Phospahting coated WE43 magnesium alloy was prepared by an immersion method. The microstructure, corrosion resistance and biocompatibility of the coated alloy were investigated. Scanning electron microscopy （SEM） an...Phospahting coated WE43 magnesium alloy was prepared by an immersion method. The microstructure, corrosion resistance and biocompatibility of the coated alloy were investigated. Scanning electron microscopy （SEM） and X-ray diffraction （XRD） were used to examine the microstructure and the composition of the coated alloy. The corrosion resistance was studied by means of potentiodynamic polarization method and the biocompatibility of the surface modified WE43 alloy was evaluated by （3-（4,5）-Dimethylthiazol-2, yl）-2,5-diphenyltetrazolium bromide （MTT） and hemolysis test. The results show that the phosphating coating can enhance the corrosion resistance of WE43 alloy and can be a good candidate to increase the biocompatibility of WE43 alloy.展开更多
Silicate sol post-treatment was applied to form a complete composite coating on the phosphated zinc layer. The chemical compositions of the coatings were investigated using XPS. The coated samples were firstly scratch...Silicate sol post-treatment was applied to form a complete composite coating on the phosphated zinc layer. The chemical compositions of the coatings were investigated using XPS. The coated samples were firstly scratched and then exposed to the neutral salt spray(NSS) chamber for different time. The microstructure and chemical compositions of the scratches were studied using SEM and EDS. And the non-scratched coated samples were compared. The self-healing mechanism of the composite coatings was discussed. The results show that during corrosion, the self-healing ions in composite coatings dissolve, diffuse and transfer to the scratches or the defects, and then recombine with Zn2+ to form insoluble compound, which deposits and covers the exposed zinc. The corrosion products on the scratches contain silicon, phosphorous, oxygen, chloride and zinc, and they are compact, fine, needle and flake, effectively inhibiting the corrosion formation and expansion of the exposed zinc layer. The composite coatings have good self-healing ability.展开更多
Hydroxylamine sulfate （HAS） and sodium nitrite are used as the accelerators for zinc phos- phate coating on high carbon steel. Phase evolution of phosphate coating was investigated by X-ray diffraction. It is found ...Hydroxylamine sulfate （HAS） and sodium nitrite are used as the accelerators for zinc phos- phate coating on high carbon steel. Phase evolution of phosphate coating was investigated by X-ray diffraction. It is found that the phosphating coatings are mainly composed of hopeite Zn3Fe（PO4）2.4H2O and phosphophyllite Zn2Fe（PO4）2.4H2O. The microstructural changes of the phosphate coating, as a function of phosphating time, were evaluated by scanning elec- tron microscopy. Four-ball friction experiments reveal that hydroxylamine sulfate instead of sodium nitrite can effectively reduce the friction coefficient of lubricated phosphating coat- ing. Therefore, it may be expected that HAS will be widely used as a fast and ECO-friendly accelerator in phosphate industry.展开更多
The corrosion behavior of a NdFeB magnet obtained at room temperature,with and without ultrasonic were investigated.The corrosion resistance was investigated by corrosion immersion tests in 3 wt%neutral NaCl solutions...The corrosion behavior of a NdFeB magnet obtained at room temperature,with and without ultrasonic were investigated.The corrosion resistance was investigated by corrosion immersion tests in 3 wt%neutral NaCl solutions,potentiodynamic polarization tests and electrochemical impedance spectroscopy(EIS).The morphology of the conversion coatings on NdFeB surface were analyzed by scanning electron microscopy(SEM).And the forming mechanism of coatings was studied by potential-time curves.The tests of corrosion resistances show that the combination of phosphating treatment with ultrasonic will further improve the corrosion resistance of the NdFeB.The SEM also confirms that phosphating coating under ultrasonic is more homogeneous and compact.展开更多
Designing non-noble metal electrocatalysts toward alkaline hydrogen evolution reaction(HER)with high performance at a large current density is urgent.Herein,a CoO/CoP heterostructure catalyst(termed POZ)was designed b...Designing non-noble metal electrocatalysts toward alkaline hydrogen evolution reaction(HER)with high performance at a large current density is urgent.Herein,a CoO/CoP heterostructure catalyst(termed POZ)was designed by a phosphating strategy.The strong electron transfer on the interface of CoO/CoP was experimentally and theoretically proven.POZ showed a low overpotential of 236 mV at 400 mA/cm^(2),which was 249 mV lower than non-phosphated sample.It also exhibited a remarkable solar-to-hydrogen conversion efficiency of 10.5%.In this work,the construction of CoO/CoP interface realized by a simple phosphating strategy could provide an important reference to boost the HER performance on those materials not merely metal oxides.展开更多
Transition metal phosphide(TMP) based electrocatalysts possessing special crystal and electronic structures attract broad attention in the field of electrocatalysis.Immense effort is made to optimize TMP catalysts aim...Transition metal phosphide(TMP) based electrocatalysts possessing special crystal and electronic structures attract broad attention in the field of electrocatalysis.Immense effort is made to optimize TMP catalysts aiming to satisfy the electrochemical catalysis performance.In this work,an environmentally friendly in situ green phosphating strategy and spatial limiting effect of the RuCo precursor is employed to fabricate the ruthenium nanoclusters anchored on cobalt phosphide hollow microspheres(Ru NCs/Co_(2)P HMs).The obtained Ru NCs/Co_(2)P HMs electrocatalysts exhibit high hydrogen evolution reaction(HER) activity at wide pH ranges,which require an overpotential of 77 mV to achieve the current density of 10 mA/cm^(2) in 0.5 mol/L H_(2)SO_(4) and 118 mV in 1.0 mol/L KOH.Besides,the multifunctional Ru NCs/Co_(2)P HMs exhibit good oxygen evolution reaction(OER) activity with an overpotential of 197 mV to reach the current density of 10 mA/cm^(2) in 0.5 mol/L H_(2)SO_(4),which is below that of the commercial RuO_(2) electrocatalyst(248 mV).A two-electrode electrolyzer is assembled as well,in acid electrolyte,it achieves a current density of 10 mA/cm^(2) at a voltage of 1.53 V,which is superior to that of the benchmark of precious metal-based electrolyzer(1.58 V).展开更多
Zinc phosphate coating formed on 6061-A1 alloy was studied with the help of electrochemical measurements, Fourier Transform Infrared （FTIR）, and Scanning Electron Microscopy （SEM）, after dipping it in phosphating ...Zinc phosphate coating formed on 6061-A1 alloy was studied with the help of electrochemical measurements, Fourier Transform Infrared （FTIR）, and Scanning Electron Microscopy （SEM）, after dipping it in phosphating solutions containing different concentrations of Rare Earth Nitrate （REN）. REN, which acted as an accelerator in the phosphating solution, could catalyze the surface reaction and accelerate the phosphating process. REN mainly enabled the P in the phosphate coating to exist in the form of PO4^3- and promoted the hydrolysis of phosphatic acid in a liquid layer at the cathodes. This resulted in the evolution of H2 at the cathodes, which increased the local pH value and in turn drove the precipitation of the phosphate coating. Additionally, REN was adsorbed on the surface of the aluminum substrates to form a gel during the phosphating process. These gel particles were good crystal seeds, which helped to form phosphate crystal nuclei and possess the function of a nucleation agent that could decrease the phosphate crystal size. The corrosion resistance of the formed zinc phosphate coatings was improved.展开更多
To improve the corrosion resistance of phosphate coatings, the phosphated hot-dip galvanized (HDG) steel was post-sealed with cerium nitrate solution. The morphology, composition, corrosion resistance of the coatings ...To improve the corrosion resistance of phosphate coatings, the phosphated hot-dip galvanized (HDG) steel was post-sealed with cerium nitrate solution. The morphology, composition, corrosion resistance of the coatings was investigated by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and neutral salt spray (NSS) tests. The results show that after post-sealing the phosphated HDG samples with cerium nitrate solution, the pores among the zinc phosphate crystals are sealed by the compounds containing phosphorus, oxygen and cerium; the zinc phosphate crystals are covered by the flocculent cerium compounds; and the continuous composite coatings are formed on HDG steel. The corrosion resistance of the composite coatings, which increases with the increase in phosphating time and cerium nitrate post-sealing time, is far higher than that of the single phosphate coatings. The composite coatings with the optimal corrosion resistance are obtained for phosphating 300 s and post-sealing 300 s; and the corrosion resistance is more outstanding than that of the chromate coatings.展开更多
The phosphated and cerium nitrate post-sealed galvanized steel was firstly scratched to expose zinc layer and then placed in neutral salt spray （NSS） chamber for different durations. The microstructure and compositi...The phosphated and cerium nitrate post-sealed galvanized steel was firstly scratched to expose zinc layer and then placed in neutral salt spray （NSS） chamber for different durations. The microstructure and compositions of the scratches were investigated using SEM and EDS. The phases of the corrosion products were examined through XRD. The self-healing mechanism of the composite coatings was discussed. The experimental results show that the composite coatings have an excellent corrosion resistance. The corrosion products increase with corrosion time and finally cover the whole scratch. They contain phosphorous, cerium, oxygen, chloride and zinc, and are fine needle and exceedingly compact. The composite coatings are favorable self-healing. During corrosion, the self-healing ions such as Ce3＋, Ce4＋, PO43-, Zn2＋ in the composite coatings were dissolved, migrated, recombined, and covered the exposed zinc, impeding zinc corrosion. The self-healing process of the scratches on the composite coatings can be divided into three stages, about 2 h, 4 h, and 24 h, respectively.展开更多
Zinc phosphate coatings formed on 6061-Al alloy, after dipping in phosphating solutions containing different amounts of Y2O3（yttrium oxide）, were studied by scanning electron microscopy （SEM）, X-ray diffraction （...Zinc phosphate coatings formed on 6061-Al alloy, after dipping in phosphating solutions containing different amounts of Y2O3（yttrium oxide）, were studied by scanning electron microscopy （SEM）, X-ray diffraction （XRD） and electrochemical measurements. Significant variations in the morphology and corrosion resistance afforded by zinc phosphate coating were especially observed as Y2O3 in phosphating solution varied from 0 to 40 mg/L. The addition of Y2O3 changed the initial potential of the interface between aluminum alloy substrate and phosphating solution and increased the number of nucleation sites. The phosphate coating thereby was less porous structure and covered the surface of aluminum alloy completely within short phosphating time. Phosphate coating was mainly composed of Zn3（PO4）2·4H2O （hopeite） and AlPO4（aluminum phosphate）. Y2O3, as an additive of phosphatization, accelerated precipitation and refined the gain size of phosphate coating. The corrosion resistance of zinc phosphate coating in 3% NaCl solution was improved as shown by polarization measurement. In the present research, the optimal amount of Y2O3 was 10-20 mg/L, and the optimal phosphating time was 600 s.展开更多
Phosphorus plays an indispensable role in the food chain,yet phosphorus mineral resources are finite,underscoring the urgency for developing a closed-loop phosphorus economy.Although there have been advances in phosph...Phosphorus plays an indispensable role in the food chain,yet phosphorus mineral resources are finite,underscoring the urgency for developing a closed-loop phosphorus economy.Although there have been advances in phosphorus recovery from various waste materials,modern agriculture still depends on adequate phosphorus supply to support plant growth.In this study,we explored the amorphization of Ox bone using phytic acid(OxPA),and investigated how varying treatment durations influence the resulting structure.Inductively Coupled Plasma(ICP)analysis was employed to quantify phosphate solubilization.Additionally,pot experiments were conducted to assess the phosphate efficiency of Ox-PA in comparison to untreated Ox bone and control group.The results showed that Ox-PA exhibited significantly higher phosphate solubilization(2973 ppm)than untreated counterpart(13 ppm).When used as a fertilizer,Ox-PA markedly enhanced both aboveground and belowground biomass and root development in maize plants.Moreover,it facilitated increased phosphorus uptake by the plants during their early growth stages.These findings indicate that Ox-PA not only holds significant potential for promoting agronomic sustainability but also contributes meaningfully to the establishment of a circular phosphorus economy.展开更多
While nuclear energy represents a low-carbon and high-efficiency energy source that plays a vital role in the global energy mix,the limitations of spent fuel reprocessing technology pose a major challenge to its susta...While nuclear energy represents a low-carbon and high-efficiency energy source that plays a vital role in the global energy mix,the limitations of spent fuel reprocessing technology pose a major challenge to its sustainable development.The PUREX(plutonium uranium redox extraction)process is currently the dominant nuclear fuel reprocessing technology in the world.However,the key extractant in this process is tributyl phosphate(TBP),which degrades under intense radiation,high temperatures,and strong acidity.This leads to the production of dibutyl phosphate,monobutyl phosphate,and other degradation byproducts,which may reduce the extraction efficiency and trigger third-phase formation and equipment corrosion.This paper systematically reviews the degradation mechanisms of TBP and its diluents,the analytical technique suitable for characterizing degradation products,and the impact of degradation products on the post-treatment process.Additionally,optimization strategies employed for suppressing third-phase formation are discussed.This study offers a theoretical foundation and technical insights in optimizing the PUREX process and ensuring the safe operation of the post-treatment process.展开更多
For India to achieve elimination by 2030,the challenges posed by Plasmodium(P.)vivax cannot be overlooked owing to its burden and unique biology.In 2023,in India,about 224000 malaria cases were reported,and a signific...For India to achieve elimination by 2030,the challenges posed by Plasmodium(P.)vivax cannot be overlooked owing to its burden and unique biology.In 2023,in India,about 224000 malaria cases were reported,and a significant proportion(40%)were P.vivax cases.In P.vivax infection,the persistence of dormant liver stage of parasite,i.e.,hypnozoites,leading to relapses weeks or months later poses challenge in its elimination.展开更多
Waterborne acrylic coatings are widely utilized due to their cost-effectiveness,high transparency,strong resistance to weather and chemicals,impressive mechanical properties,and excellent adhesion to various substrate...Waterborne acrylic coatings are widely utilized due to their cost-effectiveness,high transparency,strong resistance to weather and chemicals,impressive mechanical properties,and excellent adhesion to various substrates.In these coatings,a reactive emulsifier containing phosphate groups can be integrated into the molecular chain during polymerization,which enhances the coating's compactness and corrosion resistance.This work focuses on the synthesis of styrene-butyl acrylate(St-BA)latex and methyl methacrylate-butyl acrylate(MMA-BA)latex using the reactive phosphate emulsifier ANPEO_(10)-P_(1) through seed emulsion polymerization,achieving a conversion rate of approximately 99%and a solid content close to 50%.The resulting coatings from St-BA and MMA-BA latexes demonstrated long-term corrosion protection for carbon steel and aluminum alloy due to in-situ phosphatization,effectively preventing flash rust.Notably,the MMA-BA coating exhibited remarkable durability,enduring immersion for up to 1224 h(51 d)on Q 235 carbon steel before reaching the failure threshold(|Z|0.01 Hz£106Ω·cm^(2))on Q 235 carbon steel.On 5052 aluminum alloy,the St-BA coating maintained|Z|0.01 Hz>10^(8)Ω·cm^(2) for 480 h(20 d).Furthermore,the corrosion resistance of St-BA and MMA BA coatings on Q 235 steel sheet and 5052 aluminum alloy surpassed that of commercially available MMA-BA and St BA coatings after immersion in a 3.5 wt%NaCl aqueous solution.This work also delves into the anticorrosion mechanism of MMA-BA and St-BA coatings.展开更多
The soaring demand for smart portable electronics and electric vehicles is propelling the advancements in high-energy–density lithium-ion batteries.Lithium manganese iron phosphate(LiMn_(x)Fe_(1-x)PO_(4))has garnered...The soaring demand for smart portable electronics and electric vehicles is propelling the advancements in high-energy–density lithium-ion batteries.Lithium manganese iron phosphate(LiMn_(x)Fe_(1-x)PO_(4))has garnered significant attention as a promising positive electrode material for lithium-ion batteries due to its advantages of low cost,high safety,long cycle life,high voltage,good high-temperature performance,and high energy density.Although LiMn_(x)Fe_(1-x)PO_(4)has made significant breakthroughs in the past few decades,there are still facing great challenges in poor electronic conductivity and Li-ion diffusion,manganese dissolution affecting battery cycling performance,as well as low tap density.This review systematically summarizes the reaction mechanisms,various synthesis methods,and electrochemical properties of LiMn_(x)Fe_(1-x)PO_(4)to analyze reaction processes accurately and guide material preparation.Later,the main challenges currently faced are concluded,and the corresponding various modification strategies are discussed to enhance the reaction kinetics and electrochemical performance of LiMn_(x)Fe_(1-x)PO_(4),including multi-scale particle regulation,heteroatom doping,surface coating,as well as microscopic morphology design.Finally,in view of the current research challenges faced by intrinsic reaction processes,kinetics,and energy storage applications,the promising research directions are anticipated.More importantly,it is expected to provide key insights into the development of high-performance and stable LiMn_(x)Fe_(1-x)PO_(4)materials,to achieve practical energy storage requirements.展开更多
Guided bone regeneration in the alveolar bone relies on the colonization and differentiation of immune cells within the defect area.The absence of osteoinductive and osteoimmune properties of currently available scaff...Guided bone regeneration in the alveolar bone relies on the colonization and differentiation of immune cells within the defect area.The absence of osteoinductive and osteoimmune properties of currently available scaffolds hinders to achieve optimal repair outcomes in clinical settings.Thus,we aimed to enhance the bone repair ability of polycaprolactone(PCL)scaffolds by incorporating osteoinductive amorphous calcium phosphate(ACP)with immune-regulating zinc ions(ACP(Zn),ACZP),to create a favorable immunomodulatory microenvironment.After one day of co-culture with PCL-ACZP,the spreading area of macrophage cells was significantly higher than that from the original PCL scaffold.Additionally,over 32.1%of macrophages exhibited M2 polarization within three days of co-culture.The PCLACZP/macrophage-conditioned medium significantly boosted osteogenic gene expression in MC3T3-E1 cells.After eight weeks of implantation in a rat femoral condyle defect,the BV/TV from the PCL-ACZP group reached 32.9%,1.4 times of that from the PCL group.Furthermore,the PCL-ACZP-GelMA biphasic module as prepared successfully achieved complete regeneration of three-walled alveolar bone defects in rabbits,resulting in arch-shaped alveolar bone repair and providing greater convenience in the clinical settings.This study showcased the effectiveness of PCL-ACZP-GelMA biphasic module as bioactive scaffolds in the morphological restoration of alveolar bone.展开更多
With the boom in electric vehicles(EVs),there is an increasing demand for high-performance lithium-ion batteries.Lithium manganese iron phosphate(LMFP)has emerged as an enhanced variation of LiFePO4(LFP),offering an e...With the boom in electric vehicles(EVs),there is an increasing demand for high-performance lithium-ion batteries.Lithium manganese iron phosphate(LMFP)has emerged as an enhanced variation of LiFePO4(LFP),offering an energy density 10%–20%greater than that of LFP.Structural distortion caused by the Jahn–Teller effect decreases the capacity and voltage platform,thus restricting the commercialization of this material.Herein,ideas to overcome these challenges,including the crystal structure of LMFP and strategies to mitigate the Jahn–Teller distortion,are first explored.Then,the migration pathways of Li+during charging and discharging and the phase transition mechanisms that affect the material’s performance are discussed.Next,the optimal Mn:Fe ratio for achieving the desired performance is described.The influences of various synthesis and modification methods on the morphology and structure of LMFP are reviewed.Additionally,different modification techniques,such as doping and coating,to enhance the performance of LMFP are highlighted.Finally,an overview of the current state of research on the recycling and reuse of LMFP is provided.By addressing these key topics,this paper offers a theoretical foundation for the further development of LMFP,thus contributing to its eventual commercialization.展开更多
In this study,a phosphate-based conversion coating(PCC)was applied as a precursor before forming silicate-fluoride(SiF)and silicate-phosphate-fluoride(SiPF)based flash-plasma electrolytic oxidation(Flash-PEO)coatings ...In this study,a phosphate-based conversion coating(PCC)was applied as a precursor before forming silicate-fluoride(SiF)and silicate-phosphate-fluoride(SiPF)based flash-plasma electrolytic oxidation(Flash-PEO)coatings on AZ31B magnesium alloy.The main novelty is the successful incorporation of calcium,zinc,manganese and phosphate species into the Flash-PEO coatings via a precursor layer rather than using the electrolyte.The precursor also led to longer lasting and more intense discharges during the PEO process,resulting in increased pore size.Corrosion studies revealed similar short-term performance for all coatings,with impedance modulus at low frequencies above 10^(7)Ωcm^(2),and slightly better performance for the SiPF-based coating.Nonetheless,the enlarged pores in the PEO coatings functionalized with the PCC precursor compromised the effectiveness of self-healing mechanisms by creating diffusion pathways for corrosive species,leading to earlier failure.These phenomena were effectively monitored by recording the open circuit potential during immersion in 0.5 wt.%NaCl solution.In summary,this study demonstrates that conversion coatings are a viable option for the functionalization of PEO coatings on magnesium alloys,as they allow for the incorporation of cationic and other species.However,it is crucial to maintain a small pore size to facilitate effective blockage through self-healing mechanisms.展开更多
In this study,synthetic wastewater containing 110μg/L arsenate(As(V)),0-20 mg/L fulvic acid(FA),and 0-12.3 mg/L phosphate was treated with 3 mg/L Fe3+.The mechanisms of FA and phosphate effects on As(V)removal by fer...In this study,synthetic wastewater containing 110μg/L arsenate(As(V)),0-20 mg/L fulvic acid(FA),and 0-12.3 mg/L phosphate was treated with 3 mg/L Fe3+.The mechanisms of FA and phosphate effects on As(V)removal by ferric chloride were determined using 0.22-10μm pore-size filtration,Zetasizer analysis,and in situ flow through cell ATR-FTIR.The results showed that up to 20mg/L FA had almost no effect on the solubility of ferric hydroxide precipitates and adsorption of As(V)by the precipitates.When FA concentration increased from 0 to 20 mg/L,the adsorption of FA led to higher negative zeta potential of the precipitates and the strong electrostatic repulsion between the precipitates decreased the particle size of ferric hydroxide flocs fromlarger than 10μmto smaller than 1μm.In the presence of 5-20 mg/L FA,46%-63%As(V)was adsorbed onto the flocs with particle size in the range of 0.45-1μm.On the other hand,phosphate did not affect the size of ferric hydroxide flocs and significantly increased the dissolved As(V)concentration because it competed with As(V)for adsorption sites on ferric hydroxide precipitates.The addition of 5mg/L cationic organic flocculant significantly reduced the effect of FA on As(V)removal,but did not reduce the effect of phosphate on As(V)removal.The findings of this study will help develop effective arsenic treatment techniques and predict the mobility of arsenic in the environment.展开更多
The green energy transition relies heavily on critical metals,such as rare earth elements(REEs).However,their reserves are primarily focused in a few countries,such as China,which accounts for approximately 70%of glob...The green energy transition relies heavily on critical metals,such as rare earth elements(REEs).However,their reserves are primarily focused in a few countries,such as China,which accounts for approximately 70%of global production.Hence,several countries are currently looking for alternative resources for REEs.Alternative REE resources in the supply chain include recycling of e-waste,industrial waste like red mud and phosphogypsum,coal ash,mine tailings,ocean floor sediments,and even certain types of sedimentary deposits like phosphorites where REEs are present in lower concentrations but at larger volumes compared to primary ore deposits which are becoming targets by REEs industry.Currently,several studies are going on the development of eco-friendly REEs extraction technologies from phosphorite deposits.Consequently,advanced data analysis tools,such as Machine Learning(ML),are becoming increasingly important in mineral prospectivity and are rapidly gaining traction in the earth sciences.Phosphorite deposits are mainly used to manufacture fertilizers as these rocks are known for their significant phosphorus content.Moreover,these formations are considered a prospective resource of REEs.The different types of phosphorite deposits such as continental,seamount,and ore deposits worldwide reported concentrations of∑REE upto 18,000µg/g.Due to the augmented claim of REEs for various ultra-modern,and green technology applications that are required to switch over to a carbon-neutral environment,these phosphorite deposits have become an important target mostly because of their relatively higher content of REEs especially heavy rare earth elements(HREE).For example,Mississippian phosphorites reported ∑ HREE 7,000µg/g.To have a comprehensive understanding of the REEs potential of these phosphorite deposits which also include several Chinese phosphorite deposits,this study is undertaken to review the phosphorite deposits in the world and their REEs potential,in addition to some of the associated aspects such as applications and formation mechanisms for different types of phosphorite deposits such as igneous phosphate deposits,sedimentary phosphorite deposits,marine phosphorite deposits,cave phosphate deposits,and insular guano deposits.Other important aspects include their occurrences,types,geochemical characteristics,the REEs enrichment mechanisms,and various recovery methods adopted to recover REEs from different phosphorite deposits.The present review paper concludes that the recent studies highlight the global potential of phosphorite deposits to satisfy the increasing demand for REEs.Extracting REEs from phosphorite presents no significant technological or environmental difficulties,as long as radioactive elements are eliminated.In India,more comprehensive geological surveys,along with the advancement of new methods and evaluations,are required to locate phosphorite deposits with high concentrations of REEs.展开更多
基金Project(2011AA030103) supported by the National High-tech Research Program of ChinaProject(201001C0104669453) supported by the Guangdong Innovation R&D Team Project,China
文摘Phospahting coated WE43 magnesium alloy was prepared by an immersion method. The microstructure, corrosion resistance and biocompatibility of the coated alloy were investigated. Scanning electron microscopy （SEM） and X-ray diffraction （XRD） were used to examine the microstructure and the composition of the coated alloy. The corrosion resistance was studied by means of potentiodynamic polarization method and the biocompatibility of the surface modified WE43 alloy was evaluated by （3-（4,5）-Dimethylthiazol-2, yl）-2,5-diphenyltetrazolium bromide （MTT） and hemolysis test. The results show that the phosphating coating can enhance the corrosion resistance of WE43 alloy and can be a good candidate to increase the biocompatibility of WE43 alloy.
基金Project(2012J05099)supported by the Natural Science Foundation of Fujian Province,ChinaProject(YKJ10021R)supported by the Scientific Research Project of Xiamen University of Technology
文摘Silicate sol post-treatment was applied to form a complete composite coating on the phosphated zinc layer. The chemical compositions of the coatings were investigated using XPS. The coated samples were firstly scratched and then exposed to the neutral salt spray(NSS) chamber for different time. The microstructure and chemical compositions of the scratches were studied using SEM and EDS. And the non-scratched coated samples were compared. The self-healing mechanism of the composite coatings was discussed. The results show that during corrosion, the self-healing ions in composite coatings dissolve, diffuse and transfer to the scratches or the defects, and then recombine with Zn2+ to form insoluble compound, which deposits and covers the exposed zinc. The corrosion products on the scratches contain silicon, phosphorous, oxygen, chloride and zinc, and they are compact, fine, needle and flake, effectively inhibiting the corrosion formation and expansion of the exposed zinc layer. The composite coatings have good self-healing ability.
基金This work was supported by the Bengbu Yucheng New Materials Science and Technology Ltd. （No.2012QTXM0375） and the Natural Science Foundation of Anhui Province （No.1208085QE99）.
文摘Hydroxylamine sulfate （HAS） and sodium nitrite are used as the accelerators for zinc phos- phate coating on high carbon steel. Phase evolution of phosphate coating was investigated by X-ray diffraction. It is found that the phosphating coatings are mainly composed of hopeite Zn3Fe（PO4）2.4H2O and phosphophyllite Zn2Fe（PO4）2.4H2O. The microstructural changes of the phosphate coating, as a function of phosphating time, were evaluated by scanning elec- tron microscopy. Four-ball friction experiments reveal that hydroxylamine sulfate instead of sodium nitrite can effectively reduce the friction coefficient of lubricated phosphating coat- ing. Therefore, it may be expected that HAS will be widely used as a fast and ECO-friendly accelerator in phosphate industry.
基金Research Foundation of The Education Department of Liaoning Province,China(L2010396)Scientific Research Starting Foundation for the DoctorsShenyang University of Technology,China(2008-33)
文摘The corrosion behavior of a NdFeB magnet obtained at room temperature,with and without ultrasonic were investigated.The corrosion resistance was investigated by corrosion immersion tests in 3 wt%neutral NaCl solutions,potentiodynamic polarization tests and electrochemical impedance spectroscopy(EIS).The morphology of the conversion coatings on NdFeB surface were analyzed by scanning electron microscopy(SEM).And the forming mechanism of coatings was studied by potential-time curves.The tests of corrosion resistances show that the combination of phosphating treatment with ultrasonic will further improve the corrosion resistance of the NdFeB.The SEM also confirms that phosphating coating under ultrasonic is more homogeneous and compact.
基金the financial support from the Hunan Provincial Science and Technology Plan Project(Nos.2017TP1001,2020JJ4710)National Natural Science Foundation of China(No.11764018)+2 种基金the Natural Science Foundation of Jiangxi Province(No.20202ACBL211004)Changsha Science and Technology Plan(No.kq1801079)National Natural Science Foundation of China(No.21776317).
文摘Designing non-noble metal electrocatalysts toward alkaline hydrogen evolution reaction(HER)with high performance at a large current density is urgent.Herein,a CoO/CoP heterostructure catalyst(termed POZ)was designed by a phosphating strategy.The strong electron transfer on the interface of CoO/CoP was experimentally and theoretically proven.POZ showed a low overpotential of 236 mV at 400 mA/cm^(2),which was 249 mV lower than non-phosphated sample.It also exhibited a remarkable solar-to-hydrogen conversion efficiency of 10.5%.In this work,the construction of CoO/CoP interface realized by a simple phosphating strategy could provide an important reference to boost the HER performance on those materials not merely metal oxides.
基金supported by Fundamental Research Funds for Central Universities of SCUT(No.D2182400)Tip-top Scientific and Technical Innovative Youth Talents of Guangdong Special Support Program(No.2016TQ03N541)+1 种基金Guangdong Natural Science Funds for Distinguished Young Scholar(No.2017B030306001)the National Natural Science Foundation of China(No.51972147)。
文摘Transition metal phosphide(TMP) based electrocatalysts possessing special crystal and electronic structures attract broad attention in the field of electrocatalysis.Immense effort is made to optimize TMP catalysts aiming to satisfy the electrochemical catalysis performance.In this work,an environmentally friendly in situ green phosphating strategy and spatial limiting effect of the RuCo precursor is employed to fabricate the ruthenium nanoclusters anchored on cobalt phosphide hollow microspheres(Ru NCs/Co_(2)P HMs).The obtained Ru NCs/Co_(2)P HMs electrocatalysts exhibit high hydrogen evolution reaction(HER) activity at wide pH ranges,which require an overpotential of 77 mV to achieve the current density of 10 mA/cm^(2) in 0.5 mol/L H_(2)SO_(4) and 118 mV in 1.0 mol/L KOH.Besides,the multifunctional Ru NCs/Co_(2)P HMs exhibit good oxygen evolution reaction(OER) activity with an overpotential of 197 mV to reach the current density of 10 mA/cm^(2) in 0.5 mol/L H_(2)SO_(4),which is below that of the commercial RuO_(2) electrocatalyst(248 mV).A two-electrode electrolyzer is assembled as well,in acid electrolyte,it achieves a current density of 10 mA/cm^(2) at a voltage of 1.53 V,which is superior to that of the benchmark of precious metal-based electrolyzer(1.58 V).
基金Project supported by the Henan Natural Science Foundation Program (200460178)
文摘Zinc phosphate coating formed on 6061-A1 alloy was studied with the help of electrochemical measurements, Fourier Transform Infrared （FTIR）, and Scanning Electron Microscopy （SEM）, after dipping it in phosphating solutions containing different concentrations of Rare Earth Nitrate （REN）. REN, which acted as an accelerator in the phosphating solution, could catalyze the surface reaction and accelerate the phosphating process. REN mainly enabled the P in the phosphate coating to exist in the form of PO4^3- and promoted the hydrolysis of phosphatic acid in a liquid layer at the cathodes. This resulted in the evolution of H2 at the cathodes, which increased the local pH value and in turn drove the precipitation of the phosphate coating. Additionally, REN was adsorbed on the surface of the aluminum substrates to form a gel during the phosphating process. These gel particles were good crystal seeds, which helped to form phosphate crystal nuclei and possess the function of a nucleation agent that could decrease the phosphate crystal size. The corrosion resistance of the formed zinc phosphate coatings was improved.
文摘To improve the corrosion resistance of phosphate coatings, the phosphated hot-dip galvanized (HDG) steel was post-sealed with cerium nitrate solution. The morphology, composition, corrosion resistance of the coatings was investigated by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and neutral salt spray (NSS) tests. The results show that after post-sealing the phosphated HDG samples with cerium nitrate solution, the pores among the zinc phosphate crystals are sealed by the compounds containing phosphorus, oxygen and cerium; the zinc phosphate crystals are covered by the flocculent cerium compounds; and the continuous composite coatings are formed on HDG steel. The corrosion resistance of the composite coatings, which increases with the increase in phosphating time and cerium nitrate post-sealing time, is far higher than that of the single phosphate coatings. The composite coatings with the optimal corrosion resistance are obtained for phosphating 300 s and post-sealing 300 s; and the corrosion resistance is more outstanding than that of the chromate coatings.
基金Funded by the National Natural Science Foundation(No.501408517)the Natural Science Foundation of Fujian Province(No.2012J05099)the Pre-research Project of National Natural Science Fund of Xiamen University of Technology(No.XYK201410)
文摘The phosphated and cerium nitrate post-sealed galvanized steel was firstly scratched to expose zinc layer and then placed in neutral salt spray （NSS） chamber for different durations. The microstructure and compositions of the scratches were investigated using SEM and EDS. The phases of the corrosion products were examined through XRD. The self-healing mechanism of the composite coatings was discussed. The experimental results show that the composite coatings have an excellent corrosion resistance. The corrosion products increase with corrosion time and finally cover the whole scratch. They contain phosphorous, cerium, oxygen, chloride and zinc, and are fine needle and exceedingly compact. The composite coatings are favorable self-healing. During corrosion, the self-healing ions such as Ce3＋, Ce4＋, PO43-, Zn2＋ in the composite coatings were dissolved, migrated, recombined, and covered the exposed zinc, impeding zinc corrosion. The self-healing process of the scratches on the composite coatings can be divided into three stages, about 2 h, 4 h, and 24 h, respectively.
基金supported by the Natural Science Foundation of Henan Province (200510476009)
文摘Zinc phosphate coatings formed on 6061-Al alloy, after dipping in phosphating solutions containing different amounts of Y2O3（yttrium oxide）, were studied by scanning electron microscopy （SEM）, X-ray diffraction （XRD） and electrochemical measurements. Significant variations in the morphology and corrosion resistance afforded by zinc phosphate coating were especially observed as Y2O3 in phosphating solution varied from 0 to 40 mg/L. The addition of Y2O3 changed the initial potential of the interface between aluminum alloy substrate and phosphating solution and increased the number of nucleation sites. The phosphate coating thereby was less porous structure and covered the surface of aluminum alloy completely within short phosphating time. Phosphate coating was mainly composed of Zn3（PO4）2·4H2O （hopeite） and AlPO4（aluminum phosphate）. Y2O3, as an additive of phosphatization, accelerated precipitation and refined the gain size of phosphate coating. The corrosion resistance of zinc phosphate coating in 3% NaCl solution was improved as shown by polarization measurement. In the present research, the optimal amount of Y2O3 was 10-20 mg/L, and the optimal phosphating time was 600 s.
基金supported by the International Partnership Program of Chinese Academy of Sciences[027GJHZ2022033GC]the National Natural Science Foundation of China[22278415 and 52225309]。
文摘Phosphorus plays an indispensable role in the food chain,yet phosphorus mineral resources are finite,underscoring the urgency for developing a closed-loop phosphorus economy.Although there have been advances in phosphorus recovery from various waste materials,modern agriculture still depends on adequate phosphorus supply to support plant growth.In this study,we explored the amorphization of Ox bone using phytic acid(OxPA),and investigated how varying treatment durations influence the resulting structure.Inductively Coupled Plasma(ICP)analysis was employed to quantify phosphate solubilization.Additionally,pot experiments were conducted to assess the phosphate efficiency of Ox-PA in comparison to untreated Ox bone and control group.The results showed that Ox-PA exhibited significantly higher phosphate solubilization(2973 ppm)than untreated counterpart(13 ppm).When used as a fertilizer,Ox-PA markedly enhanced both aboveground and belowground biomass and root development in maize plants.Moreover,it facilitated increased phosphorus uptake by the plants during their early growth stages.These findings indicate that Ox-PA not only holds significant potential for promoting agronomic sustainability but also contributes meaningfully to the establishment of a circular phosphorus economy.
基金supported by the Youth Talent Project of China Nuclear Power Engineering Co.,Ltd.(KY24045).
文摘While nuclear energy represents a low-carbon and high-efficiency energy source that plays a vital role in the global energy mix,the limitations of spent fuel reprocessing technology pose a major challenge to its sustainable development.The PUREX(plutonium uranium redox extraction)process is currently the dominant nuclear fuel reprocessing technology in the world.However,the key extractant in this process is tributyl phosphate(TBP),which degrades under intense radiation,high temperatures,and strong acidity.This leads to the production of dibutyl phosphate,monobutyl phosphate,and other degradation byproducts,which may reduce the extraction efficiency and trigger third-phase formation and equipment corrosion.This paper systematically reviews the degradation mechanisms of TBP and its diluents,the analytical technique suitable for characterizing degradation products,and the impact of degradation products on the post-treatment process.Additionally,optimization strategies employed for suppressing third-phase formation are discussed.This study offers a theoretical foundation and technical insights in optimizing the PUREX process and ensuring the safe operation of the post-treatment process.
文摘For India to achieve elimination by 2030,the challenges posed by Plasmodium(P.)vivax cannot be overlooked owing to its burden and unique biology.In 2023,in India,about 224000 malaria cases were reported,and a significant proportion(40%)were P.vivax cases.In P.vivax infection,the persistence of dormant liver stage of parasite,i.e.,hypnozoites,leading to relapses weeks or months later poses challenge in its elimination.
基金Project(52373065)supported by the National Natural Science Foundation of ChinaProject(2220004002898)supported by the Zhuhai Industry University Research Cooperation and Basic and Applied Research Projects,China。
文摘Waterborne acrylic coatings are widely utilized due to their cost-effectiveness,high transparency,strong resistance to weather and chemicals,impressive mechanical properties,and excellent adhesion to various substrates.In these coatings,a reactive emulsifier containing phosphate groups can be integrated into the molecular chain during polymerization,which enhances the coating's compactness and corrosion resistance.This work focuses on the synthesis of styrene-butyl acrylate(St-BA)latex and methyl methacrylate-butyl acrylate(MMA-BA)latex using the reactive phosphate emulsifier ANPEO_(10)-P_(1) through seed emulsion polymerization,achieving a conversion rate of approximately 99%and a solid content close to 50%.The resulting coatings from St-BA and MMA-BA latexes demonstrated long-term corrosion protection for carbon steel and aluminum alloy due to in-situ phosphatization,effectively preventing flash rust.Notably,the MMA-BA coating exhibited remarkable durability,enduring immersion for up to 1224 h(51 d)on Q 235 carbon steel before reaching the failure threshold(|Z|0.01 Hz£106Ω·cm^(2))on Q 235 carbon steel.On 5052 aluminum alloy,the St-BA coating maintained|Z|0.01 Hz>10^(8)Ω·cm^(2) for 480 h(20 d).Furthermore,the corrosion resistance of St-BA and MMA BA coatings on Q 235 steel sheet and 5052 aluminum alloy surpassed that of commercially available MMA-BA and St BA coatings after immersion in a 3.5 wt%NaCl aqueous solution.This work also delves into the anticorrosion mechanism of MMA-BA and St-BA coatings.
基金National Natural Science Foundation of China(52104294)Fundamental Research Funds for the Central Universities(FRF-TP-19-079A1)。
文摘The soaring demand for smart portable electronics and electric vehicles is propelling the advancements in high-energy–density lithium-ion batteries.Lithium manganese iron phosphate(LiMn_(x)Fe_(1-x)PO_(4))has garnered significant attention as a promising positive electrode material for lithium-ion batteries due to its advantages of low cost,high safety,long cycle life,high voltage,good high-temperature performance,and high energy density.Although LiMn_(x)Fe_(1-x)PO_(4)has made significant breakthroughs in the past few decades,there are still facing great challenges in poor electronic conductivity and Li-ion diffusion,manganese dissolution affecting battery cycling performance,as well as low tap density.This review systematically summarizes the reaction mechanisms,various synthesis methods,and electrochemical properties of LiMn_(x)Fe_(1-x)PO_(4)to analyze reaction processes accurately and guide material preparation.Later,the main challenges currently faced are concluded,and the corresponding various modification strategies are discussed to enhance the reaction kinetics and electrochemical performance of LiMn_(x)Fe_(1-x)PO_(4),including multi-scale particle regulation,heteroatom doping,surface coating,as well as microscopic morphology design.Finally,in view of the current research challenges faced by intrinsic reaction processes,kinetics,and energy storage applications,the promising research directions are anticipated.More importantly,it is expected to provide key insights into the development of high-performance and stable LiMn_(x)Fe_(1-x)PO_(4)materials,to achieve practical energy storage requirements.
基金financially supported by the National Natural Science Foundation of China(Nos.82203680 and 52273278)the Natural Scientific Foundation of Liaoning Province(No.2021-MS-176)+1 种基金Shenyang Bureau of Science and Technology(No.RC230527)the Central Guidance Funding for Local Scientific and Techno-logical Development in Liaoning(No.2023JH6/100100029).
文摘Guided bone regeneration in the alveolar bone relies on the colonization and differentiation of immune cells within the defect area.The absence of osteoinductive and osteoimmune properties of currently available scaffolds hinders to achieve optimal repair outcomes in clinical settings.Thus,we aimed to enhance the bone repair ability of polycaprolactone(PCL)scaffolds by incorporating osteoinductive amorphous calcium phosphate(ACP)with immune-regulating zinc ions(ACP(Zn),ACZP),to create a favorable immunomodulatory microenvironment.After one day of co-culture with PCL-ACZP,the spreading area of macrophage cells was significantly higher than that from the original PCL scaffold.Additionally,over 32.1%of macrophages exhibited M2 polarization within three days of co-culture.The PCLACZP/macrophage-conditioned medium significantly boosted osteogenic gene expression in MC3T3-E1 cells.After eight weeks of implantation in a rat femoral condyle defect,the BV/TV from the PCL-ACZP group reached 32.9%,1.4 times of that from the PCL group.Furthermore,the PCL-ACZP-GelMA biphasic module as prepared successfully achieved complete regeneration of three-walled alveolar bone defects in rabbits,resulting in arch-shaped alveolar bone repair and providing greater convenience in the clinical settings.This study showcased the effectiveness of PCL-ACZP-GelMA biphasic module as bioactive scaffolds in the morphological restoration of alveolar bone.
基金supported by National Natural Science Foundation of China(Grant Nos.52302293 and 22272110)Innovation Project of Education Department of Guangdong Province(Grant No.2023KTSCX124)+2 种基金Shenzhen Science and Technology Program(Grant No.KJZD2023092311460401)Guangdong Higher Education Letter(Grant No.[2024]No.30)Shenzhen Key Laboratory of Applied Technologies of Super-Diamond and Functional Crystals(Grant No.ZDSYS20230626091303007).
文摘With the boom in electric vehicles(EVs),there is an increasing demand for high-performance lithium-ion batteries.Lithium manganese iron phosphate(LMFP)has emerged as an enhanced variation of LiFePO4(LFP),offering an energy density 10%–20%greater than that of LFP.Structural distortion caused by the Jahn–Teller effect decreases the capacity and voltage platform,thus restricting the commercialization of this material.Herein,ideas to overcome these challenges,including the crystal structure of LMFP and strategies to mitigate the Jahn–Teller distortion,are first explored.Then,the migration pathways of Li+during charging and discharging and the phase transition mechanisms that affect the material’s performance are discussed.Next,the optimal Mn:Fe ratio for achieving the desired performance is described.The influences of various synthesis and modification methods on the morphology and structure of LMFP are reviewed.Additionally,different modification techniques,such as doping and coating,to enhance the performance of LMFP are highlighted.Finally,an overview of the current state of research on the recycling and reuse of LMFP is provided.By addressing these key topics,this paper offers a theoretical foundation for the further development of LMFP,thus contributing to its eventual commercialization.
基金support of the PID2021-124341OB-C22/AEI/10.13039/501100011033/FEDER,UE(MICIU)J.M.Vega also acknowledges the Grant RYC2021-034384-I funded by MICIU/AEI/10.13039/501100011033 and by“European Union Next Generation EU/PRTR”.
文摘In this study,a phosphate-based conversion coating(PCC)was applied as a precursor before forming silicate-fluoride(SiF)and silicate-phosphate-fluoride(SiPF)based flash-plasma electrolytic oxidation(Flash-PEO)coatings on AZ31B magnesium alloy.The main novelty is the successful incorporation of calcium,zinc,manganese and phosphate species into the Flash-PEO coatings via a precursor layer rather than using the electrolyte.The precursor also led to longer lasting and more intense discharges during the PEO process,resulting in increased pore size.Corrosion studies revealed similar short-term performance for all coatings,with impedance modulus at low frequencies above 10^(7)Ωcm^(2),and slightly better performance for the SiPF-based coating.Nonetheless,the enlarged pores in the PEO coatings functionalized with the PCC precursor compromised the effectiveness of self-healing mechanisms by creating diffusion pathways for corrosive species,leading to earlier failure.These phenomena were effectively monitored by recording the open circuit potential during immersion in 0.5 wt.%NaCl solution.In summary,this study demonstrates that conversion coatings are a viable option for the functionalization of PEO coatings on magnesium alloys,as they allow for the incorporation of cationic and other species.However,it is crucial to maintain a small pore size to facilitate effective blockage through self-healing mechanisms.
基金financially supported by the New Jersey Department of Environmental ProtectionUS EPA。
文摘In this study,synthetic wastewater containing 110μg/L arsenate(As(V)),0-20 mg/L fulvic acid(FA),and 0-12.3 mg/L phosphate was treated with 3 mg/L Fe3+.The mechanisms of FA and phosphate effects on As(V)removal by ferric chloride were determined using 0.22-10μm pore-size filtration,Zetasizer analysis,and in situ flow through cell ATR-FTIR.The results showed that up to 20mg/L FA had almost no effect on the solubility of ferric hydroxide precipitates and adsorption of As(V)by the precipitates.When FA concentration increased from 0 to 20 mg/L,the adsorption of FA led to higher negative zeta potential of the precipitates and the strong electrostatic repulsion between the precipitates decreased the particle size of ferric hydroxide flocs fromlarger than 10μmto smaller than 1μm.In the presence of 5-20 mg/L FA,46%-63%As(V)was adsorbed onto the flocs with particle size in the range of 0.45-1μm.On the other hand,phosphate did not affect the size of ferric hydroxide flocs and significantly increased the dissolved As(V)concentration because it competed with As(V)for adsorption sites on ferric hydroxide precipitates.The addition of 5mg/L cationic organic flocculant significantly reduced the effect of FA on As(V)removal,but did not reduce the effect of phosphate on As(V)removal.The findings of this study will help develop effective arsenic treatment techniques and predict the mobility of arsenic in the environment.
基金the Anusandhan National Research Foundation(ANRF),Science and Engineering Research Board(SERB),Department of Science&Technology,Government of India for a start-up research grant(M-14/0599,Sanction order no.SRG/2022/001478)Seed Grant under Institutions of Eminence(IoE),Banaras Hindu University(BHU)(Dev.Scheme No.6031)for financial assistance.
文摘The green energy transition relies heavily on critical metals,such as rare earth elements(REEs).However,their reserves are primarily focused in a few countries,such as China,which accounts for approximately 70%of global production.Hence,several countries are currently looking for alternative resources for REEs.Alternative REE resources in the supply chain include recycling of e-waste,industrial waste like red mud and phosphogypsum,coal ash,mine tailings,ocean floor sediments,and even certain types of sedimentary deposits like phosphorites where REEs are present in lower concentrations but at larger volumes compared to primary ore deposits which are becoming targets by REEs industry.Currently,several studies are going on the development of eco-friendly REEs extraction technologies from phosphorite deposits.Consequently,advanced data analysis tools,such as Machine Learning(ML),are becoming increasingly important in mineral prospectivity and are rapidly gaining traction in the earth sciences.Phosphorite deposits are mainly used to manufacture fertilizers as these rocks are known for their significant phosphorus content.Moreover,these formations are considered a prospective resource of REEs.The different types of phosphorite deposits such as continental,seamount,and ore deposits worldwide reported concentrations of∑REE upto 18,000µg/g.Due to the augmented claim of REEs for various ultra-modern,and green technology applications that are required to switch over to a carbon-neutral environment,these phosphorite deposits have become an important target mostly because of their relatively higher content of REEs especially heavy rare earth elements(HREE).For example,Mississippian phosphorites reported ∑ HREE 7,000µg/g.To have a comprehensive understanding of the REEs potential of these phosphorite deposits which also include several Chinese phosphorite deposits,this study is undertaken to review the phosphorite deposits in the world and their REEs potential,in addition to some of the associated aspects such as applications and formation mechanisms for different types of phosphorite deposits such as igneous phosphate deposits,sedimentary phosphorite deposits,marine phosphorite deposits,cave phosphate deposits,and insular guano deposits.Other important aspects include their occurrences,types,geochemical characteristics,the REEs enrichment mechanisms,and various recovery methods adopted to recover REEs from different phosphorite deposits.The present review paper concludes that the recent studies highlight the global potential of phosphorite deposits to satisfy the increasing demand for REEs.Extracting REEs from phosphorite presents no significant technological or environmental difficulties,as long as radioactive elements are eliminated.In India,more comprehensive geological surveys,along with the advancement of new methods and evaluations,are required to locate phosphorite deposits with high concentrations of REEs.
