Effect of ozone on physico-chemical and flotation properties of surface of pyrrhotite under the nanosecond electromagnetic pulse treatment

It is proved by testing that the effect of nanosecond powerful electromagnetic pulses (PEMP) tends to give rise to both pyrrhotite disintegration and alterations of its particles’ surface chemistry. It is found that PEMP exerts an effect on the surface composition, floatability, sorption ability and solubilization intensity of pyrrhotite. The non-monotone variation of sulphur content, removed from pyrrhotite surface under hexane action, and ferrous and ferric sulfates detected in the aqueous phase of suspension, are found to induce a nonmonotone alteration of sorption and flotation properties of the mineral depending on the number of pulses. The mode has been established for the preliminary PEMP treatment for pyrrhotite and pentlandite, aimed at improving the flotation separation as compared to a conventional mode. __________ Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 1, pp. 91–99, January–February, 2007.     

Influence of nanosecond electromagnetic pulses on electrophysical properties of pyrite and arsenopyrite

The present investigation concerns influence of high power nanosecond electromagnetic pulses on thermoelectric properties, conduction and electrode potential of pyrite and arsenopyrite, Darasunskoe deposit. Experimental data obtained are in full compliance with classical concepts on interrelation between electrochemical and flotation properties of minerals.     

Oxidation of pyrite and arsenopyrite in sulphidic spoils in Lavrion

This paper aims to present the aspects of oxidation of pyrite and arsenopyrite in the sulphidic spoils in Lavrion and to assess the environmental impact of this process. Sulphidic spoils, under the combined action of atmospheric oxygen, water and bacteria are oxidised and toxic elements are released and migrate to surrounding areas contributing to widespread soil contamination and severe deterioration in the quality of surface and underground waters. The critical factors which control the generation of acidic waters are availability of oxygen and water, temperature, bacterial activity and rate of oxygen diffusion through the pores in the upper zones of spoils. Special emphasis will be given in the oxidation of sulphidic spoils at Lavrion, Greece, where the generation of acidic waters causes widespread contamination. This study is focused in the first part on the preferential oxidation of arsenopyrite. Flotation products containing pyrite and arsenopyrite were subjected to bacterial leaching tests at 3% w/v pulp density and the degrees of oxidation were calculated and compared to with previous experimental studies. These results provided the basis to assess the behaviour of the above minerals in waste stockpiles. Moreover, and in order to assess the oxidation and precipitation mechanisms, several samples were collected up to a depth of 20 cm from the surface from the same spoils profile, where successive layers of oxidation products were present and characterised chemically and mineralogically. The above information is critically evaluated for the determination of the environmental impact of the oxidation of sulphide phases in spoils.     

The effect of temperature on the pulp and froth phases in the flotation of pyrite

The effect of temperature on the flotation of pyrite has been investigated. At temperatures below ambient an increase in temperature results in an increase in the rate of flotation of fast-floating particles but has a minimal effect on that for slow-floating particles. At temperatures greater than ambient the dominant effect of increasing temperature is to decrease the viscosity of the water thus increasing the rate of elutriation of the gangue back to the pulp. In general an increase in temperature resulted in an increase in the rate of pyrite recovery and the sulphur grades and a decrease in the water recovery and size of the bubbles in the pulp.     

石英与蛇纹石异相凝聚及其对黄铁矿浮选的影响

通过单矿物和人工混合矿的浮选试验、Zeta电位测试、吸附量测试,研究了蛇纹石和石英异相凝聚的机理,以及对黄铁矿浮选的影响,以进一步探索多种矿物的体系中,蛇纹石对硫化矿物浮选影响的主要原因。结果表明:通过添加石英,可以恢复黄铁矿对捕收剂的吸附量,减弱蛇纹石的不良影响,不同粒级的石英与蛇纹石的异相凝聚作用强弱不同,粒级越细的石英,与蛇纹石的异相凝聚作用越强。     

Effect exerted by structural features of copper-zinc ores on their oxidation and technological properties

Modeling the oxidation of pyrite copper-zinc ores under evaporization shows that structural features of ores influence the process kinetics, and displays new-formed mineral phases, namely, gannigite, biankite, chalcanthite, which relate with sulfate generating on evaporation from natural and process waters at pyrite deposits. The oxidation effect on the mineral flotation properties is described. __________ Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 4, pp. 101–110, July–August, 2008.     

含砷硫铁矿浮选分离研究现状与进展

黄铁矿是地壳中分布最广的硫铁矿,毒砂常与其密切共生,它们的结构与表面化学性质相似,不易分离,故产出的黄铁矿精矿中常含有大量毒砂,会严重影响后续化工制酸产品质量,且污染环境.鉴于矿产资源高效利用与环境保护,毒砂与黄铁矿的分离与综合回收利用具有重要意义.浮选是硫砷矿物分离的主要工艺,对硫砷矿物浮选工艺与药剂进行总结,阐述了...     

Nanosecond electromagnetic pulse effect on phase composition of pyrite and arsenopyrite surfaces,their sorption and flotation properties

The X-ray photoelectronic spectroscopy data give the grounds for statement that the powerful nanosecond electromagnetic pulse pretreatment improves sorption activity of pyrite surface and lowers sorption of a collector at arsenopyrite surface. The research results are verified by test data on the powerful nanosecond electromagnetic pulse effect on the structure and chemical properties of pyrite and arsenopyrite surface, as well as their electrochemical and flotation properties.     

Electrochemical characteristics and collectorless flotation behavior of galena: With and without the presence of pyrite

The electrochemical characteristics, surface properties and collectorless flotation behavior of galena with and without the presence of pyrite have been studied. Electrochemical tests confirmed previous reports in the literature that galena is electrochemically more active than pyrite and serves as the anode in galvanic combinations with pyrite. Cyclic voltammograms and polarization curves tests indicated that the addition of pyrite did not change the oxidative and reductive products of galena, but increased the current density during oxidation process. Zeta potential of galena showed a significant difference when coupled with pyrite, due to the influence on the oxidation of the mineral surface. Flotation results showed that the presence of pyrite leading to an influence on the collectorless floatability of galena and the influence correlation with the composition proportion of each mineral.     

The effect of regrind mills on the separation of chalcopyrite from pyrite in cleaner flotation

Stirred mills have been widely used for regrinding and are more energy efficient than tumbling mills. These two types of mills present different particle breakage mechanisms and redox environments during grinding. In this study, the effect of regrinding with these two types of mills on the separation of chalcopyrite from pyrite in the cleaner stage was studied. A laboratory rod mill and a laboratory stirred mill were used to regrind rougher flotation concentrates. It was found that chalcopyrite and pyrite exhibited different flotation behavior after regrinding with the rod mill and the stirred mill, resulting in different separability of chalcopyrite from pyrite. The mechanism underpinning this phenomenon was investigated by a range of techniques including dissolved oxygen demand measurements, X-ray photoelectron spectroscopy (XPS) and Time of flight secondary ion mass spectrometry (ToF-SIMS). It was found that the two mills produced different surface oxidation and pyrite activation by copper ions which determined the separation of chalcopyrite from pyrite. This study demonstrates that the selection of a regrind mill should not only depend on its energy efficiency but also the property of surfaces produced for subsequent flotation.     

The influence of the oxidation state of pyrite and arsenopyrite on the flotation of an auriferous sulphide ore

In this paper, the influence of the oxidation state of pyrite and arsenopyrite on the flotation of an auriferous sulphide ore was investigated by different techniques, including electrode, pulp potentials, DRIFT spectroscopy and microflotation tests. In addition, the gold and sulphide recoveries were also investigate, in a laboratory-scale cell, as a function of pulp potential and reagent concentration. It was verified that the presence of oxidation products on the sulphide mineral surface demands a higher collector concentration in order to achieve a satisfactory sulphide recovery. The electrochemical behaviour of pyrite and arsenopyrite indicated that a nitrogen atmosphere can lead to a low pulp potential, which inhibits the formation of oxidation products, enhancing both the free gold and sulphide recoveries. Although copper sulphate activates even oxidised sulphide surfaces, it does not improve free gold recovery.     

氧化对毒砂可浮性的影响

在空气、水、高锰酸钾及过氧化氢等介质中分别氧化毒砂,利用红外光谱、接触角检测等手段探究了毒砂氧化程度对其可浮性的影响。结果表明,毒砂处于不同介质中氧化时被氧化程度不同,高锰酸钾及氧化氢等氧化剂的氧化效果强于空气和水; 接触角检测以及浮选实验结果表明,毒砂在空气中氧化一定时间,可以促进其可浮性; 毒砂在水中氧化,其可浮性受到了一定程度抑制; 毒砂在氧化剂中氧化,其可浮性受到抑制,其中高锰酸钾抑制作用更强。     

Correlation between elemental composition of the surface of gold-bearing pyrite and arsenopyrite and their sorption and flotation properties

Conclusions  1. Crystallostructural estimate of the ionicity of the Fe-S bond in pyrite and arsenopyrite suggests possible shifting of the pyrite electrons toward the anionic core, and this is responsible for the higher reactivity of pyrite vis-à-vis arsenopyrite. 2. The differences in the floatability of pyrite samples from different deposits are caused essentially by the state and elemental composition of the surface. 3. With rise of arsenic content as we go from pyrite to arsenopyrite, mineral extraction falls, and in gold-bearing arsenous minerals the minimum flotation activity corresponds to the maximum gold content. Institute of the Problems of Integrated Exploitation of Mineral Resources, Russian Academy of Sciences, Moscow. Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, Vol. 33, No. 6, pp. 110–115, November–December, 1997. This work was carried out with the support of the Russian Fund for Fundamental Research (Project No. 97-05-64010).     

Electrochemical polarization effect on surface composition, electrochemical characteristics and adsorption properties of pyrite, arsenopyrite and chalcopyrite during flotation

The article presents experimental research of the influence exerted by electrochemical polarization on electrode potential, phase composition of surface compounds, adsorption of collector and floatability of basic sulfides of gold-bearing ore. It is shown that phase composition of surface compounds generated under different polarization modes affects adsorption of collectors and floatability of minerals.     

The separation of chalcopyrite and chalcocite from pyrite in cleaner flotation after regrinding

In this study, the differences between the separation of chalcopyrite and chalcocite from pyrite in cleaner flotation after regrinding were investigated. In the rougher flotation prior to regrinding, high chalcopyrite and chalcocite recovery were obtained in conjunction with high pyrite flotation recovery due to the activation of pyrite by copper ions during primary grinding. The rougher flotation concentrate was reground in a rod mill before cleaner flotation. It was found that chalcopyrite and chalcocite exhibited different flotation behavior and also affected pyrite flotation differently in cleaner flotation. The mechanism underpinning these phenomena was investigated by a range of techniques including the polarization of mineral electrodes, X-ray photoelectron spectroscopy (XPS) analyses and ethylene diamine tetraacetic acid (EDTA) extraction. It was found that the flotation behavior of both copper minerals and their effect on pyrite flotation after regrinding were governed by their electrochemical activities and galvanic coupling with pyrite.     

菱锰矿与方解石浮选行为及其机理研究

研究菱锰矿与方解石的表面电性和浮选行为,浮选试验、ζ-电位测试、SEM-EDAX分析表明,在混合体系中菱锰矿溶解出的Mn2+会在方解石表面发生吸附,导致方解石表面性质向菱锰矿表面性质转化;溶液化学计算结果表明,菱锰矿溶解的Mn2+浓度大到足够在方解石表面生成MnCO3沉淀,使得两种矿物表面性质趋于相近,这是菱锰矿与方解石难以分离的主要原因。     

调浆气氛对黄铁矿浮选电化学性质影响研究

基于氧气在黄铁矿浮选电化学反应中的作用,考察了p H为4.00、6.86、9.18、10.01和10.96五种缓冲溶液浮选体系下,矿浆溶氧量(DO)对黄铁矿浮选矿浆电位(Eh)和回收率的影响。研究表明,五种缓冲溶液体系下,Eh均随着DO的增加而增加,碱性条件下DO对Eh的影响较小;浮选回收率随DO的增加呈下降趋势,碱性条件下回收率的变化较大。     

Influence of nanosecond electromagnetic pulses on phase surface composition, electrochemical, sorption and flotation properties of chalcopyrite and sphalerite

The mechanism for the powerful nanosecond electromagnetic pulse (MNEMP) effect on the phase composition of new-formed chalcopyrite and sphalerite structures is studied by IR Fourier spectroscopy method. The authors establish the effect of the higher sorption activity of sulfide minerals subjected to the electromagnetic pulse treatment. The research data are confirmed by the experimental data on MNEMP effect on electrochemical and flotation properties of chalcopyrite and sphalerite.     

Influence of liquid phase and products of its radiolysis on surface properties of pyrite and arsenopyrite

A feasibility study has been made on improving the contrast of processing properties of pyrite and arsenopyrite, irradiated by accelerated electrons, when these minerals are in the form of neutral, weakly alkaline, and alkaline aqueous suspensions. It has been shown that as a consequence of change in the surface composition, sorption species, and quantity of adsorbed xanthate and its derivatives, the contrast of flotation properties of pyrite and arsenopyrite can be increased by regulating the irradiation dose of the mineral suspension. Institute of Problems of Complex Development of Bowels, Russian Academy of Sciences, Moscow. Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 1, pp. 85–91, January–February, 1999.     

酸化水玻璃对萤石与方解石浮选分离作用研究

研究了不同pH的酸化水玻璃对萤石与方解石可浮性的影响规律。研究结果表明,酸化水玻璃的pH对药剂的抑制效果有重要影响,pH介于5.0~9.5的酸化水玻璃能有效抑制方解石,随着用量的增加抑制效果越强,在弱碱性的浮选区间内能很好地选择性抑制方解石,而强碱性和强酸性的酸化水玻璃对两种矿物的选择性抑制效果差。其作用机理可能为水玻璃与硫酸混合后,在弱碱性和弱酸性的溶液pH区间内更容易生成亲水性强的硅酸胶粒,可以选择性吸附在方解石表面上,实现萤石与方解石的浮选分离。