The present invention is directed to methods of preparing metal sulfide, metal selenide, or metal sulfide/selenide nanoparticles and the products derived therefrom. In various embodiments, the nanoparticles are derived from the reaction between precursor metal salts and certain sulfur- and/or selenium-containing precursors each independently having a structure of Formula (I), (II), or (III), or an isomer, salt, or tautomer thereof, where Q.sup.1,Q.sup.2,Q.sup.3,R.sup.1,R.sup.2,R.sup.3,R.sup.5, and X are defined within the specification.

The present invention is directed to methods of preparing metal sulfide, metal selenide, or metal sulfide/selenide nanoparticles and the products derived therefrom. In various embodiments, the nanoparticles are derived from the reaction between precursor metal salts and certain sulfur- and/or selenium-containing precursors each independently having a structure of Formula (I), (II), or (III), or an isomer, salt, or tautomer thereof, where Q.sup.1,Q.sup.2,Q.sup.3,R.sup.1,R.sup.2,R.sup.3,R.sup.5, and X are defined within the specification.

Provided is a method for separating impurities and cobalt without using an electrolysis process from a cobalt chloride solution containing impurities and producing a high purity cobalt sulfate. The production method includes: a first solvent extraction step (S1) of bringing an organic solvent containing an alkyl phosphoric acid-based extractant into contact with a cobalt chloride solution containing impurities, and extracting zinc, manganese, and calcium into the organic solvent to separate to remove zinc, manganese, and calcium; a copper removal step (S2) of adding a sulfurizing agent to a cobalt chloride solution and generating a precipitate of sulfide of copper to separate to remove copper; a second solvent extraction step (S3) of bringing an organic solvent containing a carboxylic acid-based extractant into contact with a cobalt chloride solution and back extracting cobalt with sulfuric acid after extracting cobalt into the organic solvent to obtain cobalt sulfate solution; and a crystallization step (S4) of the cobalt sulfate solution obtained after having undergone through the second solvent extraction step (S3). These steps are sequentially executed. Without using an electrolysis process, a high purity cobalt sulfate is directly produced by separating cobalt and impurities containing manganese.

Methods of sulfurizing metal containing particles in the absence of hydrogen are described. One method includes contacting a bed of metal containing particles with a gaseous stream comprising hydrogen sulfide and inert gas under reaction conditions sufficient to produce sulfided metal containing particles. The gaseous stream is introduced into a vertical reactor at an inlet positioned at the bottom portion of the reactor and any unreacted hydrogen sulfide and inert gas is removed at an outlet positioned above the inlet. The sulfided metal containing particles can be removed from the reactor and stored.

The present invention seeks to provide cadmium-free quantum dots with a narrow fluorescence FWHM. The quantum dot does not contain cadmium and its fluorescence FWHM is 30 nm or less. The quantum dot is preferably a nanocrystal containing zinc and tellurium or zinc and tellurium and sulfur or zinc and tellurium and selenium and sulfur. Further, the quantum dot preferably has a core-shell structure in which the nanocrystal serves as a core and the surface of the core is coated with a shell.

A method of controlling frothing during atmospheric or substantially atmospheric leaching of a metal sulfide is disclosed. In some embodiments, the method may comprise the steps of (a) producing a metal sulfide concentrate via flotation; (b) producing a tailings stream via flotation; and, (c) diverting a portion or all of said produced tailings stream to an atmospheric or substantially atmospheric sulfide leach circuit. A metal recovery flowsheet is also disclosed. In some embodiments, the metal recovery flowsheet may comprise a unit operation comprising: (a) a sulfide concentrator comprising a flotation circuit, the flotation circuit producing a metal sulfide concentrate stream, and a tailings stream; and, (b) an atmospheric or substantially atmospheric metal sulfide leach circuit. The sulfide concentrator may be operatively connected to the atmospheric or substantially atmospheric metal sulfide leach circuit via both of said metal sulfide concentrate stream, and said tailings stream.

A method of controlling frothing during atmospheric or substantially atmospheric leaching of a metal sulfide is disclosed. In some embodiments, the method may comprise the steps of (a) producing a metal sulfide concentrate via flotation; (b) producing a tailings stream via flotation; and, (c) diverting a portion or all of said produced tailings stream to an atmospheric or substantially atmospheric sulfide leach circuit. A metal recovery flowsheet is also disclosed. In some embodiments, the metal recovery flowsheet may comprise a unit operation comprising: (a) a sulfide concentrator comprising a flotation circuit, the flotation circuit producing a metal sulfide concentrate stream, and a tailings stream; and, (b) an atmospheric or substantially atmospheric metal sulfide leach circuit. The sulfide concentrator may be operatively connected to the atmospheric or substantially atmospheric metal sulfide leach circuit via both of said metal sulfide concentrate stream, and said tailings stream.

A methodology for synthesizing a nanoparticle batch, such as but not limited to a metal chalcogenide nanoparticle batch and further such as but not limited to a metal sulfide nanoparticle batch is predicated upon an expectation and observation that at elevated concentrations of at least one reactant material within a heat-up nanoparticle batch synthesis method, the resulting nucleated batch comprises nanoparticles that may be dimensionally focused to provide a substantially monodisperse nanoparticle batch. The embodied methodology is also applicable to a continuous reactor. The embodied methodology also considers viscosity as a dimensionally focusing result effective variable.

A methodology for synthesizing a nanoparticle batch, such as but not limited to a metal chalcogenide nanoparticle batch and further such as but not limited to a metal sulfide nanoparticle batch is predicated upon an expectation and observation that at elevated concentrations of at least one reactant material within a heat-up nanoparticle batch synthesis method, the resulting nucleated batch comprises nanoparticles that may be dimensionally focused to provide a substantially monodisperse nanoparticle batch. The embodied methodology is also applicable to a continuous reactor. The embodied methodology also considers viscosity as a dimensionally focusing result effective variable.

Methods of sulfurizing metal containing particles in the absence of hydrogen are described. One method includes contacting a bed of metal containing particles with a gaseous stream comprising hydrogen sulfide and inert gas under reaction conditions sufficient to produce sulfided metal containing particles. The gaseous stream is introduced into a vertical reactor at an inlet positioned at the bottom portion of the reactor and any unreacted hydrogen sulfide and inert gas is removed at an outlet positioned above the inlet. The sulfided metal containing particles can be removed from the reactor and stored.