Complex Copper Oxides Research Articles

Complex oxides of copper and manganese as the base material for catalytic suppression of waste gases

The composite material “ionite-sorbed ions” was obtained by ion exchange technology. The conditions for obtaining the composite material “ionite-sorbed ions” are studied. In the thermolysis of cationite with sorbed ions, the synthesis of complex oxide is carried out between ions located at atomic distances from each other. This facilitates and accelerates the formation of complex oxide. Thermolysis of carboxyl cationite KB-4P-2 with sorbed copper and manganese ions was performed at temperatures from 250-950°C . Control of the thermolysis mechanism of the composite material “ionite-sorbed ions” was carried out using thermograms. According to the scanning electron microscopy data, the obtained powder of complex copper and manganese oxide has a good crystallite structure. Data x-ray diffraction analysis confirmed the crystallization of a complex oxide of copper and manganese in orthorhombic crystal structure. A method for the synthesis of complex copper and manganese oxide powder based on the thermolysis process of the composite material “ionite-sorbed ions”, which has catalytic properties, has been developed.

Effect of temperature on leaching behavior of copper minerals with different occurrence states in complex copper oxide ores

Abstract The effect of temperature on leaching behavior of copper minerals with different occurrence states in complex copper oxide ores was carried out by phase analysis means of XRD, optical microscopy and SEM−EDS. The results indicated that at ambient temperature, the easily leached copper oxide minerals were completely dissolved, while the bonded copper minerals were insoluble. At lukewarm temperature of 40 °C, it was mainly the dissolution of copper in isomorphism state. With increasing temperature to 60 °C, the copper leaching rate in the adsorbed state was significantly accelerated. In addition, when the temperature increased to 80 °C, the isomorphic copper was completely leached, leaving 11.2% adsorbed copper un-leached. However, the copper in feldspar−quartz−copper−iron colloid state was not dissolved throughout the leaching process. Overall, the leaching rates of copper in different copper minerals decreased in the order: malachite, pseudo-malachite > chrysocolla > copper-bearing chlorite > copper-bearing muscovite > copper-bearing biotite > copper-bearing limonite > feldspar−quartz−copper−iron colloid.

A New Technique for Recovering Copper From Complex Copper Oxide Ore by Flotation and Metallurgical Processing

Copper oxide ore has a complex composition, and a low recovery rate is often achieved via the traditional sorting method. A new combined process of flotation–high-gradient magnetic separation–leaching is proposed here to recover copper minerals. The test results showed that the flotation process was successful when using sodium sulfide as a vulcanizing agent and butyl xanthate as a collector. The flotation concentrates can be qualified with a copper grade of 29.37% and a recovery rate of 32.22%. Flotation tailings separated by high-gradient magnetic separation can yield two products, namely, magnetic separation concentrates and magnetic separation tailings, via the leaching recovery of the remaining copper minerals. However, the leaching conditions are different. The leaching rates of copper from magnetic separation concentrates and tailings are 28.44% and 26.95%, respectively. The total copper recovery is 87.61%. This new technology introduces a high-gradient magnetic separation process, which achieves the requirements of low energy consumption and high-efficiency copper recovery.

Copper Recovery from Yulong Complex Copper Oxide Ore by Flotation and Magnetic Separation

A combined process of flotation and high-gradient magnetic separation was proposed to utilize Yulong complex copper oxide ore. The effects of particle size, activators, Na2S dosage, LA (a mixture of ammonium sulfate and ethylenediamine) dosage, activating time, collectors, COC (a combination collector of modified hydroxyl oxime acid and xanthate) dosage, and magnetic intensity on the copper recovery were investigated. The results showed that 74.08% Cu was recovered by flotation, while the average grade of the copper concentrates was 21.68%. Another 17.34% Cu was further recovered from the flotation tailing by magnetic separation at 0.8 T. The cumulative recovery of copper reached 91.42%. The modifier LA played a positive role in facilitating the sulfidation of copper oxide with Na2S, and the combined collector COC was better than other collectors for the copper flotation. This technology has been successfully applied to industrial production, and the results are consistent with the laboratory data.

Effect of desliming on the flotation of a complax copper ore from China

The complex copper oxide ore sample was taken from Deerni copper deposit, Qinghai Province of China. Batch flotation tests had been conducted to upgrade the copper concentrate by conventional amyl xanthate reagents under 73% -74 μm of the particle size; however, the unsatisfied results (Cu grade of 18.21% and recovery of 59.25%) were obtained. Also there are a large amount of slimes trapped in the concentrate and high-dosages consumption of reagents, for example, more than 2.5 kg/t sodium sulfide and 1.5 kg/t sodium silicate at only one-staged roughing. Based on the analysis of the sample, most of gangues are clay, feldspar and mica, which may easy to over-grind and deteriorate the flotation process either on reagents consumption or slurry fluidity or viscosity. A hydro-cyclone had been introduced to pre-concentrate the oxide ore by scrubbing the slime before flotation, which can result obviously in reducing the dosages of sodium sulfide from 2.5 Kg/t to 1 Kg/t, and raising the grade of Cu in the concentrate from 18.21% to 26.65% at the expense of about 1% recovery of Cu. In this paper, the effects on the recovery of Cu by the different dosages of flotation reagents with or without de-sliming were studied, with the objective of determining the different effects on the functions of flotation reagents by slime during flotation.

RESEARCH OPPORTUNITIES FERRITE 2000NM THE SHORT PROCESS FLOW

The possibility of obtaining Mn—Zn-ferrite 2000 NM on the short process flow, which differs from the usual lack of diffusion operations roasting and grinding. It is shown that the use of the basic composition in sintering processes develop secondary recrystallization and zonal isolation, leading to the formation of highly inhomogeneous microstructure obtained with low values of the magnetic permeability. A homogeneous microstructure characteristic recrystallization, managed by doping copper oxide and zinc. By doping CuO permeability far from the desired value, but its temperature coefficient is small. By doping ZnO reached the desired value of magnetic permeability, but dramatically increases its temperature coefficient.The optimum combination of the magnetic parameters obtained in complex copper oxides doped ferrite and zinc.

Influence Factors of Permeability during Heap Leaching of Complex Copper Oxide Ore

In order to explore the influence factors of permeability during heap leaching of Yangla copper ore in China, falling head permeability test was applied to draw a comparison between the permeability of various samples, and then permeability evolutionary law of the sample ore from leaching heap was analyzed under different ore size or compaction degree. Finally, acid leaching experiments was carried out to reveal the influential mechanism of heap blockage on its permeability. The data show that the permeability coefficient of washed ore is 12.7 times than that of raw ore; permeability coefficient with the compaction degree 38.3% is only 3.78% of that in natural state; Chemical blockage brings about a fall of permeability coefficient by 93.5%, and earlier physical blockage leads to the decrease of it by 43.2%. Results show that much argillaceous fine particles in ore heap with high mud content can result in decreased permeability coefficient; and permeability coefficient of the samples decreases significantly with increased compaction degree. In addition, chemical blockage is the main reason for penetration deterioration.

Electrochemical fabrication of complex copper oxide nanoarchitectures via copper anodization in aqueous and non-aqueous electrolytes

Described is the synthesis of various copper oxide nanostructured thin films by anodization of Cu foil in aqueous and ethylene glycol electrolytes containing hydroxide, chloride and/or fluoride ions at room temperature. The nanostructure topology was found to depend on the pH of the anodization electrolyte, KOH concentration, applied voltage and the presence of chloride and fluoride ions. Our results demonstrate the opportunity to grow complex copper oxide nanostructured films possessing sub-micron thick layers by a simple and straightforward electrochemical route. Although no film was observed on the Cu surface when the anodization was carried out at 10V in KOH solutions with pH≤10, various nanoarchitectures were formed upon increasing the electrolyte pH in the presence of chloride ions. Replacing chloride ions with fluoride ions resulted in the formation of highly porous nanoarchitectures. A simple mechanism for the formation of such porous structures is proposed. Anodizing in ethylene glycol-based electrolytes resulted in the formation of leaf-like nanoarchitectures up to 500nm in thickness. XPS analysis was performed to study the composition of the formed nanoarchitectures. Vacuum annealing of the material at 280°C resulted in the formation of porous Cu2O nanoarchitectures.

Technological conditions and kinetics of leaching copper from complex copper oxide ore

The kinetic behavior of leaching copper from low grade copper oxide ore was investigated. The effects of leaching temperature, H2SO4 concentration, particle size of crude ore and agitation rate on the leaching efficiency of copper were also evaluated. And the kinetic equations of the leaching process were obtained. The results show that the leaching process can be described with a reaction model of shrinking core. The reaction can be divided into three stages. The first stage is the dissolution of free copper oxide and copper oxide wrapped by hematite-limonite ore. At this stage, the leaching efficiency is very fast (leaching efficiency is larger than 60%). The second stage is the leaching of diffluent copper oxides, whose apparent activation energy is 43.26 kJ/mol. During this process, the chemical reaction is the control step, and the reaction order of H2SO4 is 0.433 84. The third stage is the leaching of copper oxide wrapped by hematite-limonite and silicate ore with apparent activation energy of 16.08 kJ/mol, which belongs to the mixed control.

Structural design of superconductors based in complex copper oxides

Structural design of superconductors based in complex copper oxides

Electron density changes at the crystal lattice sites upon superconducting phase transition

It is established that complex copper oxides exhibit a relationship between a change in the electron density at the metal crystal lattice site and the temperature (Tc) of a phase transition to the superconducting state. In crystals containing two structurally inequivalent positions of copper atoms, a change in the electron density upon the transition is different for these lattice sites. In particular, there is a limiting value of the electron density variation upon the superconducting transition, which is different for Cu(1) and Cu(2) lattice sites and corresponds to the two different minimum values of the correlation length. The electron density changes at the sites of a Kronig-Penney crystal lattice upon the superconducting transition are calculated. It is established that the transition from normal to superconducting phase is accompanied by an increase in the charge density at the center of the unit cell. This growth increases with Tc, which agrees with the Mossbauer spectroscopy data.

High‐Temperature Superconductors Based on Complex Layered Copper Oxyfluorides

AbstractFor Abstract see ChemInform Abstract in Full Text.

Structure transformations in fluorinated complex copper oxides

Structure transformations in fluorinated complex copper oxides

High-Tc Superconductivity in Electron-Doped Layer Structured Nitrides

▪ Abstract A new series of superconductors based on layer structured nitrides has been developed. The general compositions of the nitrides are MNX (M = Zr, Hf; X = Cl, Br, I). The β-type polymorph consists of MN double layers sandwiched between close-packed halogen layers, which are characterized as semiconductors with a band gap of 3–4 eV. Electrons can be doped to the nitride layers by intercalation of alkali metals between the layers. Upon the intercalation, the compounds become superconductors with the transition temperatures (Tc s) as high as 13 and 25.5 K for β-ZrNCl and β-HfNCl systems, respectively. The Tc of the electron doped β-HfNCl is higher than that observed in any intermetallic compound and suggests that layered nitrides may exhibit Tc s comparable to those observed in layer structured complex copper oxide superconductors. The layer structured nitrides can be variously modified by the amounts of doping, the types of alkali metals, and the interlayer separation, which can be controlled by co-intercalation of organic molecules with alkali metals. This article dicusses topics including the synthesis and structure of the transition metal nitride halides, intercalation, superconductivity, and band structures.

Herstellung, Bearbeitung und Eigenschaften von Hochtemperatursupraleiter- Massivmaterial / Production, Melt Processing and Properties of High Temperature Superconducting Bulk Material

The production of massive HTSL material for cryomagnetic applications is concerned mainly with the processing of single domain YBCO monoliths. Starting with optimised precursors and green bodies, large preferentially orientated single grains (monoliths) are produced using a modified melt crystallisation process. The properties of these monoliths, e.g. their inductive remanence, levitational force, fracture strength in bending, are optimised by the defined by the distribution of non-super conducting inclusions. The microstructure of these complex copper oxide ceramics is described.

Redox Processes in Polynary Copper Oxides and Copper Oxide / Mesoporous Silica Composites

AbstractDynamic redox processes in different complex copper oxides and oxide / mesoporous silica composites are characterized. In the spinel-type CuxMn3.xO4 the atomic and electronic structures are described with respect to the reversible process Cu2+ + Mn3+ ⇒ Cu3+ + Mn4+, the crucial dynamic equilibrium for the catalytic oxidation of CO to CO2 at ambient temperatures. A comparison with the perovskite-type LaCu1-xMnxO3-δ is presented. In the K2NiF4-type La2-xSrxCu1-yRuyO4-δ the electronic structure is characterized with respect to the equilibrium Cu2+ + Ru5+ ⇒ Cu3+ + Ru4+. Analogous redox processes are characterized in composite compounds made up of copper oxides inserted in mesoporous MCM-type silica. Due to their structural order in the nanoscopic range, the investigation of these materials required multiple, complementary characterization methods, i.e. X-ray diffractometry, thermal analysis, scanning and transmission electron microscopy, magnetic measurements, XPS, and particularly X-ray absorption spectroscopy (EXAFS / XANES) measurements.

The Syntheses and Structures of the Complex Oxide Carbonates Ba11Pd11O20(CO3)2and Ba88Ni87O156(CO3)19)

A new palladate analog, Ba11Pd11O20(CO3)2, of the complex copper oxide carbonate, Ba44Cu48(CO3)6O87.9, has been synthesized by reaction of PdO and BaCO3at 810°C. The structure of this phase and the isostructural nickelate have been refined from high resolution powder neutron diffraction data. The structure consists of cagesM18O24andM6O12rings (M=Pd,Ni) separated by barium ions and carbonate groups. A section of the structure separating twoM18O24units is strongly disordered and has been refined as containing either carbonate groups or isolatedMO4square planes. The presence and symmetry of the carbonate groups in these structures has been investigated by infrared and Raman spectroscopy.

Understanding and Manipulating Inorganic Materials with Scanning Probe Microscopes

AbstractScanning probe microscopies, such as scanning tunneling microscopy and atomic force microscopy, are uniquely powerful tools for probing the microscopic properties of surfaces. If these microscopies are used to study low‐dimensional materials, from two‐dimensional solids such as graphite to zero‐dimensional nanostructures, it is possible to elucidate atomic‐scale structural and electronic properties characteristic of the bulk of a material and not simply the surface. By combining such measurements with chemical synthesis or direct manipulation it is further possible to elucidate relationships between composition, structure, and physical properties, thus promoting an understanding of the chemical basis of material properties. This article illustrates that the combination of scanning probe microscopies and chemical synthesis has advanced our understanding of charge density waves, high‐temperature superconductivity, and nanofabrication in low‐dimensional materials. This new approach to studying materials has directly contributed to our knowledge of how metal dopants interact with charge density waves and elucidated the local crystal chemistry of complex copper oxides, microscopic details of the superconducting states in materials with a high superconducting transition Ic, and new approaches to the fabrication of multi‐component nanostructures. Coupling scanning probe microscopy measurement and manipulation with chemical synthesis should provide an approach to understanding material properties and creating complex nanostructures in general.

High-temperature superconductors: a structural-electronic model

An enormous amount of effort has been expended in recent years in attempts to understand the fascinating properties of that class of complex copper oxides which are high-temperature superconductors. This activity has led to the generation of an unprecedented level of chemical and structural detail concerning this rather small region of the periodic table, renewed interest in the physics behind metal-insulator transitions in general, and a renaissance in the area of superconductivity itself. (For several years investigations had labored under the prediction that 30 K was probably the highest {Tc} attainable). In spite of this activity, identification of the essential piece of the physics is lacking. This is puzzling since the magnitude of the effect, the high {Tc}`s, should make this a rather straightforward phenomenon to explain. This Account will briefly summarize some of the salient features of the structural-electronic problem in the cuprates and will present a view of the electronic structure of these materials which may well be the chemical piece needed to complete the physical jigsaw puzzle.

Synthesis and investigation of Sr-containing 223 and 1222 complex oxides in the R-Sr-Ce-Cu-O system (R = Pr, Nd, Sm-Gd, Dy-Yb and Y)

An extended family of layered complex copper oxides has been synthesized in the system R 2O 3-SrO-CeO 2-CuO (R = Pr, Nd, Sm-Gd, Dy-Yb and Y). The compounds were studied by X-ray powder diffraction, electron microscopy and EDS analysis. Eu 1.6Sr 1.8Ce 0.6Cu 3O 8.6 ( a = 3.8439 (2) Å, c = 28.09 (1) Å) and Y 1.5Sr 1.8Ce 1.0Cu 2.7O 8.6 ( a = 3.8160 (7) Å, c = 29.120 (5) Å), belonging to two structural groups of 223- and 1222-type, respectively, were chosen for Rietveld structure refinement. Their structures can be described as 14-layered stackings along the c-axis. The compounds with larger lanthanides (R=Pr-Gd) are isostructural with Ba-containing 223 phases, e.g. (R,Ba) 2(R, Ce) 2Cu 3O 8+δ. Among the synthesized compounds only the ones with R=Sm and Eu have been shown to be superconductors ( T c=30 and 36 K, respectively) after high-pressure oxygen treatment (120 atm). 1222 phases with smaller rare earth elements (R=Dy-Yb and Y) differ from 223 phases in composition and lattice parameters, having structures which are more similar to (Pb, Cu)-1222, e.g. (Pb, Cu) (Eu, Ce) 2(Sr, Eu) 2Cu 2O 8+δ. Compounds of 1222-type did not become superconducting even when treated with high-pressure oxygen.