With the world's rapid advancement of technology, the demand and need for the materials that make up that technology has exploded. An important group of materials needed in this rapid advancement are the rare earth elements (REE) used in countless necessary applications. One source of rare earths found in the United States is bastnaesite, a rare earth bearing fluorocarbonate, mined at the Mountain Pass Mine in California. To increase production, it has been essential to optimize existing processes and create new ones to exploit current reserves. This research program was run to expand the understanding of the bastnaesite leaching system. A novel single stage hydrochloric leach system was created to optimize the rare earth extraction from bastnaesite. Typically, this process has utilized a two-stage leach system involving a high temperature hydrochloric acid leach followed by a caustic crack.

With the world's rapid advancement of technology, the demand and need for the materials that make up that technology has exploded. An important group of materials needed in this rapid advancement are the rare earth elements (REE) used in countless necessary applications. One source of rare earths found in the United States is bastnaesite, a rare earth bearing fluorocarbonate, mined at the Mountain Pass Mine in California. To increase production, it has been essential to optimize existing processes and create new ones to exploit current reserves. This research program was run to expand the understanding of the bastnaesite leaching system. A novel single stage hydrochloric leach system was created to optimize the rare earth extraction from bastnaesite. Typically, this process has utilized a two-stage leach system involving a high temperature hydrochloric acid leach followed by a caustic crack.

The present invention relates to a process for purifying and concentrating rare earths contained in phosphogypsum, characterised in that it comprises the following steps of: from a phosphogypsum, a) Leaching the phosphogypsum with a solution of one or more strong acid(s) selected from among: sulphuric acid, nitric acid and hydrochloric acid, in order to obtain a leaching mixture comprising a liquid phase formed by a leaching solution containing rare earths from the phosphogypsum and the leaching acid, and a solid phase comprising the phosphogypsum, b) Adding, to the phosphogypsum, an oxidising agent to promote passage of the rare earths from the phosphogypsum into the leaching solution, and/or a reducing agent to reduce solubility of mineral impurities contained in the leaching solution in order to allow their passage from the leaching solution into the solid phase, c) Separating the liquid phase enriched in rare earths and depleted in mineral impurities, and the solid phase enriched in mineral impurities.

Disclosed herein is a method of recovering lithium or sodium from an active material of a lithium or sodium ion battery. In a preferred embodiment, the method comprises a redox-targeting reaction of a used active material LiFeP04 with a redox mediator [Fe(CN).sub.6].sup.3− in a tank to produce lithium ions, circulating the reacted redox solution into a cell to regenerate said redox mediator and enabling said lithium ions to migrate through a membrane towards a cathode wherein said lithium ions are captured as LiOH through an electrochemical reaction.

The present invention relates to a process for dissolving metals in perhalide containing ionic liquids, and to the extraction of metals from mineral ores; the remediation of materials contaminated with heavy, toxic or radioactive metals; and to the removal of heavy and toxic metals from hydrocarbon streams.

The present invention relates to a process for dissolving metals in perhalide containing ionic liquids, and to the extraction of metals from mineral ores; the remediation of materials contaminated with heavy, toxic or radioactive metals; and to the removal of heavy and toxic metals from hydrocarbon streams.

A process for multi-recycling, low-energy and high-purity extraction of lithium increases the purity and the concentration of lithium ions in produced solutions gradually through steps of adsorption/desorption ion exchange, extraction, impurity separation, agent separation and concentration, during which extractive liquids are returned, recycled and processed in previous steps for fewer dosages of chemicals and fewest discharged effluents, lower manufacturing costs than existing techniques, low specific energy consumption and consumable loss, and high-purity products with lithium ions.

A process for multi-recycling, low-energy and high-purity extraction of lithium increases the purity and the concentration of lithium ions in produced solutions gradually through steps of adsorption/desorption ion exchange, extraction, impurity separation, agent separation and concentration, during which extractive liquids are returned, recycled and processed in previous steps for fewer dosages of chemicals and fewest discharged effluents, lower manufacturing costs than existing techniques, low specific energy consumption and consumable loss, and high-purity products with lithium ions.

A process disclosed herein is related to the isolation and purification of substantially pure chemicals, including silica gel, sodium silicate, aluminum silicate, iron oxide, and rare earth elements (or rare earth metals, REEs), from massive industrial waste coal ash. In one embodiment, the process includes a plurality of caustic extractions of coal ash at an elevated temperature, followed by an acidic treatment to dissolve aluminum silicate and REEs. The dissolved aluminum silicate is precipitated out by pH adjustment as a solid product while REEs remain in the solution. REEs are captured and enriched using an ion exchange column. Alternatively, the solution containing aluminum silicate and REEs is heated to produce silica gel, which is easily separated from the enriched REEs solution. REEs are then isolated and purified from the enriched solution to afford substantially pure individual REE by a ligand-assisted chromatography. Additionally, a simplified process using one caustic extraction and one acidic extraction with an ion exchange process was also investigated and optimized to afford a comparable efficiency.

A process disclosed herein is related to the isolation and purification of substantially pure chemicals, including silica gel, sodium silicate, aluminum silicate, iron oxide, and rare earth elements (or rare earth metals, REEs), from massive industrial waste coal ash. In one embodiment, the process includes a plurality of caustic extractions of coal ash at an elevated temperature, followed by an acidic treatment to dissolve aluminum silicate and REEs. The dissolved aluminum silicate is precipitated out by pH adjustment as a solid product while REEs remain in the solution. REEs are captured and enriched using an ion exchange column. Alternatively, the solution containing aluminum silicate and REEs is heated to produce silica gel, which is easily separated from the enriched REEs solution. REEs are then isolated and purified from the enriched solution to afford substantially pure individual REE by a ligand-assisted chromatography. Additionally, a simplified process using one caustic extraction and one acidic extraction with an ion exchange process was also investigated and optimized to afford a comparable efficiency.