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 present invention relates to a method of separating radioactive elements from a mixture, wherein the mixture is treated with at least one alkanesulfonic acid and at least one further acid, selected from the group consisting of hydrochloric acid, nitric acid, amidosulfonic acid and mixtures thereof and also the use of at least one alkanesulfonic acid and at least one further acid for separating radioactive elements from mixtures comprising these.

Compositions and methods are provided that provide recovery of metals such as copper, nickel, cobalt, indium, and other metals are recovered from mine tailings, in situ ore bodies, or postconsumer waste. An amine-containing lixiviant is utilized to generate an aqueous solution of the desired metal from insoluble salts present in the source material. Metals can be recovered and further purified by various processes, including extraction into an immiscible organic solvent, electrowinning, crystallization, and chemical reduction. Spent lixiviant can be regenerated and recycled back into the metal recovery process.

A method for the recovery of a precious metal from activated carbon fines which includes the steps of adsorption of the precious metals from the activated carbon fines onto a weak-base anion exchange resin which contains guanidine functional groups in the presence of at least one suitable lixiviant, or adsorption of the precious metals from activated carbon fines onto a mixed-base resin which contains amine functional groups in the presence of at least one suitable lixiviant and eluting the resin with a suitable eluant to produce a precious metal-containing eluate.

The present invention provides an environmentally safe method of collecting rare earth elements from mineral sources such as bastnasite deposits. The invention uses calcium hydroxide to decompose rare earth element minerals and avoids the use of sulfuric acid decomposition which produces toxic hydrofluoric acid as a byproduct. The invention's use of calcium hydroxide produces calcium fluoride as a byproduct which is non-toxic and has a number of industrial uses. The invention further provides a method of separating mixed rare earth element leachates into heavy and light rare earth element fractions using inorganic sodium salts as a precipitation agent.

The present disclosure provides a method for co-extraction of vanadium, titanium and chromium from vanadium slag. The method selectively reduces pyroxene and fayalite wrapped on spinel through low-temperature hydrogen reduction, iron removal by ferric chloride, and low-temperature leaching of the vanadium slag by oxalic acid, thereby destroying a structure of the spinel, dissociating a spinel phase and a silicate phase, and fully exposing the spinel phase. The method also directly leaches the vanadium slag at a low temperature by acidity and strong complexation of the oxalic acid, and destroys the structure of the spinel, such that vanadium, titanium, chromium and oxalate are complexed into a solution to co-extract vanadium, titanium and chromium. The present disclosure extracts vanadium, titanium and chromium from the vanadium slag, with a leaching rate each being greater than 99%.

One or more embodiments relates to a process for extracting Rare Earth Elements (REEs) from REE-bearing underclays, claystones, shales, coal-mining waste, and waste coal. In at least one embodiment the process includes contacting the REE-bearing underclays, claystones, shales, coal-mining waste, and waste coal with an Organic Acid Solution (OAS) comprising at least one organic acid and at least one ionic salt at a predetermined ambient temperature and predetermined pH; and separating the REE from the REE-bearing underclays, claystones, shales, coal-mining waste, and waste coal, forming REE+Yttrium (REY) concentrate.

Methods for recovering a metal from a metal-containing material are provided. In embodiments, such a method comprises exposing a metal-containing material to a leaching solution comprising a solvent and a binoxalate, a tetraoxalate, or a combination thereof, under conditions to provide a leachate comprising a soluble metal oxalate; inducing precipitation of a metal-containing precipitate comprising the metal of the soluble metal oxalate from the leachate; and recovering the metal-containing precipitate.

Methods for recovering a metal value from a metal-bearing material are provided. The method comprises agglomerating the metal-bearing material with an agglomeration solution comprising a raffinate, an oxidant, and citric acid or salts thereof to form an agglomerated metal-bearing material; leaching the agglomerated metal-bearing material with a leaching solution comprising the raffinate and the citric acid or salts thereof to produce a pregnant leaching solution and a leached material; re-oxidizing the leached material with a curing solution comprising the raffinate and the oxidant; and recovering the metal value from the pregnant leach solution to produce the raffinate.

Processing schemes for the extraction and/or separation of rare earth elements (REEs) from rare earth containing products such as rare earth mineral ore bodies and intermediate products derived from rare earth mineral ore bodies. The processing schemes may be applied independently or in various combinations to produce end-products that have a very high purity with respect to REEs, including high value critical REEs. The processes may include acid digestion, formation of rare earth oxalate compounds, metathesizing of rare earth oxalate compounds, selective precipitation and/or solvent extraction to form the high purity REE end products.