菌适宜的生长条件为:1菌液与培养基体积比为10%;2培养液的初始p H=2.0;3恒温气浴摇床转速为180 r/min;4适宜的培养温度为30℃,其中p H为APY菌生长的限制性影响因素。APY菌在黄铁矿表面的吸附速度快,在p H=2.0时,20 min混合液中就有约1.5×108cell/m L的APY菌吸附在黄铁矿表面。     

黄铁矿的可浮性研究及生产实践

文章综合了国内外有关资料,并结合生产实际对黄铁矿的可浮性进行了评述。纯矿物试验表明,表面氧化的黄铁矿,无论是增加捕收剂、添加活化剂硫酸铜,都不能使黄铁矿的可浮性得到很好的改善。本文重点研究了影响黄铁矿可浮性的各种因素,如氧化作用、pH值、抑制剂和调整剂种类、酸洗黄铁矿矿物表面和硫酸铜活化等。指出了生产实践中回收难选黄铁矿的技术途径。     

中温及嗜热菌对不同成因黄铜矿浸出行为的影响

以斑岩型黄铜矿和矽卡岩型黄铜矿为研究对象,考察了嗜酸氧化亚铁微螺菌(L f)和嗜热硫氧化硫化杆菌(S t)对不同成因黄铜矿浸出行为的影响。结果表明,在2种不同细菌浸出体系中矽卡岩型黄铜矿均表现出比斑岩型黄铜矿浸出率高;S t浸出2种不同成因黄铜矿的效率均比L f的好。通过对不同浸矿时间黄铜矿浸出渣的XRD检测并结合黄铜矿浸出过程反应步骤的分析表明,2种细菌浸出不同成因黄铜矿的机制相同,细菌的代谢途径及反应温度是影响同类成因黄铜矿浸出率和代谢产物差异的主要原因。S t作用下浸出后期黄铜矿表面有黄钾铁矾生成,而L f浸出体系黄铜矿表面主要是S的不断积累。同种浸矿菌种浸出不同成因黄铜矿时,矽卡岩型黄铜矿在浸出第15 d有S生成,斑岩型黄铜矿在S t浸出体系S生成的时间更晚,在L f浸出体系S的生成量则更少,推测矿物性质是引起其差异的主要原因。     

嗜酸性浸矿菌对不同外源黄铁矿的利用率研究

某矿床铀矿石中黄铁矿含量较低,为提高矿石的生物可浸性,需选择并添加一种便于浸矿菌利用的黄铁矿。本文利用某铀矿富集得到的嗜酸性浸矿菌B3mYP1Q-C,对3种不同产地的黄铁矿进行黄铁矿利用摇瓶试验,试验所用混合菌群B3mYP1Q-C对选取的3种外源黄铁矿均可利用,但利用率差别较大,江西某铜矿黄铁矿精矿的利用率最高;同时,经过设置添加含氟矿石对照试验组,证明了含氟铀矿石会影响微生物菌种活性,亦会降低微生物对黄铁矿的利用能力。     

Phosphate coating on pyrite to prevent acid mine drainage

Abstract

Acid mine drainage (AMD) is a serious environmental problem that preoccupies the Canadian Mineral Industry. Considerable amounts of money are spent every year in an effort to prevent or reduce the acid mine drainage phenomenon. AMD occurs when sulfide minerals (ex. pyrite) contained in rock are exposed to air and water and subsequently oxidize to produce low pH water. This acid effluent has the potential to mobilize any heavy metals contained in the rock. Coating the sulfide minerals with iron phosphate is a new promising technology to reduce AMD.Pyrite is treated with a solution containing H₂O₂, KH₂PO₄ and sodium acetate (NaAc). H₂O₂ oxidizes a small part of pyrite producing ferric iron (Fe³⁺) anions. These cations subsequently react with the PO₄ ^3? anions to produce FePO₄ that precipitates on the pyrite surface producing a passive coating. This iron phosphate coating can protect the grains of pyrite from oxidation. This paper presents a series of experiments that confirm that iron phosphate coating can considerably reduce AMD.     

硫化铜矿新型捕收剂PZO的浮选性能与机理

为检验广州有色金属研究院研制的新型硫化铜矿浮选捕收剂PZO在铜硫分离中的选择性,比较了PZO、丁基黄药和丁铵黑药在不同矿浆pH值、不同用量条件下分别浮选黄铜矿和黄铁矿单矿物的效果,并借助紫外可见分光光谱仪、红外光谱仪对PZO在黄铜矿、黄铁矿表面的吸附量和作用机理进行了研究。结果显示：①在试验pH范围内,丁基黄药、丁铵黑药、PZO对黄铜矿的捕收能力均强于对黄铁矿。②矿浆的酸碱度对黄铜矿可浮性的影响均较小,且黄铜矿回收率的高点在弱酸或弱碱性环境下,黄铁矿在酸性环境下的可浮性明显强于在碱性环境。③3种捕收剂的选择性强弱顺序为PZO＞丁铵黑药＞丁基黄药,在pH=8.5时,黄铜矿与黄铁矿的回收率差值可达68.19个百分点。④PZO是一种酯类浮选药剂,与黄铁矿相比,其更容易在黄铜矿表面吸附,且以化学吸附为主。以上结果表明,PZO在pH=8.5的环境下可高效分离黄铜矿与黄铁矿。     

Using permeable reactive barriers for the treatment of acid rock drainage

Acid mine drainage (AMD) is the most serious environmental problem facing the Canadian mineral industry today. It results from oxidation of sulphide minerals (e.g. pyrite or pyrrhotite) contained in mine waste or mine tailings and is characterized by acid effluents rich in heavy metals that are released into the environment. A new acid remediation technology is presented, by which metallurgical residues from the aluminium extraction industry are used to construct permeable reactive barriers (PRBs) to treat acid mine effluents. This technology is very promising for treating acid mine effluents in order to decrease their harmful environmental effects.     

黄铁矿的吸附性能研究现状及进展

黄铁矿是自然界中储量最丰富的硫化矿之一,常与铅、锌、铜等价值较高的硫化矿共生。针对被高碱抑制的黄铁矿,常使用活化剂改善其可浮性,从而活化选硫,而活化剂对黄铁矿表面性质的影响是研究其作用机理的关键。本文详细阐述了黄铁矿晶体性质,包括其微观晶体结构、能带结构、态密度、Mulliken布局、电化学性质等;以黄铁矿表面物种演变为切入点,介绍了表面杂质掺杂、空位缺陷和表面氧化对其可浮性的影响。综述了离子活化和活化药剂的作用机理：铜、铅离子活化会在黄铁矿表面形成吸附活性位点,促进捕收剂吸附;酸类活化剂会清除黄铁矿表面亲水沉淀和氧化产物;盐类活化剂则会与黄铁矿表面原子反应,改变黄铁矿表面性质和水化层结构,从而促进浮选。加强对活化剂作用过程中黄铁矿表面性质的观察、表征、精确计算和模拟,可为黄铁矿的高效清洁活化剂研发、资源合理利用和环境保护提供一定科学依据。     

黄铁矿浮选活化机理研究进展

黄铁矿是自然界中储量最丰富的硫化矿之一,常与铅、锌、铜等价值较高的硫化矿共生。针对被高碱抑制的黄铁矿,常使用活化剂改善其可浮性,从而活化选硫,而活化剂对黄铁矿表面性质的影响是研究其作用机理的关键。本文详细阐述了黄铁矿晶体性质,包括其微观晶体结构、能带结构、态密度、Mulliken布局、电化学性质等;以黄铁矿表面物种演变为切入点,介绍了表面杂质掺杂、空位缺陷和表面氧化对其可浮性的影响。综述了离子活化和活化药剂的作用机理：铜、铅离子活化会在黄铁矿表面形成吸附活性位点,促进捕收剂吸附;酸类活化剂会清除黄铁矿表面亲水沉淀和氧化产物;盐类活化剂则会与黄铁矿表面原子反应,改变黄铁矿表面性质和水化层结构,从而促进浮选。加强对活化剂作用过程中黄铁矿表面性质的观察、表征、精确计算和模拟,可为黄铁矿的高效清洁活化剂研发、资源合理利用和环境保护提供一定科学依据。     

黄铁矿和镍黄铁矿混合细菌浸出过程的原电池效应

应用硫化矿细菌修饰粉末微电极，研究镍黄铁矿与黄混合矿细菌浸出过程的原电池效应。结果表明，当镍黄铁矿中加入黄铁矿及C时，浸出率有所增加，当细菌和黄铁矿综合影响时，镍黄铁矿浸出10d,Ni浸出率可达90％，C及黄铁矿与镍黄铁矿混合时，由于接触电位的影响，镍黄铁矿氧化反应电流增大，反应起始电位负移，反应加剧，而黄铁矿的氧化反应受到抑制。据表面EDS能谱分析，混合铁矿表面Ni含量较单一矿浸出时低得多。     

矿物学因素对黄铁矿浮选行为影响的研究进展

黄铁矿是一种广泛存在的硫化金属矿,其浮选问题一直是矿业工程领域的研究热点。浮选实践表明不同成因黄铁矿间可浮性存在差异性,主要由其矿物学因素差异所致。黄铁矿矿物学因素的微小变化会对其浮选行为产生不同程度的影响,如晶格缺陷会通过改变黄铁矿矿物表面吸附特性来增强或降低其可浮性。主要分析了晶格缺陷、物理性质和化学组成三方面因素对黄铁矿可浮性的影响,论述了矿物学因素与黄铁矿浮游特性间的普遍规律性,以引起选矿工作者对矿物学因素的重视,为黄铁矿浮选实践提供理论参考。     

蛇纹石与黄铁矿间的异相凝聚/分散及其对浮选的影响

通过浮选试验、浊度测定、ζ电位测定和吸附量测定, 研究了蛇纹石与黄铁矿间的异相凝聚/分散及其对浮选的影响。结果表明, 在pH=7～10.2, 蛇纹石与黄铁矿表面间静电力表现为引力, 颗粒间的异相凝聚严重, 且当蛇纹石量占黄铁矿量5%时, 就会显著降低黄铁矿回收率。原因是蛇纹石异相凝聚于黄铁矿表面, 不仅自身的可浮性差, 还会降低戊基黄药在黄铁矿表面的吸附量。增加捕收剂用量或添加六偏磷酸钠均能有效改善黄铁矿的浮选。六偏磷酸钠可以使蛇纹石表面ζ电位由正转负, 有效减弱异相凝聚。     

煤与黄铁矿表面改性的研究

阐述了用电化学法对细粒煤与黄铁矿表面的改性机理。用Raman光谱对煤表面含氧官能团减少、疏水性增强进行了定性分析。运用X射线衍射仪证实了黄铁矿表面改性的事实。研究表明,电化学处理后两者向相反的方向改性,为高硫煤浮选脱硫提供了理论依据。     

酸性矿山废水中表面钝化技术的研究进展北大核心

酸性矿山废水(AMD)是最为严重的环境污染之一,主要由黄铁矿氧化引起。AMD的治理主要有末端处理和源头控制两条途径,末端处理技术不能从根本上解决污染问题,因此从源头控制黄铁矿的氧化是治理AMD的根本途径。源头控制技术主要有覆盖法、杀菌法和表面钝化法等,表面钝化法是目前科研工作者的研究热点。在介绍AMD成因的基础上,综述了各种表面钝化技术。重点概述了有机硅烷、载体-微胶囊化、自修复等技术的研究现状,分析了不同方法的优缺点,并针对其不足之处提出了今后的研究方向。为解决黄铁矿氧化问题、实现AMD污染的有效治理提供参考。     

Effect of grinding media on the activation of pyrite flotation

In previous study, it has been found that the grinding conditions have a great effect on the flotation of chalcopyrite and galena as well as their separation from pyrite (Peng et al., 2003a, Peng et al., 2003b). In this study, the effect of the grinding conditions on the activation of pyrite by Cu²⁺ and Pb²⁺ were investigated. Based on flotation behaviour, EDTA (ethylene diamine-tetra acid) extraction, pulp potential measurement and electrokinetic study, it is found that the activation of pyrite flotation by Cu²⁺ and Pb²⁺ involves different mechanisms. Reduction of copper(II) to copper(I) and the formation of new copper sulphide phases are responsible for the activation of pyrite flotation by Cu²⁺. This is an electrochemical process. However, adsorption of lead hydroxide on pyrite surface is principally responsible for the activation of pyrite flotation by Pb²⁺. The effect of grinding media on the flotation of pyrite activated by Cu²⁺ or Pb²⁺ is through the change of pulp potential and iron oxidation species emanating from the media. The iron oxidation species from grinding media is electrostatically repulsive with respect to copper-activated pyrite and therefore, reducing conditions produced by mild steel medium promotes pyrite flotation in the presence of Cu²⁺. However, iron oxidation species from grinding media is electrostatically attractive with respect to lead-activated pyrite and therefore inert grinding medium favours pyrite flotation in the presence of Pb²⁺. This study provides a clear picture of how to increase or decrease pyrite flotation through a smart selection of grinding media.