Showing papers on "Cobalt sulfide published in 2010"

Exafs Studies of Calcined and Sulfided CO-Mo HDS Catalysts

Abstract: Information regarding the structure of the cobalt containing phases in calcined as well as sulfided Co-Mo/Al2O3 catalysts is obtained by analyzing the extended x-ray absorption fine structure (EXAFS) above the Co K-edge and comparing these results with those for model compounds. For the catalysts studied, the results show no evidence for any of the well-ordered cobalt compounds which have been proposed to be present in such catalysts. In the calcined catalyst the Co atoms are observed to be present in quite disordered surroundings with distinct backscattering observed only from the nearest neighbor oxygen atoms. From in situ EXAFS data of the sulfided catalyst it is observed that sulfiding affects a majority of the cobalt atoms such that they now become surrounded by sulfur atoms. However, a well-ordered cobalt sulfide does not form since only one strong backscatterer peak in the radial distribution function is observed. A comparison of the present Co EXAFS results with Mo EXAFS and Mossbauer spectroscopy measurements on the same catalysts suggests that in sulfided Co-Mo/Al2O3 catalysts the cobalt promoter atoms seem to be located in surface positions of the Co-Mo-S phase. Furthermore, the present results show the necessity of carrying out experiments in situ.

Selective Deposition of Cobalt Sulfide Nanostructured Thin Films from Single-Source Precursors

Abstract: The cobalt(III) complexes of 1,1,5,5-tetramethyl- and 1,1,5,5-tetraethyl-2,4-dithiobiuret and the cobalt(II) complex of 1,1,5,5-tetra-iso-propyl-2-thiobiuret have been synthesized. The single-crystal X-ray structure of the thiocyanide (1) and cobalt tetrachlorate (2) salts of the parent cyclized ligand, together with complexes [Co{N(SCNMe2)2}3] (3), [Co{N(SCNEt2)2}3] (4) and [Co{N(SOCNiPr2)2}2] (5) have been determined. The thermal decomposition of 3, 4, and 5 was studied. The complexes were used as single source precursors for the deposition of cobalt sulfide thin films by aerosol assisted chemical vapor deposition (AACVD). The X-ray diffraction (XRD) of the deposited films showed hexagonal Co1−xS from complexes (3) and (4) whereas complex (5) gave a mixture of cubic and hexagonal Co4S3. The morphology of films was characterized by scanning electron microscope (SEM) and showed rod like crystallites from 3, granular crystallites from 4 and stalagmitic structures from 5. Transmission electron microscopy (T...

Method for separating nikel and cobalt from active materials contained in spent nickel-hydrogen battery

Abstract: The present invention addresses the problem of providing a method for separating and recovering nickel, cobalt and rare earth elements (RE) from positive- and negative-electrode active materials that constitute a nickel-hydrogen secondary battery. The above problem can be solved by a method wherein nickel, cobalt and RE are recovered in the form of a sulfide that contains both nickel and cobalt and an RE-containing sulfate form a material which contains positive- and negative-electrode active materials that constitute a nickel-hydrogen secondary battery, said method including the following three steps: (1) a leaching step of subjecting a material which contains positive- and negative-electrode active materials to mixing with a sulfuric acid solution and dissolving therein, and then separating the resultant system into a leachate and a residue; (2) an RE crystallization step of adding an alkali metal sulfate to the leachate to obtain both a precipitate of an RE composite sulfate mixture and a RE-free fluid; and (3) a sulfide raw material recovery step of adding a sulfurizing agent to the RE-free fluid and thereby separating the RE-free fluid into a nickel/cobalt sulfide raw material and a residual fluid.

Method for extracting cobalt in copper cobalt sulfide ore

Abstract: The invention provides a method for extracting cobalt in a copper cobalt sulfide ore, and relates to a method for extracting the cobalt in a copper cobalt ore which is in low grade and hard to treat and contains cobalt mineral raw materials The method is characterized by comprising the following steps: (1) crushing and grinding low sulfur containing copper cobalt ore; (2) adding water into the grinded ore material for autoclave leaching; (3) neutralizing and filtering the leached ore pulp, and sending leaching residue into tailing; (4) carrying out copper extraction, extract stripping and strip liquor electrodeposition on the filtered solution to prepare cathode copper; (5) neutralizing copper extracting raffinate to remove iron and aluminum, filter-pressing and separating the neutralized ore pulp, and performing the neutralizing step after the filter-pressed and separated residue is returned to the step (3) for leaching; (6) precipitating cobalt and nickel in filter-pressed and separated solution by adopting sodium hydroxide, wherein the separated precipitate is cobalt nickel hydroxide concentrate; and (7) returning separated after-precipitating solution to the step (2) for the leaching process The method has simple technical process and less equipment corrosion, and realizes comprehensive reclamation and utilization of valuable metals in the low sulfur containing copper cobalt concentrate

Sulfide-enhanced electrochemical capacitance of cobalt hydroxide on nanofibered parent substrate

Abstract: Two approaches—substrate nanostructuring and incorporation of sulfide—were studied with the aim to increase electrochemical capacitance of cobalt (hydro)oxide. A fiber structure of cobalt was deposited electrochemically with the fibers in the order of tens of nanometers in thickness and hundreds of nanometers in length. Cobalt hydroxide film was formed on the nanostructured substrate by anodic polarization in an alkaline solution. The hydroxide formation and its electrochemical capacitance have been studied by cyclic voltammetry in conjunction with the electrochemical quartz crystal microbalance (EQCM). An irreversible behavior was typical of the first anodic polarization cycle; it turned gradually to a reversible one during subsequent cycling. EQCM measurements indicated exponential electrode mass growth during the first cycle, with subsequent transition to a quasipassive state. The redox transitions Co(II) → Co(III) → Co(IV), which determine pseudocapacitance, did not cause remarkable electrode mass change. The electrochemical capacitance of the nanofiber sample was found up to five times higher when compared to that formed on conventional cobalt (abraded surface). Specifics of “per 1 g” evaluation of capacitance performance is discussed. Measurements showed that about 10% of the entire hydroxide structure took part in the capacitive process. The capacitance value determined per 1 g of active Co(OH)2 was in agreement with the limiting value predicted by the Faraday’s law (2,421 F g−1) sulfide-enhanced system with 18% CoS exhibited up to three times higher capacitance when compared to that of the sulfide-free counterpart. The system shows promise for practical applications due to its low cost and technical simplicity.

Preliminary study of the E. S. R signals in unsupported cobalt sulfide‐molybdenum sulfide mixed masses.

Abstract: Unsupported cobalt sulfide-molybdenum sulfide mixed catalysts exhibit two distinct E. S. R. signals. A first signal (g= 2.007, ΔH=90G) is detected at room temperature. It is attributed to Mo5+. The Mo5+ content decreases with increasing Co content, from a value Mo5+/Mo of 0.01% with pure molybdenum sulfide, to negligible values for Co/(Co + No) > 0.5. A second, low temperature, signal gradually appears between 143 and 133°K (g = 2.17, ΔH = 300-600G). It is apparently related to some cobalt containing species. This signal, practically negligible for each monometallic sulfide, exhibits a sharp maximum for a value Co(Co + Mo) of 0.2, which corresponds to maximal intrinsic (per m2) catalytic activities of the samples in the hydrogenolysis of thiophene, hydrogenation of cyclohexene and isomerization of cyclohexane.

Method for separating nickel and cobalt from active material contained in spent nickel-metal hydride battery

Abstract: A method for separating nickel, cobalt and a rare earth element from a material containing positive and negative electrode active materials of a nickel-metal hydride battery includes mixing a material containing positive and negative electrode active materials with a sulfuric acid solution and dissolving therein, and then separating a leachate from a residue; adding an alkali metal sulfate to the leachate to obtain a mixed precipitate of double sulfate of rare earth elements, and a rare-earth-element-free solution; and adding a sulfurizing agent to the rare-earth-element-free solution to separate a nickel and cobalt sulfide raw material and a residual solution.

A Low Temperature Precursor Sulfuration Route to Metal Sulfides Nanomaterials

Abstract: A low-temperature precursor sulfuration route has been established to prepare metal sulfides with different nanostructures during the synthesis of nickel sulfide. The advantages of the low-temperature precursor sulfuration route were testified by the synthesis of different metal sulfides ( lead sulfide, zinc sulfide and cobalt sulfide). It offers a novel path to the preparation of other metal sulfides.