Improved hemimorphite flotation using xanthate as a collector with S(Ⅱ) and Pb(Ⅱ) activation

The flotation of hemimorphite using the S(Ⅱ)–Pb(Ⅱ)–xanthate process,which includes sulfidization with sodium sulfide,activation by lead cations,and subsequent flotation with xanthate,was investigated.The flotation results indicated that hemimorphite floats when the S(Ⅱ)–Pb(Ⅱ)–xanthate process is used; a maximum recovery of approximately 90% was obtained.Zeta-potential,contact-angle,scanning electron microscopy–energy-dispersive spectrometry(SEM–EDS),and diffuse-reflectance infrared Fourier transform spectroscopy(DRIFTS) measurements were used to characterize the activation products on the hemimorphite surface and their subsequent interaction with sodium butyl xanthate(SBX).The results showed that a Zn S coating formed on the hemimorphite surface after the sample was conditioned in an Na2 S solution.However,the formation of a Zn S coating on the hemimorphite surface did not improve hemimorphite flotation.With the subsequent addition of lead cations,Pb S species formed on the mineral surface.The formation of the Pb S species on the surface of hemimorphite significantly increased the adsorption capacity of SBX,forming lead xanthate(referred to as chemical adsorption) and leading to a substantial improvement in hemimorphite flotation.Our results indicate that the addition of lead cations is a critical step in the successful flotation of hemimorphite using the sulfidization–lead ion activation–xanthate process.     

A novel method for improving cerussite sulfidization

Evaluation of flotation behavior, solution measurements, and surface analyses were performed to investigate the effects of chloride ion addition on the sulfidization of cerussite in this study. Micro-flotation tests indicate that the addition of chloride ions prior to sulfidization can significantly increase the flotation recovery of cerussite, which is attributed to the formation of more lead sulfide species on the mineral surface. Solution measurement results suggest that the addition of chloride ions prior to sulfidization induces the transformation of more sulfide ions from pulp solution onto the mineral surface by the formation of more lead sulfide species. X-ray diffraction and energy-dispersive spectroscopy indicate that more lead sulfide species form on the mineral surface when chloride ions are added prior to sulfidization. These results demonstrate that the addition of chloride ions prior to sulfidization can significantly improve the sulfidization of cerussite, thereby enhancing the flotation performance.     

The selective effect of food-grade guar gum on chalcopyrite-monoclinic pyrrhotite separation using mixed aerofloat (CSU11) as collector

The flotation separation of chalcopyrite from monoclinic pyrrhotite using food-grade guar gum (FGG) as a depressant was studied through flotation tests, kinetic studies, dynamic potential measurements, adsorption experiments, and infrared spectral analyses. The microflotation results showed that the flotation separation of chalcopyrite from monoclinic pyrrhotite could not be realized by adding mixed aerofloat (CSU11) alone. The depressant FGG exhibited a selective depression effect on monoclinic pyrrhotite by controlling the pulp pH range from 5.0 to 6.0, with a maximum floatability variation of 79.36% in the presence of CSU11. The flotation kinetics, zeta-potential, adsorption, and infrared spectroscopy studies revealed that the FGG could absorb more strongly on the surface of monoclinic pyrrhotite than on the surface of chalcopyrite. In addition, the results revealed that the interaction of FGG with the monoclinic pyrrhotite surface was governed primarily by strong chemisorption, whereas FGG mainly bonded to chalcopyrite through hydrogen bonding. This difference was responsible for the excellent depression selectivity of FGG toward monoclinic pyrrhotite flotation and weak depression effect toward chalcopyrite flotation.     

Synthesis of a copper(Ⅱ) oxide-montmorillonite composite for lead removal

The synthesis of a copper(Ⅱ) oxide-montmorillonite composite and its application in the removal of lead(Ⅱ) ions in solution were investigated. The Acros Organics (ACOR) montmorillonite was activated using potassium hydroxide solution. The activated ACOR montmorillonite was titrated with copper(Ⅱ) nitrate solution to produce the copper(Ⅱ) oxide-montmorillonite composite. Adsorption experiments were conducted using batch-mode techniques under reducing conditions at ambient temperature. The reaction mechanism indicated a higher proton coefficient, greater intraparticle diffusion, and higher mass transfer rates compared with those achieved with bare montmorillonite. The intraparticle diffusion constant derived from the slope was 2.93-3 (mg·g-1·min-0.5), and the intercept C was 9.86, ≠ 0. In the presence of a CuO coating, the adsorption efficiency was 85.55% at pH 4 and 89.62% at pH 7. Therefore, the copper(Ⅱ) oxide-montmorillonite composite, as a novel adsorbent with a very high adsorption capacity, exhibited substantially enhanced adsorption of Pb2+ ions compared with bare montmorillonite.     

Thermodynamics and density functional theory study of potassium dichromate interaction with galena

The adsorption heat and reaction rate constant of potassium dichromate on the surface of galena were studied. The results indicate that potassium dichromate tends to adsorption on the galena surface. The reaction order is only 0.08385, suggesting that the concentration of potassium dichromate has little influence on its adsorption on the galena surface. In addition, the simulation of CrO₄2? adsorption on the PbS (100) surface in the absence and presence of O₂ was carried out by density functional theory (DFT). The calculated results show that CrO₄2? species adsorb energetically at the Pb-S bond site, and the presence of O₂ can enhance this adsorption.     

Flotation of niobite, fersmite, and ilmenorutile

The flotation ofniobite, fersmite, and ilmenorutile was studied using 3 collectors with various concentration and pulp pH. The collecting property of different representative collectors was investigated. Experimental results show that diphosphonic acid is an effective collector for valuable niobium-containing minerals. A flotation recovery of 90.87%-91.7% is obtained with 75 mg/L diphosphonic acid at pH 2-4. The chemical adsorption of diphosphonic acid on these 3 minerals' surface might lead to the high recovery efficiency of the minerals, which is proved by IR and X-ray photoelectron spectroscopy spectra.     

Growth behavior of electroless copper on silicon substrate

The growth behavior containing deposit morphology, growth rate, activation energy, and growth mechanism of copper on silicon substrate, especially at the initial stage, in the electroless plating process was studied. Copper was deposited on the surface of the silicon substrate in an electloless plating bath containing formalin (CH₂O 37vol%) as a reducing agent at a pH value of 12.5 and a temperature of 50-75℃. The copper deposit was characterized using a field emission scanning electron microscope and transmission electron microscope. The results showed that after the activation process, nanoscale Pd particles were distributed evenly on the surface of the silicon; in the deposition process, copper first nucleated at locations not only near the Pd particles but also between the Pd particles; the growth rate of electroless Cu ranged from 0.517 nm/s at 50℃ to 1.929 nm/s at 75℃. The activation energy of electroless Cu on Si was 52.97 kJ/mol.     

Solution chemistry of carbonate minerals and its effects on the flotation of hematite with sodium oleate

The effects of carbonate minerals (dolomite and siderite) on the flotation of hematite using sodium oleate as a collector were investigated through flotation tests, supplemented by dissolution measurements, solution chemistry calculations, zeta-potential measurements, Fourier transform infrared (FTIR) spectroscopic studies, and X-ray photoelectron spectroscopy (XPS) analyses. The results of flotation tests show that the presence of siderite or dolomite reduced the recovery of hematite and that the inhibiting effects of dolomite were stronger. Dissolution measurements, solution chemistry calculations, and flotation tests confirmed that both the cations (Ca2+ and Mg2+) and CO₃2- ions dissolved from dolomite depressed hematite flotation, whereas only the CO₃2- ions dissolved from siderite were responsible for hematite depression. The zeta-potential, FTIR spectroscopic, and XPS analyses indicated that Ca2+, Mg2+, and CO₃2- (HCO₃-) could adsorb onto the hematite surface, thereby hindering the adsorption of sodium oleate, which was the main reason for the inhibiting effects of carbonate minerals on hematite flotation.     

三价砷存在条件下毒砂表面微结构对热氧化硫杆菌附着性的影响

Understanding bacterial adsorption and the evolution of biofilms on arsenopyrite with different surface structures is of great significance to clarifying the mechanism of microbe–mineral interfacial interactions and the production of acidic mine drainage impacting the environment. In this study, the attachment of Sulfobacillus thermosulfidooxidans cells and subsequent biofilm formation on arsenopyrite with different surface structures in the presence of dissolved As(Ⅲ) was studied. Arsenopyrite slices with a specific surface were obtained by electrochemical corrosion at 0.26 V. The scanning electronic microscopy-energy dispersion spectra analyses indicated that the arsenopyrite surface deficient in sulfur and iron obtained by electrochemical treatment was not favorable for the initial adsorption of bacteria, and the addition of As(Ⅲ) inhibited the adsorption of microbial cells. Epifluorescence microscopy showed that the number of cells attaching to the arsenopyrite surface increased with time; however, biofilm formation was delayed significantly when As(Ⅲ) was added.     

Flotation separation of arsenopyrite from several sulphide minerals with organic depressants

In this paper, the separation of arsenopyrite from chalcopyrite, pyrite, galena with organic depressants （guergum and sodium humic ） was discussed, and the functioning mechanism of those organic depressants was discussed. The experimental results of monomineral flotation indicated that both guergum and sodium humic have depressing effect on arsenopyrite in the presence of ethyl xanthate. Guergum and sodium humic showed different depressing ability to pyrite, chalcopyrite and galena, and the higher the pH value in pulp, the stronger the depressing ability. Ultraviolet-Visible Spectrophotometric study showed that the adsorption layer of xanthate on surface of minerals had been desorhed by the two organic depressants, and the selective desorption of the collector layer was found from different minerals. The xanthate cover on minerals surface was set free when dosage of the organic depressants was high enough. For artificially-mixed minerals, the separation of arsenopyrite from other sulphides was successfully realized by controlling dosage of the organic depressants. And sodium humic had been concentrates in a commercial Lead-Zinc concentrator.     

ZnO和ZnS表面对黄药的吸附

研究4种样品(ZnO、表面硫化的氧化锌(ZnO/ZnS)、ZnS和ZnO/ZnS再氧化)的表面电性和吸附黄原酸益的性质,得出4种样品表面的Zeta电位负值的大小顺序为ZnO/ZnS ＞ZnS ＞ZnO/ZnS再氧化＞ZnO;ZnO/ZnS再氧化样品,在pH=7时对丁基黄药和辛基黄药的吸附率均在90％以上,这表明:适度再氧化可改善表面硫化氧化锌对黄药的吸附性能,推测原因为表面元素硫的生成所致;根据模拟软件MEDUSA给出溶液含硫组分分布结果,得出在标准氢电位(ESHE)为0～0.2V时,单质硫是优势组分.     

Cu（II）、Ni（II）离子在蛇纹石表面的吸附及对其浮选的影响

通过吸附量测试、纯矿物浮选和红外光谱分析,研究Cu2+和Ni2+离子在蛇纹石表面的吸附过程及对蛇纹石浮选的活化机理。 Cu2+和Ni2+离子在蛇纹石表面的吸附符合二级动力学模型,等温吸附过程符合Langmuir等温吸附模型,吸附能够自发进行,为物理吸附和化学吸附的共同作用,Cu2+和Ni2+离子在蛇纹石表面的吸附量随pН值升高而增大。 Cu2+和Ni2+离子在弱碱性条件下对蛇纹石具有活化作用,活化机理为铜镍的氢氧化物沉淀和羟基络合物作用于蛇纹石表面,形成活性位点,黄药在活性位点上吸附生成黄原酸铜或黄原酸镍,从而使蛇纹石表面疏水性增大,浮选受到活化。     

细粒滑石对孔雀石硫化浮选的影响

通过浮选试验发现细粒滑石的加入降低了孔雀石的硫化浮选可浮性,细粒滑石含量越多,对孔雀石的可浮性影响越大;通过Zeta电位测试、吸附量测试、SEM-EDS分析和EDLVO理论计算研究分析了细粒滑石影响孔雀石硫化浮选的原因.结果表明:适量的Na₂S在孔雀石矿物表面的吸附是其硫化-黄药浮选成功的关键,而细粒滑石会吸附罩盖在孔雀石矿物表面,且滑石矿物表面不会发生Na₂S的吸附,因此,细粒滑石减弱了孔雀石矿物表面的硫化效果,使其可浮性降低.     

丁基钠黄药浮选斑铜矿的吸附热力学和动力学研究

研究了斑铜矿的浮选行为，并通过吸附量测试、红外光谱、吸附动力学及热力学计算研究丁基钠黄药(简称NaBX)在斑铜矿表面的吸附机理.斑铜矿在pH为5~9时可浮性较好，药剂在矿物表面的吸附属Freundlich模型的多分子层吸附;当 pH 为12时可浮性差，属于Lamgmuir模型的单分层吸附.NaBX在矿物表面吸附符合二阶动力学方程，是自发进行的化学吸附过程，通过热力学计算得出pH 为9时的吸附反应比pH为12时更容易发生.红外光谱测试表明，当pH为5~9时NaBX在斑铜矿表面的吸附产物为Cu(BX)₂，Fe(BX)₃和(BX)₂，而当pH为12时的吸附产物为Cu(BX)₂.     

新型二烷基黄原酸酯捕收剂DIDTC浮选机理

合成了一种活性二烷基黄原酸酯捕收剂——S-十二烷基,O-异丙基-黄原酸酯(DIDTC)并将其用于浮选分离黄铜矿和黄铁矿.浮选实验结果表明DIDTC具有比丁基黄药更好的选择性,紫外可见光谱证明DIDTC对铜离子比铁离子具有更强的吸附性.采用红外光谱和吸附实验研究了DIDTC对黄铜矿表面的吸附机理,实验结果表明在碱性环境中DIDTC可能通过其分子中的S原子和O原子同时与黄铜矿表面的铜原子发生了键合,并在浓度较高时形成多层吸附.另外,还采用普遍微扰理论和基于GGA/PW91作为交换相关函的密度泛函计算对上述结果进行了捕收剂的构效关系分析.     

十二胺体系中异极矿浮选行为的研究

以十二胺为捕收剂,通过单矿物浮选试验对异极矿的可浮性及正辛醇对异极矿可浮性的影响进行了初步研究.结果表明,当pH值在10~11范围内,适量的十二胺对未经活化的异极矿具较好的捕收性;正辛醇对异极矿不具有捕收性.正辛醇能够强化十二胺阳离子在异极矿表面的吸附,降低十二胺的浮选起始浓度;当正辛醇以25%的物质的量比取代十二胺组成胺醇复合捕收剂时,使用复合捕收剂可获得与使用十二胺相同的浮选效果.     

白云石对菱镁矿浮选行为的影响

以油酸钠(NaOL)为捕收剂,六偏磷酸钠为抑制剂研究菱镁矿和白云石浮选行为,并依据动电位、吸附试验和扫描电镜测试结果,探讨了菱镁矿与白云石人工混合矿体系中Ca~(2+)对菱镁矿浮选的影响机理.浮选试验结果表明,六偏磷酸钠对菱镁矿和白云石单矿物有良好的选择抑制作用;但对二者的人工混合矿进行浮选时,两种矿物均受到六偏磷酸钠的抑制,无法实现分离.吸附试验和扫描电镜测试结果表明,在浮选过程中白云石溶解出的Ca~(2+)吸附在菱镁矿表面.动电位测试表明,由于Ca~(2+)的吸附导致菱镁矿与白云石的表面性质趋同,严重影响这两种矿物的浮选分离.     

高硫铝土矿浮选除硫药剂的选择

考察了十二烷基磺酸钠、乙黄药、乙硫氮、丁黄药和异丁黄药5种浮选剂对高硫铝土矿浮选除硫性能的影响,着重考察了浮选剂用量、浮选时间、浮选矿浆液固质量比、pH值及矿石粒度对浮选除硫率和氧化铝回收率的影响.研究表明,十二烷基磺酸钠不具备浮选除硫的能力;乙黄药和乙硫氮具有一定的浮选除硫能力;丁黄药和异丁黄药浮选除硫的能力很强,较适合用于铝土矿浮选除硫的工业化生产.丁黄药和异丁黄药一步精选开路实验表明,异丁黄药具有较高的选择性,丁黄药具有较强的捕收能力.