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Cementation

Cementation. Cathodic precipitation of a metal ion of a metal from solution by passing the solution over a more anodic (less noble) metal. Cu 2+ +2e = Cu (cathodic precipitation Fe = Fe 2+ + 2e (anodic dissolution). Cementation is less selective than gaseous reduction.

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Cementation

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  1. Cementation Cathodic precipitation of a metal ion of a metal from solution by passing the solution over a more anodic (less noble) metal Cu2+ +2e = Cu (cathodic precipitation Fe = Fe2+ + 2e (anodic dissolution) Cementation is less selective than gaseous reduction

  2. Isolation techniques Ion exchange: organic resins on to which either cations or anions have been loosely bounded Solvent extraction: organic compounds – ethers, esters, ketones- provide high solubility of some metallic and complex metal ions Reverse osmosis: concentration of metal ions by passage of water from a dilute to a more concentrated solution through a semipermeable membranes

  3. Electrowinning Electrowinning of a metal is based on the electrolysis of aqueoussolutions or melts of metal salts with insoluble anode

  4. Electrowinning

  5. Electrowinning

  6. Electrowinning

  7. Electrorefining

  8. Electrorefining

  9. Electrorefining

  10. Caron processs: laterite ore :  50% Fe - FeO.OH, 1-2% Ni - NiO,  0,1% Co - CoO Boiling up/filtration Laterite ore NH3 NiCO3.Ni(OH)2 Drying, Grinding H2, CO Calcination Reduction roasting vzduch NiO NH3 aq. (NH4)CO3 Residue Ammoniacal leaching Preparation of electrolyte H2SO4 Na2S CoS Electrolysis Partition Ni/Co Ni 99,9% Ni- liquor

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