A process for 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 including a plurality of caustic extractions of coal ash at an elevated temperature, followed by an acidic treatment to dissolve aluminum silicate and REEs. 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 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.

A process for 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 including a plurality of caustic extractions of coal ash at an elevated temperature, followed by an acidic treatment to dissolve aluminum silicate and REEs. 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 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.

The present disclosure relates to rheology-modifying agents and methods of modifying the rheology of slurries. A rheology-modifying agent may be added to a slurry. The rheology-modifying agent may include a polymer and the polymer may include at least three chemically different monomers. The slurry may include lime and/or magnesium hydroxide.

The present disclosure relates to rheology-modifying agents and methods of modifying the rheology of slurries. A rheology-modifying agent may be added to a slurry. The rheology-modifying agent may include a polymer and the polymer may include at least three chemically different monomers. The slurry may include lime and/or magnesium hydroxide.

Method embodiments useful for recycling spent lithium-ion battery (LIB) electrodes to extract critical and/or valuable elements from LIBs are provided and involve mechanochemical processing of spent LIB electrodes in the presence of certain chemical agents to recover products that can include, but are not limited to, metallic solids such as elemental metals or metal alloys, and/or inorganic compounds, metal salts, or organometallic derivatives. The desired products can be separated from by-products and contaminants and further processed into LIB electrode materials or/and other substances.

Calcium hydroxide nanoparticles (Ca(OH).sub.2NPs) synthesized using carob pulp extract may be hexagonal nanoparticles with a diameter ranging from about 31.22 nm to about 81.22 nm. The Ca(OH).sub.2NPs may be synthesized by heating ethylene glycol, adding calcium hydroxide to the ethylene glycol to provide a first mixture, heating the first mixture, adding a carob pulp aqueous extract to the first mixture to form a second mixture, heating the second mixture, adding sodium hydroxide (NaOH) to the second mixture to form a third mixture, heating the third mixture, resting the third mixture at room temperature after heating, centrifuging the third mixture, collecting a colloid sediment, extracting any unwanted contaminants from the colloid sediment, and drying the colloid sediment to obtain Ca(OH).sub.2NPs.

Calcium hydroxide nanoparticles (Ca(OH).sub.2NPs) synthesized using carob pulp extract may be hexagonal nanoparticles with a diameter ranging from about 31.22 nm to about 81.22 nm. The Ca(OH).sub.2NPs may be synthesized by heating ethylene glycol, adding calcium hydroxide to the ethylene glycol to provide a first mixture, heating the first mixture, adding a carob pulp aqueous extract to the first mixture to form a second mixture, heating the second mixture, adding sodium hydroxide (NaOH) to the second mixture to form a third mixture, heating the third mixture, resting the third mixture at room temperature after heating, centrifuging the third mixture, collecting a colloid sediment, extracting any unwanted contaminants from the colloid sediment, and drying the colloid sediment to obtain Ca(OH).sub.2NPs.

Disclosed herein are system and methods to effectively leach coal ash with hydrochloric acid and separate an insoluble silica product and then selectively precipitate, from the leachate, a number to value-added, strategic, marketable products using a hydroxide reagent. The resulting precipitated products include iron, aluminum, magnesium, calcium, and a mixture of rare earth elements and transition metals. These can be separated as hydroxides or converted to oxides or carbonates. Using hydrochloric acid for leaching and converting the chloride to sodium chloride in the final step results in practically no waste for this process. The silica can be further purified using sodium hydroxide fusion or caustic leach methods and some minor streams from this process are recycled to minimize any waste stream. These systems and methods can be applied to a number of other industrial waste products such as red mud from the aluminum process, slag from steel furnaces, mine tailings, and other metal-bearing waste streams.

Disclosed herein are system and methods to effectively leach coal ash with hydrochloric acid and separate an insoluble silica product and then selectively precipitate, from the leachate, a number to value-added, strategic, marketable products using a hydroxide reagent. The resulting precipitated products include iron, aluminum, magnesium, calcium, and a mixture of rare earth elements and transition metals. These can be separated as hydroxides or converted to oxides or carbonates. Using hydrochloric acid for leaching and converting the chloride to sodium chloride in the final step results in practically no waste for this process. The silica can be further purified using sodium hydroxide fusion or caustic leach methods and some minor streams from this process are recycled to minimize any waste stream. These systems and methods can be applied to a number of other industrial waste products such as red mud from the aluminum process, slag from steel furnaces, mine tailings, and other metal-bearing waste streams.

A method for producing a mixed calcium and magnesium compound comprising the slaking of quicklime with a magnesium hydroxide suspension, forming solid particles, said slaking by non-wet means forming said solid particles comprising a calcium phase and a magnesium phase intimately bonded to each other and of homogeneous volume distribution, and a mixed compound comprising a calcium phase and a magnesium phase.