A process may involve treating calcium sulfate separated from phosphoric acid with acid to obtain a suspension comprising purified calcium sulfate, separating the purified calcium sulfate in solid form from a liquid phase of the suspension, treating the purified calcium sulfate with water or with a salt- and/or chelate ligand-containing aqueous solution to leach rare earths out of the calcium sulfate, separating the further-purified calcium sulfate in solid form from the liquid phase of the suspension, mixing the purified calcium sulfate that is separated off with admixtures and reducing agents to obtain a raw meal mixture for cement clinker production, burning the raw meal mixture to obtain the cement clinker and thereby forming sulfur dioxide as offgas, and feeding the sulfur dioxide as raw material to sulfuric acid production to produce the sulfuric acid.

The inventions described herein provide methods and systems for recycling lithium iron phosphate batteries, including: adding an oxidizing agent to a recycling stream of lithium iron phosphate (LiFePO.sub.4) batteries to form a leach solution; filtering the leach solution to remove a residue and obtain a lithium rich solution; modifying pH of the lithium rich solution for filtering impurities and obtaining a purified Li solution; and adding a precipitant to the purified Li solution thereby precipitating a lithium compound.

The inventions described herein provide methods and systems for recycling lithium iron phosphate batteries, including: adding an oxidizing agent to a recycling stream of lithium iron phosphate (LiFePO.sub.4) batteries to form a leach solution; filtering the leach solution to remove a residue and obtain a lithium rich solution; modifying pH of the lithium rich solution for filtering impurities and obtaining a purified Li solution; and adding a precipitant to the purified Li solution thereby precipitating a lithium compound.

A method of leaching copper from a copper sulfide ore which includes adding a potential adjustment agent for lowering a potential of a leaching solution obtained after leaching copper from the copper sulfide ore by using iodide ion and iron (III) ion, the leaching solution being stored in a tank for storing the leaching solution.

A method of separating and recovering a cobalt salt and a nickel salt includes a separation step of separating, by using a nanofiltration membrane, a cobalt salt and a nickel salt from a rare metal-containing aqueous solution containing at least both the cobalt salt and the nickel salt as rare metals, in which the nanofiltration membrane has a glucose permeability of 3 times or more a sucrose permeability, the sucrose permeability of 10% or less, and an isopropyl alcohol permeability of 50% or more when a 1,000 mg/L glucose aqueous solution, a 1,000 mg/L sucrose aqueous solution, and a 1,000 mg/L isopropyl alcohol aqueous solution, each having a pH of 6.5 and a temperature of 25° C., individually permeate through the nanofiltration membrane at an operating pressure of 0.5 MPa.

A method of separating and recovering a cobalt salt and a nickel salt includes a separation step of separating, by using a nanofiltration membrane, a cobalt salt and a nickel salt from a rare metal-containing aqueous solution containing at least both the cobalt salt and the nickel salt as rare metals, in which the nanofiltration membrane has a glucose permeability of 3 times or more a sucrose permeability, the sucrose permeability of 10% or less, and an isopropyl alcohol permeability of 50% or more when a 1,000 mg/L glucose aqueous solution, a 1,000 mg/L sucrose aqueous solution, and a 1,000 mg/L isopropyl alcohol aqueous solution, each having a pH of 6.5 and a temperature of 25° C., individually permeate through the nanofiltration membrane at an operating pressure of 0.5 MPa.

The present disclosure provides a lithium extraction apparatus, which includes a frame and a transmission mesh belt. The transmission mesh belt includes water permeable holes, and is configured to carry an adsorbent. The frame includes an adsorption zone and a desorption zone along a traveling direction of the transmission mesh belt. A brine spraying device is disposed above the transmission mesh belt in adsorption zone. A desorbing liquid spraying device is disposed above the transmission mesh belt in the desorption zone, and a lithium extract collecting device is disposed below the transmission mesh belt in the desorption zone. The transmission mesh belt in the adsorption zone is folded into a multi-layer structure in the vertical direction; and/or the transmission mesh belt in the desorption zone is folded into a multi-layer structure in the vertical direction.

The present disclosure provides a lithium extraction apparatus, which includes a frame and a transmission mesh belt. The transmission mesh belt includes water permeable holes, and is configured to carry an adsorbent. The frame includes an adsorption zone and a desorption zone along a traveling direction of the transmission mesh belt. A brine spraying device is disposed above the transmission mesh belt in adsorption zone. A desorbing liquid spraying device is disposed above the transmission mesh belt in the desorption zone, and a lithium extract collecting device is disposed below the transmission mesh belt in the desorption zone. The transmission mesh belt in the adsorption zone is folded into a multi-layer structure in the vertical direction; and/or the transmission mesh belt in the desorption zone is folded into a multi-layer structure in the vertical direction.

Recovery of noble metals (including the recovery of gold and/or silver from gold and/or silver containing material) is generally described. The gold and/or silver can be recovered selectively, in some cases, such that gold and/or silver are at least partially separated from non-silver and/or non-gold material. Gold and/or silver may be recovered from material using mixtures of acids, in some instances. In some cases, the mixture can comprise nitric acid and at least one supplemental acid, such as sulfuric acid, phosphoric acid, and/or a sulfonic acid. The amount of nitric acid within the mixture can be, in some instances, relatively small compared to the amount of sulfuric acid or phosphoric acid within the mixture. In some cases, the recovery of gold and/or silver using the acid mixtures can be enhanced by transporting an electric current between an electrode and the gold and/or silver of the material. In some cases, acid mixtures can be used to recover silver from particular types of materials, such as material comprising silver metal and cadmium oxide and/or material comprising silver metal and tungsten metal.

In order to reduce the contamination of scandium oxide products, the present disclosure provides a process for removing at least one metal contaminant from a scandium (Sc) concentrate. The process is based on contacting the Sc concentrate with an ion exchange resin to obtain a purified Sc eluate or raffinate. The first ion exchange resin and the second ion exchange resin are strong acid cationic resins with sulfonic acid functional groups in a potassium or sodium form. The purified Sc eluate or raffinate can be used to make scandium oxide products having a reduced amount of metal ion contaminants.