High Purity Cobalt

The benefits of high selectivity He in the abiUty to produce high purity cobalt in a limited number of stages. This minimises capital and operating costs. It is particularly important when the solution in question contains low concentrations of cobalt. Eor example, solutions derived from laterite deposits may only contain 0.5—2 g/L Co but 90—100 g/L Ni. 

Cobalt(II) chloride hexahydrate [7791-13-1], C0CI2 6H20 is a deep red monoclinic crystalline material that deflquesces. It is prepared by reaction of hydrochloric acid with the metal, simple oxide, mixed valence oxides, carbonate, or hydroxide. A high purity cobalt chloride has also been prepared electrolyticaHy (4). The chloride is very soluble in water and alcohols. The dehydration of the hexahydrate occurs stepwise ... 

Use Catalyst in Oxo process, high-purity cobalt salts. 

Studies on Refining Cobalt Salt Solution by Extraction Chromatography to Prepare High Purity Cobalt... 

The key to get high purity cobalt is the preparation of highly refined cobalt salt solution, in such a process, the separation of nickel from cobalt solution is the core-technology. The commonly used hydrometallurgical separation method, such as chemical precipitation method [4], ion exchange method [5, 6, 7, 8] and extraction method [9, 10, 11, 12] all can not meet the requirements to prepare high-purity salt solution. 

In this paper, the process which purifies the cobalt salt solution with the PC88A levextrel resin and prepares high-purity cobalt through electrolysis is studied. 

Chen Rong et al., High Purity Cobalt Manufacturing , China Journal of Rare Metals, 29(5) (2005), 797-802... 

Isshiki M, Fukuda Y, and Igaki K., Preparation of high purity cobalt . Journal of the Less-Common Metals, 105(2) (1985), 211-220... 

Rane M V et al., Recovery of High Purity Cobalt from Spent Ammonia Craeker Catalyst , Hydrometallurgy, 77(2005),247-251... 

High purity acetaldehyde is desirable for oxidation. The aldehyde is diluted with solvent to moderate oxidation and to permit safer operation. In the hquid take-off process, acetaldehyde is maintained at 30—40 wt % and when a vapor product is taken, no more than 6 wt % aldehyde is in the reactor solvent. A considerable recycle stream is returned to the oxidation reactor to increase selectivity. Recycle air, chiefly nitrogen, is added to the air introducted to the reactor at 4000—4500 times the reactor volume per hour. The customary catalyst is a mixture of three parts copper acetate to one part cobalt acetate by weight. Either salt alone is less effective than the mixture. Copper acetate may be as high as 2 wt % in the reaction solvent, but cobalt acetate ought not rise above 0.5 wt %. The reaction is carried out at 45—60°C under 100—300 kPa (15—44 psi). The reaction solvent is far above the boiling point of acetaldehyde, but the reaction is so fast that Httle escapes unoxidized. This temperature helps oxygen absorption, reduces acetaldehyde losses, and inhibits anhydride hydrolysis. 

Other Meta.Is, Although most cobalt is refined by chemical methods, some is electrorefined. Lead and tin are fire refined, but a better removal of impurities is achieved by electrorefining. Very high purity lead is produced by an electrochemical process using a fluosiUcate electrolyte. A sulfate bath is used for purifying tin. Silver is produced mainly by electrorefining in a nitrate electrolyte, and gold is refined by chemical methods or by electrolysis in a chloride bath. 

The first commercial plant to use CYANEX 272 became operational in 1985. An additional three plants were constmcted between 1985 and 1989. Of the four, one is in South America and three in Europe. An additional three plants have been built two in Europe (1994) and one in North America (1995). Approximately 50% of the Western world s cobalt is processed using CYANEX 272. Both high purity salts and electrolytic cobalt metal are recovered from solutions ranging in composition from 30 g/L each of cobalt and nickel to 0.2 g/L Co, 95 g/L Ni Operating companies usually regard use of CYANEX 272 as confidential for competitive reasons and identities cannot be disclosed. CYANEX 272 is being evaluated on the pilot-plant scale in many additional projects involving the recovery of cobalt and other metals. 

The detection and determination of traces of cobalt is of concern in such diverse areas as soflds, plants, fertilizers (qv), stainless and other steels for nuclear energy equipment (see Steel), high purity fissile materials (U, Th), refractory metals (Ta, Nb, Mo, and W), and semiconductors (qv). Useful techniques are spectrophotometry, polarography, emission spectrography, flame photometry, x-ray fluorescence, activation analysis, tracers, and mass spectrography, chromatography, and ion exchange (19) (see Analytical TffiTHODS Spectroscopy, optical Trace and residue analysis). 

The arrangement of the melting and vacuum spray chambers is critical for guiding the liquid metal to eject into the vacuum chamber. Difficulties exist in precisely controlling the expulsion of the liquid metal into the vacuum chamber. Therefore, flaky droplets may be formed in vacuum atomization. Although vacuum atomization was developed mainly for the production of high-purity nickel and cobalt based superalloy powders, it is also applied to atomize the alloys of aluminum, copper and iron. 

Heating hydrogen and sulfur vapor at 500°C in the presence of a catalyst, such as, bauxite or cobalt molybdate, which produces a high purity H2S ... 

Pauson-Khand Cycloaddition. Pauson Khand cycloaddition (see Pauson-Khand Reaction) is a cobalt-mediated method to prepare cyclopentenone from the cyclization of an alkyne with an alkene and CO (equation 14). This method is widely used to produce cychc ketones. Originally, stoichiometric amounts of Co2(CO)g were used in these reactions with the cobalt carbonyl being the CO source. However, it was shown that a strict temperature profile and high-purity reagents allowed the use of catalytic amounts of Co2(CO)g for reactions with 1 atm of CO. Currently, there is intense interest in developing catalytic cobalt starting materials for use in Pauson-Khand reactions. 

The processing of nickel oxide ores is illustrated by the sulfuric acid leaching of nickeliferous laterites and the precipitation of high-purity nickel and cobalt powder by reaction with hydrogen gas giving ammonium sulfate as by-product. This process is in use at Moa Bay, Cuba. 

Several preparations of salts of the czs-dinitrobis(ethyl-enediamine)cobalt(III) ion have been reported in the literature. The most usual is that of Werner/ modified by Holtzclaw, Sheetz, and McCarty, beginning with potassium hexanitrocobaltate(III). However, this method makes use of a starting material which is difficult to prepare in high purity and to dry thoroughly, involves critical temperature control, and produces a yield of about 15%. The following procedure, which utilizes ethylenedi-amine)cobalt(III) chloride as the starting material, provides a 60% yield of cfs-dinitrobis(ethylenediamine)cobalt-(III) nitrite. The nitrite is then easily converted to the nitrate. 

G-35 A cobalt-molybdenum catalyst supported on high-purity... 

High-purity metals and superalloys are required for the aeronautics, electronics, instruments, space, and defense industries the raw materials are at present imported. Primarily, these special metals include nickel-and cobalt-based superalloys, high-strength iron-based alloys, titanium-based alloys, controlled-expansion alloys, and magnetic materials. Keeping in view the importance of these metals and alloys and the expertise available in India for making them, the NCST has identified two projects for their development the setting up of a special metal and superalloys plant and the development of controlled-expansion alloys. 

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