CN111492073A

CN111492073A - Selective recovery of rare earth metals from acidic slurries or solutions

Info

Publication number: CN111492073A
Application number: CN201880073219.0A
Authority: CN
Inventors: 徐文庆; 沙雷斯·帕特卡; 路易·I·贝德斯; 玛丽伊莎贝尔·R·阿贝拉; 戈默·M·阿布瑞尼卡; 文森特·D·马特拉
Original assignee: II VI Delaware Inc
Current assignee: II VI Delaware Inc
Priority date: 2017-11-17
Filing date: 2018-11-16
Publication date: 2020-08-04
Also published as: WO2019099859A1; EP3710607A1; AU2018370142A1; CN116445750A; EP3710607A4

Abstract

A method for extracting rare earth metals from acidic slurries or acidic solutions. The method includes providing an acidic slurry or an acidic solution; adding a composite comprising an extractant and a polymer resin; mixing the composite with an acidic slurry or an acidic solution to form a mixed slurry or solution; and separating the mixed slurry or solution into a rare earth metal-loaded composite and a raffinate slurry or solution. The acidic slurry or acidic solution comprises at least one rare earth metal and at least one early transition metal and/or at least one actinide metal.

Description

Selective recovery of rare earth metals from acidic slurries or solutions

Cross Reference to Related Applications

This application claims priority from U.S. provisional application No. 62/587,858 filed on 17.11.2017 and U.S. utility application No. 16/186,897 filed on 12.11.2018, the disclosures of which are hereby incorporated by reference in their entirety.

Technical Field

The present invention relates to a process for the selective recovery of precious metals, particularly rare earth metals, from acidic slurries or solutions.

Background

A. Solvent extraction process

Solvent extraction is widely used for the recovery of precious metals dissolved in aqueous solutions, as disclosed in: U.S. patent No. 4,041,125; 4,624,703, respectively; 4,718,996, respectively; 4,751,061, respectively; 4,808,384, respectively; 5,015,447, respectively; 5,030,424, respectively; 5,708,958, 6,110,433; 6,238,566, respectively; 7,138,643, respectively; 7,282,187, respectively; 7,799,294, respectively; 7,829,044, respectively; 8,062,614, respectively; 8,177,881, respectively; 8,328,900, and U.S. patent application publication No. 2004/0031356; 2005/0107599, respectively; 2006/0024224, respectively; 2010/0089764, respectively; 2010/0282025, respectively; and number 2012/0160061. The precious metal is typically acid leached into an aqueous solution from ore and/or other raw materials, and a clarified aqueous solution containing the precious metal is separated from the acid leached ore slurry by filtration and washing. Solvent extraction is then performed on the clear aqueous solution.

The feedstock may include various rare earth metal-containing ores and minerals such as titanium dioxide ore tailings, uranium ore tailings, red mud typically produced from the bauxite-bayer process, and other such materials. Additionally, ores and/or feedstocks containing these precious metals may be pre-processed for threshold leachability and commercial viability purposes. Such processing may include particle size reduction, hydrothermal treatment involving hydrothermal reactions, high temperature treatment involving solid phase reactions, meso-glass phase high temperature reactions, full melt high temperature liquid phase reactions, and the like.

In a solvent extraction process, an organic liquid or solvent phase containing one or more extractants that can chemically react with one or more precious metals is intimately mixed with an aqueous solution containing one or more ions of such precious metals. The one or more noble metal ions are then transferred to the organic phase of the extraction organic solvent during mixing. Vigorous mixing ensures complete transfer of one or more noble metal ions from the aqueous phase to the organic phase. After mass transfer of the precious metal or metals from the aqueous phase to the organic phase, the process is typically subjected to phase separation via gravity settling or a high-g centrifugal phase separation mechanism (e.g., centrifuge).

Industrially, a continuous process using a combination of the following is known as a mixer and settler process: (1) mixing the organic extraction solvent with an aqueous solution containing one or more precious metals and (2) settling such mixture of aqueous and organic phases to effect phase separation by gravity. Such mixing and settling processes can also be achieved in batch processes in batch mixing tanks in manufacturing plants or in beakers equipped with magnetic or mechanical mixers in chemical laboratories. The separated organic phase is the desired product containing the precious metal. The separated aqueous phase is referred to as raffinate, and ideally contains a minimal amount of one or more target precious metals. When the aqueous solution and organic extraction solvent are mixed, vigorous mixing can result in an emulsion, oil-in-water, or water-in-oil. In the case of forming an emulsion, it may be desirable to extend the phase separation process to a level that is not economically feasible. In some cases, the emulsion formed may be stable enough that economical phase separation is not possible, and in other cases, the phase separation may be incomplete, resulting in loss of valuable organic solvent and precious heavy metals contained in the lost organic solvent.

The process of obtaining a clarified aqueous solution containing one or more water-soluble precious metals by separating it from an acid-leached ore slurry via filtration and washing may also result in low yield recovery of the one or more precious metals and/or the production of large quantities of an aqueous solution containing a low concentration of the one or more precious metals. Washing with an insufficient amount of water results in the loss of a large amount of residual precious metal or metals that are still physically trapped in the residue of the filter cake. In a practical process, even if thorough washing with an unlimited amount of water is possible, complete recovery of the precious metal from the acid leached ore slurry cannot be achieved because a fraction of the precious metal ions are chemically bound to the ion-exchangeable sites of the residue. Moreover, although thorough washing with an unlimited amount of water can theoretically be achieved at levels approaching the full recovery of one or more precious metals from acid leached ore slurries, thorough washing with an unlimited amount of water is impractical because it requires downstream processes (in this case solvent extraction) to process large volumes of aqueous solutions containing low concentrations of one or more precious metals. The use of such unlimited amounts of water also leads to problems associated with the costs involved in disposing of such huge quantities of spent raffinate, not to mention the use of huge quantities of fresh water resources.

Additionally, in the prior art, direct solvent extraction of one or more precious metals from a leach slurry in a mix tank has not been practiced commercially due to problems with scale formation and emulsion formation. Scale formation occurs when some inorganic particles chemically bond to the extractant molecules and undesirably transfer into the organic phase as the desired mass transfer of one or more precious metal ions from the aqueous phase to the organic phase occurs during contact of the organic extraction solvent with the acid leached ore slurry. Fouling is defined in the art as the formation of an organic phase, an aqueous phase and fine solids of a stable mixture by agitationGranular produced material (gordonm.ritcey, "Development of Industrial solvent extraction Processes", edited by Jan Rydberg, Michael Cox, Glaude Musikas and gregoryr.choppin and published by Marcel Dekker, Inc.) (solvent extraction principles and practices)Solvent Extraction Principles and Practices) Second edition, revised and expanded edition, page 313, in 2004). Emulsions come in two different forms, oil-in-water and water-in-oil, both of which are typically formed under vigorous mixing conditions due to the formation of oil droplets in water or water droplets in oil. The droplet size of such newly formed emulsions decreases with increasing level of mixing. The vigorous mixing conditions result in a smaller droplet size of the emulsion. Smaller droplets are more difficult to coalesce to form a continuous aqueous phase and a continuous organic phase. Thus, the emulsion of small droplets is stable, which then leads to difficulties in phase separation. However, vigorous mixing is essential to keep the ore particles contained in the leach slurry in suspension. Thus, direct solvent extraction of one or more precious metals from leached ore slurries containing suspended particles needs to be performed under vigorous mixing conditions, resulting in the formation of a substantial emulsion in the form of water-in-oil or oil-in-water. This creates a practical challenge preventing the successful implementation of direct solvent extraction of one or more precious metals from a leach ore slurry in a continuous mixer and settler process or a batch tank process.

The inventors L ucas and Ritcey of U.S. patent No. 3,969,476 disclose a pulsed sieve tray tower process known as a "solvent-pulp extraction" process in which one or more soluble precious metals are extracted from an ore slurry. L ucas and Ritcey have also recognized that until the time of their patent publication, a process for recovering one or more precious metals directly from a leached ore slurry has not been successfully operated on a plant scale.

Although the L ucas and Ritcey disclosures claim the initial success of solvent extraction of one or more precious metals directly from a leached ore slurry by using a pulsed tray tower process, the pulsed tray tower process still suffers from key limitations one of which is that any leached ore slurry has a very broad particle size distribution, large particles do not suspend well and can clog the screen openings of the tray.

Following the issuance of U.S. patent No. 3,969,476, ritcey, a Gordon m.ritcey among its inventors, published in the book "principles and practices of solvent extraction", second edition, revisions and extensions, edited by Jan Rydberg, Michael Cox, Glaude Musikas and Gregory r.choppin, and published in 2004 by massel dekel corporation, "developments in industrial solvent extraction processes", and indicated on page 313: "most solvent extraction circuits must be solids free and clarification is usually aimed at achieving about 10ppm solids", i.e. an aqueous solution with a solids content of 0.001%. On the other hand, in direct solvent extraction, the solids content of the acid leached ore slurry can be three to five orders of magnitude higher, from a few percent up to 50-70%.

L ucas and Ritcey is further limited by the fact that the extractant molecules in the organic extraction solvent are of the amine type, the amine type organic extraction solvents are typically cationic and react with and bond to the anionic surface sites of the silicate/silica related residue in the ore slurry, such bonding of the amine type extraction molecules in the organic extraction solvent to the anionic surface sites of the silica/silicate related residue results in significant loss of the organic extraction solvent, thus, the L ucas and Ritcey processes require pretreatment with an organic non-ionic hydrophilic material adsorbed by the gangue solids in order to reduce the affinity of the gangue solids for the amine, however, there is still a loss of solvent, which is a significant cost for recovering one or more precious metals from an acid leach slurry containing very low concentrations of one or more precious metals.

In summary, solvent extraction processes suffer more or less from the following problems: (1) solvent loss, (2) difficulty in achieving complete organic-aqueous phase separation, (3) emulsion formation, (4) scale formation, and (5) poor economics of processing large quantities of acid leach solutions and/or slurries containing very low concentrations of one or more precious metals.

B. Ion exchange resin process

As described in the book "extraction Metallurgy of Rare Earths" (c.k. gupta, n.krishnamurthy, CRC press, 2000, page 163), ion exchange resins are generally considered to be ionic salts in which exchangeable ions are attached to an insoluble organic matrix. Such exchangeable ions in the ion exchange resin may be either cations or anions, and the resin is referred to as a cation exchange resin or an anion exchange resin, respectively. Cation exchange resins may be used to absorb one or more precious metal ions from the acid leach solution and/or acid leach slurry.

Typical ion exchange resins are classified into strong resins, weak resins, and resins intermediate between strong and weak resins. Dow Chemical (Dow Chemical) produces strong cation exchange resins with sulfonic acid functionality (e.g., Dowe @)x^TMG-26(H)) and chelating cationic ion exchange resins having iminodiacetic acid groups (e.g., Amberlite)^TM7481)。

(Delett Co.) production of cationic ion exchange resins having phosphoric acid functionality

And S957. The alkali metal ion form of these resins, such as the sodium form or the proton form, can be used to absorb one or more precious metals.

When the ion exchange resin is contacted with an aqueous solution/slurry containing different electrolyte cations, the exchangeable ions of the ion exchange resin may be displaced; generally, (1) higher charged ions displace lower charged ions, (2) between similarly charged ions, ions of larger radius displace ions of smaller radius, and (3) displacement occurs according to the law of mass action.

Most rare earth metal ions have a 3+ valence in the acid leach solution and/or slurry; however, such acid leach solutions and/or slurries contain very low concentrations of rare earth or precious metal ions, with the majority of the soluble cations being Fe³⁺、Ti⁴⁺、Zr⁴⁺Etc., and alkali metal and alkaline earth metal cations such as Na⁺、Ca²⁺、Mg²⁺And the like. Selective adsorption of one or more rare earth metal ions or one or more noble metal ions relative to other cations (which are the majority of cations in the acid leach solution and/or slurry) is very challenging because cations such as Fe are very challenging³⁺、Ti⁴⁺、Zr⁴⁺Is higher than or similar to the chemical valence of one or more rare earth metal ions or one or more noble metal ions.

In U.S. patent No. 4,816,233, it was stated that strong cation exchange resins were ineffective for selective adsorption of one or more useful rare earth metal ions because strong cation exchange resins were quickly leached by acid leaching solutions and/or slurries (containing about 632ppm scandium in example 1) from tungsten ore residueOther cation of (Fe)³⁺And Mn⁴⁺) And (4) saturation. U.S. Pat. No. 4,816,233 discloses a method of adding Mn by hydrazine hydrate⁴⁺And Fe³⁺Reduction of ions to Mn²⁺And Fe²⁺Then the pH was adjusted to about 2.0 and the solution was mixed with Amberlite^TMHowever, such acid leach solutions have a ratio of iron to scandium of 173:1 and a ratio of manganese to scandium of 278:1, and therefore a large amount of hydrazine hydrate per unit of scandium (289L/kg scandium) is used in the process, hydrazine hydrate is a very expensive chemical, so the only step of hydrazine hydrate reduction is expensive, not to mention the other chemicals used in the leaching process and purification steps, moreover, the raw materials, such as Ni/Co containing ores (such as laterites) and red mud from bauxite processes, contain only scandium at levels of less than 100ppm in most cases, or less than 200ppm in some cases, which makes this process costly, as a large amount of hydrazine hydrate is required for the reduction of ferric ions to ferrous ions.

The present invention therefore addresses the practical need for new materials/compositions that allow a new method of extracting precious metals (such as rare earth metals, more particularly scandium) from acid leach slurries/solutions containing very low concentrations of precious metal ions (such as rare earth metals, more particularly scandium) and very high concentrations of ferric ions/titanium ions or other trivalent/tetravalent cations. In particular, embodiments of the present invention enable the economic recovery of precious metals (rare earth metals, in particular scandium) from raw materials containing said precious metals in very low concentrations, without suffering from the drawbacks of solvent extraction including solvent loss, difficulty in achieving complete solvent phase-water phase separation, emulsion formation, scale formation, etc.

Disclosure of Invention

The acidic slurry or acidic solution includes at least one rare earth metal (scandium (Sc), yttrium (Y), lanthanum (L a), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), holmium (Dy), dysprosium (Ho), californium (Er), thulium (Tm), ytterbium (Yb), and lutetium (L U)), and at least one early transition metal (titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Re), rhenium (Mn), and rhenium (Mn), indium (fe), indium (p), indium (fe), zinc (Ti), zinc (Mo), zinc (fe), zinc (ni), zinc (fe (ni), zinc (ni (p (ni).

Each of the one or more early transition metals may be present in the acidic slurry or solution in an amount up to 50,000ppm, and/or each of the one or more actinide metals may be present in the acidic slurry or solution in an amount up to 5,000 ppm. The acidic slurry or acidic solution may be an acidic slurry or acidic solution generated during processing of an ore containing at least one rare earth metal and at least one early transition metal and/or at least one actinide metal, and may be a titanium tailings waste stream from titanium ore processing, such as a chloride process for producing titanium tetrachloride or titanium dioxide from rutile and a sulfate process for producing titanium dioxide from ilmenite. The rare earth metal may be scandium.

The method may further comprise increasing the pH of the acidic slurry or acidic solution to form a precipitate of at least a portion of the at least one early transition metal and/or at least one actinide metal, such as titanium, thorium, or both. The precipitate may be filtered from the acidic slurry or acidic solution prior to addition of the complex.

The method may further include stripping the rare earth metal from the rare earth metal-loaded composite and regenerating the composite for reuse. The complex may be regenerated using a solution generated during processing of an ore containing at least one rare earth metal and at least one early transition metal and/or at least one actinide metal. The regeneration solution may be an acid wash or waste process waste solution, and may be an acid wash from titanium ore processing, such as the chloride process for producing titanium tetrachloride or titanium dioxide from rutile and the sulfate process for producing titanium dioxide from ilmenite.

The polymeric resin may have at least one phosphoric acid functional group and/or the extractant may comprise a cationic extractant. The extractant may be di (2-ethylhexyl) phosphoric acid (DEHPA).

Drawings

FIG. 1 is a graph comparing scandium recovery when using a polymer resin having phosphoric acid functionality and when using a composite extractant according to the present invention to strengthen the polymer resin in a column process for extracting rare earth metals from an acid leach solution containing a substantial amount of ferric ions (example 31);

FIG. 2 is a graph showing scandium recovery when a polymer resin is reinforced with a composite extractant according to the present invention in a column process for extracting rare earth metals from an acid leach solution containing a significant amount of ferric ions (example 32);

FIG. 3 is a graph showing scandium recovery when a polymer resin is reinforced with a composite extractant according to the present invention in a column process for extracting rare earth metals from an acid leach solution containing a significant amount of ferric ions (example 33);

FIG. 4 is a graph showing scandium recovery when a polymer resin is reinforced with a composite extractant according to the present invention in a column process for extracting rare earth metals from an acid leach solution containing a significant amount of ferric ions (example 34);

FIG. 5 is a graph showing a breakthrough curve comparing the adsorption of scandium from a titanium tailings effluent and a pH adjusted titanium tailings effluent onto a composite extractant-reinforced polymer resin (examples 36 and 37);

FIG. 6 is a graph showing the co-extraction of early transition metals such as titanium, niobium and zirconium with scandium from an unconditioned titanium tailings effluent into a composite extractant-reinforced polymer resin (example 36); and

FIG. 7 is a graph showing the absorption of scandium and titanium onto a composite extractant-reinforced polymer resin in a cyclic operation using an acid wash from titanium processing as the regeneration solution (example 38).

Detailed Description

As used herein, unless otherwise expressly specified, all numbers such as those expressing values, ranges, amounts or percentages may be read as if prefaced by the word "about", even if the term does not expressly appear. Any numerical range recited herein is intended to include all sub-ranges subsumed therein. For example, a range of "1 to 10" is intended to include any and all subranges between and including the recited minimum value of 1 and the recited maximum value of 10, i.e., all subranges beginning with a minimum value equal to or greater than 1 and ending with a maximum value of equal to or less than 10 and all subranges between 1 and 6.3, or 5.5 and 10, or 2.7 and 6.1, for example. Plural encompasses singular and vice versa. When ranges are given, any endpoints of those ranges and/or numbers within those ranges can be combined with the scope of the invention. Terms such as "comprising," such as, "" e.g., "mean" including/as/for example but not limited to.

Preparation of composite extractant reinforced polymer resin

The present invention relates to composites comprising an extractant and a polymer resin.

Any suitable extractant may be used to prepare the composite extractant-reinforced polymer resin. The extractant may be anionic, cationic or non-ionic. Such extractants include, but are not limited to, cation exchange extractants such as organic phosphoric, sulfonic and carboxylic acids, neutral extractants such as tri-n-butyl phosphate, and anion exchange extractants such as amines. The major commercial extractants include di- (2-ethylhexyl) phosphoric acid (DEHPA), 2-ethyl-hexyl-2-ethyl-hexyl phosphoric acid (EHEHPA), tributyl phosphate (TBP), versatic acid, versatic 10, and,

336 and Aliquat 336. For example, phosphorus-containing molecules can be used as an extractant to enhance the ability of the polymer resin to extract precious metals, such as rare earth metals, or di- (2-ethylhexyl) phosphoric acid (DEHPA) can be used as an extractant to prepare composite DEHPA-reinforced polymer resins.

The extractant may be used in its original form in the preparation of a composite extractant-reinforced polymer resin, or may optionally be diluted with a solvent or modified by a modifier prior to use. Suitable optional solvents for dilution include, but are not limited to, water, alcohols, esters, ethers, ketones, hydrocarbons, and combinations thereof. Suitable optional modifiers include, but are not limited to, isodecanol, coconut alcohol, octanol, ethylhexanol, one or more alcohols containing six or more carbons, and combinations thereof.

Any suitable polymer resin may be used to prepare the composite extractant-reinforced polymer resin. The polymer resin may be synthetic or natural. The polymer resin may be non-functional and porous. For example, non-functional and porous polymers include, but are not limited to, Amberlite from Dow^TMXAD7HP、Amberlite^TMXAD1180N、Amberlite^TMXAD2、Amberlite^TMXAD4 and Amberlite^TMXAD 16N. The polymer resin may also be functional. Functional groups may include, but are not limited to, sulfonic acids, iminodiacetic acids, carboxylic acids, phosphoric acids, and amines. Functional polymer resins having one or more sulfonic acid functional groups include, but are not limited to, Amberlite of Dow^TMIRC-120 and Dowex^TMG-26 (H). Functional polymer resins with carboxylic acid functionality include, but are not limited to Amberlite^TMFPC-3500 and Amberlite^TMIRC-86 SB. Functional polymer resins with phosphate functionality include, but are not limited to

S957, Monophoronix and Diphoronix. Functional polymeric resins having amine functionality include, but are not limited to

IRA96 and

Marathon。

the composite extractant-reinforced polymer resin may contain 80 wt.% or less of an extractant, such as 60 wt.% or less of an extractant, or 50 wt.% or less of an extractant.

The composite extractant-reinforced polymer resin can be prepared by the following steps: the polymer resin is soaked in a pure extractant liquid or a mixed solution containing an extractant and an organic solvent, and then filtered and washed. The solvent may be a lower alcohol, such as ethanol and isopropanol, or may be a ketone, an ether and/or another organic solvent.

The density of the wet extractant-reinforced polymer resin may be at least 0.3g/ml and at most 1.30g/ml, for example 0.3 to 1.3g/ml, 0.4 to 1.1g/ml or 0.5 to 1.1g/ml

Extraction of rare earth metals from acid leach slurries or solutions

The prepared composite extractant-reinforced polymer resin in wet form can be used directly for extracting precious metals from acid leach slurry or solution, or can be dried in air or in an oven at a temperature that does not damage the resin and the extractant, and then used for extraction. For example, the drying temperature can be 200 deg.C or less, 150 deg.C or less, 120 deg.C or less, 100 deg.C or less, 80 deg.C or less, or room temperature.

Direct extraction of rare earth metals, including scandium (Sc), yttrium (Y), lanthanum (L a), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (L u), using a complex extractant-enhanced polymer resin may be performed in a batch operation or continuously.

An aqueous acid leach slurry or solution containing one or more rare earth metals is combined in a mixing tank with a composite extractant-reinforced polymer resin prepared as described above. The aqueous pickling solution is a liquid obtained by filtration of the pickling slurry or by separating the liquid and solid components of the pickling slurry using any liquid-solid separation method.

The feed material to the slurry is any ore, mineral or residue containing trace amounts of rare earth metals up to 50,000ppm, for example up to 10,000ppm, up to 1,000ppm, up to 500ppm or up to 500 ppm. The feedstock material includes, but is not limited to, rare earth metal-containing minerals such as scandium yttrium, fluorocarbon lanthanite, phosphocerite, xenotime, allanite, apatite, uraninite, allophane, aurite, limonite, phosphocerite, beryllite, glaparanite, perovskite, pyrochlore, zircon, wolframite, scandite, silicophosphosiderite, sodaascopsite, silicoscantite, yellow feldspar, scandium tetraoxide, scandium bentonite, silicoscandite, red mud, titanium tailings, tungsten tailings, uranium tailings, and cobalt and nickel minerals such as laterite. The raw materials may be ground into fine particles and mixed with water and at least one suitable acid to dissolve the metals in the ore. Suitable acids may include, but are not limited to, mineral acids including sulfuric acid, hydrochloric acid, and nitric acid. When the solution is thoroughly mixed, for example at 145-150rpm or under static conditions, the leaching may be carried out at a temperature equal to or lower than the boiling point of water (e.g. 100 ℃ or lower or 80-100 ℃), or under hydrothermal conditions at a temperature up to 300 ℃.

The aqueous acid leach slurry may have a viscosity of 400 centipoise or less, for example, a viscosity of 100 centipoise or less or a viscosity of 20 centipoise or less.

The pH of the aqueous acid leach slurry and/or acid leach solution is not limited, but should be sufficient to prevent partial or complete precipitation of the rare earth metals. Thus, the pH of the aqueous acid leach ore slurry or solution may be up to 6.5, for example up to 4.0.

The aqueous acid leach slurry and/or solution may comprise iron in the form of ferric ions and/or ferrous ions. Raw materials such as red mud, titanium tailings, uranium tailings, cobalt and nickel minerals such as laterite ores and other such rare earth metal-containing ores or minerals may contain some level of iron, and sometimes iron may even be the major component of the raw material (e.g., red mud from the bauxite-bayer process). During the acid leaching process, the iron is dissolved by the acid to form ferric ions, which compete with the rare earth metal ions for the complex extractant molecules in the composite extractant-reinforced polymer resin. Ferric ions can be chemically reduced to ferrous ions prior to adding the composite extractant to strengthen the polymer resin.

The amount of the composite extractant-reinforced polymer resin used may be determined by the target recovery of one or more target noble metal ions. The ratio of the volume of the acid-leached slurry or solution to the volume of the composite extractant-reinforced polymer resin may vary accordingly depending on the nature of the slurry or solution, particularly the concentrations of ferric ions, titanium ions and the target noble metal ions. The ratio of the volume of the acid leach slurry or solution to the volume of the composite extractant-reinforced polymer resin may be at least 0.5 and at most 3000, for example, at least 1 and at most 2000.

The composite extractant-reinforced polymer resin is then mixed with the combination of acid leach slurry or solution for at least several minutes, such as one hour or more. Mixing may be accomplished using any suitable method, including but not limited to mixing bars, paddle stirrers, pumps, and sparging.

For aqueous acid leach slurries and/or solutions, the direct extraction of rare earth metals may be performed at room temperature or at an elevated temperature (e.g., 100 ℃) up to the boiling point of water. When high temperatures are used, the extraction rate increases.

After mixing, the composite extractant-reinforced polymer resin can be loaded with at least 2,000wt. ppm, e.g., at least 1,800wt. ppm, at least 1,600wt. ppm, at least 1,400wt. ppm, at least 1,200wt. ppm, at least 1,000wt. ppm, at least 800wt. ppm, at least 600wt. ppm, at least 400wt. ppm, or at least 200wt. ppm of a rare earth metal, such as scandium. In other words, after mixing, the composite extractant-reinforced polymer resin can be loaded with at least 0.2 grams of rare earth metal, e.g., scandium, per liter of wet composite extractant-reinforced polymer resin, e.g., at least 0.4 grams of rare earth metal per liter of wet composite extractant-reinforced polymer resin, at least 0.8 grams of rare earth metal per liter of wet composite extractant-reinforced polymer resin, at least 1.2 grams of rare earth metal per liter of wet composite extractant-reinforced polymer resin, or at least 1.4 grams of rare earth metal per liter of wet composite extractant-reinforced polymer resin.

Separation of the precious metal-loaded composite extractant-reinforced polymer resin from the raffinate slurry and/or solution may be accomplished by gravity settling, screening, filtration, or other suitable methods.

The precious metal from the loaded extractant-reinforced polymer resin may be stripped from the composite extractant-reinforced polymer using a stripping solution comprising an acid, base, salt, or chelating agent to form a solution or slurry containing the precious metal, such as a rare earth metal. The acid may comprise typical inorganic and/or organic acids, or mixtures of inorganic and/or organic acids, for example, the acid may be, but is not limited to, hydrochloric acid, nitric acid, sulfuric acid, hydrofluoric acid, phosphoric acid, citric acid, oxalic acid, acetic acid, formic acid, and the like. The base may comprise a typical alkali metal base (such as, but not limited to, sodium hydroxide, potassium hydroxide, lithium hydroxide, and the like), an alkaline earth metal base (such as, but not limited to, magnesium hydroxide, calcium hydroxide, barium hydroxide, and the like), ammonium hydroxide, an organic amine (which may be a primary amine, a secondary amine, a tertiary amine, and/or mixtures thereof). The salt may comprise any type of salt, for example, salts that allow the rare earth metal to dissolve in the aqueous solution, such as carbonates, for example sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, lithium carbonate, lithium bicarbonate, ammonium carbonate, and ammonium bicarbonate. The salts, bases and/or acids may be used together, separately or as a mixture. For example, a carbonate or bicarbonate can be used with a hydroxide base, such as a mixture of sodium carbonate and hydroxide, sodium carbonate and carbonate, potassium carbonate and hydroxide, and ammonium carbonate and hydroxide.

The acid, base, and/or salt may be included in the stripping solution at a concentration of at least one gram per liter, and may reach a saturated solubility of the acid, base, or salt in the stripping solution (e.g., up to 350 grams per liter). For example, the concentration of sodium carbonate may be at least 1 gram per liter and the solubility of sodium carbonate may be achieved. The solubility of sodium carbonate increases with increasing temperature and is about 164 g/l at 15 c and about 340 g/l at 27 c.

The stripping process may be performed at any suitable temperature as long as the rare earth metals can be removed from the resin. For economy and safety and speed of the stripping process, the process may be carried out at room temperature or at an elevated temperature up to the boiling point of the stripping solution (e.g., 100 ℃). Stripping can also be carried out at temperatures below room temperature, but the process will be slower and less economical.

The stripping process may be performed ex situ or in situ in a batch process or in a continuous process.

To achieve nearly complete stripping of the rare earth metals from the loaded resin, the stripping process can be repeated as many times as necessary to achieve the desired purpose. However, the stripping of rare earth metals from the loaded resin may be partial, and need not be complete.

The precious metals and other impurities in the stripping solution may be precipitated with an acid such as, but not limited to, hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, or an organic acid such as oxalic acid or tartaric acid, and then filtered, centrifuged, or decanted to produce a filter cake. The filter cake can be further purified to scandium chemicals or metals having a purity of greater than 30%, e.g., greater than 50%, greater than 70%, greater than 90%, greater than 95%, greater than 99%, greater than 99.9%, greater than 99.99%, or greater than 99.999%. The chemical may be a hydroxide, oxide, oxalate, carbonate, fluoride, phosphate, chloride, or other valuable chemical. Scandium metal may be used to produce an alloy with aluminium, copper or one or more other metals. Scandium-containing materials may be used in ceramics for fuel cells, optics, catalysts, pharmaceuticals, automobiles, aerospace, and the like.

The composite extractant-reinforced polymer resin after stripping can be used as is, or can be regenerated with a solution containing an acid or mixture of acids (e.g., hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, and/or organic acids such as citric acid, oxalic acid, and tartaric acid) and recycled for use in the next batch or cycle. The acid concentration of the regeneration solution may be at least 1 g/l and at most 500 g/l, or may be pure concentrated acid (such as concentrated hydrochloric acid (typically 36-37 wt.%), concentrated nitric acid (68-70 wt.%), or concentrated sulfuric acid (at most 98 wt.%)).

The regeneration process may be performed in situ or ex situ. The regeneration process may be a batch process or a continuous process. The regeneration process may be performed more than once. In a multiple pass regeneration process, different types of acids may be used. Sometimes, the regeneration solution may contain additives such as, but not limited to, surfactants, reducing agents, chelating agents, or oxidizing agents.

Alternatively, a continuous process may be used. The composite extractant-reinforced polymer resin may be placed in a column to form a resin bed. The acid leach slurry or solution may be continuously pumped through the resin bed at a flow rate in the range of at least one tenth of the bed volume per hour to at most 30 bed volumes per hour (e.g., one bed volume per hour to 100 bed volumes per hour). The raffinate solution exiting the resin bed can be monitored to determine when the composite extractant-reinforced polymer resin begins to lose its efficiency in extracting precious metals. As described above, precious metals can be removed from the loaded extractant-reinforced polymer resin.

The acidic slurry or solution may be aqueous and may include at least one rare earth metal (scandium (Sc), yttrium (Y), lanthanum (L a), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (L U)) and at least one early transition metal (titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), and rhenium (Re)) and/or at least one actinide metal (actinium (Ac), thorium (thorium), protactinium (Pa), uranium (U), neptunium (Np), plutonium (puu), americium (cmium), lutetium (Bk), indium (bf), at least one actinide (bno), at least one acidic slurry or solution may include at least one early transition metal (Ti), at least one actinide metal (Hf), at least one early transition metal (cn (Hf), and at least one acidic slurry or solution may include at least one actinide metal (mth (Hf), at least one acidic slurry and at least one acidic slurry, at least one rare earth (L).

The acidic slurry or acidic solution may be an acidic slurry or acidic solution generated during processing of a material containing at least one rare earth metal and at least one early transition metal and/or at least one actinide metal. Such materials include scandium-yttrium-ore, fluoro-carbon-lanthanum-ore, phosphoceratitite, xenotime, lutetium-lime, apatite, uraninite, allophane, aurite, limonite, phosphocerite, beryllite, calaperlite, perovskite, pyrochlore, zircon, wolframite, scandite, silicoscandite, sodasiscanite, silicoscandite, geite, scandium tetraoxide, scandium bentonite, silicoscandite, red mud, titanium ore (such as ilmenite and rutile), titanium tailings, tungsten ore, tungsten tailings, uranium ore, uranium tailings, thorium ore, thorium tailings and laterite ore. Acidic slurries or acidic solutions can also be waste streams generated during such processing. As described herein, valuable rare earth metals, early transition metals, and/or actinide metals can be recovered, or otherwise lost, by treating waste streams or other acidic slurries or acidic solutions generated during such processing. In particular, the acidic slurry or solution may be a titanium tailings waste stream from titanium ore processing, such as the chloride process for producing titanium tetrachloride or titanium dioxide from rutile and the sulfate process for producing titanium dioxide from ilmenite. The noble metal may be scandium.

The acidic slurry or acidic solution may contain trace amounts of rare earth metals up to 50,000ppm, such as up to 10,000ppm, up to 1,000ppm, up to 500ppm or up to 50 ppm.

The aqueous acidic slurry or acidic solution may also comprise up to 50,000ppm, such as up to 10,000ppm, up to 1,000ppm or up to 500ppm of an early transition metal, such as titanium, zirconium, vanadium and niobium, and up to 5,000ppm, such as up to 1,000ppm, up to 500ppm, up to 100ppm of an actinide metal, such as thorium.

The aqueous acidic slurry or acidic solution may also comprise iron in the form of ferric ions and/or ferrous ions, which may even be the major component. Because ferric ions can compete with rare earth metal ions for extractant molecules in the composite extractant-reinforced polymer resin, ferric ions can be chemically reduced to ferrous ions prior to contacting the acidic slurry or acidic solution with the composite extractant-reinforced polymer resin.

The acidic slurry or acidic solution can comprise one or more acids, such as hydrochloric acid, sulfuric acid, nitric acid, or mixtures thereof, and can have a free acid concentration of 400gp L or less, such as 200gp L or less free acid, or 100gp L or less free acid.

Because the early transition metal ions and actinide metal ions compete with the rare earth metal ions for the extractant molecules in the complex extractant-reinforced polymer resin, the acidic slurry or acidic solution can be treated to remove all or a portion of these ions prior to contacting the complex extractant-reinforced resin. The pre-transition metal ions and/or actinide metal ions can be preferentially chemically precipitated by adjusting the pH of the acidic slurry or acidic solution with a base to form a pH adjusted slurry or solution. Such bases include, but are not limited to, sodium hydroxide, calcium hydroxide, hydrated lime, calcium carbonate, magnesium hydroxide, or combinations thereof. The pH of the resulting pH-adjusted slurry or solution may be at a pH value of at least 0 and at most 6, such as at least 0.2 and at most 4, at least 0.3 and at most 2, or at least 0.4 and at most 1. The pH adjustment may be performed at a temperature equal to or lower than the boiling point of water (e.g., 100 ℃ or lower, 80 ℃ or lower, 60 ℃ or lower, or 40 ℃ or lower). The resulting pH adjusted slurry will comprise the precipitate and a pH adjusted solution, which can be separated into a wet precipitate and a pH adjusted solution by suitable separation techniques including, but not limited to, filtration, decantation, and centrifugation.

The resulting pH adjusted solution may contain an amount of early transition metal ions (e.g., titanium, zirconium, vanadium and niobium) of up to 10,000ppm, such as up to 5,000ppm, up to 1,000ppm or up to 100ppm each, and an amount of actinide metal ions (e.g., thorium) of up to 1,000ppm, such as up to 500ppm, up to 100ppm or up to 10 ppm.

As shown in examples 35 and 36, the maximum scandium loading achieved on the composite extractant-reinforced polymer resin when processing one such acidic solution is higher than 200 mg/L composite however, the breakthrough point is achieved early in the process.

In addition, while the regeneration solution used to regenerate the composite after stripping may be a fresh preparation of a mineral acid (e.g., hydrochloric acid, sulfuric acid, and/or nitric acid), the regeneration solution may also be a solution generated during processing of the material, the material is, for example, scandium-yttrium-ore, bastnasite, phosphasite, xenotime, allanite, apatite, uraninite, allophane, gilinite, limonite, psilomelane, beryllite, calaperlite, perovskite, pyrochlore, zircon, wolframite, scandite, silicoscandite, sodasite, silicoscandite, akermanite, scandium tetraoxide, scandium bentonite, silicoscandite, red mud, titanium ore (e.g., ilmenite and rutile), titanium tailings, tungsten ore, tungsten tailings, uranium ore, uranium tailings, thorium ore, thorium tailings and laterite ore, including waste streams generated during such processing. By using a waste stream or another solution generated during such processing, the need to prepare fresh regeneration solution can be avoided and waste streams or other solutions not otherwise used can be recovered. In particular, the regeneration solution may be an acid wash and may be an acid wash from titanium ore processing, such as chloride processes for producing titanium tetrachloride or titanium dioxide from rutile and sulfate processes for producing titanium dioxide from ilmenite.

The regeneration solution may also be a previously used regeneration solution.

The following examples illustrate the process:

comparative example 1:

according to the general disclosure in the previously cited patents, acid-leached ore slurries containing precious metals, in this case scandium and other rare earth metals, which may be completely water soluble or may be chemically bonded to ion-exchangeable sites of inorganic residues in the feedstock, are typically produced in 7000 litre glass Fibre Reinforced Plastic (FRP) reactors. The feedstock, water and acid (in this case sulfuric or hydrochloric acid) were mixed at 144rpm with a 12 inch triple blade which pumped the slurry down at a temperature of 80-100 ℃. The pH of such leach slurries is between 0.0 and 0.5. In this example, the composition of the acid-leached slurry was analyzed by (1) digestion with concentrated hydrochloric acid, (2) volume dilution, and (3) filtration to remove the residue (inductively coupled plasma emission spectroscopy (ICP-OES) method), and the elemental results obtained are listed in table 1. It should be noted that the results of the analyses of sodium, potassium, aluminum, silicon and indium are not accurate; however, it is believed that the sample does contain these elements. In addition, it should be noted that with noble metals such as rare earth metals, and more specifically Sc³⁺In contrast, the acid leach slurry in this example contained a high amount of trivalent and tetravalent cations, particularly Fe³⁺And Ti⁴⁺. In the slurry of this example ([ Fe ]³⁺]+[Ti⁴⁺]) And [ Sc ]³⁺]Is greater than 75.3: 1.

In prior art extraction processes, an aqueous acid leach slurry is subjected to a normal solid liquid separation process and filtered to produce a liquid filtrate containing rare earth metals and a solid filter cake of leach residue, typically waste. The filter cake of the leaching residue is usually washed with a volume of fresh water corresponding to one time the volume of the filter press. The filtrate stream and the wash stream are then combined into a product stream. The additional washing with fresh water having a volume corresponding to four times the volume of the filter press results in the formation of a very large amount of washing filtrate containing such low concentrations of rare earth metals and is therefore not economically viable. Even with a thorough washing with fresh water having a volume corresponding to five times the volume of the filter press, a large amount of rare earth metals still remains in the residue, since free metal ions are trapped within the filter cake or bonded to the ion-exchangeable sites of the leaching residue. Thus, the conventional process of acid leaching followed by filtration and washing can recover 60% to 80% or less of rare earth metals. In addition to filtration and washing, solvent extraction of the filtrate is required to recover the rare earth metals.

The above leaching procedure was used to prepare different acid leach slurries in laboratory beakers and plant scale reactors and is not described repeatedly; this acid leach slurry was used to conduct the following comparative examples and examples.

^TMComparative example 2: from water with a Strong cation exchange resin containing sulfonic acid functional groups Dowex G-26(H) Direct extraction of scandium from acidic acid leaching slurry

1g of Dowex containing sulfonic acid functional groups^TMG-26(H) Strong cation ion exchange resin (as received) was weighed into a 150m L beaker with a magnetic bar stirrer.25 m L feed acid leach slurry from comparative example 1 was added to the beaker. the resin and slurry mixture was stirred with a magnetic stirrer for about one hour. The concentration of scandium decreased only from 95.9ppm in the feed slurry to 90.5ppm in the raffinate filtrate, with a recovery of only about 5.6%. Strong cation ion exchange resins with sulfonic acid groups are rapidly exchanged with ferric ions and other high valent metal ions (Ti) without reducing ferric ions to ferrous ions⁴⁺) Saturation and the resin becomes ineffective for selective absorption of scandium ions from the acid leach slurry.

^TMComparative example 3: acid leaching of the aqueous slurry with Amberlite IRC-7481, a weak cationic ion exchange resin Direct extraction of scandium

1g of Amberlite containing iminodiacetic acid functional group^TMIRC-7481 cationic ion exchange resin (as received) was weighed into a 150m L beaker with a magnetic bar stirrer.25 m L feed acid dip slurry from comparative example 1 was added to the beaker. the resin and slurry mixture was stirred with a magnetic stirrer for about one hour.the resin and slurry mixture was then filtered to produce a raffinate filtrate the filtrate was then analyzed with ICP-OES and the results are listed in Table 1. scandium concentration was only reduced from 95.9ppm in the feed slurry to 93.1ppm in the raffinate filtrate with a recovery of only about 2.9%. without reducing ferric to ferrous ions, the chelated cationic ion exchange resin with iminodiacetic acid groups was quickly replaced with ferric and other high valent metal ions (Ti)⁴⁺) Saturation, and therefore the resin becomes inactive and fails to selectively absorb scandium from the acid leach slurry, further confirming the conclusion of U.S. patent No. 4,816,233: cation exchange resin (Amberlite) containing iminodiacetic acid functional group^TMIRC-7481) (Amberlite used in U.S. Pat. No. 4,816,233^TMIRC-718 like) in ([ Fe ]³⁺]+[Ti⁴⁺]) And [ Sc ]³⁺]When the molar ratio of (c) is high, for example, more than 75.3:1 in the raw material slurry, scandium cannot be efficiently absorbed. In the disclosure of U.S. Pat. No. 4,816,233, trivalent Fe³⁺And tetravalent Mn⁴⁺Is reduced to divalent Fe²⁺And Mn²⁺Ionic, thereby permitting Amberlite^TM718 (iminodiacetic acid functional group) selectively absorb scandium ions.

Example 4: with ion exchange resins having phosphoric acid functionality

S957 from aqueous acid leach slurries Extracting scandium

DEHPA (di-2-ethylhexyl phosphoric acid) is a very effective liquid extractant, as discussed in the background. It is usually diluted with a hydrocarbon solvent such as diesel, kerosene or mineral spirits and provided with a modifier of a high molecular weight alcohol. However, solvent extraction with liquid organic extractants suffers from disadvantages such as solvent loss, scale formation, emulsions, and difficulty in achieving complete organic-aqueous phase separation. To overcome these disadvantages of solvent extraction, the present invention utilizes immobilized extractants having functional groups similar to those of DEHPA. Purolite S957 is a commercial product containing phosphate functional groups chemically bonded to the polymer matrix. It has been found that cation exchange resins

The fixed phosphoric acid functionality in S957 performs similarly in extracting one or more precious metals, such as rare earth metals, without suffering from the above-mentioned disadvantages relating to solvent extraction with liquid organic solvents.

1g of a compound containing phosphoric acid functional groups

S957 cationic ion exchange resin (as received) was weighed into a 150m L beaker with a magnetic bar stirrer.25 m L raw acid leach slurry from comparative example 1 was added to the beaker. the resin and slurry mixture was stirred with a magnetic stirrer for about one hour.the resin and slurry mixture was then filtered to produce a raffinate filtrate the filtrate was then analyzed with ICP-OES and the results are listed in Table 1. scandium concentration was reduced from 95.9ppm in the raw slurry to 38.1ppm in the raffinate filtrate with a recovery of about 60.3% vs Dowex^TMG-26(H) and Amberlite^TMIRC-7481 is much better. With phosphorus without reducing ferric to ferrous ionsCationic ion exchange resins of acid-based Purolite S957 can selectively absorb scandium from acid leach slurries, but not completely.

Despite the presence of phosphoric acid functional groups

S957 performs better than Dowex with sulfonic acid functionality^TMG-26(H) and Amberlite containing iminodiacetic acid functional group^TMIRC-7481, but a scandium recovery of 60.3% is in need of further improvement for a commercially viable process. It has been found that polymer resins reinforced with a complex extractant can successfully achieve scandium recoveries above 60% and at the same time successfully overcome the disadvantages of solvent extraction such as solvent loss, difficulty in achieving complete organic-aqueous phase separation, emulsion and scale formation, as shown in the examples below.

TABLE 1-ICP-OES analysis results of feedstock and raffinate slurries from comparative examples 1-3 and example 4

TABLE 1-CONTINUOUS-ICP-OES analysis results of feedstock and raffinate slurries from comparative examples 1-3 and example 4

Examples 5 to 9: preparation of composite extractant reinforced polymer resin

A. Preparation of Mixed solution of ethanol and DEHPA

125m L analytical grade ethanol and 125m L DEHPA were measured into a 400m L beaker with a magnetic bar stirrer, followed by stirring with a magnetic stirrer for 30 minutes, after which a similar procedure was carried out to prepare a mixed solution of DEHPA and ethanol for the experiment in part B (as needed) without further repetition of the description.

B. Preparation of composite extractant reinforced polymer resin

Examples 5 and 6 detail the preparation of composite extractant-reinforced polymer resins. DEHPA is used as extractant and Amberlite of Dow chemical^TMXAD7HP and XAD1180N were used as polymer resins. These resins have no specific functional group. 50 g of Amberlite^TMXAD7HP Polymer resin weighed into a 150m L beaker, a mixed solution of about 75m L DEHPA and ethanol was added to the beaker, the Polymer resin was soaked in the mixed solution for about 3 hours to produce a composite, the composite was filtered from the mixed solution by gravity and washed with 30m L ethanol^TMXAD7 HP-DEHPA-Wet. About half of the wet composite was dried at about 110 ℃ for at least two hours. The sample obtained is called Amberlite^TMXAD7 HP-DEHPA-Dry. The same procedure was repeated to prepare Amberlite^TMXAD1180N-DEHPA-Wet and Amberlite^TMXAD1180N-DEHPA-Dry。

Examples 7 to 9 detail the preparation of other complex extractant-enhanced functional ion exchange resins. DEHPA is used as extractant, while Dowex^TMG-26(H)、Amberlite^TMIRC-7841 and

s957 was used as a functional ion exchange resin. Dowex was prepared using the procedure described above for examples 5 and 6^TMG-26(H)-DEHPA-Wet、Dowex^TMG-26(H)-DEHPA-Dry、Amberlite^TMIRC-7461-DEHPA-Wet、Amberlite^TMIRC-7461-DEHPA-Dry、

S957-DEHPA-Wet and

S957-DEHPA-Dry. The DEHPA loading of the five complex extractant-reinforced polymer resins was analyzed by X-ray fluorescence (XRF) and is listed in table 2.

TABLE 2 DEHPA Loading of composites of DEHPA-reinforced Polymer resins

Examples 10 to 17: strengthening polymer resin from high concentration of unreduced ferric ion by using composite extractant Direct scandium extraction from aqueous acid leaching slurry

1g of Dowex polymer resin reinforced with a complex extractant containing sulfonic acid functional groups and DEHPA^TMG-26(H) -DEHPA-Wet was weighed into a 150m L beaker with a magnetic bar stirrer.25 m L of the raw acid leach slurry from comparative example 1 was added to the beaker. the composite and slurry mixture was stirred with a magnetic stirrer for about one hour.the composite and slurry mixture was then filtered to produce a raffinate filtrate.the filtrate was then analyzed with ICP-OES and the results are listed in Table 3, example 10. in tables 3-6, all monovalent and divalent cations were not listed because these were not competing for extraction with the predominantly trivalent rare earth metal ions.furthermore, some minor elements (very low concentration) were not listed in these tables, the concentration of scandium was reduced from 95.9ppm in the raw slurry to 70.4ppm in the raffinate filtrate, with a recovery of about 26.6%, as opposed to using Dowex alone^TMThe 5.6% ratio in comparative example 2 was improved in the case of the G-26(H) resin. In example 11, Dowex was used^TMG-26(H) -DEHPA-Dry, and scandium concentration was reduced from 95.9ppm to 86.9ppm with a recovery of 9.4%, which is comparable to when Dowex alone was used^TMThe 5.6% ratio in comparative example 2 was improved in the case of the G-26(H) resin. However, in the composite extractant enhanced Dowex^TMScandium recovery in the case of G-26(H) was still somewhat low, mainly due to the excess trivalent cations, such as ferric ions (Fe), present in the feed slurry³⁺) And tetravalent cations such as Ti⁴⁺Ion, ([ Fe ]³⁺]+[Ti⁴⁺])/[Sc³⁺]>75.3。

Examples 12 and 13 show composite extractant-reinforced porous resin Amberlite^TMXAD7HP-DEHPA-Dry and XAD1180N-DEHPA-Dry reduced scandium concentration from 92.1ppm to 63.3ppm and 60.1ppm, respectively, which converted to 31.3% and 34.7% recovery, respectively. Amberlite without addition of extractant^TMXAD7HP and Amberlite^TMThe resin of XAD1180N showed no tendency to absorb scandium ions. Thus, these composite extractant-reinforced porous resins have enhanced secondary ([ Fe ]³⁺]+[Ti⁴⁺]) And [ Sc ]³⁺]Is greater than the scandium ion absorbing capacity of the acid leach slurry at a ratio of 231: 1.

In the raw material slurry ([ Fe ]³⁺]+[Ti⁴⁺]) And [ Sc ]³⁺]In the case that the ratio of (A) is more than 231:1, the composite extractant strengthens the polymer resin Amberlite^TMIRC-7481-DEHPA-Dry reduced scandium concentration from 92.1ppm to 38.5ppm (example 14) with scandium recovery of 58.2%, which is comparable to when Amberlite alone was used^TMThe recovery of 2.9% scandium was improved compared to that of comparative example 3 in the case of IRC-7481. When the amount of this complex doubled to 2 grams, as shown in example 16, ([ Fe ] in the raw material slurry³⁺]+[Ti⁴⁺]) And [ Sc ]³⁺]When the ratio of (1) was more than 234:1, the scandium concentration was further reduced from 87.4ppm to 15.9ppm, and the scandium recovery rate was 81.8%.

In the raw material slurry ([ Fe ]³⁺]+[Ti⁴⁺]) And [ Sc ]³⁺]When the ratio of (A) to (B) is more than 231:1, the composite extractant reinforces the polymer resin

S957-DEHPA-Dry reduced the scandium concentration from 92.1ppm to 15.07ppm (example 15) and the scandium recovery was 83.6%, which was improved over the 60.3% scandium recovery in example 4 when only Purolite S957 resin was used. When the amount of this composite was doubled to 2 grams, as shown in example 17, ([ Fe ] in the slurry³⁺]+[Ti⁴⁺]) And [ Sc ]³⁺]When the ratio of (A) to (B) is more than 234:1, the scandium concentration is further reduced from 87.4ppm to 0.69ppm, and the scandium recovery rate is 99.2%.

In summary, examples 10 to 17 show that the composite extractant-reinforced polymer resin enhances the ability to absorb scandium ions from acid leach slurries containing large excesses of trivalent ions, such as ferric ions, and tetravalent ions, such as titanium ions.

TABLE 3 elemental analysis for direct scandium extraction from unreduced acid leach slurries by composite extractant-reinforced polymer resins

Examples 18 to 25: fortifying polymer resins with complex extractants from aqueous acids containing unreduced ferric ions Direct extraction of scandium from leaching solution

When in acid leaching solution ([ Fe ]³⁺]+[Ti⁴⁺]) And [ Sc ]³⁺]When the ratio of (A) to (B) is reduced to a level of about 8.2:1, the phosphoric acid functional group-containing compound is the same as in the case of the raw materials (Table 4) used in examples 18 to 20

The S957 resin reduced scandium ion concentration from 124.9ppm to less than 0.0074ppm with scandium recovery of about 100% (example 19). However, the strong cation exchange resin Dowex containing sulfonic acid functional groups^TMG-26(H) only reduced the scandium concentration from 124.9ppm to 46.91ppm, with a scandium ion recovery of 62.4% (example 18). Amberlite containing iminodiacetic acid functional groups^TMIRC-7481 reduced scandium concentration from 124.9ppm to 28.23ppm with scandium recovery of 77.4% (example 20), consistent with the disclosure of U.S. patent No. 4,816,233. Immobilization on a polymeric substrate (e.g. of a polymer matrix with phosphoric acid functional groups (analogous to the DEHPA functional groups)

The extractant on S957) selectively extracts precious metals like scandium from the acid leach solution/slurry, like DEHPA in solvent extraction processes.

S957 extraction overcomes the disadvantages of solvent extraction, such as solvent lossComplete organic-aqueous phase separation, emulsion formation and scale formation are difficult to achieve.

The starting materials of examples 21-25 also had a ([ Fe ] of 8.2:1³⁺]+[Ti⁴⁺]) And [ Sc ]³⁺]The ratio of (a) to (b). Example 21 shows composite extractant-reinforced Polymer resin Dowex^TMG-26(H) -DEHPA reduced scandium ion concentration from 125.4ppm to 15.89ppm with scandium recovery of 87.3% (example 22), which is comparable to when Dowex alone was used^TMThe 62.4% recovery in example 18 was improved over that of the G-26(H) resin. Composite extractant reinforced polymer resin Amberlite^TMIRC-7481-DEHPA showed complete scandium absorption from 125.4ppm down to<0.0037ppm (example 23), this corresponds to the use of Amberlite alone^TMThe recovery of 77.4% was improved compared to that of example 20 in the case of IRC-7481. Composite extractant reinforced polymer resin

S957-DEHPA from ([ Fe ]³⁺]+[Ti⁴⁺]) And [ Sc ]³⁺]The acid leaching solution with a ratio of (1) to (8.2) completely absorbs scandium ions because

S957 itself absorbed 100% scandium (example 19).

As shown in examples 24 and 25, the composite extractant reinforced polymer resin Amberlite^TMXAD1180N-DEHPA and Amberlite^TMXAD7HP-DEPHA reduced scandium from 125.4ppm to 40.18ppm and 1.46ppm, respectively, with recovery rates of 68.0% and 98.8%, respectively, while Amberlite used alone^TMXAD1180N and Amberlite^TMXAD7HP has no activity to absorb scandium ions from the acid leach slurry.

Examples 18 to 25 further show that the composite extractant-reinforced polymer resin (in this case, DEHPA-reinforced polymer resin) is capable of directly extracting precious metals such as scandium ions from acid leach solutions or slurries, while overcoming the disadvantages of solvent extraction in terms of solvent loss, difficulty in achieving complete solvent phase-water phase separation, emulsions, scale formation, and the like.

TABLE 4 direct extraction of scandium from aqueous acid leach solutions having a relatively high concentration of unreduced ferric ions

Examples 26 to 29: strengthening polymer resin with composite extractant to reduce ferric ion into ferrous ion Direct extraction of scandium from aqueous acid leach solutions of seeds

As shown in table 5, for examples 26 to 29, the ferric ions in the acid leach solution were reduced to ferrous ions. Amberlite used alone^TMXAD1180N and Amberlite^TMXAD7HP resin did not show any activity in absorbing scandium ions from the acid leach solution in which ferric ions were reduced to ferrous ions, as shown in examples 26 and 27, respectively. Composite extractant reinforced polymer resin Amberlite^TMXAD1180N-DEHPA or Amberlite^TMXAD7HP-DEHPA showed complete absorption of scandium ions from a slurry in which ferric ions were reduced to ferrous ions, as shown in examples 28 and 29, respectively. Examples 26 to 29 further illustrate that the composite extractant-reinforced polymer resin absorbs scandium ions and overcomes the disadvantages of solvent extraction in terms of solvent loss, difficulty in achieving complete separation of solvent and aqueous components, emulsions, scale formation, and the like.

TABLE 5 direct extraction of scandium from aqueous acid leach solutions with high concentration of iron ions in the form of ferrous ions

Example 30: from high-concentration unreduced ferric iron by using cation ion exchange resin with phosphoric acid function Direct extraction of scandium from ionic aqueous acid leach solutions (column process)

7.8g

S957 resin (10m L) was added to the analytical glass burette used as a column, the bottom of which was connected to

Tubing(S/L 14)。Purolite

The resin bed of (a) is filled with deionized water and bubbles are removed from the resin bed. The acid leach solution was carefully added to an analytical glass burette (column). The composition of the acid leach solution is shown in Table 6 and it ([ Fe ]³⁺]+[Ti⁴⁺]) And [ Sc ]³⁺]Is about 75:1, the acid leach solution is pumped through the resin bed at a flow rate of 0.75m L/min (4.5 bed volumes per hour), and raffinate effluent samples are collected at 30 minute intervals, the analysis of the raffinate effluent and extraction results is set forth in table 6 and shown in figure 1. during the first 30 minutes, 98% of the scandium ions are absorbed by the Purolite S957 resin where in

The loading on the S957 resin was about 368ppm Sc. At the same time, about 91% of the ferric ions are also absorbed by the resin, which causes [ Fe ] in the effluent]/[Sc]Is 353: 1. However, after 30 minutes, as more ferric ions were loaded to

Scandium extraction efficiency was greatly reduced to 85%, 60% and 42% at 60, 90 and 120 minutes, respectively, on the cation exchange sites of the S957 resin. Thus, [ Fe ] in the effluent]/[Sc]The ratios of (a) were reduced to 102:1, 45:1 and 31:1, while the corresponding scandium loadings on the resin were increased to 1007, 1684 and 2313 ppm.

This example shows that Purolite S957 with phosphate functionality can extract about 98% of scandium from an acid leach slurry containing at least 13,339ppm ferric ions and a scandium loading of about 368 ppm.

TABLE 6 elemental analysis of raffinate at different run times when extracting rare earth metals from acid leach solutions containing high levels of ferric ions using Purolite S957

Example 31: strengthening polymer resins with complex extractants having phosphoric acid functionality to high levels of unreduced Direct extraction of scandium from aqueous acid leach solution of ferric ions

10 grams of the composite extractant-reinforced polymer resin Purolite S957-DEHPA-Dry was added to the analytical glass burette, the volume of the analytical glass burette (resin bed) was about 23m L after contacting water, the bottom of the analytical glass burette was attached

Tubin (L/S14). resin bed was filled with deionized water and air bubbles were removed from the resin bed A pickling solution was added to the analytical glass burette, the composition of the pickling solution is listed in Table 7, and it ([ Fe ]³⁺]+[Ti⁴⁺]) And [ Sc ]³⁺]Is about 83:1 the acid leach solution is pumped through the resin bed at a flow rate of 0.75m L/min (about 2 bed volumes per hour), raffinate effluent samples are collected at 30 minute intervals, the analysis of the raffinate effluent and extraction results is set forth in table 7 and illustrated in fig. 1. during the first 150 minutes, 98% or more of the scandium ions are absorbed by Purolite S957-DEHPA where

The loading on S957-DEHPA was as high as 2249ppm Sc, which is greater than that used alone

The efficiency of the S957 resin is 6.4 times higher. During this period, the percentage of ferric ion loaded onto the resin was reduced from 100% (30 minutes) to 93% (60 minutes), 67% (90 minutes), 39% (120 minutes) and 26% (150 minutes). More importantly, [ Fe ] in the effluent]/[Sc]Is extremely high, about 30,000 or more in the first 90 minutes, andto about 3000 at 120 and 150 minutes. Loading extractant DEHPA into

S957 reinforcement on resin

The S957 resin achieves the ability to selectively and completely absorb scandium ions from an acid leach slurry containing a high concentration of ferric ions. This is particularly useful for extracting low concentrations of scandium from acid leach slurries or solutions containing high concentrations of trivalent cations, such as ferric ions, and tetravalent cations, such as titanium.

Furthermore, after 150 minutes, the concentration of ferric ions was substantially the same as the concentration of the raw material solution, indicating that no ferric ions were absorbed. However, compounding

S957-DEHPA continued scandium ion uptake, with extraction efficiencies of 90% (180 min), 78% (210 min) and 67% (240 min), and [ Fe ] in the effluent]/[Sc]Ratios of (c) at 787(180 minutes), 346(210 minutes) and 230(240 minutes). These results show that the composite extractant strengthens the polymer resin (C

S957-DEHPA) has the ability to exchange scandium ions with ferric ions with very high selectivity. After 240 minutes of operation, about 4714ppm scandium was loaded into the composite

S957-DEHPA.

This example shows that the composite extractant-reinforced polymer resin is well suited for economically extracting rare earth metal ions from a stream of acid-leached slurry or solution, even though the stream of aqueous slurry or solution contains a significant amount of ferric ions, without reducing the ferric ions to ferrous ions. At the same time, the composite extractant-reinforced polymer resin allows for increased extraction rates of rare earth metals from streams of acid-leached slurries or solutions, and overcomes the disadvantages of solvent extraction in terms of solvent loss, difficulty in achieving complete organic phase-aqueous phase separation, emulsion formation, and scale formation.

TABLE 7 when used

Elemental analysis of raffinate at different run times for extraction of rare earth metals from acid leach solutions containing large amounts of ferric ions

Example 32: fortifying a polymeric resin with a complex extractant having phosphoric acid functionality to contain about 3,000ppm iron Direct extraction of scandium from ionic synthetic solution (regeneration with multiple acid passes, less cost-effective)

Contains 24.9ppm scandium, 4,302ppm nickel, 246ppm cobalt, 2,988ppm iron, 2,598ppm aluminum, 207ppm chromium and other divalent cations such as calcium ((C))>20,000ppm), copper, magnesium (M: (M)>11,000ppm), manganese, zinc, silicon, etc., by packing with about 4.25 liters of a composite extractant-reinforced polymer resin

S957-DEHPA PVC column.

Strengthening of polymer resins in previous runs with a composite extractant loaded with scandium ions and other undesirable cations: (

S957-DEHPA). Scandium ions were stripped from the loaded resin under mixing conditions for about 1 hour using a sodium carbonate solution (about 16 liters) heated to about 80 ℃. The carbonate solution used as stripping solution contained about 200 grams of sodium carbonate per liter. The stripping procedure was repeated again.

The Sc-stripped resin was then regenerated under mixing conditions for 1 hour using 10 liters of sulfuric acid solution (440 g/liter) containing about 5% hydrogen peroxide. The resin was then regenerated for 1 hour with mixing using 10 liters of hydrochloric acid solution (200 g/l). The resin was then loaded onto a PVC tower and a stream of 10 litres sulphuric acid solution (440 grams/litre) and a stream of 10 litres hydrochloric acid (200 grams/litre) were passed through the tower in sequence. After rinsing with water, the column was then used for the following run.

About 100 liters of synthetic solution was pumped to the top of the column for about 15 hours. At the beginning, the flow rate is relatively high and to the end, the flow rate is relatively low, which may be due to different pumping forces corresponding to different levels of feed solution contained in the 55 gallon barrel. The effluent solution from the column (raffinate) was sampled hourly for detection. The collected raffinate solution is then added to additional scandium solution to form a further feed solution containing between 15 and 27ppm scandium; and the process was repeated 7 times.

The results of scandium recovery from the synthesis solution are shown in fig. 2. The scandium ions in the raw material are partially reinforced by the extractant to strengthen the polymer resin

S957-DEHPA retention; scandium ions in the raffinate increased with increasing run time. The initial scandium recovery was almost 100%; the scandium recovery then slowly dropped while the resin continued to be loaded with scandium ions. The resin continues to load scandium even in the presence of very large amounts of other trivalent cations such as iron ions (Fe: Sc mass ratio of about 100: 1). After about 150 hours of operation, the scandium concentration in the raffinate increased to a level greater than 15 ppm; the cumulative scandium recovery at the end of the run was about 77%.

The loaded resin was then stripped with the first sodium carbonate solution using the same procedure as described above. The first stripping solution contained 1,013ppm Sc, 2.3ppm Al, 291ppm Ca, 1.7ppm Co, 0.9ppm Cr, 2.6ppm Cu, 45ppm Fe, 106ppm Mg, 1.6ppm Mn, <0.2ppm Ni, 164ppm Si and 1.8ppm Zn. The scandium and other impurities in the stripped solution were then precipitated with hydrochloric acid, followed by filtration to produce a filter cake. The resin was then stripped with a second sodium carbonate solution, and the stripped solution contained a lower concentration of scandium; the second stripping solution may be used as the first stripping solution in the next cycle.

The resin was then subjected to the same regeneration procedure described in this example. Then, in the following examples, the regenerated resin was ready for the next cycle.

Example 33: fortifying a polymeric resin with a complex extractant having phosphoric acid functionality to a level of about 16,000ppm Direct extraction of scandium from a synthetic solution of iron ions (less cost-effective regeneration with multiple acid passes) and subsequent stripping And uses one-pass hydrochloric acid to regenerate in-situ at low cost

A composition stream containing about 9ppm scandium and 56ppm nickel, 8.0ppm cobalt, 16,145ppm iron, 1,247ppm aluminum, 202ppm chromium and other divalent cations such as calcium (1,005ppm), copper (1.0ppm), magnesium (18,654ppm), manganese (1,761ppm), zinc (4.7ppm), silicon (234ppm), etc. was passed through a packed bed of about 4 liters of a composite extractant-reinforced polymer resin regenerated in the previous examples (0

S957-DEHPA).

About 100 liters of synthetic solution was pumped to the top of the column for about 10 hours. The raffinate solution was sampled hourly for detection. The collected raffinate solution is then added to additional scandium solution to form a further feed solution containing scandium in a concentration between 8 and 10 ppm; and the process was repeated 13 times.

The results of scandium recovery from the synthesis solution are shown in fig. 3. The scandium ions in the raw material are partially reinforced by the extractant to strengthen the polymer resin

S957-DEHPA retention; scandium ions in the raffinate increased with increasing run time. The initial scandium recovery was almost 100%; the scandium recovery then slowly dropped while the resin continued to be loaded with scandium ions. Even if very large amounts of other cations, such as iron ions, are present in the solution (Fe: Sc mass ratio)>1,600:1), the resin still continued to be loaded with scandium. After about 150 hours of operation, the scandium concentration in the raffinate increased to a level greater than 6 ppm; the cumulative scandium recovery at the end of the run was about 81%.

The loaded resin was removed from the column and stripped with a first sodium carbonate solution (10.5 l, 200g sodium carbonate/l) under mixing conditions at 80 ℃ for one hour. The first stripping solution contained 905ppm Sc, 29ppm Al, 295ppm Ca, <0.7ppm Co, <0.2ppm Cr, <0.1ppm Cu, 78ppm Fe, 218ppm Mg, 3.2ppm Mn, <0.7ppm Ni, 258ppm Si, and <0.5ppm Zn. The scandium and other impurities in the stripped solution were then precipitated with hydrochloric acid, followed by filtration to produce a filter cake.

The loaded resin was then stripped with a second sodium carbonate solution (10 l, 200g sodium carbonate/l) under mixing conditions at 80 ℃ for 1 hour. The second stripping solution contained 326ppm Sc, 7ppm Al, 114ppm Ca, <0.1ppm Co, <0.1ppm Cr, <0.04ppm Cu, 20ppm Fe, 88ppm Mg, 0.6ppm Mn, <0.3ppm Ni, 79ppm Si, and <0.2ppm Zn. The second stripping solution may be used as the first stripping solution in the next cycle.

The resin was then regenerated by passing a hydrochloric acid solution (200 g/l, 9 l) through the column. The hydrochloric acid solution used contained 0.1ppm Sc, 228ppm Al, 179ppm Ca, 0.4ppm Co, 35ppm Cr, 0.5ppm Cu, 3,222ppm Fe, 752ppm Mg, 101ppm Mn, <0.7ppm Ni, 84ppm Si and 5.6ppm Zn. The regenerated resin is ready for the next cycle.

Example 34: fortifying a polymeric resin with a complex extractant having phosphoric acid functionality to a level of about 15,000ppm Direct extraction of scandium from a synthetic solution of iron ions (ex situ regeneration with a single pass of acid, very economical) and subsequent recovery In situ stripping and in situ regeneration with one pass of hydrochloric acid was carried out.

Contains about 9ppm scandium, 36ppm nickel, 8ppm cobalt, 15,210ppm iron, 1,272ppm aluminum, 122ppm chromium and other divalent cations such as calcium ((C))>372ppm, copper (0.8ppm), magnesium (23,048ppm), manganese (b) (iii)>1,055ppm), Zinc (23ppm), silicon (33ppm), etc. by packing with about 4 liters of composite extractant-reinforced polymer resin regenerated in the previous example: (

S957-DEHPA).

About 100 liters of synthetic solution was pumped to the top of the column for about 10-12 hours. The raffinate solution was sampled hourly for detection. The collected raffinate solution is then added to additional scandium solution to form a further feed solution containing scandium at a concentration between 8 and 11 ppm; and the process was repeated 12 times.

The results of scandium recovery from the synthesis solution are shown in fig. 4. The scandium ions in the raw material are partially reinforced by the extractant to strengthen the polymer resin

S957-DEHPA retention; scandium ions in the raffinate increased with increasing run time. The initial scandium recovery was almost 100%; the scandium recovery then slowly dropped while the resin continued to be loaded with scandium ions. The resin continues to load scandium even in the presence of very large amounts of other cations such as iron ions (Fe: Sc mass ratio of about 1,500: 1). After about 150 hours of operation, the scandium concentration in the raffinate increased to a level greater than 7 ppm; the cumulative scandium recovery at the end of the run was about 82%.

The loaded resin was then stripped in situ with a first sodium carbonate solution (which is the second stripping solution from example 33, about 8.5 liters) by flowing through a column at 60 ℃. Such a first stripping solution contains 1,277ppm Sc, 9.4ppm Al, 88ppm Ca, <0.3ppm Co, <0.2ppm Cr, 1.0ppm Cu, 63ppm Fe, 41ppm Mg, <0.1ppm Mn, 4.1ppm Ni, 140ppm Si and 10ppm Zn. The scandium and other impurities in the stripped solution were then precipitated with hydrochloric acid, followed by filtration to produce a filter cake.

The resin was then stripped in situ at 60 ℃ with a second sodium carbonate solution (fresh solution, 200g sodium carbonate/l, 10 l) by passage through the column. The second stripping solution contained 326ppm Sc, 31ppm Al, 116ppm Ca, <0.3ppm Co, <0.2ppm Cr, <0.1ppm Cu, 42ppm Fe, 57ppm Mg, <0.1ppm Mn, <0.7ppm Ni, 180ppm Si, and <0.5ppm Zn; the second stripping solution may be used as the first stripping solution in the next cycle.

The resin was then regenerated in situ by passing a hydrochloric acid solution (200 g/l, 10 l) through the column. The hydrochloric acid solution used contained 0.1ppm Sc, 111ppm Al, 44ppm Ca, <0.03ppm Co, <18.5ppm Cr, <0.008ppm Cu, >5,552ppm Fe, >190ppm Mg, 38ppm Mn, 0.7ppm Ni, 22ppm Si and 0.9ppm Zn. The regenerated resin is ready for the next cycle.

Example 35: method for extracting scandium-component from unadjusted titanium tailing waste liquid by using composite extractant reinforced polymer resin Batch process

The metal content of the titanium tailings waste liquid was analyzed using ICP-OES (inductively coupled plasma emission spectrometry), and the results are shown in table 8.

Table 8: ICP-OES analysis of titanium tailing waste liquid sample

Element(s)

ppm

Element(s)

ppm

Element(s)

ppm

Element(s)

ppm

Element(s)

ppm

Sc

71.4

S

61.5

Ni

58.0

Mo

1.26

Pb

19.6

Li

5.31

K

>388

Cu

10.1

Cd

0.80

Bi

<0.03

Be

1.89

Ca

>419

Zn

22.4

In

<0.32

Ce

173

B

<0.04

Ti

4907

Ga

<0.12

Sn

16.1

Nd

46.2

Na

>912

V

1943

As

<0.02

Ba

148

Sm

12.3

Mg

2694

Cr

1080

Sr

22.8

La

52.5

Gd

11.2

Al

5912

Mn

9037

Y

26.0

Hf

37.8

Yb

8.98

Si

26.4

Fe

33333

Zr

>729

W

28.1

Th

84.1

P

62.9

Co

16.4

Nb

1439

Hg

<0.09

U

<0.92

About 100m L of the titanium tailings waste liquid was measured and placed in a 250m L reagent bottle, where

About 4m L wet compounded extractant reinforced polymer resin with S957 as the polymer resin and di (2-ethylhexyl) phosphoric acid (DEHPA) as the extractant was added to the titanium effluent solution, the mixture was agitated for 24 hours using a bottle roller to reach equilibrium, the compounded extractant reinforced polymer resin was separated from the raffinate by filtration using Whatman42 filter paper, and the metal content of the raffinate was analyzed using ICP-OES the results are listed in Table 9. the calculated scandium loading on the compound (co-adsorption with other metals such as titanium and zirconium) was about 598 mg/L.

TABLE 9 elemental analysis of the feed and raffinate solution after extraction by batch method (water phase to resin ratio 25)

Example 36: scandium-tower for extracting unregulated titanium tailing waste liquid by using composite extractant reinforced polymer resin Method of

Thirty m L parts of the titanium tailings waste liquor from example 35 were continuously contacted with 30m L of the composite extractant-reinforced polymer resin of example 35 placed in a 50m L glass burette at a rate of 60m L/hr or 1 bed volume/hour using a peristaltic pump_o) Ratio (C/C) to metal (C) in raffinate solution_o) The breakthrough point for scandium was reached very early after about the first Bed Volume (BV) passed through the column, where the scandium loading on the composite extractant-reinforced polymer resin was calculated to be about 98 mg/L. therefore, the depletion point was reached at about the nineteenth bed volume, where the cumulative scandium loading on the composite extractant-reinforced polymer resin was calculated to be about 977.2 mg/L composite.

Example 37: extraction of scandium from pH-adjusted titanium tailing waste liquor by using composite extractant reinforced polymer resin

The titanium tailings effluent of example 35, at about 150m L, was measured and placed in a beaker, while the liquor was agitated using a magnetic stirrer, it was slowly adjusted to a pH of about 0.80 with slaked lime, at which time a precipitate began to form in the solution, after maintaining the pH for 30 minutes, a sample of the pH adjusted liquor was taken and filtered through Whatman42 filter paper, the pH adjustment was continued until pH values of about 1.5, 2.5 and 3.5, the same procedure was repeated each time, the liquor filtrate was analyzed for metal content with ICP-OES, and the results for scandium, titanium, iron, zirconium, niobium and other rare earth metals are listed in table 10.

TABLE 10 elemental analysis of pH adjusted solutions at various pH values

A sufficient volume of titanium tailings effluent to produce at least 1,000m L filtrate was transferred to a 4000m L beaker and hydrated lime was added slowly to adjust the pH to between 0.80 and 0.90 while stirring using an overhead stirrer after one hour of equilibration the pH adjusted slurry was filtered using a buchner funnel with the aid of a vacuum pump the pH adjusted solution was analyzed for metal content using ICP-OES as shown in table 11.

Table 11: elemental composition of pH adjusted solution (pH 0.80-0.90) from titanium tailings effluent

Element(s)

ppm

Element(s)

ppm

Element(s)

ppm

Element(s)

ppm

Element(s)

ppm

Sc

62.5

S

28.8

Ni

62.2

Mo

0.55

Pb

15.1

Li

7.87

K

>517

Cu

1.68

Cd

0.31

Bi

1.55

Be

<0.001

Ca

>2479

Zn

23.9

In

<0.71

Ce

146

B

<0.29

Ti

15

Ga

<0.29

Sn

<0.02

Nd

45.3

Na

>961

V

>1656

As

0.48

Ba

131

Sm

2.71

Mg

>2116

Cr

>864

Sr

60.5

La

59.2

Gd

14.9

Al

>6013

Mn

>317

Y

29.8

Hf

3.65

Yb

10.1

Si

>287

Fe

>1223

Zr

2.98

W

<0.09

Th

20.9

P

<0.06

Co

10.1

Nb

>211

Hg

<0.02

U

<1.11

Sixty m L parts of the pH adjusted solution were continuously contacted with 30m L of the composite extractant-reinforced polymer resin of example 35 placed in a 50m L glass burette at a rate of 60m L/hr or 1 bed volume/hour using a peristaltic pump_o) With raffinate solutionThe ratio (C/C) of the metal (C) in (C)_o) The breakthrough point for scandium was reached when operating at about the 44 th bed volume of the pH adjusted filtrate, where the calculated cumulative scandium loading was about 2,670 mg/L complex, which was 27.2 times the scandium loading obtained in example 36.

Example 38: acid wash from carbothermic chlorination process for treating titanium ore in a recycle operation Use of a regenerated solution of stripped composite extractant-reinforced polymer resins

Samples of the acid wash from carbothermic chlorination processing of titanium ore were analyzed for metal content with ICP-OES and the results are shown in table 12 the acid wash was also titrated with a standard sodium hydroxide solution to determine the free acid content, which was found to be about 157gp L.

TABLE 12 elemental composition of acid wash liquor from carbothermic chlorination process for treating titanium ore

Element(s)

ppm

Element(s)

ppm

Element(s)

ppm

Element(s)

ppm

Element(s)

ppm

Sc

62.5

S

>980

Ni

<0.04

Mo

0.42

Pb

1.81

Li

0.017

K

8.62

Cu

0.10

Cd

<0.008

Bi

<0.007

Be

<0.001

Ca

50.2

Zn

0.08

In

<0.71

Ce

<0.14

B

1.14

Ti

1541

Ga

0.47

Sn

54.3

Nd

<0.04

Na

>157

V

18.2

As

0.92

Ba

<0.001

Sm

0.19

Mg

8.78

Cr

<0.01

Sr

0.95

La

<0.008

Gd

<0.01

Al

<0.26

Mn

<0.001

Y

<0.001

Hf

0.16

Yb

<0.003

Si

99.1

Fe

8.96

Zr

0.01

W

<0.09

Th

0.15

P

<0.06

Co

2.90

Nb

<0.03

Hg

<0.02

U

<1.11

Two batches of pH adjusted solutions were prepared from the titanium tailings effluent according to example 37 and analyzed for metal content using ICP-OES. The results are given in table 13.

TABLE 13 elemental composition of pH adjusted solutions

Two feed solutions were used for the cyclic loading-stripping-regeneration experiments.

Step 1. measure a pH adjusted solution of about 720m L and add it to a 1,000m L beaker along with 30m L of the composite extractant-reinforced polymer resin of example 35. the resulting mixture was mixed for 2 hours at 100rpm with the aid of an overhead stirrer the composite extractant-reinforced polymer resin was separated by decantation.

Step 2 transfer washed loaded complex extractant-reinforced polymer resin to a 250m L beaker for a stripping step. for the first stripping phase, about 75m L of 200gp L sodium carbonate solution is added to the loaded complex extractant-reinforced polymer resin and the mixture is agitated by means of an overhead stirrer at about 80 ℃ for about 30 minutes. the mixture is allowed to cool to room temperature and then the complex extractant-reinforced polymer resin is separated by decantation.

Step 3 the water washed stripped complex from step 2 was then mixed with about 75m L of acid wash solution as regeneration solution and mixed for about 30 minutes by means of an overhead stirrer the complex extractant-reinforced polymer resin was separated by decantation, mixed with a sufficient amount of deionized water to ensure removal of entrained regeneration solution and again separated by decantation.

Steps 1 to 3 were repeated 12 times (cycles 2 to 13). in cycle 14, the regeneration solution used was a 200gp L hydrochloric acid solution prepared from technical grade concentrated hydrochloric acid, in cycle 15, only Steps 1 and 2 were carried out.

The results of the analysis are shown in Table 14. scandium loading was reduced by about 6% from about 1915 to 1873mg Sc/L complex after 8 cycles using the sour wash as the regeneration solution due to titanium uptake however, when a second feed solution (containing higher amounts of Ti and other impurities) was used in the test, a change in equilibrium appeared to occur, which was evident by an increase in titanium uptake. this change resulted in a further 7% reduction in scandium loading to 1651mg Sc/L complex.

TABLE 14 scandium and titanium contained in the aqueous phase and in the composite extractant-reinforced Polymer resin in the Cyclic Loading-stripping-regeneration experiment

TABLE 14-continuous cycle Loading-stripping-regeneration experiment scandium and titanium contained in aqueous phase and composite extractant-reinforced Polymer resin

The absorption of scandium and titanium in mg/L complex units (converted from mg/kg complex by using a density of 0.72 g/ml) was calculated from the analysis results and plotted on the graph depicted in fig. 7.

While specific embodiments of the invention have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. The presently preferred embodiments described herein are meant to be illustrative only and not limiting as to the scope of the invention which is to be given the full breadth of the appended claims and any and all equivalents thereof.

Claims

1. A method of extracting rare earth metals from an acidic slurry or solution comprising:

providing an acidic slurry or an acidic solution;

adding a composite comprising an extractant and a polymer resin;

mixing the composite with the acidic slurry or acidic solution to form a mixed slurry or solution; and

separating the mixed slurry or solution into a rare earth metal-loaded composite and a raffinate slurry or solution,

wherein the acidic slurry or acidic solution comprises at least one rare earth metal and at least one early transition metal, and/or at least one actinide metal selected from the group consisting of titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), rhenium (Re), and the at least one actinide metal is selected from the group consisting of actinium (Ac), thorium (Th), protactinium (Pa), uranium (U), neptunium (Np), plutonium (Pu), americium (Am), curium (Cm), berkojim (Bk), californium (Cf), carum (Es), ferm (Fm), medum (Md), absent (No), and L r.

2. The process of claim 1 wherein each of the early transition metals present in the acidic slurry or solution is present in an amount up to 50,000ppm and each of the actinide metals present in the acidic slurry or solution is present in an amount up to 5,000 ppm.

3. The method of claim 1, wherein the acidic slurry or acidic solution is an acidic slurry or acidic solution generated during processing of a material containing at least one rare earth metal and at least one early transition metal and/or one actinide metal.

4. A process according to claim 3, wherein the acidic slurry or solution is a waste titanium tailings stream from carbothermic chlorination processing of titanium ore.

5. The method of claim 4, wherein the rare earth metal is scandium.

6. A method according to claim 1, further comprising increasing the pH of the acidic slurry or acidic solution to form a precipitate of at least a portion of the at least one early transition metal and/or at least one actinide metal prior to adding the complex.

7. The method of claim 6, further comprising filtering the precipitate from the acidic slurry or acidic solution prior to adding the complex.

8. The method of claim 6, wherein the precipitate comprises titanium, thorium, or both.

9. The method of claim 1, further comprising stripping the rare earth metal from the rare earth metal-loaded composite.

10. The method of claim 5, further comprising regenerating the composite resin for reuse.

11. A method according to claim 10, wherein the composite is regenerated using a regeneration solution generated during processing of a material containing at least one rare earth metal and at least one early transition metal and/or one actinide metal.

12. The method of claim 11, wherein the regeneration solution is an acid wash or a waste process stream.

13. The method of claim 12, wherein the regeneration solution is an acid wash from carbothermic chlorination processing of titanium ore.

14. The method of claim 1, wherein the polymer resin has at least one phosphoric acid functional group.

15. The method of claim 1, wherein the extractant comprises a cationic extractant.

16. The composite of claim 15, wherein the extractant is di (2-ethylhexyl) phosphoric acid (DEHPA).

17. The method of claim 1, wherein the acidic slurry or solution comprises at least one rare earth metal and at least one early transition metal selected from the group consisting of titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), rhenium (Re).

18. The method of claim 1, wherein the acidic slurry or solution comprises at least one rare earth metal and at least one actinide metal selected from the group consisting of actinide (Ac), thorium (Th), protactinium (Pa), uranium (U), neptunium (Np), plutonium (Pu), americium (Am), curium (Cm), berkelium (Bk), californium (Cf), einsteins (Es), fermium (Fm), mendelerium (Md), nobel (No), and lawrencium (L r).

19. The method of claim 1, wherein the acidic slurry or solution comprises at least one rare earth metal, at least one early transition metal, and at least one actinide metal selected from the group consisting of titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), rhenium (Re), the at least one actinide metal selected from the group consisting of actinium (Ac), thorium (Th), protactinium (Pa), uranium (U), neptunium (Np), plutonium (Pu), americium (Am), curium (Cm), kelvin (Bk), californium (Cf), cementum (Es), fermi (Fm), mendeleum (Md), mone (No), and L r.