The invention relates to a method for recovering precious metals from electronic waste utilising biometallurgical techniques. In one aspect, a method of recovering one or more target metals from electronic waste, includes (a) removing at least a portion of non-target material from the electronic waste or grinding to a preselected size particle to give pre-processed electronic waste; (b) contacting the pre-processed electronic waste with a lixiviant such that at least a portion of the target metal(s) dissolve into the lixiviant to produce a pregnant solution; (c) contacting a microorganism with the pregnant solution such that at least a portion of the target metal(s) ions biosorb to the microorganism wherein the microorganism becomes metal laden and the pregnant solution becomes barren; (d) substantially separating the metal laden microorganism from the barren solution; and (e) recovery of the target metal(s) from the metal laden microorganism.

Provided is a method for separating copper, nickel, and cobalt, the method being capable of efficiently and selectively separating copper, nickel, and cobalt from alloys containing copper, nickel, and cobalt, such as highly corrosive alloys containing copper, nickel, and cobalt obtained by dry-processing used lithium ion batteries. The alloy containing copper, nickel, and cobalt is brought into contact with nitric acid in the co-presence of a sulfiding agent to obtain a solid containing copper and a leachate containing nickel and cobalt.

The present invention relates to a method for selectively precipitating and extracting gold in aqueous solution by niacin. Aqueous Au.sup.3+ is precipitated selectively as it's complex from gold containing acidic mixtures by biomolecule niacin, with the formula [AuCl.sub.4].sup.[2Niacin+H].sup.+. After precipitation, the complex is separated from impurities by filtration. Recovered complex is reduced by using a reductant like sodium metabisulfite (Na.sub.2S.sub.2O.sub.5) to recover gold metal. The method is highly cost-effective, sustainable and recovers about 96.5% of gold in 2 minutes from an electronic waste composed of Au. Cu and Ni. The method is also employed to extract gold from nanomaterials waste generated in laboratories.

A system for recovering rare earth elements from coal ash includes a leaching reactor, an ash dryer downstream of the leaching reactor, and a roaster downstream of the ash dryer that is cooperatively connected to both the leaching reactor and the ash dryer. Coal ash is mixed with an acid stream such that rare earth elements present in the coal ash are dissolved in the acid stream, thereby creating (i) a leachate containing the rare earth elements and (ii) leached ash. The leachate is heated to obtain acid vapor and an acid-soluble rare earth concentrate. Mixing of the coal ash with the acid stream can occur in a leaching reactor and heating of the leachate can occur in a roaster. The acid-soluble rare earth concentrate can be fed to a hydrometallurgical process to separate and purify the rare earth elements.

A system for recovering rare earth elements from coal ash includes a leaching reactor, an ash dryer downstream of the leaching reactor, and a roaster downstream of the ash dryer that is cooperatively connected to both the leaching reactor and the ash dryer. Coal ash is mixed with an acid stream such that rare earth elements present in the coal ash are dissolved in the acid stream, thereby creating (i) a leachate containing the rare earth elements and (ii) leached ash. The leachate is heated to obtain acid vapor and an acid-soluble rare earth concentrate. Mixing of the coal ash with the acid stream can occur in a leaching reactor and heating of the leachate can occur in a roaster. The acid-soluble rare earth concentrate can be fed to a hydrometallurgical process to separate and purify the rare earth elements.

Methods of recovering rare earth elements, vanadium, cobalt, or lithium from coal are described. The coal is dissolved in a first solvent to dissolve organic material in the coal and create a slurry containing coal ash enriched with rare earth elements, vanadium, cobalt, or lithium. The enriched coal ash is separated from the first solvent. Residual organic material is removed from the coal ash. The rare earth elements, vanadium, cobalt, or lithium can then be recovered from the coal ash. The coal ash is mixed with an acid stream that dissolves the rare earth elements, thereby creating (i) a leachate containing the rare earth elements and (ii) leached ash. The leachate is heated to obtain acid vapor and an acid-soluble rare earth concentrate. The acid-soluble rare earth concentrate can be fed to a hydrometallurgical process to separate and purify the rare earth elements.

In general, according to one embodiment, a recycling method is provided. The method includes dispersing an electrode containing a niobium titanium oxide in water; separating the niobium titanium oxide from the electrode dispersed in the water; and applying a first heat treatment to the separated niobium titanium oxide.

A method of making a zeolite comprises: adding a zeolite seed to a leach solution containing silicon and aluminum; and heating the leach solution to obtain the zeolite. The leach solution can be made by mixing coal ash with a basic stream, thereby creating (i) a leach solution containing silicon and aluminum, and (ii) leached ash; and separating the leach solution from the leached ash.

An improved beta(?)-spodumene (?LiAlSi.sub.2O.sub.6) nitric acid conversion process produces discrete lithium (Li), aluminum (Al) and silica (SiO.sub.2) materials by: (i) converting lithium nitrate, LiNO.sub.3, to lithium carbonate, Li.sub.2CO.sub.3; (ii) creating a Al-rich precipitate either by thermally decomposing aluminum nitrate, Al(NO.sub.3).sub.3, or by reacting Al(NO.sub.3).sub.3 with aqueous and/or solid ammonium carbonate, (NH.sub.4).sub.2CO.sub.3; and (iii) forming a solid SiO.sub.2-rich aluminosilicate residue by selectively leaching Li and Al from ?-spodumene. Three key reactants consumed during processingnitric acid (HNO.sub.3), ammonia (NH.sub.3), and magnesium oxide (MgO)may be regenerated internally by closed-loop chemical cycles, this feature of the process greatly improving its economics in commercial applications.

An assembly and a method for photovoltaic (PV) panel recycling is disclosed. The assembly comprises (a) a mechanical means to remove aluminium frames; (b) a furnace; (c) a cooling station; (d) a wet bench; (e) a filtration system; (f) a tilt furnace, and (g) a plurality of crushers for used in crushing recovered glass and silicon wafers.