Scandium Metal Research Articles

Novel environment-friendly magnetic bentonite nanomaterials functionalized by carboxymethyl chitosan and 1-(2-pyridinylazo)-2-naphthaleno for adsorption of Sc(III)

For effective adsorption and separation of precious rare metal scandium (Sc) from waste water, a new bifunctional magnetic bentonite material was prepared, named bentonite/CoFe2O4@SiO2-CMC/PAN to enhance the selective extraction of scandium. Magnetic bentonite was functionalized with carboxymethyl chitosan (CMC) and 1-(2-pyridinylazo)-2-naphthaleno (PAN). The adsorbent was characterized by BET, XRD, EDS, SEM, TEM and FTIR. Factors such as pH, initial concentration, reaction time, adsorbent dosage, selectivity, and reusability were systematically investigated. The results showed that the adsorption isotherm and kinetic data were accurately described by Langmuir model and pseudo second order model, indicating that the adsorption conformed to the monolayer chemical adsorption, and the adsorption rate was controlled by multiple steps. The adsorption rate was 98%, and the maximum adsorption capacity was up to 49.05 mg·g−1. The bentonite/CoFe2O4@SiO2-CMC/PAN showed high selectivity. Additionally, the adsorbent could be magnetically separated quickly. XPS analysis results showed that scandium ion (Sc(III)) could not only carry out electrostatic and complexation with carboxyl groups and hydroxyl, but also chelate with amino, azo and pyridine groups. In general, bentonite/CoFe2O4@SiO2-CMC/PAN showed a hopeful way for the recovery and utilization of Sc.

Selective Coupling of Lanthanide Metallacyclopropenes and Nitriles via Azametallacyclopentadiene and η2-Pyrimidine Metallacycle.

Exploring new lanthanide metallacycles and finding their unique chemistry different from the analogues of transition metals are of great interest and importance. In this work, we reported the synthesis, characterization, and reactivity toward nitriles of two lanthanide metallacyclopropenes: lutetacyclopropene 2a and dysprosacyclopropene 2b. The selective coupling of 2a and three molecules of PhCN was found for the first time to provide the unexpected fused lutetacycle 3a with one 1,6-dihydropyrimidine ring. Mechanistic studies by DFT calculations reveal that the triple insertion of PhCN into 2a proceeds through four key steps: the insertion of the first PhCN into 2a giving azalutetacyclopentadiene IM1, the insertion of the second PhCN into the Lu-N bond of IM1, the intramolecular electrocyclization providing a highly strained η2-pyrimidine metallacycle, and the insertion of the third PhCN into the Lu-Csp3 bond. Isolation and characterization of two active intermediates, azalutetacyclopentadiene IM1 and η2-pyrimidine dysprosacycle, provide critical evidence for the formation of 3a. Furthermore, IM1 was also reported to react with TMSCN, isocyanides, or W(CO)6 to furnish the fused [4,5] lutetacycles. The chemistry of two lanthanide metallacyclopropenes with nitriles is significantly different from these metallacyclopropenes of scandium and other metals. Most notably, the azalutetacyclopentadienes, η2-pyrimidine complex, and other metallacycles all represent the first examples in rare-earth organometallic chemistry; the formation of these new lutetacycles provides concrete evidence for understanding the mechanism of transition metal promoted or catalyzed [2+2+2] cycloaddition between alkynes and nitriles.

High purity scandium extraction from red mud by novel simple technology

Storage of red mud – bauxite processing waste – leads to serious environmental problems due to its high alkalinity and particle dispersity. Full or partial utilization or recycling of red mud could reduce the harmful effect on the environment. Scandium is the most valuable ingredient of red mud, yet it's extraction is poorly commercialized due to its high cost. The new efficient extraction technologies promise an ensured supply of scandium and a significant drop in cost. Here, scandium concentrate, extracted from leachate after carbonate treatment of red mud, was subjected to sulfatisation by H2SO4 to separate silica from water-soluble sulfates. To recover and selectively separate scandium from other impurity metals, the crystallization of two complex scandium and ammonium sulfates – NH4Sc(SO4)2 and (NH4)3Sc(SO4)3 – is proposed. The solubilities of these sulfatoscandiates in water, established by isothermal method, are 33.4 and 72.4 g/L, respectively. For the less soluble NH4Sc(SO4)2 a further considerable reduction of solubility has been observed in H2SO4 solutions of concentration above 3.5 М in the presence of 0.5 М NH4Cl at 20 ± 1 °C. More than 99% of scandium in the form of micron-sized NH4Sc(SO4)2 crystals has been recovered from a multicomponent liquid at 5–6 М H2SO4 and 0.5 М NH4Cl. The product contains extremely low levels of impurities. The precipitation of NH4Sc(SO4)2 offers a much higher selectivity in separation of Sc from the other main constituents, as demonstrated by the large separation coefficients between scandium and other metals βSc/M (e.g., for the couple with aluminum βSc/Al = 4280). The recrystallization product after calcination at 1000°С contains 99% Sc2O3.

Potential of garnet sand as an unconventional resource of the critical high-technology metals scandium and rare earth elements

Scandium is a critical raw material that is essential for the EU economy because of its potential application in enabling technologies such as fuel cells and lightweight materials. As there is currently no secure supply of Sc, several projects worldwide evaluate potential Sc sources. While elsewhere in Europe emphasis is placed upon secondary resources such as red mud, we investigated the potential of industrial garnet sand and its waste products. Since Sc readily substitutes for Mg and Fe in the crystal lattice of garnet, the garnet minerals almandine and pyrope, in particular, may show high Sc concentrations. Garnet sand, after being used as an abrasive in the cutting and sandblasting industry, is recycled several times before it is finally considered waste which eventually must be disposed of. Extraction of Sc (and rare earth elements, REE) from such garnet sand may generate added value and thereby reduce disposal cost. The studied garnet sands from different mines in Australia, India and the U.S., and industrial garnet sands commercially available in Germany from different suppliers show average Sc concentrations of 93.7 mg/kg and 90.7 mg/kg, respectively, i.e. similar to red mud. Our data also show that “fresh” and recycled garnet sands yield similar Sc concentrations. Within the framework of a minimum-waste approach, it may be feasible to utilize the industrial waste-product “garnet sand” as an unconventional source of Sc and REE, that reduces disposal cost.

Effect of Scandium and Other Transition Metals on the Recrystallization of Al–Mg2Si Alloys after Equal-Channel Angular Pressing

Effect of Scandium and Other Transition Metals on the Recrystallization of Al–Mg2Si Alloys after Equal-Channel Angular Pressing

Response to Geoffrey Neuss on how to teach the 4s and 3d orbital conundrum

In the accompanying article in this issue Neuss challenges the explanation that was first suggested by Schwarz for how to teach the relative occupation and ionization of atomic orbitals in the atoms of metals in the first transition series. The present article is a response to Neuss’ critique which includes a detailed examination of his claim that there is no conclusive evidence for the view that the scandium and other first transition metal atoms lose 4s electrons in preference to those located in 3d orbitals.

Synthesis and surface modification of magnetic Fe3O4@SiO2 core-shell nanoparticles and its application in uptake of scandium (III) ions from aqueous media.

The main objective of this work is to produce an eco-friendly and economically nano-adsorbent which can separate scandium metal ions Sc from a model aqueous phase prior to applying these adsorbents in industrial filed. The magnetic core-shell structure Fe3O4@SiO2 nanoparticles were synthesized by modified Stöber method and functionalized with (3-aminopropyl) triethoxysilane APTES as a coupling agent and ethylenediaminetetraacetic acid (EDTA) as a ligand. Magnetic nano support adsorbents exhibit many attractive opportunities due to their easy removal and possibility of reusing. The ligand grafting was chemically robust and does not appreciably influence the morphology or the structure of the substrate. To evaluate the potential, the prepared hybrid nanoparticles were used as nano-adsorbent for Sc ions from model aqueous solutions due to the fact that rare earth elements (REEs) have a strong affinity for oxygen and nitrogen donors. The iron oxide nanoparticles were prepared by co-precipitation method at pH 10 and pH 11 to get the best morphology and nanoscale dimensions of iron oxide magnetic nanoparticles. The particle size, morphology, specific surface area, and surface modification were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), vibrating sample magnetometer (VSM), and X-ray powder diffraction (XRD). The results showed that the Fe3O4 nanoparticles with average particle size of 15 ± 3 nm were successfully synthesized at pH 11, and 25 °C. Moreover, the prepared Fe3O4 nanoparticles were coated with amorphous SiO2 and functionalized with amino and carboxyl groups. The adsorption study conditions of Sc are as follows: the initial concentrations of the Sc model solution varied 10-50 mg/L, 20 mL volume, 20-80 mg of the Fe3O4@SiO2-COO adsorbent, pHrange of 1-5, and 5 h contact time at 25 °C temperature. The adsorption equilibrium was represented with Langmuir, Freundlich, and Temkin isotherm models. Langmuir model was found to have the correlation coefficient value in good agreement with experimental results. However, the adsorption process followed pseudo-second-order kinetics.

Novel Hybrid Nanoparticles: Synthesis, Functionalization, Characterization, and Their Application in the Uptake of Scandium (III)Ions from Aqueous Media.

The aim of this study was to prepare novel supramolecular hybrid nanoparticles (HNPs) that can selectively separate and recover scandium metal ions, Sc(III), from an aqueous phase based on molecular recognition technology (MRT). Moreover, this approach is fully compatible with green chemistry principles. In this work, natural amorphous silica (SiO2) nanoparticles were prepared by a precipitation method from Iraqi rice husk (RH) followed by surface modification with 3-amino-propyl triethoxysilane (APTES) as coupling agent and Kryptofix 2.2.2 (K2.2.2) as polycyclic ligand. To evaluate the potential of the hybrid nanoparticles, the prepared HNPs were used for the solid–liquid extraction of scandium, Sc(III), ions from model solutions due to the fact that K2.2.2 are polycyclic molecules. These polycyclic molecules are able to encapsulate cations according to the corresponding cavity size with the ionic radius of metal by providing a higher protection due their cage-like structures. Moreover, the authors set the objectives to design a high-technology process using these HNPs and to develop a Sc recovery method from the aqueous model solution prior to employing it in industrial applications, e.g., for Sc recovery from red mud leachate. The concentrations of Sc model solutions were investigated using the UV-Vis spectrophotometer technique. Different characterization techniques were used including scanning electron microscope (SEM), atomic force microscopy (AFM), Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), X-ray fluorescence (XRF), and Fourier transform infrared (FTIR). The extraction efficiency of Sc varied from 81.3% to 96.7%. Moreover, the complexed Sc ions were efficiently recovered by HCl with 0.1 mol/L concentration. The stripping ratios of Sc obtained ranged from 93.1% to 97.8%.

Carbonization processing of bauxite residue as an alternative rare metal recovery process

A prerequisite for commercial production of rare metals is a continuous effort given to developing knowledge-intensive recovery and refining techniques. Commonly known natural raw materials and conventional processing techniques, which are based on initial acid activation and recovery of minerals, as well as selective recovery of the target component (i.e. by sorption and extraction) cannot always ensure sufficient productivity or cost-effectiveness. This paper considers certain aspects of continued research in this area, which would require novel techniques. Such techniques should be based on new approaches allowing for the use of alternative raw materials to produce valuable rare metals on a cost-effective basis. It is demonstrated that red mud, i.e. waste material generated by bauxite industry and rich in scandium and other rare metals, can serve as such alternative source material. The paper describes the results of a study that looked at finding an optimum carbonization process for red mud that would ensure a consistent and predictable complexing process with regard to certain components. The paper also examines the environment in which soluble carbonate complexes can be stabilized and concentrated in the pregnant solution before the primary scandium-bearing concentrate can be recovered. The authors identified target parameters that determine enhanced filtration properties of carbonized slurry to ensure complete separation of the pregnant solution from the dehydrated (to the residual moisture content of 18%) carbonized residue. The paper highlights some positive factors of the carbonization process which enable a comprehensive utilization of alumina production waste. They include a long-term sequestration of carbon dioxide in the air and modified physical and chemical properties of red muds. This makes carbonized muds more compactable and thus more suitable for transportation and minimizes waste disposal hazards. The experimental research was carried out in conformance with the governmental assignments of the Institute of Solid State Chemistry of the Ural Branch of the Russian Academy of Sciences and Saint-Petersburg Mining University.

A Scandium MOF with an Unprecedented Inorganic Building Unit, Delimiting the Micropore Windows.

A new scandium metal-organic framework (Sc-MOF) with the composition of [Sc(OH)(OBA)], denoted as Sc-CAU-21, was prepared under solvothermal reaction conditions using 4,4'-oxidibenzoic acid (H2OBA) as the ligand. Single-crystal structure determination revealed the presence of the new inorganic building unit (IBU) {Sc8(μ-OH)8(O2C)16}. It is composed of cis-connected ScO6 polyhedra forming an eight-membered ring through bridging μ-OH groups. The connection of the IBUs leads to a 3D framework, containing 1D pores with a diameter between 4.2 and 5.6 Å. Pore access is limited by the size of the IBU, and in contrast to the isoreticular aluminum compound Al-CAU-21 [Al(OH)(OBA)], which is nonporous toward nitrogen at 77 K, Sc-CAU-21 exhibits a specific surface area of 610 m2 g-1. The title compound is thermally stable in air up to 350 °C and can be employed as a host for photoluminescent ions. Sc-CAU-21 exhibits a ligand-based blue emission, and (co)substituting Sc3+ ions with Ln3+ ions (Eu3+, Tb3+, and Dy3+) allows the tuning of the emitting color of the phosphor from red to green. Single-phase white-light emission with CIE color coordinates close to the ideal for white-light emission was also achieved. The luminescence property was utilized in combination with powder X-ray diffraction to study in situ the crystallization process of Sc-CAU-21:Tb and Sc-CAU-21:Eu. Both studies indicate a two-step crystallization process, with a crystalline intermediate, prior to the formation of Sc-CAU-21:Ln.

Scandium Metal–Organic Frameworks Containing Tetracarboxylate Linker Molecules: Synthesis, Structural Relationships, and Properties

Three structurally related metal–organic frameworks (MOFs) of composition [Sc2(OH)2(L)] denoted Sc-CAU-9-PTCDA, Sc-CAU-9-TCPB, and Sc-CAU-9-H2TCPP containing the tetratopic linker molecules L14– = PTCDA4– (perylene-3,4,9,10-tetracarboxylate), L24– = TCPB4– (1,2,4,5-tetrakis(4-carboxylatophenyl)-benzene), or L34– = H2TCPP4– (meso-tetra(4-carboxylatophenyl)-porphyrin), have been obtained from solvothermal syntheses. The crystal structures were determined from powder X-ray diffraction data. The title compounds contain chains of trans corner-sharing [ScO6] octahedra, connected by the linker molecules to form three-dimensional networks. Depending on the shape of the respective linker the compounds crystallize in a frz or fry topology and with increasing size of the linker, an expansion of the framework and the formation of accessible channels are observed. The compounds were thoroughly characterized and exhibit high thermal stabilities up to 500 °C. Sc-CAU-9-TCPB and Sc-CAU-9-H2TCPP possess permanent porosity toward nitrogen with specific surface areas of asBET = 1350 m2/g and 650 m2/g, respectively. Luminescence measurements revealed a ligand-based emission in the blue spectral region for Sc-CAU-9-TCPB.

Scandium extraction from multicomponent systems by crystallization of complex sulfates

Red mud generated from alumina production is one of the most promising scandium resources. Leaching for concentrating scandium and other valuable metals is often performed with the use of acid solutions in specially selected conditions. Different precipitants can be employed for selective precipitation of scandium in the form of poorly soluble compounds. A new method for the crystallization of ammonium scandium sulfates from sulfuric solutions was carried out in this study. Depending on the ammonium cation concentration, precipitation is possible in the form of NH4Sc(SO4)2 or (NH4)3Sc(SO4)3. The solubility values for NH4Sc(SO4)2 and (NH4)3Sc(SO4)3 in water established by the isothermal saturation method were 9.02 and 12.89 g/l Sc2O3, respectively. Complete precipitation of the most promising gravimetric form of scandium represented by NH4Sc(SO4)2 was achieved at 5-6 M H2SO4 and 0.5 M NH4 +. The product of crystallization from sulfuric solution used for treating poor scandium concentrate produced from red mud is a mixture of polymorphs of the composition NH4Sc(SO4)2. Co-precipitated impurities of Al, Fe, Ti, Zr etc. are separated after repeated dissolution and precipitation of ammonium scandium sulfate under analogous conditions. The recrystallization product after calcination at 1000°C contains 99% Sc2O3.

Ресурсы стратегического минерального сырья Республики Бурятия: состояние и перспективы развития

The study is aimed at determining the current state and prospects of strategic mineral resources development in the Republic of Buryatia for use in knowledge-based high-tech industries of the Russian Federation. Comprehensive geological, geophysical and forecast metallogenic studies have been carried out based on the previously conducted geological survey, prospecting, exploration, and research work. To analyze the ores’ material composition and to establish the genetic types of the strategic mineral deposits, advanced mineralogical, petrological, geochemical, and isotope geochronological methods have been used. It has been established that the geological structure of the region is determined by its position in the folded frame of the Siberian platform south. The formation of the strategic mineral deposits of various genetic types is associated with the favorable tectonic-magmatic and ore-bearing structures distinguished in the region. Of primary commercial importance are the deposits and occurrences discovered in the region: beryllium, tungsten, molybdenum, uranium, gold, lead, silver, nickel, platinum, titanium, as well as aluminum, pure quartz raw materials, cadmium, indium, thallium, scandium, strontium, barium, rare and trace metals. The Republic of Buryatia has significant reserves of strategic metals capable to meet the needs of certain high-tech industries in the country. Over 700 mineral deposits are concentrated here, of which about 600 have been inventoried in the state balance. The study has identified over 20 types of mineral raw materials as demanded strategic resources.

Correlation of Auger electron spectroscopy and microsynchrotron radiation x-ray photoelectron spectroscopy investigations of Ba-Sc-O desorption on W(100)

Thin films of barium and scandium metal were deposited onto W(100) from metal evaporation sources in ultrahigh vacuum. The Ba-Sc-W(100) surface was then exposed to oxygen and heated in stages to several temperatures up to 1400 °C to examine the desorption behavior of these adsorbates. In one case, microsynchrotron radiation x-ray photoelectron spectroscopy (micro-SRXPS) was performed on this surface using a low energy electron microscope. In another experiment, reported here, Auger electron spectroscopy data were collected from the Ba-Sc-O-W(100) surface as a function of heating to temperatures corresponding to the same temperatures used for the micro-SRXPS. Both measurements show that barium desorbs with scandium and oxygen at or below 800 °C.

Compelling Case for Fostering Titanium-45 for Positron Emission Tomography Tracer Applications.

The growth of diagnostic nuclear medicine is substantially based on the development, availability, and regular clinical use of cyclotron-based positron emission tomography (PET) tracers. Apart from 18F (110 min) products, the radiometal 68Ga isotope (68 min) has found an increasingly wide clinical acceptance. There is hence much merit in identifying and fostering other radiometal positron emitters, of preferably longer half-life. Titanium-45 (3.08 h) fits the bill well in this context, as it is easy to produce using natural scandium metal target and Ep of 13–14 MeV for 45Sc(p, n) 45Ti reaction. This Commentary cites a compelling case to foster the development of 45Ti products for PET imaging.

A new 4Σ − a4Π electronic transition of ScC in the near infra-red

A new 4Σ − a4Πi electronic transition of ScC with (0,0) band near 12,700 cm−1 has been discovered using laser-induced fluorescence, following the reaction of laser-ablated scandium metal with acetylene or methane under supersonic jet-cooled conditions. The new bands are weak, since the a4Πi lower state is known from previous work to lie 160 cm−1 above the X2Π ground state; several spectra needed to be co-added in order to improve the signal-to-noise ratio. The rotational structure of the new transition is dense and heavily blended, but analysis has been possible for the strongest sub-bands of the (1,0) and (2,0) bands, respectively at 13,301 and 13,899 cm−1; extensive use was made of a band contour program for 4Σ − 4Π bands which listed the details of each line that it plotted. The bond length in the new 4Σ state is r0 = 1.964 Å, which is 0.01 Å longer than in the ground state; its vibrational frequency is 607 cm−1. There is no information in the spectrum giving the Kronig symmetry of the new state, though its electron configuration is probably (C 2pσ)1 (C 2pπ)2 (Sc 4sσ)1 (Sc 3dδ)1. Unexpectedly, the spin-spin interaction parameter, λ, in the new 4Σ state is negative, which suggests complicated interactions with nearby unseen electronic states.

Scandium function in “scandate” thermionic cathodes: A microspot synchrotron radiation x-ray photoelectron spectroscopy study of co-adsorbed Ba-Sc-O on W(100)

The coadsorption of barium, scandium, and oxygen on W(100) was investigated with microspot synchrotron radiation x-ray photoelectron spectroscopy ( μ-SRXPS) in the emission microscope at the electron-spectro-microscopy beam line at the National Synchrotron Light Source II. The Ba-Sc-O-W(100) system is a model for “scandate” thermionic electron emitters. The barium 4d, tungsten 4f, and scandium 3p (Sc3p) levels were observed after metal deposition and adsorption of oxygen. The initial deposits of metallic scandium and barium were confirmed with μ-SRXPS. After oxygen adsorption, the Sc3p peaks shifted to higher binding energy (by >4 eV), indicating the formation of Sc2O3 or a related compound. After heating to 800 °C, the barium 4d peaks were no longer observed. The shifted Sc3p peak was also absent. The results indicate that scandium acts as a cleaning agent to remove oxygen from the tungsten surface. The oxidized scandium is removed by reaction with barium and desorption below 800 °C. The temperature of desorption indicates that scandium does not remain on the surface at a temperature where a contribution to the reduction of the surface barrier to electron emission could be expected.

Synthesis, 45Sc NMR characterization, and interconversion of structurally diverse scandium chloride hydrates

The dissolution of scandium metal (Sc°) in concentrated hydrochloric acid was found to generate a wide variety of products based on the reaction/processing conditions. The compounds [Sc(H2O)6]3[Cl] (1) and [ScCl2(H2O)4][Cl]·H2O (2) were isolated from the above reaction when an ice bath is used. If the reaction was allowed to warm uncontrolled during synthesis, [Sc(μ-OH)(H2O)5]24[Cl]·2H2O (termedOH) was produced. If 1 or 2 were heated (130 °C) in toluene or H2O, [ScCl2(H2O)4][ScCl4(H2O)2] (3) crystallized. Interconversion of the various hydrates and OH structure were studied via 45Sc NMR spectroscopy studies. Efforts to easily dehydrate 2 through the addition of a Lewis base led to the characterization of monohydrate solvates: [ScCl3(THF)2(H2O)]·THF (4·THF) or [ScCl3(κ2-DME)(H2O)] (5) where THF = tetrahydrofuran and DME = dimethoxyethane. In contrast, the use of pyridine formed [Sc(μ-OH)(Cl)2(py)2]2·py (6) where py = pyridine. The formation of the OH moiety is attributed to the higher reaction temperatures achieved using py as the solvent. These compounds were also characterized using 45Sc NMR spectroscopy and compared to commercial ScCl3 dissolved in the parent solvent.

Modern condition and proposed solutions for processing chloride waste of titanium-magnesium production

The problem of utilization of chloride wastes formed in the production of sponge titanium from ilmenite concentrates in the process of Krol and metallic magnesium by electrolysis from natural carnallite is considered. Technogenic chlorinated wastes represent a significant danger to the environment, polluting soils and natural waters when they are released into the atmosphere, when acidic industrial wastewater is discharged into water bodies, when solid wastes are placed in sludge storages. Chloride wastes of titanium production are effective additives in drilling muds, improving the various structural and mechanical properties of the latter. A method for neutralizing chlorine-containing waste is proposed by transferring it into a water-insoluble, low-toxic form by neutralizing acidic pulps with lime milk. With chloride waste, potassium, magnesium, niobium, tantalum, scandium, manganese, chromium and other valuable metals are lost. In the waste of titanomagnesium production there are also rubidium and cesium, the distribution of which by industrial products and wastes is not sufficiently studied. An overview of ecologically safe, economically viable technologies for the processing of chloride wastes is presented, which showed the possibility of extracting scandium, niobium and rare earth elements and returning to the production of titanium and magnesium. In connection with the depletion of mineral raw materials sources of rare metals, processing of man-made waste is relevant and promising.

Goethite, a tailor-made host for the critical metal scandium: The FexSc(1-x)OOH solid solution

Scandium is the subject of increasing interest and is even becoming critical for a number of institutions in Europe and the U.S.A. among others because of its economic value and supply risk. Despite this growing awareness, little is known about its geochemical behaviour. Recent studies have shown that Sc can be strongly associated with iron oxides including goethite but the mode of interaction is not yet fully understood. We investigated the incorporation of Sc in goethite structure in controlled batch systems. For the first time, we show the formation of a solid alpha FeOOH-aScOOH solution consistent with an ideal solution despite significant differences in atomic radii between Sc3+ and Fe3+. We believe that beyond this fundamental knowledge concerning the affinity of Sc for goethite, these results provide important insights into Sc speciation in primary or secondary sources, including Sc-rich lateritic deposits and bauxite residues after alumina extraction, for the future design of extraction processes with a low environmental footprint, as an alternative to current energy-intensive technologies.