嗜酸氧化亚铁硫杆菌浸出黄铜矿中氧化还原电位、黄铁钾钒和胞外聚合物的关系和影响(英文)

在合成的胞外聚合物(EPS)溶液中,研究不同起始总铁量、不同Fe(III)与Fe(II)摩尔比条件下嗜酸氧化亚铁硫杆菌浸出黄铜矿过程中pH、电位、可溶性铁离子和Cu2+浓度随浸出时间的变化。结果表明:当溶液电位低于650mV(vsSHE)时,因细菌产生的EPS可通过絮凝黄铁钾钒延缓污染,即使铁离子浓度达到20g/L,黄铁钾钒对细菌浸出黄铜矿的阻碍作用也不是致命的,但随着铁离子浓度的增加而增加;细菌氧化的铁离子容易吸附在黄铜矿表面的EPS表层,有黄铁钾钒的EPS层是弱离子扩散壁垒,细菌通过把EPS空间内外的Fe2+氧化成Fe3+,进一步创造高于650mV的电位,导致EPS层离子扩散性能的快速恶化,严重地和不可逆地阻碍生物浸出黄铜矿。     

铜湿法冶金中的萃取剂

介绍国内外铜湿法冶金中萃取剂的研究进展,描述五种羟肟萃取剂的结构、性能及使用情况,比较LIX系列、Acorga系列、前苏联和我国合成的萃取剂的萃取性能,探讨羟肟萃取剂分离Cu/Fe的作用机理,阐述选择萃取剂的原则.     

从含铜铁的生物浸出液中选择性萃取铜的试验研究

本文采用Lix984作萃取剂，从含铜铁的生物浸出液中选择性萃取铜。通过考察溶液pH、相比O／A、初始铜浓度、萃取温度、搅拌速度及搅拌时间、萃取级数等因素对萃取率、分配比、分离系数的影响，结果表明：pH大于2．22，相比O／A=1：1，搅拌速度为200rpm，搅拌时间为4min，萃取级数为3级，铜的萃取率能达到99．8％以上，铜分配比能达到600以上，铁分配比小于1，铜铁分离系数能达到1900以上，同时发现低初始铜浓度及高萃取温度对萃取有利，可见生物浸出液中铜铁能达到很好的分离效果。     

提高地浸氧化剂效率的探索性研究

根据伊宁铀矿512矿床1号采区现场生产监测数据，并通过有无氧化助剂的柱浸对比试验，研究了影响氧化剂效率的因素及氧化剂的作用机制，探索性研究了氧化助剂对渗透性、浸出电位及铀浸出的影响。结果表明，由于氧化助剂能选择性地沉淀或吸附于耗氧矿物和粘土表面，减少了争耗氧化剂的多相副反应，改善了渗透性，提高了浸出电位及铀的浸出性能。     

EPS-contact-leaching mechanism of chalcopyrite concentrates by A. ferrooxidans

The effect of extracelluar polymeric substances（EPS） on the bioleaching chalcopyrite concentrates in the presence of ironand sulphur-oxidizing bacteria （A. ferrooxidans） was studied. The bacterial number, pH, redox potential, and the concentrations of Fe^2＋ and Cu^2＋ ions were investigated. The leached residues were analyzed by the X-ray diffraction and FT-IR. The results indicate that the EPS makes the bacteria adhere to the chalcopyrite surface easily and it is helpful for bacteria in disadvantageous environment At the same time, EPS film layer with Fe^3＋ deposits on the surface of chalcopyrite and becomes a barrier of oxygen transfer to chalcopyrite to passivate chalcopyrite, and creates the high redox potential space through concentrating Fe^3＋ ions to accelerate bioleaching pyrite in chalcopyrite concentrates. The results suggest that EPS formation promotes bioleaching pyrite and inhibits bioleaching chalcopyrite, especially under high potential condition.     

Removal of SO4, uranium and other heavy metal ions from simulated solution by sulfate reducing bacteria

In the case of in-situ leaching of uranium, the primitive geochemical environment for groundwater is changed since leachant is injected into the water bearing uranium deposit. This increases the concentration of SO4^2-, uranium and other heavy metal ions and results in the groundwater contamination. The effects of pH values of the simulated solution on the reduction of SO4^2- and the removal of uranium and other heavy metal ions by sulfate reducing bacteria（SRB） were studied. The results show that, when the pH value of the simulated solution is about 8, the reduction rate of SO4^2- by SRB and the removal rate of uranium, Mn^2＋, Zn^2＋, Pb〉 and Fe^2＋ will reach their highest values. A bioremediation technique for remediation of groundwater in in-situ leaching uranium mine can be developed.     

~（252）Cf自发裂变产物中~（114）Pd的快速放射化学分析

建立了一个手动快速放射化学分离程序以测定￣（２５２）Ｃｆ自发裂变产物中的￣（１１４）ｐｄ，其主要分离步骤是萃取和沉淀Ｐｄ（ＤＭＧ）＿２配合物。分离程序耗时５．５－６ｍｉｎ，化学回收率为３０％－６０％。方法的精密度以单次测量值的相对标准偏差表示，为３．９％。     

Corrosive electrochemistry of j amesonite by cyclic voltammetry

The corrosive electrochemistry of jamesonite was studied by cyclic voltammetry. Every peak in voltammograms was identified through thermodynamic calculation. The results show an irreversible electrode process by the strong adsorption of oxidation elemental sulfur on jamesonite. A deficient-metal and sulfur-rich compound is formed under the potential of 80 mV at pH 6.86. The passive action by elemental sulfur occurs from 80 to 470 mVand S2O3^2-, SO4^2- are produced at potential over 470 mV. The anodic peak producing SOz- is inhibited due to the deposition of PbSO4 at higher potential in Na2SO4 solution. The corrosive action of jamesonite becomes strong and the redox characterization similar to PbS, FeS and Sb2S3 appears at pH 9.18.     

合成碳羟基磷灰石对水中苯胺的吸附机理

利用红外光谱、扫描电子显微镜、X射线衍射仪等测试技术对脲素和蛋壳制成的碳羟基磷灰石(carbonate hydroxylapatite,CHAP)样品表面化学组成进行了表征,并考察了pH值、吸附时间和苯胺浓度对CHAP吸附水中苯胺的影响,以及其吸附动力学和热力学特征。结果表明:当pH=6,吸附时间为60min,苯胺初始浓度为30mg/L,CHAP对苯胺的吸附效果更好。该过程可用Langmuir Freundlich等温式进行描述,但更符合Freundlich经验公式。分别采用准一级动力学模型和准二级动力学模型考察吸附动力学行为,2个模型与实验数据之间有很好的相关性。吸附热力学行为表明该吸附过程是放热和自发的。     

合成碳羟基磷灰石对水中苯酚的吸附

利用废弃蛋壳为原料、尿素为添加剂,合成了碳羟基磷灰石(CHAP),用于吸附水中苯酚. 利用红外光谱、扫描电镜、X射线能谱测试技术对CHAP样品表面化学进行了表征,同时考察了环境pH值、吸附时间、苯酚初始浓度及温度对苯酚吸附的影响. 结果表明,在酸性(pH=3~5)和碱性(pH=9~10)条件下,CHAP对苯酚的吸附效果较好,吸附过程符合Langmuir和Freundlich等温式,同时也符合准二级动力学模型.