Sulfuric Acid → cobalt (III) pentammine sulphate

HRID 129350Notes

Reaction equation

HRID 129350 reaction equation
[CH:1](=[NH:6])[CH2:2][CH2:3][CH2:4][CH3:5].[Co+2:7].C(=N)CCCC.[Co+3].[S:15](=[O:19])(=[O:18])([OH:17])[OH:16]>C(=N)CCCC.[Ni+2].[Ni].S([O-])([O-])(=O)=O.[NH4+].[Ni+]>[S:15]([O-:19])([O-:18])(=[O:17])=[O:16].[CH:1](=[NH:6])[CH2:2][CH2:3][CH2:4][CH3:5].[Co+3:7].[S:15]([O-:19])([O-:18])(=[O:17])=[O:16].[S:15]([O-:19])([O-:18])(=[O:17])=[O:16].[Co+3:7]

Participants

7

Reactant 3

HCID 1118Sulfuric AcidHCID 86590344cobalt (II) pentammineHCID 86590345cobalt (III) pentammine

Product 1

HCID 86590343cobalt (III) pentammine sulphate

Reagents, catalysts & solvents 3

HCID 935NickelCatalystHCID 86590346nickel (II) pentammineCatalystHCID 171000000CID 171000000Catalyst

Procedure

A commercial cobalt refining process based on the soluble cobaltic pentammine process for separating nickel from cobalt, is operated in conjunction with the above nickel refining process. This process is based on U.S. Pat. Nos. 2,694,005, 2,694,006, 2,767,054 and 2,767,055 to Schaufelburger. In the refining process, mixed nickel-cobalt sulphides with a typical Ni:Co ratio of 1:1, are first leached at elevated air pressure and temperature in dilute sulphuric acid solution to dissolve the nickel and cobalt and oxidize the sulphide to sulphate. The acidic leach solution, containing cobalt and nickel sulphates, is purified to remove iron and trace metals such as Cu, Cd and Zn. Ammonia is then added to neutralize the free acid and to adjust the ammonia to metals mole ratio to form the-pentammine ions of divalent nickel and cobalt. The solution is then treated with air under pressure in an autoclave, to oxidize the cobalt (II) pentammine ion to the cobalt (III) pentammine ion. The nickel (II) pentammine ion is not oxidized under these conditions. The oxidized solution is then treated in a two-stage process with concentrated sulphuric acid to selectively precipitate nickel as the nickel ammonium sulphate double salt (NiSO4. (NH4)SO4), leaving cobalt (III) pentammine sulphate in solution. After the second stage of nickel removal, the cobaltic solution is essentially nickel-free, with a Co:Ni ratio greater than 1000:1. The cobalt (III) ion is reduced to cobalt (II), and acid is added to adjust the NH3 :Co mole ratio to about 2:1. This solution is treated with hydrogen at elevated temperature and pressure to produce cobalt metal powder containing less than 0.1% Ni. This two-stage process, as described in U.S. Pat. No. 2,822,264, produces cobalt powder with a Co:Ni Ratio of greater than 1000:1.

Workup

  1. additionThe solution is then treated with air under pressure in an autoclave

Sources & evidence

ORD record
ord-c9381df049f04fc1bc8d579a81a41fa9
Source dataset
uspto-grants-1995_11
Patent number
US05468281

Reaction notes

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