蛇纹石对黄铁矿浮选的影响及机理

通过浮选实验、沉降实验、显微镜下观测、接触角测试和吸附量实验,研究蛇纹石对黄铁矿浮选的影响,并对其机理进行分析。结果表明：矿物粒度在蛇纹石与黄铁矿的浮选分离中起着重要作用,比黄铁矿粒度小的蛇纹石颗粒能够通过异相凝聚作用吸附在黄铁矿表面,改变黄铁矿的表面性质,影响黄铁矿的浮选。机理研究表明：蛇纹石表面是亲水的且不吸附捕收剂戊黄药(PAX)。蛇纹石吸附在黄铁矿表面,降低了黄铁矿表面疏水性和戊黄药在黄铁矿表面的吸附量,使黄铁矿浮选回收率降低。增加戊黄药在黄铁矿表面的吸附量能够一定程度上恢复被抑制黄铁矿的浮选回收率,但蛇纹石用量较高时,黄铁矿浮选回收率仍降低。因此,微细粒蛇纹石通过异相凝聚作用在黄铁矿表面附着,降低黄铁矿表面疏水性是蛇纹石影响黄铁矿浮选的主要原因。     

铜离子对CMC浮选分离滑石和黄铁矿的影响

为实现黄铁矿和滑石更好地浮选分离，基于CMC对滑石抑制能力不强的弱点，在pH值为9的条件下，以CMC作为抑制剂，戊黄药作为捕收剂，探究了铜离子的加入对滑石和黄铁矿浮选的影响。结果表明，浮选过程中加入铜离子，在不影响黄铁矿浮选的情况下（浮选回收率90.8%），有效的抑制了滑石的浮选（浮选回收率由57.07%降低到8.99%）。另外还对CMC和铜离子加药顺序做了探究，发现铜离子在CMC前加入不影响黄铁矿的浮选，但更有利于滑石的抑制。     

Adsorption of guar gum and CMC on pyrite

The depression of pyrite in sulfide flotation by two types of polysaccharides, CMC and guar, was investigated using micro-flotation tests, zeta potential measurements and adsorption tests. Environmentally and from an occupational safety standpoint – this would be a better processing option than cyanide. The range of variables tested included molecular weight of guar, degree of substitution of CMC, pH and the concentration of calcium ions in the flotation process water. The guar gums depressed pyrite considerably even at low dosages. An optimum dosage of 10 ppm was recommended. The CMC’s were not as effective as the guar gums, and required much higher dosages to achieve pyrite depression. Within the range of CMC’s tested, lower degree of substitution was more effective than high degree of substitution. This was presumably due to lower electrostatic repulsion between the negatively charged CMC and pyrite. When calcium ions were introduced with CMC’s, the adsorption of the CMC was considerably enhanced. No such effect was observed for guar gums. Both CMC and guar gums demonstrated Langmuirian behavior in their adsorption isotherms. Two different adsorption mechanisms were displayed. The guar gum adsorption was attributed to hydrogen bonding and Bronsted acid–base interaction. The CMC was considered to occur through electrostatic interaction in the presence of calcium ions, and Bronsted acid–base interaction depending on pH.     

钛铁矿和钛辉石对羧甲基纤维素的吸附机理研究

羧甲基纤维素(CMC)对钛铁矿和钛辉石都具有很强的抑制性。单矿物浮选试验表明CMC是钛铁矿浮选中良好的抑制剂,Zeta电位测试试验表明与CMC作用后,钛铁矿和钛辉石的表面Zeta电位都明显降低,pH值为5时钛铁矿和钛辉石对于CMC的吸附量都达到最大,但钛辉石对CMC的吸附量要明显大于钛铁矿,存在竞争吸附。     

Selective chalcopyrite flotation from pyrite with glycerine-xanthate as depressant

Micro-flotation tests, adsorption, electrokinetic and FTIR measurements were carried out in order to investigate the selective depression mechanism of sodium glycerine-xanthate (SGX) on pyrite in chalcopyrite flotation. The flotation results showed a large difference in chalcopyrite (>85%) and pyrite (<30%) recovery as stirred pulp-mixing with SGX before the addition of collector sodium butyl xanthate (SBX), at the range of pH 7–10. A much stronger adsorption of SGX on pyrite than chalcopyrite was dramatically revealed by zeta potential measurements, which can explain the better floatability of chalcopyrite than pyrite. The adsorption of SBX onto pyrite was depressed intensely while that onto chalcopyrite was affected slightly when SGX was used as depressant, because of more stronger adsorption between SGX and SBX occurring onto the pyrite surfaces. The absorbed amount of SGX on chalcopyrite increases slightly, over the pH range from 3 to 12, while that on pyrite increases rapidly with the increased SGX concentration, which is consistent with the flotation results. FTIR reflection spectroscopic measurements further demonstrated the depression effect of pre-absorbed SGX on SBX adsorption, which is attributed to its hydrophilic hydroxyl groups.     

不同结构羧甲基纤维素对绿泥石的抑制作用及机理

通过浮选、吸附量测试及动电位测量,研究不同结构的羧甲基纤维素对绿泥石浮选的影响,并考察其作用机理。结果表明,绿泥石具有一定的天然可浮性,羧甲基纤维素对绿泥石的浮选具有抑制作用,抑制效果随矿浆pH的升高而增大。羧甲基纤维素的结构对其抑制作用效果影响较大,羧甲基纤维素的取代度越低,分子量越高,对绿泥石的抑制效果越强。动电位测量及吸附量测试结果表明,在弱碱性pH条件下,绿泥石表面荷负电,羧甲基纤维素分子中的羧甲基也荷负电,二者之间存在阻碍羧甲基纤维素吸附的静电排斥作用,羧甲基纤维素取代度越低,分子量越大,在绿泥石表面吸附量越高,对绿泥石的抑制效果越强。     

Pyrite activation in amyl xanthate flotation with nitrogen

The low potential hydrophobic state of pyrite in amyl xanthate (PAX) flotation with nitrogen is of particular interest with regard to the N₂TEC flotation technology currently being used for the recovery of auriferous pyrite at Newmont’s Lone Tree Plant in Nevada. Initially, the N₂TEC system had been found to operate satisfactorily, but cyanide in the flotation mill water appeared to be responsible for a loss in pyrite recovery. This supposition was confirmed with laboratory experiments, and a program was initiated to study flotation chemistry variables by electrochemically controlled contact angle measurements. Experimental results show that activation of pyrite in such cyanide solutions can be achieved more effectively with lead than with copper. Subsequently, based on these fundamental studies, significant improvement at the Lone Tree Plant was achieved by lead activation, in which case the recovery increased to expected levels.The effect of activator is particularly significant not only with respect to pyrite depression by residual cyanide, but also with respect to collector (PAX) consumption and the initial state of the pyrite surface. Experimental results show the importance of the pyrite surface state and the rather interesting features of the activation process.     

CMC浮选分离萤石与方解石作用机理研究

为了更有效地浮选分离萤石和方解石,通过浮选试验、接触角、Zeta电位、吸附量及微量热分析,研究了羧甲基纤维素（CMC）在萤石、方解石浮选分离中的作用,揭示了CMC对萤石、方解石选择性抑制机理。结果表明：CMC用量为20 mg/L时能够高效抑制方解石,当pH=8时,可最大化实现两者浮选分离。由于CMC优势组分—RCOO—大量吸附于方解石表面,使得方解石表面只能吸附较少油酸根离子,同时造成方解石Zeta电位显著负移,使其亲水增强,这与接触角测试结果一致。吸附模型表明,方解石表面Ca²⁺活性位点大量减少,难以继续吸附油酸根离子,是其被抑制的主要原因,且体系反应级数n=1。     

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。     

The use of ToF-SIMS and microflotation to assess the reversibility of binding of CMC onto talc

Carboxymethyl cellulose (CMC) is commonly used as a depressant for talcaceous minerals. To assess whether CMC depressants are strongly, or weakly and reversibly bound to the surface of talc, desorption experiments were conducted on New York talc. The floatability was monitored through microflotation experiments, combined with the determination of the CMC coverage on talc by ToF-SIMS. CMC adsorption and desorption were carried out in distilled water and in electrolyte containing Ca²⁺ ions. CMC adsorption levels were higher using Ca²⁺ electrolyte, in line with the depression behavior in the microflotation tests. Washing did not affect the flotation behavior. ToF-SIMS showed that CMC coverage of the talc particles was good and the distribution homogeneous. Adsorption and subsequent desorption in distilled water however, showed a partially restored floatability after desorption, which could be related to an inhomogeneous CMC distribution on the talc surface as shown by ToF-SIMS. By additional exposure to Ca²⁺ ions CMC redistribution occurs causing depression.     

羧甲基纤维素的应激反应规律及对滑石表面疏水性的影响

通过浮选实验、接触角测试、动电位测量及红外光谱试验研究不同的溶液条件对吸附在滑石表面的羧甲基纤维素(CMC)作用效果的影响,并考察其作用机理。结果表明,滑石具有较好的天然可浮性,CMC能够吸附在滑石表面,降低滑石的表面疏水性。吸附后的CMC对滑石的抑制作用效果受溶液pH及溶液中离子的浓度影响较大。当吸附有CMC的滑石位于pH=9的溶液中,CMC的羧甲基之间存在较强的静电排斥作用,吸附的CMC分子呈伸展状态存在,形成的吸附层较薄,造成的亲水性较弱;当矿浆pH变为酸性或溶液中有离子存在时,CMC羧甲基之间的静电排斥作用减弱,CMC分子在滑石表面呈蜷缩状态,所形成的吸附层较厚,造成的亲水性较强,这种变化是可逆的。     

乙硫氮作捕收剂时无机调整剂加药顺序对典型硫化矿物浮选的影响

研究了乙硫氮作捕收剂时无机调整剂硫酸锌、亚硫酸钠、硫化钠和硫酸铜不同加药顺序对典型硫化矿物黄铜矿、方铅矿、闪锌矿和黄铁矿浮选行为的影响。结果表明,调整剂与捕收剂的加药顺序对硫化矿物浮选的影响不同。与调整剂先加时相比,乙硫氮先加时,硫酸锌对黄铜矿和方铅矿浮选的抑制作用减弱;硫酸锌、低用量硫酸铜、亚硫酸钠或硫化钠对闪锌矿浮选以及硫酸铜对黄铜矿和方铅矿浮选的抑制作用更强;硫酸锌或硫酸铜对黄铁矿浮选以及较高用量硫酸铜对闪锌矿浮选的活化作用相当;亚硫酸钠或硫化钠对黄铜矿、方铅矿和黄铁矿浮选的影响很小。研究结果可为部分硫化矿通过改变调整剂与捕收剂的加药顺序提高矿物浮选分离效率提供借鉴。     

Effects of free cyanide and cuprous cyanide on the flotation of gold and silver bearing pyrite

At gold and silver mineral processing plants, cyanide species are always present in the process water recycled to flotation circuits, despite the cyanide destruction process. The effect of cyanide, in particular, cuprous cyanide on gold and silver flotation has not been well understood. In the present study, free cyanide and cuprous cyanide species were isolated and their effects on the flotation of a pyritic ore were evaluated. It was found that free cyanide depressed gold and silver flotation through their carrier, pyrite. Cuprous cyanide mainly in the form of Cu(CN)₃²⁻ depressed pyrite flotation similarly as free cyanide. Electrochemical studies including open circuit potential (OCP), cyclic voltammetry and electrochemical impedance spectroscopy (EIS) techniques were carried out to understand the underpinning depression mechanism of cyanide species on pyrite flotation using xanthate as collector. It was found that all surface electrochemical reactions were inhibited by either free cyanide or cuprous cyanide. The surface layer as a result of xanthate adsorption on pyrite was completely removed in the presence of these cyanide species, which was suggested to contribute to the hydrophilic pyrite surface.     

Diethylenetriamine depression of Cu-activated pyrite hydrophobised by xanthate

In copper sulphide flotation, copper adsorbs on pyrite through superficial oxidation of the copper minerals (e.g. chalcopyrite) which promotes pyrite flotation in the presence of xanthate. This “inadvertent” activation of pyrite by copper ions is undesirable in copper sulphide flotation. In order to minimise this effect, depressants are used to suppress the effect of the activating ions. The effect of diethylenetriamine (DETA) in different combinations (under aerated and non-aerated conditions) on Cu-activated pyrite hydrophobised by xanthate was examined using flotation, spectroscopic and solution analyses, at pH 10. The results showed that DETA affects the flotation behaviour and surface chemistry of pyrite. However, high dosages are required. The depression action of DETA on Cu-activated pyrite was attributed to both the removal of surface copper to form soluble Cu–DETA complex in solution and competition for Cu sites on the activated pyrite surface. The significant depression of pyrite in the presence of DETA under the aerated condition was due to increased amount of iron oxy–hydroxides (Fe–O/OH), copper oxides and Cu(I)–DETA hydrophilic species.     

自然氧化对黄铁矿可浮性的影响及其机理研究

为了弄清黄铁矿在自然条件下的氧化规律及黄铁矿表面氧化对浮选的影响。研究了自然氧化条件下氧化时间对黄铁矿单矿物可浮性的影响,黄铁矿的回收率随着氧化时间的延长而降低。X射线光电子能谱分析(XPS)结果显示,氧化后的黄铁矿表面新出现了硫单质、硫酸铁和氢氧化铁等物质的相关特征峰,且黄铁矿氧化过程以氢氧化铁覆盖其表面为终止。浮选过程中,氧化后黄铁矿表面的氢氧化铁等亲水性物质改变了黄铁矿的表面性质,阻碍了捕收剂的吸附,降低了黄铁矿的可浮性。研究结果可以为硫化矿浮选中降低黄铁矿可浮性以实现其与贵金属等的浮选分离提供参考。     

The effect of a new polysaccharide on the depression of talc and the flotation of a nickel–copper sulfide ore

The effect of the depressant galactomannan (KGM) on the depression of talc and the flotation of a nickel–copper sulfide ore have been investigated through microflotation, batch flotation and industrial flotation tests, zeta potential and infrared spectrum measurements. The flotation results indicated that KGM had a straining influence on the depression of talc while had little effect on nickel minerals flotation. Compared with the depressant carboxymethyl cellulose (CMC) and guar gum, the KGM increased the nickel recovery dramatically, it not only negated the need for a talc removal process, but also achieved a significant decrease in the depressant consumption by half. Zeta-potential and infrared spectrum measurements illustrated that chemical adsorption was seen between KGM and talc, and a possible weak physical adsorption was seen between KGM and pentlandite. This was the reason why KGM had high depression selectivity for talc and little depression effect on nickel minerals.     

绿泥石晶体各向异性及与其可浮性关系研究

通过对-37 μm、37~44 μm、44~74 μm 3 个粒级绿泥石进行 X 射线衍射（XRD）分析、单矿物浮选试验、捕收剂吸附规律研究和分子动力学模拟，研究了绿泥石晶体的各向异性及与可浮性的关系。XRD 分析结果显示，随着绿泥石粒度降低，平行解理面的含量持续升高，层间解理面优先解离。浮选试验结果表明，3 个粒级绿泥石可浮性顺序为中间粒级（37~44 μm）>细粒级（-37 μm）>粗粒级（44~74 μm）。捕收剂吸附规律检测和分子动力学模拟结果显示：十二胺在绿泥石表面的吸附密度随绿泥石粒级减小而降低，而吸附量随绿泥石粒度减小而升高；十二胺主要通过亲固基氨基吸附在绿泥石（001）面，十二胺分子碳链主要沿绿泥石（001）面法线方向分布；与绿泥石（001）面相比，（100）面含有大量正电性金属离子，减弱了十二胺与绿泥石（100）的静电吸附作用，十二胺在绿泥石（100）面的吸附靶向度不高，为非有效吸附；绿泥石（001）面对十二胺的吸附强度大于（100）面。绿泥石晶体的各向异性表现明显，（001）面含量升高对绿泥石浮选有利，在阳离子捕收剂体系中，通过选择性磨矿，提高绿泥石层间解离效率是改善绿泥石选矿效果的关键。     

硫酸锌添加顺序对乙硫氮在方铅矿和闪锌矿表面吸附的影响

研究了无机抑制剂硫酸锌及其与乙硫氮不同添加顺序对方铅矿和闪锌矿浮选行为的影响。当先加入硫酸锌时,硫酸锌对闪锌矿有较强的抑制作用,对方铅矿有轻微的抑制作用;当硫酸锌后于乙硫氮加入时,对方铅矿的抑制作用减弱,而对闪锌矿的抑制作用增强。吸附量测定结果表明,乙硫氮强烈吸附在方铅矿表面,硫酸锌对乙硫氮在方铅矿表面吸附影响很小,而乙硫氮与闪锌矿表面作用较弱,吸附量较小。红外光谱研究表明,无论硫酸锌先加还是后加,均明显降低乙硫氮在闪锌矿表面的吸附,而硫酸锌对乙硫氮在方铅矿表面的吸附影响较小,特别是硫酸锌后加时对乙硫氮在方铅矿表面吸附强度的抑制作用减弱。飞行时间二次离子质谱研究表明,与硫酸锌先加时相比,硫酸锌后加时,方铅矿表面吸附的氢氧化锌亲水胶体更少、乙硫氮略多,而闪锌矿表面吸附的氢氧化锌亲水胶体更多、乙硫氮更少。因此,硫酸锌后于乙硫氮添加时更有利于铅锌分离。     

The effect of zinc cyanide on the flotation of gold from pyritic ore

In gold processing plants, the process water contains a considerable amount of weak acid dissociable (WAD) cyanide species. The cyanide-containing water recycled to flotation circuits has a deleterious effect on mineral flotation. Zinc cyanide can be a major constituent of the process water due to the cyanide leaching of zinc minerals and the zinc cementation applied to precipitate gold and silver. In the present study, the effect of zinc cyanide on the flotation of gold from a pyritic ore was evaluated and the competitive adsorption between zinc cyanide species and the collector, potassium amyl xanthate (PAX) or Aerophine promoter (3418A), on gold was studied by surface enhanced Raman spectroscopy (SERS). It was found that free cyanide did not depress the flotation of liberated gold, but zinc cyanide with a CN/Zn ratio of 2 did. The depression of gold flotation by zinc cyanide was due to the preferential adsorption of Zn(CN)₂ on gold surface over either 3418A or amyl xanthate in the solution, rendering gold surface hydrophilic.     

Adsorption of tailored carboxymethyl cellulose polymers on talc and chalcopyrite: Correlation between coverage,wettability, and flotation

A carefully chosen selection of CMC polymers was used to probe the depression of talc and chalcopyrite and to highlight the effect of specific alterations of the bulk polymer chemistry on the power and selectivity of the depressants. In situ tapping mode atomic force microscopy (AFM), captive bubble contact angle measurements, and flotation tests were used to study the adsorption of the CMC polymers on chalcopyrite and talc. The degree of substitution and distribution of substitution of carboxymethyl groups on CMC was seen to have a strong influence on the ability of the polymers to adsorb onto the surface of talc and chalcopyrite. High substitution results in low coverage on both minerals whereas low substitution results in higher coverage. The influence of distribution of substitution (random or clustered) was also seen to affect the adsorption, with more random/even substitution giving rise to greater adsorption on talc and chalcopyrite. The contact angle of talc and chalcopyrite is significantly altered in the presence of the three polymers, with increased surface coverage (determined by AFM) correlating with the ability of the polymers to decrease the wettability of talc and chalcopyrite. This trend was also followed in single and mixed mineral talc and chalcopyrite flotation.