Chemistry of inorganic compounds – Treating mixture to obtain metal containing compound – Platinum group metal
Reexamination Certificate
2001-01-12
2003-06-17
Bos, Steven (Department: 1754)
Chemistry of inorganic compounds
Treating mixture to obtain metal containing compound
Platinum group metal
Reexamination Certificate
active
06579504
ABSTRACT:
BACKGROUND TO THE INVENTION
This invention relates to the hydrometallurgical treatment process for extracting platinum group metals from a flotation concentrate.
Conventionally, platinum group metals are extracted from a flotation concentrate in a matte smelting and converting process followed by further refining for the extraction of the platinum group metals.
SUMMARY OF THE INVENTION
According to the invention there is provided a hydrometallurgical treatment process for extracting platinum group metals from a flotation concentrate comprising the steps of:
leaching of the flotation concentrate to dissolve base metal sulphides in the flotation concentrate so as to form a filtrate and a residue;
separation of the filtrate from the residue;
roasting the residue to form a calcine; and
chlorination of the calcine to dissolve the platinum group metals into solution.
Typically, the process includes the additional steps of:
adsorption of the platinum group metals onto an ion exchange resin; and
recovery of the platinum group metals from the ion exchange resin.
Preferably, the roasting step involves oxidation or reduction, more preferably oxidation at up to 1000° C.
Typically, the method includes the step of recovering Osmium from the off-gas from the roasting step.
The chlorination step preferably comprises countercurrent chlorination of the calcine at approximately 80° C. and 3.5N HCl.
The separation step typically comprises filtration followed by the additional steps of neutralisation of the filtrate; precipitation of base metal sulphides and flotation of precipitated sulphides into a concentrate.
The step involving adsorption of the platinum group metals onto an ion exchange resin may be followed by:
desorption of the platinum group metals from the resin with thiourea at approximately 80° C. followed by water washing of the stripped resin; and/or
precipitation of the platinum group metals from the eluate with caustic solution.
Various embodiments of the invention are described in detail in the following passages of the specification which refer to the accompanying drawings. The drawings, however, are merely illustrative of how the invention might be put into effect, so that the specific form and arrangement of the features shown is not to be understood as limiting on the invention.
REFERENCES:
patent: 4108639 (1978-08-01), Lake et al.
patent: 5238662 (1993-08-01), Dubrovsky
patent: 5292490 (1994-03-01), Duyvesteyn et al.
patent: 5364444 (1994-11-01), McDoulett, Jr. et al.
patent: 1078453 (1967-08-01), None
patent: 56-013445 (1981-02-01), None
“Hydrometallurgy of Precious Metals Recovery”; Fleming; Hydrometallurgy; vol. 30, No. 1/03; Jun. 1, 1992; pp. 127-162.
Bos Steven
Roylance Abrams Berdo & Goodman L.L.P.
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