Agitation copper

Bath B. The following agitated copper bath was used at 35 "C. 

The crankcase of a gasoline or diesel engine is in reality a hydrocarbon oxidation reactor oil is submitted to strong agitation in the presence of air at high temperature (120°C) furthermore, metals such as copper and iron, excellent catalysts for oxidation, are present in the surroundings. 

Prior to about 1920, flotation procedures were rather crude and rested primarily on the observation that copper and lead-zinc ore pulps (crushed ore mixed with water) could be benefacted (improved in mineral content) by treatment with large amounts of fatty and oily materials. The mineral particles collected in the oily layer and thus could be separated from the gangue and the water. Since then, oil flotation has been largely replaced by froth or foam flotation. Here, only minor amounts of oil or surfactant are used and a froth is formed by agitating or bubbling air through the suspension. The oily froth or foam is concentrated in mineral particles and can be skimmed off as shown schematically in Fig. XIII-4. 

To 200 ml of 48% hydrobromic acid was added 0.40 mol of phosphorus tribromide (note 1). The mixture was agitated vigorously, while the temperature was kept between 20 and 30 0 by cooling in a water-bath at 10-15 0. After about 1 h the lower layer had disappeared completely. The solution was cooled to 0°C, then 0.40 mol of ammonium bromide, 0.10 mol (note 2) of copper(I) bromide (commercial product),... 

The process operated by ACl is outlined in Figure 7. Bales of cotton linter are opened, cooked in dilute caustic soda, and bleached with sodium hypochlorite. The resulting highly purified ceUulose is mixed with pre-precipitated basic copper sulfate in the dissolver, and 24—28% ammonium hydroxide cooled to below 20°C is added. The mixture is agitated until dissolution is complete. If necessary, air is introduced to aUow oxidative depolymerization and hence a lowering of the dope viscosity. 

The continuous softening process used by The Broken Hill Associated Smelters Pty., Ltd. is particularly suitable for lead buUion of fairly uniform impurity content. The copper-drossed blast furnace buUion continuously flows in the feed end of a reverberatory furnace at 420°C, and the softened lead leaves the opposite end at 750°C. Oxidation and agitation is provided by compressed air blown through pipes extending down through the arch of the furnace into the bath. 

The cementation of gold and the purification of the ziac electrolyte ate usually carried out ia cylindrical vessels usiag mechanical agitation. The cementation of copper is carried out ia long narrow tanks called launders, ia rotating dmms, or ia an iaverted cone precipitator (see Copper). 

Va.t, or Agitated Leeching. Vat or agitated leaching usually extracts copper from oxide or mixed oxysulfide ores containing more... 

Tanimoto, A.K., Kobayashi, K. and Fujita, S., 1964. Overall crystallization rate of copper sulfate pentahydrate in an agitated vessel. International Chemical Engineering, 4(1), 153. 

The simplest and most thoroughly studied solutions are those based on phosphoric acid at low temperatures (<35°C) which alone can fulfil all three requirements of acid solvent, film former (as metal phosphate) and diffusion agent by virtue of its viscosity. Thus copper and its main alloys of brasses and bronzes can be very effectively electropolished in 60-70% orthophos-phoric acid with the temperature maintained below 35°C under other conditions copper passivates or dissolves freely under mass transfer controlled conditions, but by varying the conditions appropriately polishing can be continued under mild agitation. An annotated polarisation curve is given in Fig. 11.7 readers are referred to recent studies for more detailed 2ispects " . 

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