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The Ab initio molecular dynamics (AIMD) simulation was adopted to elucidate the alumina vacuum carbothermal reduction and nitridation (VCRN) reaction mechanism, and an experimental method was adopted to verify the AIMD results. According to the results, the VCRN reaction occurs only when N2 is adsorbed on both the C and Al atoms. C plays two important roles during the reaction of alumina VCRN: one is to act as a charge exchange carrier for N and Al atoms to catalyze N2 molecule decomposition, and the other is to react with O atoms and reduce Al2O3.

In this study, the phase composition, morphology, and element distribution of Mg impurities in a low-grade titanium slag and in its chlorinated residue after carbochlorination were identified using XRD, SEM-EDS, and MLA. Most Mg impurities existed as anosovite, rutile, titanaugite, and Ti silicate phases before the carbochlorination process. The thermodynamic analysis revealed that the chlorination tendencies of Mg, Ti, Ca, Fe, and Mn oxides in the original titanium slag was much higher than those of Si and Al oxides in the temperature range of 700–850 °C. In addition, the binary phase diagram analysis indicates that the magnesium chloride (MgCl2) byproduct formed Na2MgCl4 eutectic salts in the NaCl-based salt bath. The carbochlorination experiments of the Mg-bearing titanium slag show that the chlorination ratio of magnesium oxide was above 93% under the suitable industrial conditions used for the extraction of titanium from Mg-bearing titanium slag. In addition, the formation of Na2MgCl4 eutectic salts after carbochlorination was confirmed, indicating that the negative effect of MgCl2 on the chlorination process was effectively eliminated. The Mg impurities in the chlorinated residue existed as titanaugite, quartz, chlorite, and rutile phases. Furthermore, we found that the carbochlorination of Mg-bearing titanium slag in chloride media effectively improved the comprehensive utilization efficiency of the Mg-bearing titanium slag. We believe that the proposed carbochlorination mechanism of the Mg-bearing titanium slag will provide thorough understanding and useful guidance on the practical industrial application of Mg-bearing titanium slag.

Lead acid batteries have been widely used in different fields, so abundant waste lead acid battery was generated. Waste lead acid battery is regarded as a toxic material due to the metallic lead and the lead paste compounds. Once lead and its compounds enter the human body and the environment, which will cause serious threats. At present, the waste lead acid batteries are mainly recovered in the form of metal lead, which has many problems. Thus, this paper put forward a novel technology to recycle waste lead acid battery. Vacuum thermal decomposition was employed to treat recycled lead carbonate from waste lead acid battery. Thermodynamics analysis and experiments were finished from the reaction free energy of lead carbonate decomposition and vacuum furnace. The results showed that the recycled lead carbonate began to be decomposed when the temperature reached 250°C. Above 340°C, most of intermediate PbCO3•2PbO were converted to red α-PbO and then transformed to yellow β-PbO when the temperature was raised further to 460°C. Furthermore, the study provided the fundamental data for the preparation of α-PbO and β-PbO in vacuum, which also demonstrated a new way for the reuse of spent lead acid battery resource and an outlook of sustainable production.

Ultrafine AlN powders were synthesized by carbothermal reduction nitridation method under vacuum (VCRN) in a double temperature zones vacuum furnace with alumina and carbon black as raw materials. The mechanism of the process was investigated. The results show that when the soaking time was 1.5 h at 1650 °C, 300 Pa N2 pressure, the purity ultrafine AlN powders were obtained. By analyzing the results of density function theory (DFT) calculation and XRD, the mechanism of VCRN can be identified as Al2O3 → Al2OC/Al4C3 → Al6C3N2/AlN → AlN. The results of theoretical study further proved that the compound of Al6C3N2 can be nitrogenized quickly through the reaction of Al6C3N2 + 2 N2(g) → 6AlN + 3C.

With the widespread use of cadmium telluride solar cells, environmental protection, and effective recycling approaches for solar cell component waste have become topics of concern. As an emerging metal smelting technology, vacuum metallurgy technology has broad application prospects in primary metal refining and the recycling of secondary non-ferrous scraps. Thus, this study proposes a new method for the separation and recovery of rare metals from cadmium telluride waste through sulfur smelting and vacuum distillation. In this process, sulfur is smelted with cadmium telluride to produce tellurium with a high vapor pressure. The tellurium was then separated and purified by multi-stage vacuum distillation. The results show that the tellurium purity can reach up to 99.97% and the tellurium recovery rate was above 99%. The cadmium and sulfur contents in the tellurium were 0.0061% and 0.0194%, respectively. Moreover, the cadmium sulfide produced during the smelting process can be enriched by vacuum distillation, resulting in 99.6% purity. This technology strongly aligns with the “reduce, reuse, and recycle” principle for solid waste, and provides a basis for the sustainable development of the photovoltaic industry.

The growth of AlnNn (n = 2–9) clusters is evaluated by using density functional theory (DFT) to determine the growth pathway of AlnNn (n = 2–9) clusters. Fukui function was adopted to confirm the active spots of these structures, furthermore, the formation ways of AlnNn (n = 2–9) reactant clusters can be divided into three types. Based on the results of transition state search and equilibrium constant calculations, the growth pathway of AlnNn (n = 2–9) clusters can be identified as follows: AlN(plane) → Al2N2(plane) → Al3N3(plane) → Al4N4(plane) → Al5N5(bulk) → Al6N6(bulk) → Al7N7(bulk) → Al8N8(bulk) → Al9N9(bulk), the growth mechanism of AlN nano clusters can be explained in detail.

With good electrical, thermal and mechanical properties, aluminium nitride is widely used in microelectronics and other fields. However, high temperatures are still needed for the method of alumina carbothermal reduction nitridation (CRN) for AlN preparation. Herein, thermodynamics calculation and experimental research were adopted to investigate the preparation of AlN under vacuum by the alumina CRN reaction in order to lower reaction temperature. The results demonstrate that lower pressure benefits the alumina CRN reaction. A single phase of AlN was successfully obtained at 1823 K for 2.5 h with a N2 gas pressure of 300 Pa. Moreover, an underlying growth mechanism of AlN during the alumina CRN process under vacuum was proposed, which is different from that under atmosphere or elevated pressure. The rate limiting step of alumina CRN process was determined. The results also indicate that Al4C3 and Al2OC play important roles in the process of alumina CRN under vacuum.

In the present research, the structural, the relative stable, and the electronic properties of AlnLin (n = 2 – 12) clusters were investigated by density functional theory (DFT). By comparing the calculated values of Al2 and Li2 dimers with experimental ones, the reliability of the proposed method was proved. Furthermore, by considering the values of average binding energy (Eb), vertical ionization potential (VIP), vertical electron affinity (VEA), fragmentation energy (△E), second-order energy difference (△2E), HOMO-LUMO (HL) gap, and chemical hardness (η) were calculated. It was found Fragmentation energy, second-order energy difference, VIP, VEA, the chemical stability and HOMO-LUMO gap exhibit odd-even oscillatory behaviours along with cluster size and have extreme values at n = 5 revealed Al5Li5 cluster yielded excellent stability. Those can be well explained by the density of states (DOS) that Li and Al atoms with stronger covalent bonds. Therefore, Al5Li5 cluster can be used as an ideal candidate for calculating Wilson parameters of Al-Li alloys.

Lead acid batteries are often used, and they produce an abundant amount of lead acid battery waste, which is a source of lead carbonate. Lead oxide was manufactured via thermal decomposition in a vacuum from recycled lead carbonate that was extracted from lead acid battery waste. The decomposed products were characterized by X-ray diffraction and decomposition rate. The impact of the decomposition conditions, including temperature, preservation time, particle size and system pressure, on the lead carbonate decomposition rate were evaluated. The results show that the newly developed lead carbonate vacuum decomposition technique does a good job, and that the decomposition conditions strongly affect the lead carbonate decomposition rate and phase compositions. For instance, at a temperature range of 310–580 °C, a pressure ranging from 10 to 60 Pa, and a preservation time of 30 min, decomposition rates reached as high as 95.77%. At the temperature of 310 °C, when the preservation time increased from 30 min to 180 min, the decomposition rate increased from 29.62% to 78.40%. In terms of the effect of particle size, the mixed particles (≤20 mesh and ≤400mesh) worked best. Furthermore, the lower pressure can explain the lower temperature obtained, and the vacuum system is suited for decomposition, coinciding with a higher decomposition rate.

The interactions between Fe2SiO4 and ZnO play an essential role in the recovery of zinc from copper slag. The dissolution and substitution mechanism of ZnO in fayalite were investigated by using TG-DSC, XRD, PPMS DynaCool, XPS, Mossbauer and SEM-EDS analyses and compared with MS calculation results. The results indicate that the dissolution and substitution are actually processes of the penetrating dissolution of Zn(II) ions that can be divided into three steps: 1) ZnO dissociates into Zn1-yO and Zn(II) ions; 2) Zn(II) penetrates the gap of the octahedron outer layer to substitute Fe(II) sites in the internal structure of SiOFe(II) (M2) to form (Fe2-x, Znx)SiO4; 3) Fe(II) is forced to migrate to the surface of (Fe2-x, Znx)SiO4 to form (Zn1-y, Fe(II)y)O. These findings can be derived the occurrence state and distribution of zinc in copper slag theoretically.

To selectively separate arsenic from arsenic-containing copper dust, this paper reports a new method of treating the dust by carbothermal reduction and roasting it with coke powder at low temperatu...

Stibnite is the main raw material employed to produce antimony. With the excessive exploitation of high-grade stibnite, low-grade stibnite become more and more important. This study aimed to introduce a vacuum process for recovering and enriching antimony from low-grade stibnite. At the pressure of 10 Pa, by controlling heating temperature, Sb2S3 and Sb2O3 from stibnite (12.8 wt% Sb) was evaporated and enriched. We investigated the influence of vacuum distillation temperature and time on the recovery of low-grade Sb2S3. The result indicated antimony recovery could reach about 97% for suitable vacuum distillation conditions, and the purity of Sb2S3 was about 95 wt%. As for high-grade stibnite, through two-step vacuum distillation, Sb could not only be recovered in the form of Sb2S3, but also purified to commercial Sb2S3 with a purity about 99.5 wt%. The results demonstrated that vacuum distillation is a possible way to recover antimony from low-grade stibnite and purify Sb2S3 from high grade stibnite.

A new process to fabricate porous titanium by calcium vapor in-situ reduction of titanium sespuioxide was presented in this paper. The mixture of Ti2O3 and CaCl2 powders was preformed and reduced by calcium vapor. The porous titanium structure was obtained after leaching reduction products with hydrochloric acid and deionized water. The pore structure, morphology, composition of reduction products were investigated by SEM-EDS and XRD. The influence of different contents of anhydrous calcium chloride on porosity was discussed. The results show metallic titanium products with two types of pore structures and vacuum sintering treatment strengthened effectively connection between titanium particles. The porosity of porous titanium samples was 62%–82% and more than 90% of pores are open-pores.

The volatilization and condensation behaviours of magnesium during the sublimation and desublimation processes were investigated at 10 Pa, respectively. The average volatilization rate increases with increasing temperature, but decreases with increasing specific surface area. The condensation position at which the magnesium vapor becomes solid is further away from the heating source with the temperature of the heating source increasing, but the value of the condensation temperature is maintained in an interval (603–733 K). It can be beneficial to the condensation and crystallization of magnesium vapor with increasing the temperature and temperature gradient of the condensing zone appropriately.

Recently, bimetallic clusters have attracted a great deal of attention from research community because clusters yield intriguing properties ranging from the molecular and the bulk materials, which have extensive applications in nanomaterials. Clusters with tailored properties are governed by cluster size, geometrical structures, and elemental composition. Motivated by that we systematically investigated the structural, relative stable, and electronic properties of PbnSbn (n = 2–12) clusters by means of density functional theory. In this paper, the ground state structures, average binding energies, fragmentation energies, HOMO–LUMO gaps, and density of states were theoretically calculated. The results demonstrate that the large clusters adopt distorted ellipsoid structures with no symmetry. The average binding energies tend to be stable when cluster size n ≥ 4. Pb5Sb5 and Pb9Sb9 clusters are more chemically stable compared with the neighboring PbnSbn clusters, which may serve as the cluster assembled materials. The density of states of PbnSbn (n = 2–12) clusters moving toward more negative energy levels with the growing cluster size n, which also becoming more nonlocalized as the clusters size n increasing.

Lead sulfide is the main raw material employed to produce lead. And it is believed to be a very stable substance. The dissociation pathway of lead sulfide is believed to be 2PbS = 2Pb(l)+S2, and its initial dissociation temperature at 10 Pa is believed about 1273 K, and there is no report that it could directed dissociate into lead and sulfur. In this work, we theoretically calculated the stability of lead sulfide at the pressure of 10 Pa, and experimentally investigated the dissociation product of lead sulfide. The first part of this article investigated the dissociation pathways of lead sulfide based on thermodynamic calculation. The second part studies the dissociation as well as volatilization product using X-ray diffraction, ICP-AES and SED. The result indicated we could obtain lead from the direct dissociation of lead sulfide, and the dissociation pathway is 2PbS (g) = 2Pb(l)+S 2 . At 1153 K, the decomposition rate is 39.23%, and the purity of lead is 99.9%.

Structural and electronic properties of Pb n Ag n (n=2–12) clusters were investigated by density functional theory with generalized gradient approximation at BLYP level in DMol3 program package. The optimized bimetallic Pb n Ag n (n=2–12) clusters were viewed as the initial structures, then, those were calculated by ab initio molecular dynamics (AIMD) to search possible global minimum energy structures of Pb n Ag n clusters, finally, the ground state structures of Pb n Ag n (n=2–12) clusters were achieved. According to the structural evolution of lowest energy structures, Ag atoms prefer gather in the central sites while Pb atoms prefer external positions in Pb n Ag n (n=2–12) clusters, which is in excellent agreement with experimental results from literature and the application in metallurgy. The average binding energies, HOMO-LUMO gaps, vertical ionization potentials, vertical electron affinities, chemical hardness η, HOMO orbits, LUMO orbits and density of states of Pb n Ag n (n=2–12) clusters were calculated. The results indicate that the values of HOMO-LUMO gaps, vertical ionization potentials, vertical electron affinities and chemical hardness η show obvious odd-even oscillations when n≤5, Pb n Ag n (n=2–12) clusters become less chemically stable and show insulator-to-metal transition with the variation of cluster size n, Pb n Ag n (n≥9) cluster are good candidates to study the properties of PbAg alloys. Those can be well explained by the density of states (DOS) distributions of Pb atoms and Ag atoms between–0.5 Ha and 0.25 Ha in Pb n Ag n (n=2–12) clusters.

This paper introduces a new process to process noble lead by vacuum distillation, which is produced from the fire reduction smelting of lead anode slime with a large number of valuable and precious metals. Lead anode slime is important as a raw material for the extraction of precious metals. However, some of the shortcomings of the traditional process, such as serious pollution, complex processes, large resource consumption, and low metal recovery rate, must be overcome. Based on a study of the saturated vapor pressure in the metal and vapor–liquid equilibrium diagram of a binary system, we carried out a large-scale recovery experiment for bismuth and lead with the enrichment of silver and copper. The experimental results show that the copper and silver contents in the residue are higher than 80%. Secondary continuous vacuum distillation resulted in a residue with a Ag content of less than 20 g/t. At the same time, the direct yield of silver from the whole process is higher than 99%, and the evaporation contents of Pb and Bi are above 90%. Achieved a comprehensive recovery of valuable metals recycling.

Gd2O3 − xSx:Er crystals were prepared through high-temperature solid-state reaction method in vacuum, with the vacuum synthesis mechanism determined by thermal analysis. The crystal structure and upconversion luminescence properties were investigated respectively by XRD, TEM and spectrophotometer. Well crystallized Gd2O2S:Er phosphors were prepared under 1000 °C in vacuum with a certain excessive amount of sulfur content than stoichiometric. It is confirmed that with the increasing sulfur content the green emission was enhanced and red emission was weakened. The cooperative upconversion luminescence of Er3 + in non-stoichiometric Gd2O3 − xSx crystals was interpreted as a result of two photon absorption and the photon avalanche process.

This paper introduces a new process for refining crude lead by vacuum distillation. The saturated vapor pressures of lead and impurity elements were calculated, and the removal effect of impurity elements was quantitatively predicted using the vapor-liquid equilibrium diagram. In addition, the low temperature followed by high temperature vacuum distillation method and the high temperature followed by low temperature method were adopted to adjust the order of impurity removal. The refining effect was experimentally studied using these two methods, and the best parameters were determined. The predictions are in close agreement with the experimental results. Based on theoretical and experimental analyses, a new, clean and efficient process for refining crude lead was developed. First, the crude lead was distilled by vacuum distillation at 10 Pa and 1673 K for 30 min, and then, the volatiles and residues were collected. Second, the volatiles were vacuum distilled at 10 Pa and 1273 K for 30 min. The removal rates of Cu, Sn, Ag, Zn, Sb and Bi were 99.73%, 99.72%, 96.23%, 90.78%, 74.80% and 8.82% respectively, and the purity of Pb reached 99.03%.

Thermodynamic calculation, ab initio molecular dynamics (AIMD) and vacuum decomposition experiments were performed to study the volatilization behaviors of Mo and S from molybdenite concentrate by vacuum decomposition. In thermodynamic calculation, starting decomposition temperatures of reactions were calculated, and saturated vapor pressures of Mo, S and MoS2 were also analyzed. In AIMD, geometries of the S n (n≤8), Mo m (m≤8) and Mo m S n (m+n≤8) clusters have been optimized using density functional theory (DFT) with generalized gradient approximation (GGA). And these clusters were simulated in DFT with Cambridge Sequential Total Energy Package (CASTEP) code of Material Studio software. Structures and stabilities of these clusters before and after molecular dynamics simulations were discussed, and diffusion coefficients were also calculated. In vacuum decomposition experiments, relationship between heat preservation time and volatilization rate of Mo and S was obtained, while the constant temperature and chamber pressure were 1823 K and 5–35 Pa, respectively. Above all, both the theoretical and experimental results showed that volatilization behaviors of Mo and S during vacuum decomposition process of molybdenite concentrate were as follows: Mo could partly evaporate into the condensate in the form of clusters, and S could easily evaporate into the condensate.

Structure, stability, and dynamics of Pb m Sb n (m + n ≤ 9) clusters were investigated using ab initio molecular dynamics. Size dependence of binding energies, the second-order energy difference of clusters, dissociation energy, HOMO-LUMO gaps, Mayer bond order, and the diffusion coefficient of Pb m Sb n clusters were discussed. Results suggest that Pb3Sb2, Pb4Sb2, and Pb5Sb4 (n = 2 or 4) clusters have higher stability than other clusters, which is consistent with previous findings. In case of Pb-Sb alloy, the dynamics results show that Pb4Sb2 (Pb-22.71 wt pct Sb) can exist in gas phase at 1073 K (800 °C), which reasonably explains the azeotropic phenomenon, and the calculated values are in agreement with the experimental results (Pb-22 wt pct Sb).

In this work, the kinetics of Pb evaporating from Pb-Sn alloy has been investigated. The experiments were performed in the temperature range 1200 K–1400 K and the pressure of 10 Pa. The results indicated that the evaporation of Pb follow first order kinetics. The overall mass transfer coefficients of lead evaporation from Pb-Sn alloy are 2.68 × 10−6 m s−1, 5.01 × 10−6 m s−1 and 1.92 × 10−5 m s−1 at 1200 K, 1300 K and 1400 K, respectively. Additionally, the apparent activation energy of lead evaporation from molten Pb-Sn alloy was calculated. It revealed that the mass transfer of lead in the vapor phase is not rate limiting in the vacuum distillation. The Pb evaporation from Pb-Sn alloy was mix-controlled by vaporization and liquid mass transfer. The mass transfer in the liquid phase is a major rate-limiting step under the present experimental conditions.

The vapor–liquid equilibrium (VLE) phase diagrams of Pb–Pd and Pb–Pt alloy systems in vacuum distillation were obtained based only on pure-component properties and the structures of the atoms. The interaction energies between pairs of atoms were calculated from ab initio methods and were used as the input energy parameters for the Wilson equation. The calculated activity data of the components, using energy parameters which were obtained by ab initio methods, are in good agreement with the experimental data. It is revealed that a cluster size of eight atoms, optimized using the NVT ensemble at 300 K, a time step of 1 femtosecond, and the simulation time 10 ps gives a good representation of the liquid phase systems. This approach can be used to obtain accurate VLE predictions for alloy systems in vacuum distillation. The VLE phase diagram has a significant advantage in guiding experiment and industrial production in vacuum metallurgy.

Vapor-liquid equilibria (VLE) and purification of tin from crude Sn containing Bi and Sb has been studied in vacuum distillation. The Sb-Sn and Bi-Sb-Sn systems were investigated in the temperature range from 1000 to 1500 K and at pressure of 5 Pa. Consequently, the content of Sn for the Bi-Sb-Sn system in the liquid phase reached more than 0.99 mol fraction as the temperature higher than 1500 K. It is shown that Bi and Sb can be satisfactorily removed from crude Sn. The VLE data of Sb-Sn and Bi-Sb-Sn alloys were calculated by using Wilson equation and compared with experimental values under vacuum condition. The capability of the equation to predicting the activities of components in whole composition range was also tested. It provides an efficient way to guide the process of vacuum distillation. The experiment results revealed that vacuum distillation is a promising method for the separation and purification of crude metals.

The structural, relative stable and electronic properties of PbnSnn (n = 2–12) alloy clusters were systematically studied using density functional theory. The isomers of PbnSnn alloy clusters were generated and determined by ab initio molecular dynamics. By comparing the calculated parameters of Pb2 dimer and Sn2 dimers with the parameters from experiments, our calculations are reasonable. With the lowest-energy structures for PbnSnn clusters, the average binding energies, fragmentation energies, second- order energy differences, vertical ionization potentials, vertical electron affinities, HOMO–LUMO gaps, and density of states were calculated and analyzed. The results indicate that the Sn atoms have a tendency to bond together, the average binding energies tend to be stable up to n = 8, Pb8Sn8 cluster is a good candidate to calculate the molecular interaction energy parameter in Wilson equation, the clusters become less chemical stable and show an insulator-to-metallic transition, 3, 6, 8 and 11 are magic numbers of PbnSnn (n = 2–12) clusters, the charges always transfer from Sn atoms to Pb atoms in PbnSnn clusters except for Pb10Sn10 cluster, and density of states of PbnSnn clusters becoming continuous and shifting toward negative with the increasing size n.

In this paper, thermal decomposition process of molybdenum concentrate in vacuum was thermodynamically analyzed, and decomposition mechanism of Mo S system in molybdenum was mainly studied. To further investigate and analyze the electronic properties in different temperature, the simulation calculations of MoS 2 (0 0 1) surface and Mo 2 S 3 (0 0 1) surface density of states, electron density difference, electronic orbital and Mulliken overlap population were carried out by density functional theory(DFT) formalism. The dynamics simulations results of MoS 2 (0 0 1) surface and Mo 2 S 3 (0 0 1) surface were obtained the temperature range of phase transforming are 1573 K–1673 K and from 1473 K to 1573 K at 20Pa, respectively. The interaction of MoS 2 and Mo 2 S 3 shows that thermal-decomposition of MoS 2 and Mo 2 S 3 does react, when new S S bonds and Mo Mo bond are formed instead of Mo S bond fracture. The experimental results of the thermal decomposition of MoS 2 and Mo 2 S 3 were in accordance with the thermodynamics theoretical calculation results and ab-initio molecular dynamics simulation results.

In order to investigate the structural and electronic properties of bimetallic Pb n Cu n (n = 2–14) clusters, density functional theory (DFT) were applied. The ground-state structures, average bond distances, binding energies, Mulliken population analysis, vertical ionization potentials, vertical electron affinities, HOMO-LOMO gaps and electronic density of states of Pb n Cu n (n = 2–14) bimetallic clusters were calculated by DFT, The results show that Cu atoms gathering together and encapsulated by peripheral Pb atoms. In addition, the charges always transfer from Pb atoms to Cu atoms, the metallicity of Pb n Cu n clusters increase with the increasing size n, the trend of VIPs is contrary to the trend of VEAs, 4, 8 and 11 are the magic numbers of Pb n Cu n clusters, s-p hybrizations play a crucial role in Pb n Cu n clusters.

Vacuum distillation of a zinc-silver (Zn–Ag) alloy under a system pressure of 5–10 Pa was conducted in the temperature range of 1173–1373 K. The Zn content in the Zn–Ag alloy was reduced from 70.80 wt% to 0.0026 wt% via a single-stage distillation process at a temperature >1373 K. The molecular interaction volume model (MIVM) was reasonably simplified. The activities of the Zn–Ag alloy components were calculated using the simplified molecular interaction volume model (SMIVM). The calculated average standard deviation for Zn and Ag were ±0.0078 and ±0.0082, and the average relative deviations were ±4.6758% and ±4.7564%, respectively. Simplicity and reliability are significant advantages of the SMIVM. The vapor-liquid equilibrium (VLE) phase diagram (T-x diagram) of the Zn–Ag alloy during vacuum distillation was calculated using the SMIVM and VLE theory. The results agree with the VLE data determined from experiments, which indicate that the resulting VLE phase diagram is reliable. The VLE phase diagram of alloys provides an intuitive and effective method for process optimization, development, and prediction of the dependence of product composition on system pressure and temperature during vacuum distillation.

Hazardous selenium sludge is a critical intermediate byproduct of the comprehensive recovery of selenium from copper anode slime, and the sustainable extraction of Se is an important basis for the development of high-tech Se-containing materials. Unfortunately, current processes are constrained by complex procedures, serious pollution, ineffectiveness and difficulty in separating Se-Te. This study has developed an innovative green approach utilizing the phase transformations of impurities combined with vacuum distillation to efficiently extract high-purity selenium from selenium sludge and to overcome these issues. The main impurities of Te, Cu, and Pb exist as elemental Te, PbTe, TeO, Cu2Se, and PbSe, and a green oxidizing reagent (H2O2) is employed to convert these impurities into low volatile TeO, CuSeO3, and PbSeO3. Then, high-purity selenium (Se 99.998%) is extracted by vacuum distillation. The appropriate dose of H2O2 is 15 ml per 100 g of sludge at 300 rpm, 0.5 h, and room temperature. Furthermore, the optimal vacuum distillation conditions are 733 K, 1 h, and 1–10 Pa. After completing the whole process, the total yield of high-purity selenium reaches 87.86%. This study provides an efficient and environmentally friendly process to dispose of hazardous selenium sludge and extract high-purity selenium for further use, which has important industrial applications.

Jamesonite is an important complex antimony mineral which treated by conventional methods have shortcomings, such as sulfur dioxide emission and low antimony and lead recovery. This study applied vacuum metallurgy technology to treat jamesonite. The vacuum decomposition behavior of jamesonite (Pb4FeSb6S14) was investigated, and a two-step vacuum distillation process of separation of antimony trisulfide (Sb2S3) and lead sulfide (PbS) from jamesonite was developed. First of all, the decomposition behavior of Pb4FeSb6S14 under vacuum condition was comprehensively studied. The results indicate it decompose into Sb2S3, PbS and FeS at 823 K under vacuum condition, then, Sb2S3 and PbS volatilize at different temperatures. Based on above results, we investigated the effects of vacuum distillation temperature and time on the recovery of Sb2S3 and PbS as well as the effects of temperature on the purity of them. The results indicate that the optimal temperature for separating Sb2S3 and PbS are 923 K and 1173 K, respectively. Under optimal conditions, up to 98% of Sb2S3 with a purity of 99.17% and up to 99.5% of PbS with a purity of 98.7% could be recovered.

The vapor-liquid equilibria (VLE) for Sn Bi binary alloy at 5 Pa were carried out at distillation temperatures in the range of 1150 K–1550 K under vacuum condition. The experimental results indicate that Bi can be satisfactorily removed from crude Sn, the content of tin in liquid phase reaching more than 99.99 wt% at a temperature higher than 1300 K. The thermodynamic consistency of the experimental data was checked by Van Ness method. The Wilson equation is used to predicate VLE data. The results show good agreement with the experimental data, indicating that VLE phase diagram is feasible and practical for the process of vacuum distillation of alloys.

Recently, Au-based clusters have been provoking great interest due to their potential applications in nanotechnology. Herein, the structural, relative stable, electronic, and gas sensing properties of PbnAun (n = 2–12) clusters were systematically investigated using density functional theory together with scalar relativistic pseudopotential. The ground state structures, average binding energies, dissociation energies, second order energy differences, HOMO–LUMO gaps, and average Mulliken charges of PbnAun (n = 2–12) clusters were calculated. The results revealing that the PbnAun (n = 4, 6, and 8) clusters are more relatively stable than their neighboring clusters. Furthermore, charges are always transferred from the Pb atoms to Au atoms based on Mulliken charge analysis. Furthermore, through the investigations of CO or NO molecule adsorption onto PbnAun (n = 4, 6, and 8) clusters, it is found that CO or NO molecule can chemisorb on those clusters with high sensitivity, and the charges are transferred from PbnAun (n = 4, 6, and 8) clusters to the gas molecules. According to the analysis of the electric conductivity, PbnAun (n = 4, 6, and 8) clusters can be served as potential gas sensors in CO and NO molecules detection.

The possibility of the separation of Pb-Sb alloys by vacuum distillation was investigated theoretically. The results show that Pb and Sb can be separated by vacuum distillation. However, the experimental results show that vacuum distillation technique does not provide clear separation. According to the literature, Pb-Sb alloys belong to azeotropic compounds under some certain temperature; the experiment and computer simulation were carried out based on the exceptional condition so as to analyze the reason from the experiment and microstructure of Pb-Sb alloys perspective. The separation of Pb-Sb alloys by vacuum distillation was experimentally carried out to probe the azeotropic point. Also, the functions, such as partial radial distributions functions, the structure factor, mean square displacement, and the density of state, were calculated by ab-initio molecular dynamics for the representation of the structure and properties of Pb-Sb alloys with different composition of Sb. The experimental results indicate that there exists common volatilization for Pb-Sb alloys when Sb content is 16.5 wt pct. On the other hand, the calculation results show that there is an intense interaction between Pb and Sb when Sb content is 22 wt pct, which supports the experimental results although Sb content is slightly deviation.

In this work, new experimental vapor–liquid equilibrium (VLE) data of lead-antimony alloy (Pb-Sb alloy) in vacuum distillation are reported. The activity coefficients of components of Pb-Sb alloy were calculated by using the NRTL model. The calculated average relative deviations were ±0.1425 and ±0.2433 pct, and the average standard deviations were ±0.0009 and ±0.0007, respectively, for Pb and Sb. The VLE phase diagrams, such as the temperature composition (T-x) and pressure composition (P-x) diagrams of Pb-Sb alloy in vacuum distillation were predicted based on the NRTL model and VLE theory. The predicted results are consistent with the new experimental data indicating that VLE phase diagrams obtained by this method are reliable. The VLE phase diagrams of alloys will provide an effective and intuitive way for the technical design and realization of recycling and separation processes. The VLE data may be used in separation processes design, and the thermodynamic properties as the key parameters in specific applications.

In this work, interaction energies between pairs of atoms for the Ag–Pb, Cu–Pb and Sn–Pb systems have been calculated using ab initio methods. These energies are then used as the interaction energy parameters in the Wilson equation. Phase diagram of vapor–liquid equilibria (VLE) for the Pb-based alloy systems in vacuum distillation are obtained based on the calculated parameters. The results indicate that this approach can lead to accurate VLE predictions for alloy systems in vacuum distillation based only on properties of pure components and the structure of the clusters. The comparisons show the computational results are in good agreement with the experimental data.

In this work, vapor–liquid equilibria (VLE) of the Ag–Cu–Pb system were experimentally investigated in vacuum distillation. The experimental results show that the content of Pb in liquid phase is 0.005 (mole fraction) under the experimental condition of 1173 K, 90 min and 10 Pa. The amount of Pb in volatiles increased to 0.9911 (mole fraction). It indicates that Pb can be satisfactorily removed from Ag–Cu alloy. With the Wilson equation, the partial Gibbs free energies of Pb in liquid Ag–Cu–Pb alloys were calculated, and the predicted values agree well with the experimental data, which shown that the interaction parameters are reliable. Using binary data only, the VLE for the Ag–Pb and Ag–Cu–Pb systems under vacuum condition were obtained. The calculation results demonstrate that this approach can lead to accurate VLE data predictions for the binary and ternary systems based on the Wilson equation.

Vacuum distillation experiments were conducted for tin-antimony alloy (Sn–Sb alloy) under the system pressure of 5 Pa. The content of Sb (mole fraction) in crude Sn, viz., xSb was reduced from 0.5000 to 0.0619 in a single stage distillation process under the condition of residual pressure of 5–10 Pa, distillation temperature of 1373 K and distillation time of 60 min. The activity coefficients of components of Sn–Sb alloy were calculated by using the molecular interaction volume model (MIVM), and the calculated average relative deviation and the average standard deviation were ±0.00039 and ± 0.173%, respectively for both Sn and Sb. The vapor–liquid equilibrium (VLE) phase diagrams, including the temperature-composition (T-x) and pressure-composition (p-x) diagrams of Sn–Sb alloy in vacuum distillation were calculated based on VLE theory and the MIVM. A reasonable agreement between the calculated results and the experimental data indicates that VLE phase diagrams obtained by this method are reliable. The VLE phase diagrams of alloys will provide an effective and convenient way for the designing of the process parameters of industrial production of vacuum metallurgy, and for the prediction of the needed product component dependence of temperature and pressure during the process of vacuum distillation.

Ab-initio molecular dynamics simulations are performed to study the structural and electronic properties of liquid Pb–Sb alloys at eight concentrations. This alloy is known as azeotropic compounds within a certain ingredients at different temperature. The separation of Pb–Sb alloys is experimental carried out by vacuum distillation at 1173 K. Our predictions are coincident with the available experimental data. The experiment results indicate that there exists common volatilization for Pb–Sb alloys when Sb content is 15–20 wt.%. In addition, the calculation results show that when the content of Sb is around 15 wt.%, there is an intense interaction between Pb and Sb, which supports the experimental results. And this point (Pb-15 wt.%Sb) is azeotropic point.

The feasibility study of the AlCl(g) generated by Al2O−AlCl2−C system under vacuum was carried out by thermodynamic analysis and CASTEP package of the Material Studio program which was based on density functional theory (DFT) formalism. Thermodynamic calculations indicate that AlCl and CO molecules can be formed under conditions of temperature 1760 K and the pressure of 60 Pa. The interaction of Al2O and AlCl2 with C shows that the chemical adsorption of Al2O and AlCl2 does take place on C(001) crystal plane, and at the same time, new chemical bond is formed between Al atom in Al2O and Cl atoms from one of the Al—Cl bonds in AlCl2. The results, after 1.25 ps dynamics simulation, indicate that adsorbed AlCl molecules are generated and CO molecule will be formed in this system, and they will escape from C(001) surface after a longer period of dynamic simulation time. It means that the reaction of Al2O and AlCl2 with C can be carried out under given constraint condition.

High-value-added hazardous selenium sludge extracted from copper anode slime may cause serious selenium contamination and potential threats to human health if improperly treated. In this study, a sustainable chemical reaction-free vacuum separation process was used to extract selenium and recycle valuable metals from selenium sludge. The process comprises low-pressure dehydration and Se extraction by vacuum distillation. The laboratory-scale results indicate that 90.76% of selenium was extracted from volatiles at a purity of 98.68% under the optimum distillation conditions of 693 K, 90 min and 30–50 Pa. Ag and Au were enriched to 28004 g/t and 1226 g/t in residues from 2560 g/t and 112 g/t, respectively, in raw materials, representing increases of 10.4 and 10.25 times. On this basis, a low-pressure melting-vacuum distillation process and equipment with an annual selenium sludge disposal capacity of 500 metric tons were developed for industrial production. The continuous production data show that the purity of the extracted selenium always exceeded 98.0%, the direct yield ratio of selenium exceeded 96.5%, and the consumption was only 1150 kW h electricity per ton of selenium ingot output. Additionally, Ag and Au were enriched by over 11 times in the residue. The discharged water evaporated, and residues were returned to the comprehensive copper anode slime treatment process for the further valuable metal extraction. Compared with chemical processes, the proposed technology consumes fewer resources and reduces the environmental impacts, resulting in better economic and sustainability assessment results. The proposed process meets the demand for cleaner production within the selenium metallurgical industry.

A new yttrium metal-organic framework was synthesized by using 2,5-furandicarboxylic acid as ligand under hydrothermal conditions. The crystal structures and stability of MOF were characterized by X-ray Diffraction and Thermogravimetric Analyzer, respectively. In particular, Y-MOF exhibits sensitive and highly selective detection for Cu2+ ions, the detection limit can be as low as 0.1 μg/ml. Moreover, Y-MOF also exhibits high selectivity for small molecules such as nitrobenzene and o-chlorophenol and the detection limit are 5 mg/L and 10 mg/L, respectively. The luminescent behavior of Y-MOF signify a promising use as fluorescent probe for sensing of metal ions and small molecules.

Molten salt electrolysis is an important and low-cost method to prepare titanium powders. The separation and recycling of chloride salts from electrolytic titanium powder(ETP) is quite crucial for the purpose of improving the quality and reducing production cost. In this study, a novel process was developed to remove and recycle the chloride salts impurities (e.g., NaCl, KCl) in ETP by using vacuum distillation. The saturated vapor pressures of components in ETP were theoretically analyzed to predict the system pressure and temperature conditions during distillation process. It shows that the vaporization of the mixture of NaCl–KCl salt strengthens upon increasing the temperature. The volatilization behavior of NaCl-KCl salt and the effects of system pressure, distillation temperature and holding time on the separation were investigated using a lab scale vertical vacuum distillation furnace. Experimental studies indicates that the chlorine impurity content in purified titanium powder can be maintained at a percentage of below 0.04 wt. % under the optimal experimental condition of 850 °C, 3.5–4 h, and 0.1–1 Pa. These results demonstrate that the chloride salts can be efficiently separated and recycled from ETP in an environmentally-friendly manner by using vacuum distillation. The process comparison and evaluation show that the vacuum distillation post-treatment is a method without the generation of waste acid and wastewater, and the titanium powder with a low oxygen impurity can be produced.

A novel, clean and highly efficient vacuum separation technique for the commercial processing of copper dross is introduced in this article. The industrial treatment of 500 kg copper dross showed that under the conditions of 1523 K, 20–150 Pa and 5 h of heat preservation, three kinds of products can be obtained by vacuum distillation, namely, crude lead, lead sulfide, and a Cu-As-Sb alloy. During the process, waste gas and wastewater were not generated, and no reagents were added. The combined power consumption is less than 1500 kW·h/t. The process was perfectly coupled to the lead smelting system, and the product was returned to the main process without the need for additional equipment to process it separately.

A metallurgical material integration concept, using porous calcium titanate (CaTiO3) as raw material, was put forward for preparation of metallic titanium powder and porous titanium by calciothermic reduction. Porous metallic titanium was prepared by calcium vapor reduction at 1273 K for 6 h with two types of interconnected pores in titanium samples. The interconnected macropores about 50–300 μm were inherited from porous CaTiO3, and the micropores about 5–40 μm were made by leaching removal of byproduct CaO in reduction products. Metallic porous titanium was fabricated in Ca-dissolved CaO-CaCl2 molten salt mixtures by self-sintering and had a good interconnectivity inside with thickness about 155 μm and the porosities of the porous titanium are 65–81%.

Cadmium telluride waste contains a portion of rare metals. In this paper, a new, clean and efficient vulcanization-vacuum distillation process is used to separate the rare metal Te from cadmium telluride. Taking CdTe (99.99%) and S (99.99%) as examples, the feasibility of this process was verified on a laboratory scale. Recovery of cadmium telluride waste was simplified to two-step vulcanization and vacuum distillation process. The effects of temperature and time on vulcanization-vacuum distillation were investigated. The experimental results show that the purity of Te obtained by vacuum distillation was 99.92%, and the purity of cadmium sulfide was up to 99.5%. This method provides theoretical guidance for the recycling of cadmium telluride photovoltaic modules. Compared with the traditional methods, this process has a short refining process, does no generate waste water or waste gas, and is environmentally friendly. The Te and CdS obtained from vulcanization-vacuum distillation can be utilized as raw materials for semiconductor production after subsequent processing.

In this paper, The structures and properties changes for single unit cell of alumina, Al-O-C compounds and aluminium carbide were simulated by first principles method. According to theoretical calculation results, alumina carbothermal reductions with coal and charcoal separately used as reductant were carried out under vacuum. The major equations in carbonthermal reduction reduced to three general equations by reaction temperature; the sequence for each substance which formed in reductions was Al4O4C→Al2OC→Al4C3

In this research, thermodynamic analysis and CASTEP package of the Material Studio program which is based on density functional theory (DFT) formalism were used to study the carbothermic-chlorination (AlCl3) reaction of Al2O under vacuum. Thermodynamic calculations indicated that AlCl(g) can be generated by carbothermic-chlorination process at 1760K and 60Pa. The interaction of Al2O and AlCl3 with C showed that the chemical adsorption of Al2O and AlCl3 did take place on C(001) crystal plane, at the same time, new chemical bond have been formed between Al atom dissociated from Al2O and Cl atom dissociated from AlCl3 molecule. The result, after 1ps dynamics simulation, indicated that adsorbed AlCl and CO molecules have been generated in Al2O-AlCl3-C system, and they would escape from C surface after a longer period of dynamics simulation time. It means that the reaction of Al2O and AlCl3 with C can be carried out under given constraint condition.