Cobaltite

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Cobaltite 
Frequency common 
Hardness 5.5 
Density 6.33
Chemical Formula CoAsS 
Core Elements Co, As 
Thermal Decomposition
CoAsS
750°C
CoO

Character

Pure Cobaltite (CoAsS) would be 165.854g/mol, thus 35.5% by mass cobalt, 45% by mass arsenic, and 20% by mass sulfur.

Roasting

Oxidative roasting below 550°C did not show any crystal structural change in cobaltite but heating to 650°C, yielded Co-As-oxide whose composition varied. Direct oxidation of cobaltite to cobalt oxides with traces of arsenic was observed by roasting at 750°C or above.[1]

Refining

Wikipedia writes:

If purifying by electrolysis, an aqueous sulfate solution at 50 to 70°C is usually used with a lead anode (corrosion products from which will not contaminate the cobalt oxy-hydroxide (CoOOH) electrolyte solution) and a stainless steel cathode which will allow for the easy removal of the deposited cobalt. Electro refining in a chloride or sulfate medium at -0.3 V will make a cathode coating of 99.98% Cobalt.

See Also

References

  1. Wang, Guoxin (1993) "Oxidation of Cobaltite"
    University of Nevada, Reno; Master's Thesis