Cobalt origin

In 2005, the British Geological Survey published data that indicated that 45% of the world primary cobalt originated from the Shaba province, in the DRC (3). Moreover, no primary cobalt production exists in the USA, which is completely dependent on foreign imports for their cobalt usages. The announced additional supply of cobalt from the HPAL laterite leaching plants has not yet met with expectations. To minimize the risks of supply due to world competition and political instability, it is therefore essential to maximize the recycling of cobalt... 

B. Recycling Cobalt at a Custom Sulphide Smelter. Cobalt-containing alloy scrap have been for many years industrially recycled as custom feeds, for example at the Falconbridge (now Xstrata) smelter in Sudbury, Ontario, together with primary cobalt (and nickel) sulphide concentrates and other scrap (8). In fact, a significant proportion of Sudbury smelter cobalt production derives fi om cobalt originating from custom feeds, in particular alloy scrap. 

Titanium alloy systems have been extensively studied. A single company evaluated over 3000 compositions in eight years (Rem-Cm sponsored work at BatteUe Memorial Institute). AHoy development has been aimed at elevated-temperature aerospace appHcations, strength for stmctural appHcations, biocompatibiHty, and corrosion resistance. The original effort has been in aerospace appHcations to replace nickel- and cobalt-base alloys in the 250—600°C range. The useful strength and corrosion-resistance temperature limit is ca 550°C. 

The original catalysts for this process were iodide-promoted cobalt catalysts, but high temperatures and high pressures (493 K and 48 MPa) were required to achieve yields of up to 60% (34,35). In contrast, the iodide-promoted, homogeneous rhodium catalyst operates at 448—468 K and pressures of 3 MPa. These conditions dramatically lower the specifications for pressure vessels. Yields of 99% acetic acid based on methanol are readily attained (see Acetic acid Catalysis). 

Alloy Compositions and Product Forms. The nominal compositions of various cobalt-base wear-resistant alloys are Hsted in Table 5. The six most popular cobalt-base wear alloys are Hsted first. SteUite alloys 1, 6, and 12, derivatives of the original cobalt—chromium—tungsten alloys, are characterized by their carbon and tungsten contents. SteUite aUoy 1 is the hardest, most abrasion resistant, and least ductile. 

Most ring syntheses of this type are of modern origin. The cobalt or rhodium carbonyl catalyzed hydrocarboxylation of unsaturated alcohols, amines or amides provides access to tetrahydrofuranones, pyrrolidones or succinimides, although appreciable amounts of the corresponding six-membered heterocycle may also be formed (Scheme 55a) (73JOM(47)28l). Hydrocarboxylation of 4-pentyn-2-ol with nickel carbonyl yields 3-methylenetetrahy-drofuranone (Scheme 55b). Carbonylation of Schiff bases yields 2-arylphthalimidines (Scheme 55c). The hydroformylation of o-nitrostyrene, subsequent reduction of the nitro group and cyclization leads to the formation of skatole (Scheme 55d) (81CC82). 

Fischer-Tropsch ohgomerization of CO -1- H9 to make hydrocarbons and oxygenated compounds was originally catalyzed by cobalt, which forms the active carbonyl, but now iron promoted by potassium is favored. Dissociative chemisorption of CO has been observed in this process. 

A 1.40-g sample containing radioactive cobalt was kept for 2.50 a, at which time it was found to contain 0.266 g of 67Co. The half-life of 67Co is 5.27 a. What percentage (by mass) of the original sample was f,Co ... 

Investigations of the cobalt-carbon bond energies in organometallic cobalt porphyrins continue to attract interest, originally because of their similarity to coenzyme B 2, and more recently because of their role in the catalysis of free radical... 

The reconstruction of the magnetization density was done by the MaxEnt method with a uniform prior. The projection on the basal plane is shown in Figure 2. Besides a small contribution at the origin due to the Y substituted by cobalt pairs, the magnetization is well localized on the five atoms of the two cobalt sites. 

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