Cobalt clays

Cobalt Clays and Double-Layered Hydroxides as Fischer—Tropsch Catalysts... 

Table I. Dependence of Cobalt Clay Phases on Aluminum Content...

BRUCEETAL. Cobalt Clays Double-Layered Hydroxides... 

Cobalt Clay Syntheses. Precipitation of cobalt salts by alkali... 

Cobalt pigments are usually produced by mixing salts or oxides and calcining at temperatures of 1100—1300°C. The calcined product is then milled to a fine powder. In ceramics, the final color of the pigment maybe quite different after the clay is fired. The materials used for the production of ceramic pigments are... 

When the temperature of a carbonate reservoir that is saturated with high-viscosity oil and water increases to 200° C or more, chemical reactions occur in the formation, resulting in the formation of considerable amounts of CO2. The generation of CO2 during thermal stimulation of a carbonate reservoir results from the dealkylation of aromatic hydrocarbons in the presence of water vapor, catalytic conversion of hydrocarbons by water vapor, and oxidation of organic materials. Clay material and metals of variable valence (e.g., nickel, cobalt, iron) in the carbonate rock can serve as the catalyst. An optimal amount of CO2 exists for which maximal oil recovery is achieved [1538]. The performance of a steamflooding process can be improved by the addition of CO2 or methane [1216]. 

Another important consideration pertains to the metal content of the deposit. A deposit with a content of iron of about 20% can have little value as an iron ore since there are several deposits with 30-50% iron. Earlier, a copper ore with a minimum of 5% copper was regarded or accepted as a copper ore. However, today, thanks to advancements in technology, rocks with as little as 0.5% copper are mined and processed economically despite the fact that the price of copper, in comparison with those of some other metals, might be showing a downward trend. It is possible that in the future, other resources, which are not considered to be worth exploiting today (such as the manganese nodules or the clays), would become acceptable ores for manganese, copper, nickel, cobalt, and aluminum. 

A range of metals including iron, copper, cobalt, permalloy and nickel were used to form conductive and paramagnetic coatings on the halloysite clay. These conductive small particles may then be used in polymeric systems to form composites with interesting electromagnetic properties. 

In addition to other polystyrene [138] and silica supports [139, 140, 141, 142, 143,144], iron and cobalt precatalysts have been immobilised on calcosilicate [145], magnesium dichloride [146,147,148,149], MCM-41 zeolite [150,151], clay [152] and fluorotetrasilicic mica [153], Supported systems have also been examined using alternative activators [154, 155, 156, 157, 158, 159]. For example, silica- and alumina-supported samples 5 have been activated with AK/ -Bu), to afford highly active, thermally robust catalysts [154], IR spectroscopy in DRIFT mode... 

Copper oxide mixed ore - Type 1. The main copper minerals found in these ores include malachite, pseudo-malachite, chrysocolla and some tenorite. These ores also may contain mainly siliceous gangue minerals, including spherocobaltite as the main cobalt minerals. The carbonaceous types also contain an appreciable amount of clay slime minerals. 

Cornell, R.M. Giovanoli, R. (1989) Effect of cobalt on the formation of crystalline iron oxides from ferrihydrite in alkaline media. Clays Clay Min. 37 65-70... 

Sediments in the Mississippi River were accidentally contaminated with a low-level radioactive waste material that leaked from a nuclear power plant on the river. Pore water concentrations of radioactive compounds were measured following the spill and found to be 10 g/m over a 2-mm depth. The water contamination was 30% radioactive cesium ( Cs), with a half-life of 30 years, and 70% radioactive cobalt ( °Co), with a half-life of 6 years. Objections by the local residents are preventing clean-up efforts because some professor at the local state university convinced them that dredging the sediments and placing them in a disposal facility downstream would expose the residents to still more radioactivity. The state has decided that the sediments should be capped with 10 cm of clay and needs a quick estimate of the diffusion of radioactive material through the clay cap (Figure E2.8.1). If the drinking water limit (10 g/m ) is reached at mid-depth in the cap, the state will increase its thickness. Will this occur ... 

Relevant Data. For radioactive cesium and cobalt, =1 x. 10 and 10, respectively. Assume Pb/e= 6 g/cm for clay under low compressive force. The coUoidal concentration in the interstitial water is 10 mg/m ( o.g/L). The foUowing assumptions wiU help to achieve our estimate ... 

Nonstereospecific aerobic epoxidations of alkenes in the presence of aldehydes catalyzed by nickel(II),298 iron(in),299 and cobalt(II)300 complexes, and clay-supported nickel acetylacetonate301,302 have been reported. A radical mechanism has been postulated. The involvement of active copper species and peracids were suggested in a similar reaction catalyzed by copper salts.303... 

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