Hydrometallurgical process using multi-stage nanofiltration
AssigneeChemetics Inc.
InventorsSiamak Lashkari, Felix Mok, Ganapathy Ramasubbu, Anthony Mumba
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Abstract
Nanofiltration can be used to improve a hydrometallurgical process in which valuable metal is extracted from ore or tailings by leaching with a suitable lixiviant. The process requires at least two nanofiltration subsystems in which raffinate from a solvent extraction process is treated in a nanofiltration subsystem, after which permeate therefrom is combined with a pregnant solution stream and is treated in a second nanofiltration subsystem. This arrangement can lead to advantages in the amount of lixiviant recovered, in the raw materials required, in the effluent produced, in the size of plant, and in overall cost.
Claims15
A hydrometallurgical process for extracting a valuable metal from a material comprising the steps of:
- a) leaching the material with a lixiviant to produce a leach solution of the metal and impurity solids;
- b) concentrating and purifying the leach solution to produce a metal-rich pregnant solution stream and a metal-poor raffinate, wherein the step of concentrating and purifying the leach solution comprises solvent extracting the leach solution;
- and
- c) recovering the metal from the pregnant solution stream;
- characterized in that the hydrometallurgical process comprises:
- directing the raffinate from solvent extracting the leach solution to the inlet of a first nanofiltration subsystem to produce a first retentate stream and a first permeate stream;
- combining the first permeate stream from the first nanofiltration subsystem with the pregnant solution stream;
- directing the combined first permeate stream and pregnant solution stream to the inlet of a second nanofiltration subsystem to produce a second retentate stream and a second permeate stream;
- and
- employing the second permeate stream in at least one of steps a) and b).
A system for extracting a valuable metal from a material comprising:
- apparatus for leaching the material with a lixiviant;
- apparatus for concentrating and purifying the leach solution to produce a metal-rich pregnant solution stream and a metal-poor raffinate comprising a solvent extracting apparatus for solvent extracting the leach solution;
- and
- apparatus for recovering the metal from the pregnant solution stream;
- characterized in that the system comprises:
- a first nanofiltration subsystem comprising an inlet connected to the raffinate from the solvent extracting apparatus, a first retentate stream outlet, and a first permeate stream outlet connected to the pregnant solution stream;
- and
- a second nanofiltration subsystem comprising an inlet connected to the combined first permeate stream and pregnant solution stream, a second retentate stream outlet, and a second permeate stream outlet connected to at least one of the apparatus for leaching and the apparatus for concentrating and purifying the leach solution.
Dependencies are inferred from the claim text.