Yava Technologies Inc.

Madhav Dahal

Robert A Geisler

Trevor Byrne

Described is a method of recovering a metal from a substrate having a metal sulphide, metal oxide, or combination thereof, by contacting the substrate with an aqueous oxidant to oxidize the metal sulphide to elemental sulphur and oxidized metal or convert the complex metal oxide to a metal salt, contacting the oxidized metal or simple metal oxide with ammonium hydroxide to form soluble a ammine complex of the metal to obtain a leachate and residual solids; separating the leachate from the residual solids; and recovering the metal.

Integrated recovery of metals from complex substrates

A method of preparing insoluble transition metal compound particles is described, comprising: providing a transition metal salt solution having the formula (TM)(S) wherein TM is one or more of Mn, Ni, Co, Mg, Zn, Ca, Sr, Cu, Zr, P, Fe, Al, Ga, In, Cr Ge or Sn; providing a source of a carbonate-, hydroxide-, phosphate-, oxyhydroxide- or oxide-based anionic compound wherein the anionic component, represented by S', is reactive with TM to form the particles; adding the transition metal salt solution and anionic compound to a reaction chamber; and subjecting the chamber to sonication at an intensity of about 0.1 to about 50 W/mL. In an exemplary embodiment, MnCOparticles are formed from: MnSO; and NaCOand/or NHHCO, wherein the ratio of MnSOto NaCOand/or NHHCOis from about 1:1.5 to 1.5:1. The particles may have narrow size distribution and a tap density of about 1.7-2.3 g/mL.

Transition metal compound particles and methods of production

Zinc and lead are usually concomitantly present in Zn&#x2014;Pb ores and tailings. A novel non-polluting hydrometallurgical process for selectively leaching and recovering zinc (Zn) from a composite lead (Pb) and zinc sulphide containing mineral, crushed untreated rock or unconsolidated mineral particles, mill tailings and/or agglomerated or unagglomerated sulphidic zinc containing waste material without necessitating smelting and refining operation has been developed. A combination of selected oxidant and alkali metal hydroxide has been found effective. A leachant consisting of e.g. a mixture of sodium hydroxide (NaOH) and sodium hypochlorite (NaOCl) is employed to selectively dissolve zinc sulphide at high pH at standard temperature and pressure (STP). The kinetics of leaching along with the effect of varying concentration (preferably of sodium hydroxide and sodium hypochlorite) were systematically investigated. Feed ore containing diverse set of minerals e.g. sulphides and carbonates can also be conveniently treated to selectively and almost quantitatively recover zinc as high purity zinc carbonate. This technology can be employed either in-situ or ex-situ based on the amenability of a particular type of mineral deposit or feed ore.

Selective leach recovery of zinc from a composite sulphide ore deposit, tailings, crushed ore or mine sludge

Calcium (Ca), manganese (Mn) and magnesium (Mg) carbonate plus lead (Pb) and zinc (Zn) sulphide minerals in a permeable host, crushed ore, concentrates or as mine discharge tailing are selectively solution mined (in-situ or ex-situ) with a selected acid e.g. acetic acid to extract Ca, Mn, and Mg followed by multivalent oxidizing salts e.g. ferric salts to extract Pb and Zn sequentially. For in-situ leaching, an inter relationship has been identified between pressure, temperature, target depth and leachate concentration such that carbonate leaching is performed in a manner to prevent carbon dioxide gas (CO) discharge thereby plugging host rock permeability avenues to preclude further leaching. This requires controlling the rate of acetic acid leaching to be in step with availability of solution to dissolve the resulting discharged CO. Sulphide leaching is subsequently conducted on the carbonate-depleted host. The two resulting leachates are chemically treated to selectively recover extracted minerals as value added industrially ready products. The in situ method is particularly advantageous in preparing the high purity manganese products necessary for lithium ion batteries because it prevents occurrence of very fine metallic particles in the products that may happen during conventional mining. Alternatively, the in situ carbonate recovery steps can be independently employed; all in an environmentally friendly manner.

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Toronto, Canada

Madhav Dahal