铜离子在黄铜矿表面的吸附及活化作用：一个自活化的新观点

通过Zeta电位分析、X射线光电子能谱分析、铜离子吸附试验、第一性原理计算及Hallimond浮选试验综合揭示了铜离子在黄铜矿表面同样存在着吸附行为,铜离子对黄铜矿同样具有活化作用,主要诱因是铜离子与表面活化位的硫作用,从而增加疏水性。这种吸附作用在一定条件下有利于黄铜矿自身的浮选。浮选矿浆中的铜离子主要来源于黄铜矿的表面氧化溶解和矿物内流体包裹体的释放,这些离子的存在及吸附使黄铜矿具有自活化特性。     

水杨羟肟酸在钛铁矿表面的吸附特性研究

目的从药剂吸附热力学和动力学角度揭示水杨羟肟酸在钛铁矿表面的作用特性。方法采用水浴振荡法,通过改变矿浆pH、药剂浓度、矿浆温度并结合紫外-可见分光光度法,总结药剂在矿物表面的吸附规律。应用准一级、准二级及粒子扩散模型探索药剂吸附动力学特性,利用Langmuir、Freunlich模型和平均吸附能公式分析药剂吸附的热力学行为。结果水杨羟肟酸离子在钛铁矿表面的吸附动力学符合准一级动力学方程。酸性及中性条件下,水杨羟肟酸离子在矿物表膜中的扩散是吸附过程的控制性步骤;而碱性条件下,矿物表面活性质点在矿物表膜中的扩散则是吸附过程的控制性步骤。低温下,药剂吸附符合Freunlich模型;温度升高时,吸附等温线遵守Langmuir单分子层吸附模型。吸附过程的ΔG随温度上升而降低,但随药剂浓度的增加而增加。平均吸附能结果表明,药剂在温度低时属于离子交换吸附模式,但在温度升高时属于化学反应吸附模式。结论水杨羟肟酸在钛铁矿表面的吸附规律受矿浆温度、pH及药剂浓度的影响较大,在生产实践中可通过改变上述条件来优化钛铁矿的浮选指标。     

硫化矿物的浮选电化学与浮选行为

研究黄铜矿、黄铁矿、方铅矿等矿物在有/无捕收剂两种情况下的浮选行为,考察浮选与矿浆电位的关系。结果表明:当pH值分别小于4.0时,黄铜矿无捕收剂浮选的电位区间为0~0.9 V;当pH值为4.0或11.0时,矿浆电位大于0.85 V以后,黄铁矿的浮选回收率低于20%;当pH值为11.0时,黄铜矿无捕收剂浮选的矿浆电位区间为0.35~0.85 V。当pH值为10.0、丁黄药浓度为5×10-5 mol/L时,方铅矿浮选的矿浆电位为0.45~0.55 V,而黄铜矿在0.45~0.80 V的电位区间具有良好的浮选性能;对闪锌矿而言,当pH值为9.0时,矿浆电位在-0.40~0.80 V区间都不具有良好的可浮性。在浮选体系中,黄铜矿表面氧化会产生元素S0,当矿浆电位从-0.2V增大至0.6 V,黄铜矿表面氧化产生的元素S的数量逐渐增大,黄铜矿的无捕收剂浮选性能越来越好。从南京和青海2个铅锌矿山的应用情况来看,采用电位调控浮选技术可以大幅度缩短铅矿石的浮选时间,减少浮选机数量。例如在南京某铅锌矿,由于采用电位调控浮选技术,原来2个系列每天处理900 t矿石,现在采用一个系列即可处理。     

黄原胶在黄铜矿和闪锌矿浮选分离中的作用及机理

通过纯矿物浮选试验、吸附量和动电位测试及X射线光电子能谱(XPS)分析,研究黄原胶对黄铜矿、闪锌矿浮选行为的影响,考察黄原胶对闪锌矿的抑制作用机理。结果表明:捕收剂为丁黄药时,黄铜矿和闪锌矿基本都可浮,难以分离。黄原胶能较强地抑制闪锌矿且不随pH的变化而变化,而对黄铜矿的抑制作用较弱且随pH降低抑制效果增强。使用黄原胶为抑制剂时,在pH 7～11区间可以实现黄铜矿和闪锌矿的浮选分离。黄原胶在黄铜矿和闪锌矿表面均能吸附,但其在黄铜矿表面的吸附量显著高于在闪锌矿表面的吸附量,同时对闪锌矿表面性质影响也较大。黄原胶主要通过与闪锌矿表面生成的氧化锌或氢氧化锌发生化学反应而吸附在闪锌矿表面,因此黄原胶更容易吸附在容易氧化的闪锌矿表面。     

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。     

溶液中阴离子对萤石和方解石可浮性的影响

通过单矿物浮选试验、溶液化学计算、ICP检测和动电位测试,考察在油酸钠(NaOl)体系下碳酸根离子、氟离子和硫酸根离子对萤石和方解石可浮性的影响及作用机理。结果表明:当矿浆pH值大于萤石或方解石饱和溶液的pH值(记作pH_(sat))时,碳酸根离子、氟离子、硫酸根离子能活化萤石或方解石的浮选,当矿浆pH值小于萤石或方解石的pH_(sat)值时,阴离子则能抑制萤石或方解石的浮选;添加三种阴离子并不都能使矿浆溶解的钙离子沉淀,但可以改变萤石和方解石的溶解行为;阴离子对萤石和方解石可浮性的影响与溶液中钙离子含量无关,但可能与阴离子在萤石和方解石表面发生吸附并改变矿物的表面性质有关。     

H_2O_2处理后的黄铜矿和黄铁矿对黄药的吸附作用及其浮选分离（英文）

通过一系列浮选试验和矿物表面分析技术研究H_2O_2处理对黄药浮选分离黄铜矿与黄铁矿的影响。浮选试验结果表明,H_2O_2对两种矿物的浮选行为具有一定影响,H_2O_2对黄铁矿的抑制效果强于黄铜矿。在一定H_2O_2浓度条件下,黄铜矿在pH 9.0时可从黄铁矿中选择性分离出来,此时黄铜矿的回收率达84%以上,而黄铁矿回收率低于24%。Zeta电位、紫外-可见分光光谱以及红外光谱等分析结果表明,H_2O_2处理后的两种矿物对捕收剂的吸附量不同,黄铜矿表面对黄药的吸附量远远大于黄铁矿表面对黄药的吸附量。红外光谱和XPS分析结果表明,H_2O_2处理可大幅度提高黄铁矿表面的亲水性,从而抑制捕收剂的吸附,使其可浮性下降;而黄铜矿对H_2O_2不产生吸附,因此对黄药的吸附和对二黄原酸的氧化效果较好,黄铜矿的浮选回收率较高。     

嗜铁钩端螺旋菌对黄铜矿表面性质的影响(英文)

通过吸附、动电位、接触角和摇瓶浸出试验研究Leptospirillum ferriphilum菌作用前后黄铜矿表面性质的变化。采用不同能源物质(亚铁和黄铜矿粉)培养L.ferriphilum菌。结果表明,细菌可以很快吸附在黄铜矿表面,并且固体能源物质培养的细菌比液体能源物质培养的细菌可以更多、更快地吸附在矿物表面。与细菌作用后,黄铜矿的等电点朝着细菌等电点的方向移动。在添加与不添加能源物质时,黄铜矿的接触角表现出不同的变化趋势。XRD、SEM/EDS检测表明浸出过程中在黄铜矿表面生成了硫和黄钾铁矾。通过EDS检测可知在黄铜矿的分解过程中,铁优先从黄铜矿表面释放出来。在浸出过程中黄铜矿表面生成了钝化层,从而导致其浸出率很低。通过研究推测钝化层的主要成分是硫,而不是黄钾铁矾。     

球磨介质及尺寸对铜锌矿矿浆化学性质及矿物表面化学性质的影响

采用飞行时间二次离子质谱仪和改良球磨机研究了磨矿环境对铜锌矿矿浆的化学性质和闪锌矿的表面化学性质的影响。通过采用改良后的球磨机实现磨矿过程中溶液p H、矿浆电位、电导率、溶解氧含量及离子浓度等矿浆化学性质的实时监测。随着磨矿时间的延长,矿浆p H值缓慢升高,矿浆电位和溶解氧含量迅速下降。结果表明:球形磨矿介质的直径越小,矿浆中溶解氧消耗越快,磨矿后矿浆静电位越低,矿浆的离子浓度也越低。飞行时间二次离子质谱仪对磨矿后闪锌矿的表面化学分析表明,磨矿后铁氧化物和氢氧化物会附着于闪锌矿表面,球磨介质的材料与尺寸大小对矿物表面存在的二次离子有较大影响。分别与不锈钢球或者2.54 cm的大球相比,铸铁球或1.27 cm的小球可为矿浆提供更多的铁离子,促进磨矿环境下的电化学反应,从而在闪锌矿表面累积更多的铁氧化物或氢氧化物,降低铜离子的吸附。因此,矿浆化学性质和闪锌矿的表面化学性质受磨矿介质的材料与介质的尺寸控制。     

N-异丁氧羰基硫脲浮选黄铜矿的机理

合成一种新型的表面活性剂——N-异丁氧羰基硫脲(iBCTU),对其结构进行红外和核磁共振表征,并考察其对黄铜矿的浮选性能以及在黄铜矿表面的吸附热力学和机理。浮选和吸附结果表明:在pH 3~11的范围内,iBCTU对黄铜矿具有良好捕收能力,且黄铜矿对iBCTU的吸附量随着温度的升高而增大。热力学分析表明:iBCTU在黄铜矿表面的吸附等温线符合Langmuir模型,吸附焓变△H为56.42 kJ/mol,熵变△S为284.76 J/(mol·K),吸附自由能变△G为-29.12 kJ/mol(298K),iBCTU在黄铜矿表面的吸附为自发、吸热化学吸附过程。XPS分析进一步说明iBCTU可能通过其硫代羰基的硫原子和-NH_2基氮原子与黄铜矿表面的铜原子结合生成iBCTU-Cu(Ⅰ)表面络合物吸附在黄铜矿表面。     

Interfacial electrokinetic characteristics before and after bioleaching microorganism adhesion to pyrite

Zeta potentials of pyrite and Acidithiobacillusferrooxidans cultured by sulfur in different levels of ionic strength and pH values were measured by Coulter Delsa 440SX zeta potential determinator. Meanwhile, the effects of bacterial adhesion and bacterial concentration on zeta potential of pyrite after adsorption were investigated. The results show that with the increase of ionic strength, zeta potentials of pyrite decrease in the range ofpH 2.5-10.5 and the isoelectric point（IEP） of mineral shifts to the left. It is also found that the specific adsorption on pyrite of chloride ion can affect zeta potentials of pyrite sharply. As bacterial adsorption occurs, IEP of pyrite shifts towards that of Acidithiobacillus ferrooxidans; as bacterial concentration is inerescent, this tendency is even larger and more obvious. Finally, a reasonable explanation for above-mentioned experimental phenomena was given by electrical double layer model and surface ionization model.     

Leptosririllum ferrooxidans-sulfide mineral interactions with reference to bioflotation nad bioflocculation

The adhesion of ferrous ions grown Leptospirillumferrooxidans cells on pyrite and chalcopyrite minerals was investigated through adsorption,Zeta-potential and diffuse reflectance FT-IR measurements.The influence of bacterial species on minerals floatability was determined by Hallimond flotation tests while the flocculation behaviour was examined by Turbiscan measurements. The minerals iso-electric point(pH 6.5-7.5)after interaction with bacterial cells shifted towards cells iso-electric point(pH 3.3), in...     

Leptosririllum ferrooxidans-sulfide mineral interactions with reference to bioflotation nad bioflocculation

The adhesion of ferrous ions grown Leptospirillumferrooxidans cells on pyrite and chalcopyrite minerals was investigated through adsorption, Zeta-potential and diffuse reflectance FT-IR measurements. The influence of bacterial species on minerals floatability was determined by Hallimond flotation tests while the flocculation behaviour was examined by Turbiscan measurements. The minerals iso-electric point （pH 6.5-7.5） after interaction with bacterial cells shifted towards cells iso-electric point （pH 3.3）, indicating the chemical nature of cells adsorption on mineral surfaces. The FT-IR spectra of minerals treated with bacterial cells showed the presence of all the cell functional groups signifying cells adsorption. The bacterial cells adsorption on chalcopyrite was higher compared with pyrite, which agreed with cells greater depression effect on chalcopyrite flotation and pronounced flocculation behaviour in comparison with pyrite.     

Application of cetylpyridinium chloride in dispersion of antibacterial ceramic glaze

1Introduction The adsorption of soluble surfactants to the solid/aqueous solution interface is a major factor in many processes including ceramics processing,waste water treatment,mineral flotation,dispersion stabilization and soil remediation[1,2].Most o…     

Bacterial leaching of chalcopyrite and bornite with native bioleaching microorganism

A native mesophilic iron-oxidizing bacterium, Acidithiobacillus ferrooxidans, has been isolated （30 ℃） from a typical, lead-zinc concentrate of Dachang Mine in the region of Liuzhou located in the southwest of China. Two typical copper sulfide minerals, chalcopyrite and bornite, were from Meizhou Copper Mine in the region of Guangdong Province, China. Variation of pH and cell growth on time and effects of some factors such as temperature, inoculation cell number, and pulp density on the bioleaching of chalcopyrite and bornite were investigated. The results obtained from the bioleaching experiments indicate that the efficiency of copper extraction depends on all of the mentioned variables, especially the pulp density has more effect than the other factors on the microorganism. In addition, the results show that the maximum copper recovery was achieved using a mesophilic culture. The copper dissolution reached 51.34% for the chalcopyrite while it was 72.35% for the bornite at pH 2.0, initial Fe（ Ⅱ ） concentration 9 g/L and pulp density 5%, after 30 d.     

Effects of microorganisms on surface properties of chalcopyrite and bioleaching

The alteration of surface properties of chalcopyrite after biological conditioning with Acidithiobacillusferrooxidans and Acidithiobacillus caldus was evaluated by Zeta-potential, adsorption studies, FT-IR spectra and contact angle measurement. The Zeta-potential studies show that the iso-electric point（IEP） of chalcopyrite after bacterial treatment moves towards the IEP of pure cells, indicating the adsorption of cells on chalcopyrite surface. The FT-IR spectra of chalcopyrite treated with bacterial cells show the presence of the cell functional groups signifying cells adsorption. Due to the formation of elemental sulfur and intermediate copper sulphides on chalcopyrite surface, the contact angle and surface hydrophohicity of chalcopyrite increase at the initial bioleaching stage. Chalcopyrite bioleaching by Acidithiobacillus ferrooxidans has higher copper extraction, which agrees with the fact that Acidithiobacillus ferrooxidans adsorbed on chalcopyrite surface is much more than Acidithiobacillus caldus. The results support the direct mechanism of sulfide oxidations in bioleaching chalcopyrite.     

Effect of pH values on extracellular protein and polysaccharide secretions of Acidithiobacillus ferrooxidans during chalcopyrite bioleaching

The effect of pH values on the extracellular protein and polysaccharide secretions of Acidithiobacillus ferrooxidans was comparatively investigated in different phases of bacterial growth during chalcopyrite bioleaching. The results indicate that the extracellular protein is always more than the extracellular polysaccharide secreted by attached cells on the chalcopyrite, on the contrary, and is always less than the extracellular polysaccharide secreted by free cells in the solution at bacterial adaptive phase, logarithmic phase and stationary phase whenever pH value is at 1.0, 1.5, 2.0 or 2.5; free cells are mainly through the secretion of extracellular polysaccharide rather than the extracellular protein to fight against disadvantageous solution environment, such as high concentration of metal ions and unsuitable pH solution; both amounts of polysaccharide and protein secreted by attached cells are mainly positively related to the solution acidity rather than the total concentration of soluble metal ions. The experimental results imply that bacteria are mainly through secreting more extracellular polysaccharide to fight against disadvantageous environment and the extracellular protein perhaps plays an important role in oxidation–reduction reactions in the bioleaching system.     

Behavior of ammonium adsorption by clay mineral halloysite

Ammonium pollution becomes severe during mining of ionic rare earth-ores in southern China. As one of the main clay minerals in soils of ionic rare earth mines, halloysite plays an important role in ammonium adsorption. In this study, the saturated adsorption capacity, factors affecting adsorption and adsorption kinetics of halloysite for ammonium were investigated. The results indicated that the ammonium adsorption of halloysite was saturated with 1.66 mg/g at 303 K, pH of 5.6 and initial ammonium concentration of 600 mg/L (about half of the actual initial in-situ leaching concentration). When the initial concentration of –N, pH values and temperatures (288 K to 313 K) increased, the ammonium adsorption capacity of halloysite increased. The ammonium isothermal adsorption of halloysite matched the Langmuir and Freundlich isotherms. The adsorption process of ionic rare earth mining soils for ammonium was favorable. And the adsorption process followed closely the pseudo-second kinetic equation.