Cobalt manganese coprecipitation

Laboratory Tests of Cobalt Manganese Coprecipitation Models... 

Where both cobalt and manganese are present in solution, the coprecipitation of hausmannite and C03O4 might be expected. Sinha et al. (25) found that random substitution of cobalt for Mn " or Mn could occur in such material occurrence of Co in manganese oxide crystal-lattice positions was noted by Bums (4). Apparently there are no thermodynamic data for mixed cobalt + manganese oxides, but the behavior of the ions can probably be represented over a considerable range of solid composition by a solid—solution model based on the equilibrium between the pure end members. Thus... 

Mechanisms for coprecipitation of lead and cobalt with manganese oxide can be derived based on thermodynamic calculations. They can explain the increased oxidation state of manganese reached in the mixed oxide precipitates, and they provide a potential control of the solubility of the accessory metals. The effectiveness of the control has been evaluated in a preliminary way by laboratory experiments described here, and by some fleld observations. Cobalt activity seems to be controlled by manganese coprecipitation in many natural systems. Although more testing by both laboratory experiments and fleld studies is needed, the proposed mechanisms appear to be applicable to many coupled oxidation-reduction processes. 

Hiraide et al. [737] developed a multielement preconcentration technique for chromium (III), manganese (II), cobalt, nickel, copper (II), cadmium, and lead in artificial seawater using coprecipitation and flotation with indium hydroxide followed by ICP-AES. The metals are simultaneously coprecipitated with indium hydroxide adjusted to pH 9.5, with sodium hydroxide, ethano-lic solutions of sodium oleate and dodecyl sulfate added, and then floated to... 

Several methods have been reported for concentrating lead, cobalt, and nickel in blood, urine, brines, and water prior to final determination by atomic absorption. Sprague and Slavin (6) described a procedure for determining these elements plus copper, cadmium, iron, and manganese in concentrated potassium chloride solutions. The metals were chelated with ammonium pyrrolidine dithiocarbamate (APDC) and extracted with methyl isobutyl ketone (MIBK). It was reported that the optimum pH for the extraction was approximately 2.8. Berman (J) described a similar chelation-extraction procedure for determining lead in urine and blood. Burrell (2) developed a procedure for determining cobalt and nickel in natural waters by atomic absorption in which both metals are first coprecipitated with ferric chloride from ten liters of water. The separated precipitate is subsequently dissolved and made up to 100 ml. volume with hydrochloric acid and water so that the final pH of the solution is 2.5. The nickel and cobalt are then chelated with APDC and extracted with three 10 ml. volumes of MIBK. Three extractions are necessary to achieve complete recovery of the chelated cations. A detection limit of 0.3 fig. of nickel per liter and 0.15 fig. of cobalt per liter was found. 

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