Original potential flotation of galena and its industrial application

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Physical chemistry mechanisms of CDR system in sulphide mineral flotation

The flotation tests,zeta potential measurements,and Fourier transform infrared spectroscopy(FTIR) analysis on galena,sphalerite,and pyrite were studied in a collecting-depressing-reactivating(CDR) system.In this system,sulphide minerals were first collected and acti-vated by the collector,and then depressed strongly by Ca(OH)2 in a strong alkaline solution.Finally,they were reactivated by H2SO4.The flotation tests of pure minerals showed that in the Ca(OH)2 depressing process sulphide minerals had similar flotation characteristics because they had already been influenced by the collector.Hence,the flotability differences between them were reduced.However,in the H2SO4 re-activating process considerable differences in the flotability between galena and sphalerite/pyrite were produced.That is to say,galena was relatively easy to be reactivated by H2SO4,but sphalerite and pyrite were not reactivated at pH 11.The zeta potentials of sulfide minerals measured by the Zeta Plus presented irreversible characteristics on the change of pH values.The results of the FTIR spectra analysis indi-cated that the collectors already adsorbed on the mineral surface were removed partially by Ca(OH)2.     

某氧化铅锌矿选矿试验研究

某铅锌矿矿石含有铅、锌有价组分和可综合利用的组分银。矿石矿物组成较为复杂,氧化率高,为氧化铅锌矿石。试验表明,采用优先浮选分选硫化铅、硫化锌、氧化铅矿物可获得较好的分选指标,但浮选法分选氧化锌矿物指标较差。通过分选工艺的研究,采用原矿粗磨(细度-200目占60%～70%),优先浮选—重选—磁选联合流程,可以获得较好的选矿指标。     

Effect of 2-aminothiophenol on the separation of jamesonite and marmatite

The minerals jamesonite and marmatite have similar surface properties.Separating them using a flotation method is inefficient.For separation of lead and zinc the lead mineral is generally floated preferentially to the zinc mineral,which appears in the sinks.In this study a new of collector,2-aminothiophenoi,is introduced that can float a zinc mineral,as a product entrapped in foam,preferentially.Single mineral flotation tests revealed that 2-aminothiophenol has good selectivity for flotation of marmatite.An artificial mixture of minerals used in a flotation test showed that 2-aminothiophenol can effectively separate marmatite from jamesonite.A product assaying at 45.06% Zn and 4.06% Pb was produced.FTIR spectra were employed to probe the adsorption mechanism of 2-aminothiophenol onto marmatite.The results indicate that adsorption of 2-aminothiophenol onto jamesonite and marmatite were,respectively,physical adsorption and chemical adsorption.This agrees with the flotation results.     

Effect of sodium pyrophosphate on the flotation separation of chalcopyrite from galena

The effect of sodium pyrophosphate (SPH) on the separation of chalcopyrite from galena was examined through flotation, adsorption, electrokinetic studies and infrared spectral analysis. Differential flotation tests indicate that satisfactory separation can be achieved within the pH range from 2.5 to 6 using SPH to depress the galena, but not the chalcopyrite when O-isopropyl-N-ethyl thionocarbamate (IPETC) is used as the collector. The electrophoretic mobilities of both the minerals dramatically become negatively charged following SPH adsorption in the pH range from 2.5 to 12. The infrared spectral analysis suggests that chemical adsorption occurs on galena surface treated by SPH, indicating that a chelate complex has formed. At weakly acidic pH values, the adsorption density of IPETC onto galena is significantly reduced in the presence of SPH. However, the amount of IPETC adsorbed onto chalcopyrite almost remains at the same level. Since the observed adsorption density of IEPTC onto chalcopyrite is quite high compared to galena, the observed flotation results are explained. A possible mechanism for the interaction between the two sulphide minerals and SPH is discussed.     

Potential control flotation of galena in strong alkaline media

The electrochemical oxidation of galena in collectorless and collector flotation systems, particularly in strong alkaline media, was studied. The results show that, with pH value higher than 12.5 and potentials below 0.17 V, the oxidation products of galena are elemental sulfur and HPbO2^- . Elemental sulfur was present on the mineral surface in excess of oxidized lead species due to dissolution of HPbO2^- , which is beneficial to the flotation of galena. Under the same conditions, sphalerite and pyrite were depressed as a result of significant surface oxidation. Diethyldithioearbamate (DDTC) was found to be the most suitable collector for galena flotation in strongly alkaline media. The very potential produced hydrophobic PbD2-the surface reaction produet of DDTC with galena, is 0 to 0.2 V. Meantime DDTC can depress the surface over-oxidation of galena.Investigations also indicate that, in the range of - 0.9 V to 0.6 V, hydrophobic PbD2 can be firmly adsorbed on galena.     

Depression behaviors of N-thiourea-maleamic acid and its adsorption mechanism on galena in Mo-Pb flotation separation

In present study, a novel organic depressant N-thiourea-maleamic acid (TMA) was synthesized and applied as a galena depressant in the flotation separation of Mo-Pb ores. The depression behaviors of TMA were tested through flotation experiments. A wider separation window for single minerals over 90.0% was obtained at 30.0 mg/L TMA, confirming that TMA could depress galena significantly, while effected molybdenite floatability slightly. An effective separation was obtained for artificially mixed minerals and actual Mo-Pb ores. The adsorption mechanism on galena was revealed by UV–Vis spectra, zeta potential tests, Fourier transform infrared spectroscopy (FT-IR) analysis, contact angle tests and X-ray photoelectron spectroscopy (XPS) analysis. The zeta potentials of galena became more negative and the contact angle of galena dropped from initial 74.36° to 57.8° with 30.0 mg/L TMA depressant, inferring that TMA had adsorbed on galena surface. The analysis results of UV–Vis spectra, FT-IR and XPS gave further evidence that TMA might chemisorb on galena surface via Pb sites on galena surface and the thiourea group in TMA molecular structure, while the carboxyl group played a role of hydrophilicity.     

Sulfidation roasting of lead and zinc carbonate with sulphur by temperature gradient method

In order to enhance the lead and zinc recovery from the refractory Pb-Zn oxide ore, a new technology was developed based on sulfidation roasting with sulphur by temperature gradient method. The solid-liquid reaction system was established and the sulfidation thermodynamics of lead and zinc carbonate was calculated with the software HSC 5.0. The effects of roasting temperature,molar ratio of sulphur to lead and zinc carbonate and reaction time in the first step roasting, and holding temperature and time in the second roasting on the sulfidation extent were studied at a laboratory-scale. The experimental results show that the sulfidation extents of lead and zinc are 96.50% and 97.29% under the optimal conditions, respectively, and the artificial galena, sphalerite and wurtzite were formed. By the novel sulfidizing process, it is expected that the sulphides can be recovered by conventional flotation technology.     

组合药剂对方铅矿浮选性能的影响

利用纯矿物研究单一捕收剂黄药和组合药剂对方铅矿浮选行为的影响．首先确定黄药的试验条件，在此基础上添加pepa药剂，进一步考察组合药剂的最佳试验条件、Pepa药剂对方铅矿的黄药浮选有明显的活化作用、试验结果表明：组合药剂比黄药对方铅矿具有更好的捕收性能，在最佳的工艺条件下，把浮选回收率从80％提高到了96％．     

方铅矿磨矿体系表面电化学性质及其对浮选的影响

采用电化学测试技术研究方铅矿磨矿体系中磨矿介质类型（瓷介质和铁介质）、机械力以及捕收剂对方铅矿表面电化学性质的影响。研究结果表明：瓷介质中,方铅矿表面会发生适当的氧化反应,有利于方铅矿浮选：增大方铅矿与瓷介质间的机械力,体系的还原性增强,同时削弱矿物表面的氧化反应,给浮选造成一定影响。铁介质中,一方面,由于铁与方铅矿的腐蚀电偶作用增强了体系的还原性,降低了药剂在方铅矿表面的吸附性能,另一方面,由于腐蚀电偶作I用产生的铁离子增强了方铅矿表面的亲水性,两方面的影响都不利于方铅矿的浮选;增大方铅矿与铁介质间的机械力,二者之间的腐蚀电偶作用和体系的还原性增强,同样不利于方铅矿浮选。当pH=9时,在瓷介质和铁介质磨矿体系中是否添加捕收剂,对方铅矿表面电化学性质和浮选影响不大。     

Insight into mineral flotation fundamentals through the DFT method

Flotation is a complex process that occurs in solid–liquid-gas multiphase systems, and its main factors include the minerals, separation medium, as well as various flotation reagents. The study of mineral properties and interactions with other components such as reagents and water lays the basic theoretical foundation for flotation. Density functional theory (DFT) calculations can qualitatively evaluate the exchange of matter and energy between the mineral system and the surroundings and quantitatively characterize these behaviors, which greatly expands the breadth and depth of flotation studies. This review systematically summarizes the advances of flotation research based on DFT studies, including the study of mineral crystal chemistry represented by the theory of lattice defects, mineral surface hydration such as hydrophilicity and hydrophobicity, surface regulation mechanism, and collecting mechanism based on surface adsorption theory. More significantly, it systematically elaborates different types of collectors according to their characteristics and emphatically explains the mechanism of some typical collectors in detail.     

有色冶炼废渣的矿物学特征与环境活性

通过扫描电子显微镜与X射线衍射仪分析、BCR法三步连续提取及元素化学分析，对某有色冶炼废渣中重金属的赋存状态、环境活性及其释放机理进行研究。研究结果表明：废渣中主要有价金属为Fe，Zn，Cu，Pb，Ag和In等，主要毒害元素为Pb，Cd和As等。废渣矿物相中Fe主要以单质铁、铁的氧化物和硫化亚铁存在，Zn主要以闪锌矿存在，Pb主要以方铅矿存在，Cu和Cd主要以硫化矿物等形式存在；Ag和In则很可能以类质同相镶嵌在闪锌矿晶格中：废渣中Zn，Cd，Cu和Pb主要以残渣态为主：酸可提取态含量相对较低，而可还原态和可氧化态含量相对较高：在我国南方地区，酸沉降、微生物作用及原电池效应共同影响废渣中重金属的溶出，为生物浸出废渣中有价金属，实现其资源化和无害化提供了理论依据。     

Flotation behaviors of chalcopyrite and galena using ferrate(Ⅵ) as a depressant

This paper investigated the effects of potassium ferrate(PF) on the flotation performances of chalcopyrite and galena. The flotation results showed that PF obviously depressed galena, but had little effects on the floatability of chalcopyrite within p H range of 4.0–12.0. Zeta potential tests showed that the addition of PF induced the formation of more amounts of hydrophilic species on the surface of galena under an alkaline environment. Industrial grade O-isopropyl-N-ethyl thionocarbamate(IPETC...     

Investigation into the flotation response of refractory molybdenum ore to depressant mixtures:A case study

In this paper, bulk flotation followed by separation was investigated to concentrate purified molybdenite product from Jinduicheng molybdenum ores(Shanxi province, China). The bench scale tests mainly focussed on separation of molybdenite from other sulfide minerals using the new type of depressants.The effect of each single depressant, including organic depressant-modified dextrin(MD), P-Nokes reagent(PN) and sodium trithiocarbonate(ST), and their mixtures on galena, chalcopyrite and other sulfide ores, was examined in turn by changing the concentrations used in cleaner flotation tests. Closed circuit experiments were carried out under the optimal condition and satisfying recovery and grade of molybdenite concentrate could be achieved(86.294% and 53.157%, respectively). A potential reagent regime was developed, with more environmental friendly and more economical advantages due to the introduction of modified dextrin.     

Synthesis of glycerine-xanthate and its depressing mechanism in separation of marmatite from arsenopyrite

A small molecular organic depressor glycerine-xanthate was synthesized. The effect of glycerine-xanthate on the flotation of sulfide minerals was investigated based on a function of pH value and concentration of glycerine-xanthate through flotation experiments in the presence and absence of Cu^2＋. The results show that glycerinee-xanthate has a strong dressing effect on marmatite at pH〉6 and on arsenopyrite in weak acid and base conditions with butyl-xanthate as collector. In the presence of glycerine -xanthate, marmatite is activated by addition of Cu^2＋, but arsenopyrite cannot be activated and remains unfloatable. So the selective separation can be achieved for two minerals. The depression of glycerine-xanthate on sulfide minerals was discussed based on the radical electronegative calculation and the theory of HSAB. Infrared spectrum shows that there are some -OH and-CSS-in glycedne-xanthate molecule, which competes with butyl-xanthate on the mineral surface. As a result of many hydrophilic groups in glycerine-xanthate, the surfaces of marmatite and arsenopyrite become hydrophilic, thus the flotation of marmatite and arsenopyrite is depressed. The collector is adsorbed preferentially on the surface of marmatite and it shows a better floatability in the presence of Cu^2＋, whereas, the surface of arsenopyrite absorbs glycerine-xanthate and the flotation of arsenopyrite is depressed by glycerine-xanthate.     

Effect of radiation on wettability and floatability of sulfide minerals

The feasibility for modifying the wettability and floatability of sulfide minerals by electron beam irradiation has been studied experimentally. The wettability of crystalline pyrite and floatability of some sulfide as pyrite, arsenopyrite, chalcopyrite and marmatite after irradiation were examined by flotation in a modified Hallimond tube. Experimental results show that the hydrophobicity of crystal-line pyrite enhances with the increase of irradiation dose in a low dose range. And the flotation responses of sulfide minerals on irradiation dose vary with the mineral species and particle size. The floatability of minerals can be regulated by altering irradiation dose. An explanation for the mechanism has been suggested based on the principle of radiation chemistry.     

Theoretical study of 2-mercaptobenzimidazole derivatives as chelating collectors in flotation separation of galena and pyrite

Three 2-mercaptobenzimidazole derivatives, 1-ethyl-2-mercapto-benzimidazole (EMBI), 1-propyl-2-mercapto-benzimidazole (PMBI) and 1-benze-2-mercapto-benzimidazole (BMBI), were designed and synthesized in the paper, and their collecting behavior in flotation separation process of galena over pyrite was investigated by flotation tests on lab scale. Apart from this, density functional theory (DFT) calculation and molecular dynamics (MD) simulation were also used to elucidate their collecting mechanism. Results of flotation tests indicate that separation of galena over pyrite is feasible at pH 10, and BMBI has the best floatability among three collectors. DFT calculations show that BMBI has the highest occupied molecular orbital (HOMO) energy and strongest collecting efficiency. The adsorption mode of three collectors on mineral surface by MD method indicates that the combination processes of collectors with mineral are exothermic, and the higher the binding energy, the firmer the collector adsorbs on the mineral surface and the higher collecting capacity. The calculation results demonstrate that the floatability of three collectors follows the order: BMBI > PMBI > EMBI, which is highly consistent with the flotation tests.     

Flotation of copper oxide minerals: A review

Copper oxide minerals are important copper resources, which include malachite, azurite, chrysocolla, cuprite, etc. Flotation is the most widely used method for the enrichment of copper oxide minerals in the mineral processing industry. In this paper, the surface properties of copper oxide minerals and their effects on the mineral flotation behavior are systematically summarized. The flotation methods of copper oxide minerals and the interaction mechanism with reagents are reviewed in detail. Flotation methods include direct flotation (using chelating reagents or a fatty acid as collector), sulfidization flotation (using xanthate as collector), and activation flotation (using chelating reagents, ammonium/amine salts, metal ions, and oxidant for activation). An effective way to realize efficient flotation of copper oxide minerals is to increase active sites on the surface of copper oxide minerals to enhance the interaction of collector with the mineral surface. Besides, various perspectives for further investigation on the efficient recovery of copper oxide minerals are proposed.     

从会理锌矿铅锌矿石中分选铜的试验研究

为从会理锌矿含铜的铅锌硫化矿中分选铜,对会理锌矿含铜的铅锌硫化矿进行了系统的工艺矿物学研究和选矿工艺研究．工艺矿物学研究结果表明会理锌矿含铜的铅锌硫化矿中铜矿物以黄铜矿、银黝铜矿-砷黝铜矿、硫锑铜银矿、车轮矿等矿物形式存在,并以黄铜矿为主,其次为银黝铜矿-砷黝铜矿系列矿物．铜矿物嵌布特征复杂,与闪锌矿互相包裹及呈固溶体分离结构较为普遍．铜矿物嵌布粒级较均匀,多集中于＋0．08mm以上粒级中,铜矿物单体解离度相对较好．基于会理锌矿舍铜铅锌硫化矿的矿石特性,采用“铜铅混浮-铜铅分离-再浮锌”浮选工艺,在原矿含铜0．94％、铅0．92％、锌10．60％的情况下,可获得含铜17．76％、铅4．35％、锌12．87％,铜回收率62．89％的铜精矿,含铜2．99％、铅54．52％、锌10．48％,铅回收率50．34％的铅精矿,含铜0．75％、铅1．20％、锌55．86％,锌回收率88．56％的锌精矿,银在铜、铅、锌精矿中的回收率分别为50．93％、2．32％、29．51％,实现了从会理锌矿含铜铅锌硫化矿中分选铜的目标．     

Effect of L-cysteine on bioleaching of Ni-Cu sulphide by A.manzaensis

The effect of L-cysteine in different concentrations on the bioleaching of Ni-Cu sulfide was studied with an extremely thermophilic archaea, Acidianus manzaensis. It is found that adding certain amounts of L-cysteine to the bioleaching system of Ni-Cu sulfide largely enhances the leaching rate. X-ray diffraction (XRD) patterns show the change of bioleached solid residues and the effect of L-cysteine on the surface charges of minerals. Zeta potential and IR spectra of mineral surface show that the interaction between L-cysteine and mineral leads to the formation of metal complex, which is propitious to the bioleaching of Ni-Cu sulfide by Acidianus manzaensis.