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1、促进剂（TETD）在黄铁矿表面的电化学反应 矿物工程等专业毕业设计外文翻译-中英文对照Electrodeposition of dixanthogen(TETD) on pyrite surfaceLI Wei-zhong(黎维中), QIN Wen-qing(覃文庆), SUN Wei(孙伟), QIU Guan-zhou(邱冠周) School of Mineral Processing and Bioengineering, Central South University, Changsha 410083, China Received 20 July 2006; accepted 2
2、8 October 2006Abstract: The electrochemical reaction of xanthate on the surface of pyrite was studied using cyclic voltammogrametry, chronopotentiometry and rotating-disc electrode measurements. Experimental results demonstrate that the first step in the reaction is electrochemical adsorption of xan
3、thate ion, and then the adsorbed ion associates with a xanthate ion from the solution and forms a dixanthogen on the pyrite electrode surface. The diffusion coefficient of butyl xanthate on pyrite electrode surface can be determined to be about 1.09106 cm2/s. Using the galvanostatic technique, the k
4、inetic parameters of oxidation of the butyl xanthate ion on the pyrite surface are calculated as Ja=200 A/cm2, = 0.203 and J0=27.1 A/cm2Key words: electrochemical reaction; pyrrhotite; xanthate1 Introduction In the past decade, much progress has been made in understanding the reactions of sulfide mi
5、neral surfaces with xanthate reagents. It is widely recognized that the reactions in a flotation system involve electron transfer. Many electrochemical techniques have been employed to study the reaction mechanism of sulfide minerals (such as pyrite, galena and chalcopyrite) with xanthate reagents1.
6、 As well known, flotation of pyrite is an electrochemical process, and adsorption of collectors on the surface of mineral results from the electron transfer between mineral surface and oxidation-reduction composition in pulp. These investigations indicate that the oxidation of both the mineral and t
7、he collector plays an important role in the flotation process. It is generally believed that the reactions produce the hydrophobic particle surfaces required in flotation, and the dominant hydrophobic reactions are electrochemical in nature. Many distinct anode processes can produce hydrophobic prod
8、ucts, such as the chemical adsorption reaction of xanthate ions, and the oxidation reaction of the xanthate ion to its disulfide compound. It is important in flotation to identify the different anodic reactions coupled to a cathodic process that is generally represented by the reduction of oxygen24.
9、 Pyrite(FeS2 ) is the most abundant sulfide mineral in crust of earth and an important raw material of chemical engineering process. The surface chemistry and surface reactivity of FeS2 have been extensively studied, particularly their importance in the processing of sulfide ores59. The electrochemi
10、cal reaction on the surface of pyrite during flotation has been studied well, but there are only a few references available on the oxidation chemical kinetics and mechanism of the reaction on its surface1014. In this study, the electrochemical behavior of the pyrite electrode in a xanthate solution
11、was investigated. Some advanced electrochemical techniques were employed to research the electrodeposit of dixanthogen on the pyrite surface.2 Experimental The pyrite used in this investigation consisted of 58.20% (mass fraction) Fe, 36.20%S, 3.1%SiO2 and was from Mengzi Mine of Yunnan Province, Chi
12、na. Sections cut from the highly mineralized pyrite were fashioned into the form of electrodes for electrochemical measurement. The cut section of mineral was mounted on the tip of a perspex tubule of d 7 mm using epoxy resin and the exposed outer surface was well polished. The exposed surface area
13、of the electrode was about 1 cm2. The reference and auxiliary electrodes were saturated calomel electrode(SCE) and graphite rods, respectively. All potential in this study were quoted in volts, with respect to a standard hydrogen electrode (SHE). The electrochemical measurements were performed with
14、a conventional three-electrode cell using a electronics potentiostat/galvanostat model EG&G 273A and a model 636 Electrode Rotator. Both were operated by a computer. The EG&G corrosion measurement system (Princeton Applied Research Model 352) and Analysis Software (Model 270) were used in the experi
15、ment. The studies were carried out using the pyrite as electrode in a 0.5 mol/L KCl solution in the presence of butyl xanthate.3 Results and discussion 3.1 Two stages of electrochemical reaction on pyrite surface in butyl xanthate solution While the potentiostat applies a constant current on the pyr
16、ite electrode for a specified duration, the overall consumed charge Q can be calculated by the following equation: Q=Q+Qc (1) where Qc is the charge consumed by the diffusion of xanthate ion on the pyrite surface, and Q is the charge consumed by the electrochemical adsorption of xanthate ion. According to the Sand formula15: Q=Q0+3.14n2F2Dc02/
