Kinetics of electrochemical process of galena electrode in diethyldithiocarbamate solution

1　ＩＮＴＲＯＤＵＣＴＩＯＮＤｉｅｔｈｙｌｄｉｔｈｉｏｃａｒｂａｍａｔｅ (ＤＤＴＣ)ｉｓｏｎｅｏｆｔｈｅｍｏｓｔｆｒｅｑｕｅｎｔｌｙｕｓｅｄｃｏｌｌｅｃｔｏｒｓｆｏｒｆｌｏｔａｔｉｏｎｏｆｈｅａｖｙ ｍｅｔａｌｓｕｌｆｉｄｅｍｉｎｅｒａｌｓ ,ｓｕｃｈａｓｇａｌｅｎａ ,ｃｈａｌｃｏｐｙｒｉｔｅａｎｄｊａｍｅｓｏｎｉｔｅ ,ａｎｄｉｔｓｈｏｗｓｓｔｒｏｎｇｓｅｌｅｃｔｉｖｉｔｙ[1] .ＷｈｅｎＤＤＴＣｗａｓｕｓｅｄｉｎｈｉｇｈｌｙａｌｋａｌｉｎｅ (ｐＨ >11.4 )ｆｏｒｓｅｐａｒａｔｉｎｇｇａｌｅｎａｆｒｏｍｓ…     

Characterization of solid embeddable reference electrodes for corrosion monitoring in reinforced concrete structures

Metal-metal oxide (MMO), graphite and laboratory-made Ag/AgCl electrodes were electrochemically characterized to be used as reference electrodes embedded in concrete structures. Electrodes were studied in both, aqueous solutions of pH ranging from 7 to 13.5 and embedded into cement mortars; and the electrochemical studies were carried out in the absence and presence of chloride ions. Potential evolution, polarization behaviour, galvanostatic pulse response and impedance characteristics of the electrodes were carried out in aqueous solutions. Besides, the electrochemical stability of the electrodes embedded in mortar was studied for an exposure period of 2 years. It was found that the MMO pseudo-reference electrode is pH-sensitive, the graphite pseudo-reference electrode is oxygen sensitive and the Ag/AgCl pseudo-reference electrode is chloride sensitive. In spite of the fact that any of them can be used to determine the corrosion rates of rebars because they do not depend on the absolute potential and/or the long-term stability of the reference electrode when using traditional electrochemical techniques, long-term drifts in the electrode potentials may lead to misinterpretations of the rebar state. In this context graphite electrodes are recommended because they provide conservative results regarding the active/passive state of the rebars.     

论我国南方优质锰矿产资源调查评价工程

国土资源部动员全社会开展新一轮国土资源大调查，设立矿产资源大调查评价工程项目。冶金地质勘查总局总结了近年来在中国南方从事锰矿科研和勘查取得的新进析发现、新成果，积极急取设立南方优质锰矿调查评价工程项目，充分讨论了在我国南方开展优质锰矿资源调查评价的必要性、可行性、工作目标、技术路线和实施方案。     

加强矿山“三率”管理之我见

矿山生产的开采回收率、采矿贫化率、选矿回收率，是矿产资源开发利用和矿山企业管理的综合质量指标，文中简要介绍这“三率”的定义和计算方法，及加强“三率”指标管理的一点经验。     

A graphite sheet modified with reduced graphene oxide-hyper-branched gold nanostructure as a highly efficient electrocatalyst for hydrogen evolution reaction

Hydrogen is considered as the most important energy carrier for the future. Water electrolysis is a green method for hydrogen production and simple technology that produces very clean gases. However, the main problems with this method are that this process possesses slow kinetic, consumes many energies and its common electrocatalyst is platinum (Pt) based which is an expensive and rare substance. The use of accessible electrocatalyst materials with new shape or structure, which can reduce the overpotential for the hydrogen evolution reaction (HER) is one of the ways to increase the efficiency of the electrolyzers. Herein, first, a graphite sheet was modified with graphene oxide (GO) and then a hyperbranched structure of gold was electrodeposited on it by controlling the electrodeposition conditions. The electrode surface was characterized by scanning electron microscopy (SEM), field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS) and Fourier transform infrared spectroscopy (FT-IR). The HER performance of the prepared electrodes was evaluated using linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) methods in 0.5 M H₂SO₄ solution. The as-prepared electrode revealed outstanding HER performance with a near-zero onset overpotential (4.7 mV), overpotential of 44 mV at 10 mA cm⁻², a high current density of 127.9 mA cm⁻² at 200 mV and also satisfactory stability. Such results suggest that this electrocatalyst is promising for generating clean energy on an industrial scale.     

Experimental investigation on the conversion of fuel-N to NOx of quasi-particle in flue gas recirculation sintering process

Flue gas recirculation sintering process is a potential technology to decrease fuel consumption and NOx emissions compared with conventional sintering process. In present work, a vertical quartz tube reactor was used to investigate the combustion characteristics and conversion of fuel-N to NOx of quasi-particle. The mass conversion rate of quasi-particle increases with higher temperature. It was found that D₁ model is more appropriate than other models to describe quasi-particle combustion process through comparing correlation coefficients calculated by different mechanism models. Effects of temperature, coke size and proportion, circulating flue gas components on the conversion of fuel-N to NOx of quasi-particle were studied. The conversion rate of fuel-N to NOx of quasi-particle increases with higher temperature. With increasing coke size and proportion, the conversion rate of fuel-N to NOx decreases obviously. O₂ has a positive impact on the conversion of fuel-N to NOx of quasi-particle. CO could decrease the conversion rate of fuel-N to NOx by reducing NO directly or reacting with char to decrease NOx indirectly. CO₂ has an obviously inhibitory effect on the conversion of fuel-N to NOx of quasi-particle because it reacts with char to generate CO. The results were conducive to further understanding the combustion behavior and NOx formation mechanism of quasi-particle during flue gas recirculation sintering.     

多金属复杂硫化铜矿中有价金属的分离研究现状与进展

综述了复杂铜铅硫化矿中铜锌及铅等有价金属的分离回收技术。通过阐述最近的几种处理复杂硫化铜矿的方法,分析和比较了各处理方法的特点,展望了研究趋势。指出:氧化焙烧预处理-浸出法和硫酸化焙烧-水浸法尽管工艺流程短且简单,但焙烧过程产生的SO₂气体对环境污染严重;硫化焙烧-酸浸法能有效降低SO₂气体的排放量,但其焙烧条件苛刻,难以实现工业化;高价铁盐浸出法存在高价铁盐损耗大、再生难的问题;使用氯盐体系直接浸出时还存在Cl^-对设备腐蚀严重等问题;而氧压浸出和微生物浸出虽然也存在一些不足,但在处理复杂硫化铜矿过程中无有害废气产生,环境友好并且硫以单质硫的形式回收,能有效解决硫酸储存难问题,相信其在今后处理复杂多金属硫化矿中具有广阔的发展前景。     

提高原子吸收分光光度计结果准确度的有效途径

原子吸收分光光度计主要用于分析微量到痕量级的元素,具有检出限低、选择性好、精密度高、抗干扰能力强等特点,广泛应用于地质、冶金、化工、农业、食品、生物、医药、环境保护等领域。原子吸收分光光度计主要有火焰和石墨炉原子化器两大类,在分析过程中影响测量的可变因素很多,各种测量条件不易重复,对测定结果的准确度影响较大,因此,如何选择仪器的最佳工作条件十分重要。本文通过对仪器准备工作、仪器状态以及实验过程等影响因素进行分析优化,总结出一些提高原子吸收分光光度计准确度的有效途径,以保证检测结果的准确性。     

转底炉还原红土镍矿工艺设计与实践

为解决低品位红土镍矿的合理利用问题,介绍了转底炉还原红土镍矿新工艺的技术特点和镍铁生产实践,及其工程化应用。     

锂辉石浮选机理研究现状

论文从锂辉石的晶体结构、浮选溶液中Fe3离子和其它金属阳离子、阴离子等三个方面,系统评述了锂辉石浮选机理的研究进展.认为矿石浮选机理的研究有助于选矿药剂的开发,根据锂辉石的特点开发适宜的浮选药剂,对我国锂资源的综合高效利用具有理论和实际意义.