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Hydrolyzed Metal Ions as Pyrite Depressants in Coal Flotation: A Laboratory Study.

Authors
Baker-AF; Miller-KJ
Source
NTIS: PB 200 700 :21 pages
Link
NIOSHTIC No.
10008753
Abstract
Laboratory flotation of synthetic coal-pyrite mixtures and high- pyritic-sulfur coal indicated that ferric chloride fecl3), aluminum chloride (alcl3), chromium chloride (crcl3), and cupric sulfate (cuso4) are potential pyrite depressants. Pyrite was depressed in the ph range from 4.5 to 7.0 With ferric chloride, from 5.8 to 7.0 With aluminum chloride, from 6.4 to 7.1 With chromium chloride, and from 6.4 to 7.4 With cupric sulfate. Best separation of pyrite from coal was achieved in flotation solutions containing from 2 x 10-5 to 5 x 10-5 mole/liter of each salt. In solutions containing excess salt concentrations, coal was also depressed. These Bureau of Mines tests demonstrated on a laboratory scale that, in solutions containing 4 x 10-5 mole/liter ferric chloride and from 1 x 10-4 to 2 x 10-4 mole/liter sodium hydroxide, the pyritic sulfur content of a Lower Freeport bed coal sample could be reduced from about 2.51 percent to less than 0.60 percent with recoveries of over 83 percent. The depression of pyrite appears to be due to the adsorption of positively charged colloidal metal hydroxide at the pyrite-solution interface. This hypothesis is supported by zeta potential determinations which showed that suspended coal and pyrite particles in solutions containing metal salts are positively charged in the ph range where depression occurs.
Publication Date
19710101
Document Type
IH; Report of Investigation;
Fiscal Year
1971
NTIS Accession No.
PB-200700
NTIS Price
A03
Identifying No.
RI 7518
NIOSH Division
PERC;
Source Name
NTIS: PB 200 700
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