This invention relates to treated geothermal brine compositions containing reduced concentrations of lithium, iron and silica compared to the untreated brines. Exemplary compositions contain concentration of lithium ranges from 0 to 200 mg/kg, concentration of silica ranges from 0 to 30 mg/kg, concentration of iron ranges from 0 to 300 mg/kg. Exemplary compositions also contain reduced concentrations of elements like arsenic, barium, and lead.

A method for extracting rare earth elements (REEs) from a REE hyperaccumulator, including: subjecting the REE hyperaccumulator to microwave-assisted digestion to obtain a REE extract; subjecting the REE extract to absorption with a chelating resin and elution to obtain a purified REE solution; and subjecting the purified REE solution to precipitation and calcination to obtain high-purity rare earth compound.

Provided is a method for producing calcium zincate. The method comprises: an extraction step: mixing a ground zinc-containing raw material with an extracting agent, followed by filtration to obtain an extract, wherein the extracting agent is a mixed aqueous solution of ammonia and {NH.sub.4HCO.sub.3 and/or (NH.sub.4).sub.2CO.sub.3; optionally, purifying the extract; a decarburization step: adding calcium oxide and/or calcium hydroxide to the extract, stirring, and filtering to obtain a first solid and a first filtrate; a calcium zincate synthesis step: adding calcium hydroxide and/or calcium oxide to the first filtrate, stirring to react, and filtering to obtain a second solid and a second filtrate; optionally, rinsing the second solid with water; a drying step: drying the second solid to obtain the final calcium zincate product.

Provided is a method for producing calcium zincate. The method comprises: an extraction step: mixing a ground zinc-containing raw material with an extracting agent, followed by filtration to obtain an extract, wherein the extracting agent is a mixed aqueous solution of ammonia and {NH.sub.4HCO.sub.3 and/or (NH.sub.4).sub.2CO.sub.3; optionally, purifying the extract; a decarburization step: adding calcium oxide and/or calcium hydroxide to the extract, stirring, and filtering to obtain a first solid and a first filtrate; a calcium zincate synthesis step: adding calcium hydroxide and/or calcium oxide to the first filtrate, stirring to react, and filtering to obtain a second solid and a second filtrate; optionally, rinsing the second solid with water; a drying step: drying the second solid to obtain the final calcium zincate product.

The present disclosure provides a method for optimizing a liquid injection process of ionic rare earth ore, including the following steps of: 1) testing the hydraulic properties of an ore body; 2) determining the diffusion degree of the ore body; 3) determining the spatial distribution of the rare earth grade and the impurity grade of the ore body prior to leaching; 4) determining model parameters of competitive exchange of rare earth ions and impurity ions with ammonium ions; 5) obtaining distribution of rare earth ion concentration within the ore body after completion of leaching; 6) obtaining a profile plot of a rare earth leaching rate as a function of the concentration and dosage of an injected leaching agent; and 7) determining a minimum leaching agent dosage to achieve a target leaching rate according to the profile plot, and then determining the ammonium sulfate concentration according to the minimum leaching agent dosage.

The present disclosure provides a method for optimizing a liquid injection process of ionic rare earth ore, including the following steps of: 1) testing the hydraulic properties of an ore body; 2) determining the diffusion degree of the ore body; 3) determining the spatial distribution of the rare earth grade and the impurity grade of the ore body prior to leaching; 4) determining model parameters of competitive exchange of rare earth ions and impurity ions with ammonium ions; 5) obtaining distribution of rare earth ion concentration within the ore body after completion of leaching; 6) obtaining a profile plot of a rare earth leaching rate as a function of the concentration and dosage of an injected leaching agent; and 7) determining a minimum leaching agent dosage to achieve a target leaching rate according to the profile plot, and then determining the ammonium sulfate concentration according to the minimum leaching agent dosage.

An improved method for recovering metals from spent supported catalysts, including spent supported hydroprocessing catalysts. The method and associated processes comprising the method are useful to recover spent supported catalyst metals used in the petroleum and chemical processing industries. The method generally involves a combination of a pyrometallurgical and a hydrometallurgical method and includes forming a potassium carbonate calcine from the spent supported catalyst containing Group VIIIB/Group VIB/Group VB metal compound(s) combined with potassium carbonate, and extracting and recovering soluble Group VIB metal and soluble Group VB metal compounds from the potassium carbonate calcine.

Certain method embodiments are described and useful for recycling permanent magnet materials (e.g. permanent magnet alloys) and battery materials (e.g. battery electrode materials) to extract critical and/or valuable elements including REEs, Co and Ni. Method embodiments involve reacting such material with at least one of an ammonium salt and an iron (III) salt to achieve at least one of a liquid phase chemical reaction and a mechanochemical reaction.

Certain method embodiments are described and useful for recycling permanent magnet materials (e.g. permanent magnet alloys) and battery materials (e.g. battery electrode materials) to extract critical and/or valuable elements including REEs, Co and Ni. Method embodiments involve reacting such material with at least one of an ammonium salt and an iron (III) salt to achieve at least one of a liquid phase chemical reaction and a mechanochemical reaction.

The present invention concerns a process for producing calcium carbonate from a calcium-containing alkaline slag material, the process containing the steps of extracting the alkaline slag material in a series of extraction steps, including at least 2 extraction steps, using extraction solvent(s) containing salt in an aqueous solution, whereby a calcium-containing filtrate and a residual slag is formed in each extraction step, separating the residual slag from the filtrate after each extraction step, carrying each residual slag to the following extraction in the series of extractions, to be used as raw material in said following extraction, and discarding the residual slag separated from the last extraction, carrying each filtrate to the previous extraction in the series of extractions, to be used as extraction solvent in said previous extraction, and carrying the first filtrate, separated from the first extraction step, to a carbonating step, carbonating calcium as calcium carbonate from the first filtrate, the first filtrate also used as the carbonation solvent, and using a carbonation gas, whereby calcium carbonate precipitates, separating and recovering the calcium carbonate from the remaining carbonation solvent, and recycling the remaining carbonation solvent to the last extraction step in the series of extraction steps, to be used as extraction solvent.