Separation of lithium and nickel using ionic liquids and tributyl phosphate

With the vigorous development of the electronics industry,the consumption of lithium continues to increase,and more lithium needs to be mined to meet the development of the industry.The content of lithium in the solution is much higher than that of minerals,but the interference of impurity ions increases the difficulty of extracting lithium ions.Therefore,we prepared an imidazole-based ionic liquid(1-butyl-3-methylImidazolium bis(trifluoromethyl sulfonyl)imide)(IL)for efficient lithium extraction from aqueous solutions by solvent extraction.Using an extraction consisting of 10%IL,85% tributyl phosphate(TBP),and 5% dichloroethane and an organic to aqueous phase ratio(O/A)of 2/1,over 64.23% of Li were extracted,and the extraction rate after five-stage extraction could reach more than 96%.The addition of ammonium ions to the solution inhibited the extraction of Ni,and the separation coefficient between lithium and nickel approached infinity,showing a very perfect separation effect.Fouriertransform infrared spectroscopy and slope methods were used to analyze the changes that occurred during extraction,revealing possible extraction mechanisms.In addition,the LiCl solution generated during the preparation of ionic liquids was mixed with the stripping solution,and the battery-grade lithium carbonate was prepared by Na_(2)CO_(3) precipitation,with a purity of 99.74%.This study provides an efficient and sustainable strategy for recovering lithium from the solution.

Simultaneous preparation of TiO2 and ammonium alum,and microporous SiO2 during the mineral carbonation of titanium-bearing blast furnace slag

In this study,a route for simultaneous mineralization of CO2 and production of titanium dioxide and ammonium alum,and microporous silicon dioxide from titanium-bearing blast furnace slag(TBBF slag)was proposed,which is comprised of(NH4)2 S04 roasting,acid leaching,ammonium alum crystallization,silicic acid flocculation and Ti hydrolysis.The effects of relevant process parameters were systematically investigated.The re sults showed that under the optimal roasting and leaching conditions about 85%of titanium and 84.6%of aluminum could be extracted while only 30%of silicon entered the leachate.84%of Al^3+was crystallized from the leachate in the form of ammonium aluminum sulfate dodecahydrate with a purity up to 99.5 wt%.About 85%of the soluble silicic acid was flocculated with the aid of secondary alcohol polyoxyethylene ether 9(AEO-9)to yield a microporous SiO2 material(97.4 wt%)from the crystallized mother liquor.The Al-and Si-depleted solution was then hydrolyzed to generate a titanium dioxide(99.1 wt%)with uniform particle size distribution.It was figured out that approximately 146 kg TiO2 could be produced from 1000 kg of TBBF slag.Therefore,the improved process is a promising method for industrial application.

Indirect mineral carbonation of blast furnace slag with(NH4)2SO4 as a recyclable extractant

Large quantities of COand blast furnace slag are discharged in the iron and steel industry. Mineral carbonation of blast furnace slag can offer substantial COemission reduction and comprehensive utilisation of the solid waste. In this study, a recyclable extractant,（NH）SO, was used to extract calcium and magnesium from blast furnace slag（main phases of gehlenite and akermanite） by using low-temperature roasting to fix COthrough aqueous carbonation. The process parameters and efficiency of the roasting extraction, mineralisation, and Al recovery were investigated in detail. The results showed that the extractions of Ca, Mg, and Al can reach almost 100% at an（NH4）SO-to-slag mass ratio of 3:1 and at 370°C in 1 h. Adjusting the p H value of the leaching solution of the roasted slag to 5.5 with the NHreleased during the roasting resulted in 99% Al precipitation, while co-precipitation of Mg was lower than 2%. The Mg-rich leachate after the depletion of Al and the leaching residue（main phases of CaSOand SiO） were carbonated using（NH）COand NHHCOsolutions, respectively, under mild conditions. Approximately 99% of Ca and 89% of Mg in the blast furnace slag were converted into CaCOand（NH）Mg（CO）·4 HO,respectively. The latter can be selectively decomposed to magnesium carbonate at 100-200 °C to recover the NHfor reuse. In the present route, the total COsequestration capacity per tonne of blast furnace slag reached up to 316 kg, and 313 kg of Al-rich precipitate, 1000 kg of carbonated product containing CaCOand SiO, and 304 kg of carbonated product containing calcium carbonate and magnesium carbonate were recovered simultaneously. These products can be used, respectively, as raw materials for the production of electrolytic aluminium, cement, and light magnesium carbonate to replace natural resources.

Process simulation and energy integration in the mineral carbonation of blast furnace slag

Large quantities of blast furnace(BF) slag and CO_2 are discharged annually from iron and steel industries, along with a large amount of waste heat.The mineral carbonation of BF slag can not only reduce emissions of solid waste but also realize the in-situ fixation of CO_2 with low energy consumption if integrated with the waste heat utilization.In this study, based on our previous works, Aspen Plus was employed to simulate and optimize the carbonation process and integrate the process energy.The effects of gehlenite extraction, MgSO_4 carbonation,and aluminum ammonium sulfate crystallization were studied systematically.The simulation results demonstrate that 2.57 kg of BF slag can sequester 1 kg of CO_2, requiring 5.34 MJ of energy(3.3 MJ heat and 2.04 MJ electricity), and this energy includes the capture of CO_2 from industrial flue gases.Approximately 60 kg net CO_2 emission reduction could be achieved for the disposal of one ton of BF slag.In addition, the by-product,aluminum ammonium sulfate, is a high value-added product.Preliminary economic analysis indicates that the profit for the whole process is 1127 CNY per ton of BF slag processed.

Recovery of titanium,aluminum,magnesium and separating silicon from titanium-bearing blast furnace slag by sulfuric acid curing-leaching

An energy-efficient route was adopted to treat titanium-bearing blast furnace slag(TBBFS)in this study.Titanium,aluminum,and magnesium were simultaneously extracted and silicon was separated by low temperature sulfuric acid curing and low concentration sulfuric acid leaching.The process parameters of sulfuric acid curing TBBFS were systematically studied.Under the optimal conditions,the recovery of titanium,aluminum,and magnesium reached 85.96%,81.17%,and 93.82%,respectively.The rapid leaching model was used to limit the dissolution and polymerization of silicon,and the dissolution of silicon was only 3.18%.The mechanism of sulfuric acid curing-leaching was investigated.During the curing process,the reaction occurred rapidly and released heat massively.Under the attack of hydrogen ions,the structure of TBBFS was destroyed,silicate was depolymerized to form filterable silica,and titanium,magnesium,aluminum,and calcium ions were replaced to form sulfates and enriched on the surface of silica particles.Titanium,aluminum,and magnesium were recovered in the leaching solution,and calcium sulfate and silica were enriched in the residue after leaching.This method could effectively avoid the formation of silica sol during the leaching process and accelerate the solid-liquid separation.

Indirect mineral carbonation of titanium-bearing blast furnace slag coupled with recovery of TiO_2 and Al_2O_3

Large quantities of CO2 and blast furnace slag are discharged in the iron and steel industry. Mineral carbonation of blast furnace slag can offer substantial CO2 emission reduction and comprehensive utilization of the solid waste. This paper describes a novel route for indirect mineral carbonation of titanium-bearing blast furnace （TBBF） slag, in which the TBBF slag is roasted with recyclable （NH4）2SO4 （AS） at low temperatures and converted into the sulphates of various valuable metals, including calcium, magnesium, aluminium and titanium. High value added Ti-and Al-rich products can be obtained through stepwise precipitation of the leaching solution from the roasted slag. The NH3 produced during the roasting is used to capture CO2 from flue gases. The NH4HCO3 and （NH4）2CO3 thus obtained are used to carbonate the CaSO4-containing leaching residue and MgSO4-rich leaching solution, respectively. In this study, the process parameters and efficiency for the roasting, carbonation and Ti and Al recovery were investigated in detail. The results showed that the sulfation ratios of calcium, magnesium, titanium and aluminium reached 92.6%, 87% and 84.4%, respectively, after roasting at an AS-to-TBBF slag mass ratio of 2：1 and 350℃ for 2 h. The leaching solution was subjected to hydrolysis at 102℃ for 4 h with a Ti hydrolysis ratio of 95.7%and the purity of TiO2 in the calcined hydrolysate reached 98 wt%. 99.7% of aluminium in the Ti-depleted leaching solution was precipitated by using NH3. The carbonation products of Ca and Mg were CaCO3 and （NH4）2Mg（CO3）2·4H2O, respectively. The latter can be decomposed into MgCO3 at 100-200℃ with simultaneous recovery of the NH3 for reuse. In this process, approximately 82.1% of Ca and 84.2% of Mg in the TBBF slag were transformed into stable carbonates and the total CO2 sequestration capacity per ton of TBBF slag reached up to 239.7 kg. The TiO2 obtained can be used directly as an end product, while the Al-rich precipitate and the two carbonation products can act, respectively, as raw materials for electrolytic aluminium, cement and light magnesium carbonate production for the replacement of natural resources.

Decomposition behavior of CaSO_4 during potassium extraction from a potash feldspar-CaSO_4 binary system by calcination

The extraction of potassium from a tablet mixture of K-feldspar ore and CaSO4by roasting was studied with a focus on the effects of the decomposition behavior of CaSO4on the potassium extraction process.The roasted slags were characterized by X-ray diffraction（XRD）,scanning electron microscopy（SEM）,energy-dispersive X-ray spectroscopy,and thermogravimetric（TG）analysis.The XRD analysis revealed that hydrosoluble mischcrystal K2Ca2（SO4）3was obtained by ion exchange of Ca^2＋ in CaSO4 and K^＋ in KAlSi3O8.Meanwhile,the intermediate product,SiO2,separated from KAl Si3O8and reacted with CaSO4to decompose CaSO4.The SEM results showed that some blowholes emerged on the surface of the CaSO4particles when they reacted with SiO2at 1200℃,which indicates that SO2and O2gases were released from CaSO4.The TG curves displayed that pure CaSO4could not be decomposed below 1200℃,while the mixture of K-feldspar ore and CaSO4began to lose weight at 1000℃.The extraction rate of potassium and decomposition rate of CaSO4were 62%and 44%,respectively,at a mass ratio of CaSO4to K-feldspar ore of 3：1,temperature of 1200℃,tablet-forming pressure of6 MPa,and roasting time of 2 h.The decomposition of CaSO4reduced the potassium extraction rate;therefore,the required amount of CaSO4was more than the theoretical amount.However,excess CaSO4was also undesirable for the potassium extraction reaction because a massive amount of SO2and O2gas were derived from the decomposition of CaSO4,which provided poor contact between the reactants.The SO2released from CaSO4decomposition can be effectively recycled.

Co(II)-salen complex encapsulated into MIL-100(Cr) for electrocatalytic reduction of oxygen

Co（Ⅱ）-salen was encapsulated in MIL- 100（Cr） metal organic framework by ＂ship in a bottle＂ to synthesize a new electrocatalyst, Cosalen@MIL- 100（Cr）. The material was characterized by XRD, FT-IR, UV-Vis and N2-adsorption. The Cosalen@MIL-100（Cr） modified glassy carbon electrode exhibits a well-defined reduction peak at the potential of -0.21 V toward the oxygen reduction reaction （ORR） by cyclic voltam- metry （CV） in pH = 6.84 phosphate buffer. Almost 400 mV positive shift of potential at Cosalen@MIL-100（Cr） modified electrode for ORR compared with that at bare glassy carbon, indicates that Cosalen@MIL-100（Cr） possesses excellent electrocatalytic activity. The transferred number of electrons for ORR was determined by chronocoulometry. The result suggests that the introduction of Co（II）-salen complex into MOF increases the electrocatalytic activity via a four-electron reduction pathway. Furthermore, this electrocatalyst exhibits good stability and reproducibility.

Two-stage cyclic ammonium sulfate roasting and leaching of extracting vanadium and titanium from vanadium slag

Compared with traditional sodium or calcification roasting process for vanadium extraction from raw vanadium slag(V-slag),ammonium sulfate(AS)roasting could reduce about 470℃ roasting temperature and avoid Cl_(2),HCl,sodium-containing waste-water and waste gypsum discharging.To reduce the amount of AS added in vanadium extraction process,an efficient AS two-stage cyclic roasting and acid leaching process was proposed.The result of TG analysis indicates V-slag could be decomposed in 275-380℃ using AS roasting process.Using 2.03:1 total mass ratio of AS to V-slag,90.86%V and 80.54%Ti could be extracted after 380℃ roasting for 30 min and 8%initial concentration of H_(2)SO_(4) leaching at 70℃ for 100 min.XRD analysis indicates V-containing spinel phase in the 1st stage leaching residue would be efficiently decomposed by the cyclic two-stage roasting and leaching process.Furthermore,the valence of V(Ⅲ)in raw V-slag was not changed after the 1st AS roasting stage,but a part of V(Ⅲ)in the 1st leaching residue was oxidized to V(V)after 2nd roasting process.

Design and Movement Simulation to the Cam of the Testing Device for Capacitor Encapsulation Equipment

In this paper, in order to design a cam mechanism be up to the mustard, a set of methods are put forward that using the Visual Basic programming language based on solidworks to draw cam contour line and then get its 3D models and generate the cam motion simulation by the solidworks motion. In the end, it’s proved that the cam designed though this method met the requirement.

Efficient second and third harmonic generation in dual-layer lithium niobate microdisk resonator

Lithium niobate thin film frequency doubler has extensive applications in the preparation of classical and quantum sources.In this study,we successfully fabricated microdisk resonators with a quality factor of 2.2×10^(5) in reverse-polarization dual-layer x-cut lithium niobate for the first time.Based on the modal phase matching condition,efficient second harmonic generation with a record normalized conversion efficiency of~56000%W-1 and cascaded third harmonic generation with an efficiency of~6500%W-2 were obtained in the microdisk resonator.Compared with the periodically poled lithium niobate microcavity,the complex domain structure preparation processes are avoided.Our work provides a scheme for achieving highly efficient second-order nonlinear effects in non-periodically poled microcavities.

Advances in lithium niobate thin-film lasers and amplifiers: a review

Lithium niobate(LN)thin film has received much attention as an integrated photonic platform,due to its rich and great photoelectric characteristics,based on which various functional photonic devices,such as electro-optic modulators and nonlinear wavelength converters,have been demonstrated with impressive performance.As an important part of the integrated photonic system,the long-awaited laser and amplifier on the LN thin-film platform have made a series of breakthroughs and important progress recently.In this review paper,the research progress of lasers and amplifiers realized on lithium niobate thin film platforms is reviewed comprehensively.Specifically,the research progress on optically pumped lasers and amplifiers based on rare-earth ions doping of LN thin films is introduced.Some important parameters and existing limitations of the current development are discussed.In addition,the implementation scheme and research progress of electrically pumped lasers and amplifiers on LN thin-film platforms are summarized.The advantages and disadvantages of optically and electrically pumped LN thin film light sources are analyzed.Finally,the applications of LN thin film lasers and amplifiers and other on-chip functional devices are envisaged.

Additive Manufacturing of Continuous Fiber-Reinforced Polymer Composite Sandwich Structures with Multiscale Cellular Cores

The use of composite sandwich structures with cellular cores is prevalent in lightweight designs owing to their superior energy-absorbing abilities.However,current manufacturing processes,such as hot-press molding and mold pressing,require multiple steps and complex tools,thus limiting the exploration of advanced sandwich structure designs.This study reports a novel multi-material additive manufacturing(AM)process that allows the single-step production of continuous fiber-reinforced polymer composite(CFRPC)sandwich structures with multiscale cellular cores.Specifically,the integration of CFRPC-AM and in situ foam AM processes provides effective and efficient fabrication of CFRPC panels and multiscale cellular cores with intricate designs.The cellular core design spans three levels:microcellular,unit-cell,and graded structures.Sandwich structures with a diverse set of unit-cell designs,that is,rhombus,square,honeycomb,and re-entrant honeycomb,were fabricated and their flexural behaviors were studied experimentally.The results showed that the sandwich structure with a rhombus core design possessed the highest flexural stiffness,strength,and specific energy absorption.In addition,the effect of the unit-cell assembly on the flexural performance of the CFRP composite sandwich structure was examined.The proposed design and fabrication methods open new avenues for constructing novel and high-performance CFRPC structures with multiscale cellular cores that cannot be obtained using existing approaches.

Robust moiré flatbands within a broad band-offset range

Photonic analogs of the moirésuperlattices mediated by interlayer electromagnetic coupling are expected to give rise to rich phenomena,such as nontrivial flatband topology.Here,we propose and demonstrate a scheme to tune the flatbands in a bilayer moirésuperlattice by employing a band offset.The band offset is changed by fixing the bands of one slab while shifting those of the other slab,which is accomplished by modifying the thickness of the latter slab.Our results show that the band-offset tuning not only makes some flatbands emerge and disappear but also leads to two sets of flatbands that are robustly formed even with the change of band offset over a broad range.These robust flatbands form either at the AA-stack site or at the AB-stack site,and as a result,a single-cell superlattice can support a pair of high-quality localized modes with tunable frequencies.Moreover,we develop a diagrammatic model to provide an intuitive insight into the formation of the robust flatbands.Our work demonstrates a simple yet efficient way to design and control complex moiréflatbands,providing new opportunities to utilize photonic moirésuperlattices for advanced light–matter interaction,including lasing and nonlinear harmonic generation.

Integrated lithium niobate single-mode lasers by the Vernier effect

Microcavity lasers based on erbium-doped lithium niobate on insulator(LNOI),which are key devices for LNOI integrated photonics,have attracted significant attention recently.In this study,we report the realization of a C-band single-mode laser using the Vernier effect in two coupled erbium-doped LNOI microrings with different radii under the pump of a 980-nm continuous laser.The laser,operating stably over a large range of pumping power,has a pump threshold of about 200μW and a side-mode suppression ratio exceeding 26 dB.The high-performance LNOI single-mode laser will promote the development of lithium niobate integrated photonics.

Microdisk lasers on an erbium-doped lithium-niobite chip

Lithium niobate on insulator(LNOI) provides a platform for the fundamental physics investigations and practical applications of integrated photonics. However, as an indispensable building block of integrated photonics, lasers are in short supply. In this paper, erbium-doped LNOI laser in the 1550-nm band was demonstrated in microdisk cavities with high quality factors fabricated in batches by UV exposure, inductively coupled plasma reactive ion etching, and chemomechanical polishing. The threshold and conversion efficiency of the erbium-doped LNOI microdisk laser were measured to be lower than 1 m W and 6.5×10^(-5)%, respectively. This work will benefit the development of integrated photonics based on LNOI.

On-chip erbium-doped lithium niobate waveguide amplifiers [Invited]

Lithium niobate on insulator(LNOI), as an emerging and promising optical integration platform, faces shortages of on-chip active devices including lasers and amplifiers. Here, we report the fabrication of on-chip erbium-doped LNOI waveguide amplifiers based on electron beam lithography and inductively coupled plasma reactive ion etching. A net internal gain of ~30 d B/cm in the communication band was achieved in the fabricated waveguide amplifiers under the pump of a974 nm continuous laser. This work develops new active devices on LNOI and may promote the development of LNOI integrated photonics.

Periodically poled lithium niobate whispering gallery mode microcavities on a chip

In this study, we investigate the fabrication of periodically poled lithium niobate(PPLN) microdisk cavities on a chip. These resonators are fabricated from a PPLN film with a 16 μm poling period on insulator using conventional microfabrication techniques.The quality factor of the PPLN microdisk resonators with a 40-μm radius and a 700-nm thickness is 6.7×10~5. Second harmonic generation(SHG) with an efficiency of 2.2×10^(-6) mW(-1) is demonstrated in the fabricated PPLN microdisks. The nonlinear conversion efficiency could be considerably enhanced by optimizing the period and pattern of the poled structure and by improving the cavity quality factors.

Second-harmonic generation using d(33)in periodically poled lithium niobate microdisk resonators

A fabrication process allowing for the production of periodically poled lithium niobate(PPLN)photonic devices with any domain pattern and unit size down to 200 nm is developed by combining semiconductor fabrication techniques and piezo-force-microscopy tips polarization.Based on this fabrication process,PPLN microdisk resonators with quality factors of 8×10~4 were fabricated from a Z-cut lithium niobate film.Second-harmonic generation(SHG)utilizing d(33)in the whole cavity was demonstrated in a PPLN microdisk with a 2μm-spatialperiod radial domain pattern.The SHG conversion efficiency was measured to be 1.44×10^(-5)m W^(-1).This work paves the way to fabricate complex PPLN photonic devices and to obtain efficient nonlinear optical effects that have wide applications in both classical and quantum optics.

Boosting third-harmonic generation by a mirror-enhanced anapole resonator

We demonstrate that a dielectric anapole resonator on a metallic mirror can enhance the third harmonic emission by two orders of magnitude compared to a typical anapole resonator on an insulator substrate.By employing a gold mirror under a silicon nanodisk,we introduce a novel characteristic of the anapole mode through the spatial overlap of resonantly excited Cartesian electric and toroidal dipole modes.This is a remarkable improvement on the early demonstrations of the anapole mode in which the electric and toroidal modes interfere off-resonantly.Therefore,our system produces a significant near-field enhancement,facilitating the nonlinear process.Moreover,the mirror surface boosts the nonlinear emission via the free-charge oscillations within the interface,equivalent to producing a mirror image of the nonlinear source and the pump beneath the interface.We found that these improvements result in an extremely high experimentally obtained efficiency of 0.01%.