绑定机构
扫描成功 请在APP上操作
打开万方数据APP,点击右上角"扫一扫",扫描二维码即可将您登录的个人账号与机构账号绑定,绑定后您可在APP上享有机构权限,如需更换机构账号,可到个人中心解绑。
欢迎的朋友
万方知识发现服务平台
获取范围
  • 1 / 6
找到 111 条结果
摘要: class="MsoNormal" style="text-align:justify;"> lang="EN-US">In Argentina, there are many sources of copper concentrates. Some of them are currently in operation, while others are in the exploration stage. All copper concentrates produced are exported to other countries for copper refinement and to create various finished products. lang="EN-US"> lang="EN-US">It is desirable that in the near future, these copper concentrates be processed in an Argentinean industrial plant. lang="EN-US"> lang="EN-US">The aim of this paper was to present the results of a characterisation study carried out on five different copper concentrate samples. The thermal decomposition of the copper concentrates was determined by differential thermal analysis and thermogravimetry (DTA TG). The information was correlated with the chemical composition and the mineralogical phases of the samples identified by X-ray diffraction. A melting test at temperatures of up to 1300℃ was performed to complete the study of the concentrate's behaviour during heating. After the test, all of the samples were observed by light and electronic scanning microscopy to identify the different phases generated under high-temperature conditions.

class="MsoNormal"> lang="EN-US">

...
摘要: style="text-align:justify;" class="MsoNormal"> lang="EN-CA">Hydrometallurgical technology offers a unique possibility for developing countries to exploit their mineral resources locally instead of shipping them as concentrates. Production plants may start on a small scale with small capital invest lang="EN-CA">ment then increase productivity later when the economy permits without financial penalty. This is in contract to smelt lang="EN-CA">ing operations which necessitates large scale production from the start with high capital investment that may not be available locally.

...
摘要: style="text-align:justify;"> style="font-size:12px;font-family:Verdana;">A technology for obtaining microlayered composite materials of Cu-Zr-Y-Mo, Cu-Zr-Y-Cr, Cu-Zr-Y-W and Cu-Zr-Y-C systems by means of high-speed electron-beam evaporation-condensation, structure, electrical, and mechanical properties at ambient and elevated temperatures is developed.

...
摘要:Manganese minerals are widely distributed throughout the globe. The most important industrial uses of Mn are in the manufacture of steel, non-ferrous alloys, carbon-zinc batteries and some chemical reagents. Microbial recovery of manganese from low grade manganese ores using bioleaching was investigated in this paper. A bacterial strain, Staphylococcus epidermidis (MTCC-435) was collected from microbial type culture collection, IMTECH Chandigarh and used for the experiment. The experimental results for bioleaching with S. epidermidis showed that under pH 5.5, particle size –150 μm, pulp density 10%, temperature 35℃ and agitation 200 rpm, about 80% of Mn was recovered within 20 days of incubation....
摘要: style="text-align:justify;" class="MsoNormal"> lang="EN-US">Ethylenediaminetetraacetic acid (EDTA) is a chelating agent that has been used for decontamination purposes in nu lang="EN-US">clear industry. The presence of EDTA in decontamination wastes can cause complexation of the cations resulting into interferences in their removal by various treatment processes such as chemical precipitation, ion exchange etc. Further, it might also impart elevated leachability of cationic contaminants from the conditioned wastes immobilized in cement or other matrices and can negatively influence the quality of the final form of waste. In the present study, kinetics of degradation of EDTA (20,000 mg/l) by employing either Photo-Fenton process using UV (15 lang="EN-US"> lang="EN-US">W λmax = 253.7 nm) lang="EN-US">or Sono-Fenton process using ultrasound at 130 lang="EN-US"> lang="EN-US">KHz or simultaneous Sono-Photo Fenton process has been investigated. EDTA is effectively degraded by the synergistic effect of both Photo Fenton and Sono Fenton process. All the above mentioned processes were found to follow a first order kinetics reaction. From the observed pH changes during the oxidation processes, it can be concluded that there is a loss of chelating ability of EDTA. Formation of amides was con lang="EN-US">- lang="EN-US">firmed during the degradation processes.

...
摘要: align="justify"> The Schiff base, 4-[(2-methoxybenzylidene)amino]-1,5-dimethyl-2-phenyl-1H-pyrizol-3(2H)-one (SB), was used for the first time to adsorb copper(II) ions in aqueous solution. Various parameters such as initial pH, agitation period and different initial concentration of copper(II) ions which influenced the adsorption capacity were investigated. The equilibrium adsorption data for copper(II) ions were fitted to Langmuir, Freundlich and Dubinin-Radushkevish isotherm models. The maximum monolayer adsorption capacity of SB as obtained from Langmuir isotherm was 5.64 mg/g. Kinetic data correlated well with the pseudo second-order kinetic model indicating that chemical adsorption was the rate limiting step.

...
摘要:Sulfation roasting was studied to extract copper from the copper sulfide concentrate. Sodium sulfite was added as sulfation agent to the copper sulfide concentrate during roasting in this study. Sulfur removal rate at different roasting temperatures was investigated, and the effects of roasting temperature, roasting time, and the amount of sodium sulfite on copper extraction were studied. Copper extraction higher than 96% was achieved at optimum roasting conditions....
摘要:The objective of this study is to investigate the possibility of continuous extrusion forming (Conform process) and microstructural evolution the of Cu-Mg alloy. The results indicate that Conform process can break as-cast grains and refine the structure, meanwhile. This process can improve the degree of the structure homogeneity. The TEM and EBSD techniques were used to investigate the morphology, grain size and misorientation of the samples at cavity entrance and cavity export. Refined structures after shear deformation include broken grains and subgrains formed by dislocation reconstruction. Due to the relatively high deformation temperature, dynamic recrystallization occurred during deformation. The subgrain rotation nucleation took place, and grain boundary migration resulted in grain growth. However, the coarse grains were refined by anneal twins....
摘要:

style="FONT-SIZE: 10pt" ?=""> style="font-size:12px;">The kinetics of extraction of Ni(II) in the Ni style="font-size:12px;">2+ style="font-size:12px;">-SO4 style="margin-left:-7px;"> 2_AC- style="LINE-HEIGHT: 1.5" ?=""> style="line-height:16px;font-size:12px;"> style="font-size:12px;">(Na style="font-size:10pt;"> style="font-size:12px;">+ style="font-size:12px;">, H style="font-size:10pt;"> style="font-size:12px;">+ style="font-size:12px;">) style="FONT-SIZE: 12px" ?="">- style="FONT-SIZE: 10pt" ?=""> style="font-size:12px;">Cyanex 272 (H style="font-size:12px;">2 style="font-size:12px;">A style="font-size:12px;">2 style="font-size:12px;">)-kerosene-3% (v/v) octan-1-ol system using the single falling drop technique have been reported. The flux of Ni style="font-size:12px;">2+ style="font-size:12px;"> transfer (F) at 303 K in presence of 3% style="FONT-SIZE: 10pt" ?=""> style="FONT-SIZE: 10pt" ?=""> style="font-size:12px;">(v/v) octan-1-ol (de-emulsifier) can be represented as: alt="" src="Edit_d76b3757-9f5b-4ebd-b9c0-731f2150e3b3.bmp" /> style="font-size:12px;">. style="line-height:1.5;font-size:10pt;"> style="font-size:12px;">Depending on reaction parameters, the activation energy ( style="font-size:12px;">E style="font-size:12px;">a style="font-size:12px;">) and enthalpy change in activation ( style="line-height:1.5;font-family:Symbol;font-size:12px;">D style="line-height:1.5;font-size:10pt;"> style="font-size:12px;">H style="font-family:Symbol;font-size:12px;">± style="line-height:1.5;font-size:12px;">) varies within 17 style="line-height:1.5;font-size:10pt;"> style="line-height:1.5;font-size:12px;">- style="line-height:1.5;font-size:10pt;"> style="line-height:1.5;font-size:12px;">58 kJ/mol and 17 style="line-height:1.5;font-size:10pt;"> style="line-height:1.5;font-size:12px;">- style="line-height:1.5;font-size:10pt;"> style="line-height:1.5;font-size:12px;">67 kJ/mol, respectively. Entropy change in activation ( style="line-height:1.5;font-family:Symbol;font-size:12px;">D style="line-height:1.5;font-size:10pt;"> style="font-size:12px;">S style="font-family:Symbol;font-size:12px;">± style="line-height:1.5;font-size:10pt;"> style="font-size:12px;">) is always negative. Based on the empirical flux equation, style="font-size:12px;"> E<...

摘要:

The application of D2EHPA in zinc solvent extraction has extensive background. To utilize more effectively, response surface methodology was used to optimize the concentration condition of zinc pregnant solution (ZPL) extracted by D2EHPA. In the current research, zinc, iron and manganese extraction along with separation factor of zinc-iron (Sf (Zn-Fe)) and zinc-manganese (Sf (Zn-Mn)) were considered as the response values. The optimal ZPL conditions extracted with 30% D2EHPA as the extraction solvent were as follows: Zn 21.96 g/L, Fe 382.57 ppm, Mn 1 g/L, Sf (Zn-Fe) 8.26 and Sf (Zn-Mn) 1529.82. In addition, it was found that the iron and manganese concentration were the most effective factors affecting the zinc and manganese extraction, respectively.

...
摘要:In this paper, prediction of copper and molybdenum grades and their recoveries of an industrial flotation plant are investigated using the Artificial Neural Networks (ANN) model. Process modeling has done based on 92 datasets collected at different operational conditions and feed characteristics. The prominent parameters investigated in this network were pH, collector, frother and F-Oil concentration, size percentage of feed passing 75 microns, moisture content in feed, solid percentage, and grade of copper, molybdenum, and iron in feed. A multilayer perceptron neural network, with 10:10:10:4 structure (two hidden layers), was used to estimate metallurgical performance. To obtain the optimal hidden layers and nodes in a layer, a trial and error procedure was done. In training and testing phases, it achieved quite correlations of 0.98 and 0.93 for Copper grade, of 0.99 and 0.92 for Copper recovery, of 0.99 and 0.92 for Molybdenum grade and of 0.99 and 0.94 for Molybdenum recovery prediction, respectively. The proposed neural network model can be applied to determine the most beneficial operational conditions for the expected Copper and Molybdenum grades and their recovery in final concentration of the industrial copper flotation process....
摘要:Grain-size class redistribution of non-ferrous, precious metals and iron in copper-nickel ores tailings from Norilsk industrial region was after artificial weathering investigated. Possible mechanisms of metal redistribution were suggested....
摘要:Using high temperature carbon tube furnace, reduction of manganese ore pellets containing carbon was investigated. The reaction was divided into two stages at five minutes after reaction, and the kinetics model of reduction process was established. The experimental results showed that, the reaction rate in the earlier stage was controlled by the chemical reactions between FeO, MnO and carbon reductant, and the activation energy was 28.85 KJ/mol. In the later stage, as the carbon reductant replaced by CO, the reaction rate was controlled by CO-diffusing in solid products, and the cor- responding activation energy was 86.56 KJ/mol. Reaction rate of the later stage was less than the earlier one....
摘要: style="text-align:justify;"> style="font-size:10.0pt;font-family:""> style="font-family:Verdana;font-size:12px;">For the preparation of copper nanoparticles several methods, style="font-family:Verdana;font-size:12px;">i.e style="font-family:Verdana;font-size:12px;">., thermal reduction, mechanical attrition, chemical reduction metal vapour synthesis, radiation methods, laser ablation and micro style="font-family:Verdana;font-size:12px;">emulsion techniques were developed in the past. Electrolytic deposition is one of the most suit style="font-family:Verdana;font-size:12px;">able, simplest and low cost methods which are used for wide range of materials. In the present in style="font-family:Verdana;font-size:12px;">vestigations, efforts were put to produce copper nano powder using electrolytic technique. It style="font-family:Verdana;font-size:12px;">could be possible to obtain near nano copper powder of 258 nm size using high cathode current density of 1100 A/m style="font-family:Verdana;font-size:12px;">2 style="font-family:Verdana;font-size:12px;"> in sulphate bath. The specific surface area and shape of the particles were found to be 23.2 m style="font-family:Verdana;font-size:12px;">2 style="font-family:Verdana;font-size:12px;">/g and irregular, respectively. style="font-size:10.0pt;font-family:"">

...
摘要: style="text-align:justify;"> Solvent extraction experiments of La(III) with di-(2-ethylhexyl)phosphoric acid (P204) from chloride solution in the presence of a complexing agent (lactic acid) have been performed. The effective separation factors can be achieved when the complexing agent is added to the aqueous phase of the extraction system. The complexing agent lactic acid can be effectively recycled using tributyl phosphate (TBP) as extractant, by the use of a countercurrent extraction process, and the chemical oxygen demand (COD) value in the raffinate is 57.7 mg/L, which meets the emission standards of pollutants from rare earths industry. Thus, the simple and environment-friendly complexing method has been proved to be an effective strategy for separating light rare earths, and provides a positive influence on the purification of La(III).

...
摘要: style="text-align:justify;" class="MsoNormal"> lang="EN-US">Alternating bending shear stresses lead to the formation of twin orientations in the texture of FCC materials with middle and low stacking fault energy (SFE). Only in the stainless steel with a low SFE during alternating bending with differ lang="EN-US">ent number of cycles components of shear texture {111}; {hkl}<110>; {001}<110> were formed. Copper (middle SFE), along with orientations of twinning and cubic texture formed orientation of deformation {135}<211>. During alternating bending of aluminum (high SFE), a dynamic recovery occurred. The share of initial cubic texture increases with the increase of number of cycles of alternating bending and reaches its maximum after three cycles. Share of com lang="EN-US">ponent of texture Goss increased slightly. The most significant change of the microstructure and texture occurred during the first 3 lang="EN-US"> lang="EN-US">- lang="EN-US"> lang="EN-US">5 cycles

...
摘要: align="justify"> The availability of polymetallic ores is getting leaner in grade and is larger but inferior in volumes than in the past, making the extraction of copper, nickel and other non-ferrous metals metallurgically more difficult to produce. The standard technologies, including enrichment and concentration, do not provide methods for obtaining monometallic concentrates and high extraction of metals into the commercial product. Pyrometallurgical processing of large volumes of poor raw materials is not economical and is complicated from the technological point of view. Conditions of chemical enrichment of poor natural materials have been studied with the use of technology of salt exchange leaching. The main impurity in sulfide ores of nonferrous metals is iron present in the forms of pyrite and pyrrhotite and the properties of chemical enrichment for nickel in pyrite concentrates has been investigated in this work. On the basis of thermodynamic analysis carried out with the use of Potential-pH Pourbaix's Diagrams, it has been established that, with the use of nickel salt, it is possible to leach iron sulfides from ores. Based on the study of the mechanism and kinetics of the process of dissolution of iron sulfides with nickel salts, it was established that during the dissolution, the chemical composition and thermodynamic characteristics of the dissolved iron sulfides change—the residues from leaching are enriched with iron sulfides that are rich in sulfur and also result with elemental sulfur formation. Enrichment of leaching residues with sulfide iron with increased sulfur content and formation on the surface of nickel sulfide leads to increase of diffusional resistances and the process is limited by the velocity of mass transfer. To increase the velocity of the process and completeness of the reaction, it is necessary to activate the process, in particular, by grinding the solid phase.

...
摘要:Solvent extraction of base metals using bis((1-decylbenzimidazol-2-yl)methyl)amine (BDNNN) showed a lack of pH-metric separation of the metals. The extraction system was described quantitatively using the equilibria involved to derive the mathematical explanation for the two linear log D vs pHe plots for each metal ion extraction curve, and coordination numbers could also be extracted from the two slopes. The lack of separation was attributed to the absence of stereochemical “tailor making” since the complexes isolated from the reaction of the ligand, bis((1H-benzimidazol- 2-yl)methyl)amine (NNN), with base metals suggested the formation of similar octahedral complex species from spectral and crystal structure evidence. The bis tridentate coordination observed was in agreement with information extracted from the extraction data. This investigation opens up an opportunity and an approach for the evaluation of amines as extractants but cautions against tridentate ligands....
摘要:The extraction of Bi(III) in nitrate media has been investigated using aminododecyldimethylenediphosphonic acid, ADDMDPA, which was previously synthesized and characterized. The extraction of the cation was carried out in different media with the addition of CH3COONa, KNO3 and HNO3. The maximum extraction yield for Bismuth is 70% after addition of 0.01 M of potassium nitrate at pHi = 2.9, in one step....
摘要:

Polyaniline stannic molybdate—an organic-inorganic composite material, was prepared via sol-gel mixing of organic polymer polyaniline into matrices of inorganic precipitate of stannicmolybdate. The composite material synthesized at pH 1.2 showed an ion exchange capacity 1.8 meq/g for Na+?ions. Ion exchange capacity, pH titration and distribution studies were carried out to determine the preliminary ion exchange properties of the material. The distribution studies showed the selectivity of Hg(II) ions by this material. The effect of temperature on the ion exchange capacity of the material at different temperatures had been studied. The sorption behavior of metal ions was also explored in different surfactant media.

...
公   告

北京万方数据股份有限公司在天猫、京东开具唯一官方授权的直营店铺:

1、天猫--万方数据教育专营店

2、京东--万方数据官方旗舰店

敬请广大用户关注、支持!查看详情

手机版

万方数据知识服务平台 扫码关注微信公众号

学术圈
实名学术社交
订阅
收藏
快速查看收藏过的文献