Uniform deposition of ultra-thin TiO_(2) film on mica substrate by atmospheric pressure chemical vapor deposition: Effect of precursor concentration

The performance of pearlescent pigment significantly affected by the grain size and the roughness of deposited film. The effect of TiCl_(4) concentration on the initial deposition of TiO_(2) on mica by atmospheric pressure chemical vapor deposition(APCVD) was investigated. The precursor concentration significantly affected the deposition and morphology of TiO_(2) grains assembling the film. The deposition time for fully covering the surface of mica decreased from 120 to 10 s as the TiCl_(4) concentration increased from 0.38%to 2.44%. The grain size increased with the TiCl_(4) concentration. The AFM and TEM analysis demonstrated that the aggregation of TiO_(2) clusters at the initial stage finally result to the agglomeration of fine TiO_(2) grains at high TiCl_(4) concentrations. Following the results, it was suggested that the nucleation density and size was easy to be adjusted when the TiCl_(4) concentration is below 0.90%.

Enhanced activation of peroxymonosulfate by Fe/N co-doped ordered mesoporous carbon with dual active sites for efficient removal of m-cresol

The novel Fe-N co-doped ordered mesoporous carbon with high catalytic activity in m-cresol removal was prepared by urea-assisted impregnation and simple pyrolysis method.During the preparation of the Fe-NC catalyst,the complexation of N elements in urea could anchor Fe,and the formation of C3N4during urea pyrolysis could also prevent migration and aggregation of Fe species,which jointly improve the dispersion and stability of Fe.The FeN4sites and highly dispersed Fe nanoparticles synergistically trigger the dual-site peroxymonosulfate (PMS) activation for highly efficient m-cresol degradation,while the ordered mesoporous structure of the catalyst could improve the mass transfer rate of the catalytic process,which together promote catalytic degradation of m-cresol by PMS activation.Reactive oxygen species (ROS) analytic experiments demonstrate that the system degrades m-cresol by free radical pathway mainly based on SO_(4)^(-)·and·OH,and partially based on·OH as the active components,and a possible PMS activation mechanism by 5Fe-50 for m-cresol degradation was proposed.This study can provide theoretical guidance for the preparation of efficient and stable catalysts for the degradation of organic pollutants by activated PMS.

Strategies for Improving the Effectiveness of Professional Practice for Full-Time Professional Master Degree Postgraduate in Mineral Processing Engineering

In order to gain practical experience and hands-on skills,full-time professional master degree postgraduate in mineral processing engineering should engage in professional practices.Nonetheless,a series of problems,including insufficient time for practice,low management level,inadequate implementation of the double-supervisor system,and poor results of professional practice,has reduced the effectiveness of professional practice.In view of the aforementioned problems and the characteristics of the discipline,this paper proposes several strategies for improving the effectiveness of professional practice for postgraduates in mineral processing engineering.

Extending homogeneous fluidization flow regime of Geldart-A particles by exerting axial uniform and steady magnetic field

The homogeneous/particulate fluidization flow regime is particularly suitable for handling the various gas–solid contact processes encountered in the chemical and energy industry.This work aimed to extend such a regime of Geldart-A particles by exerting the axial uniform and steady magnetic field.Under the action of the magnetic field,the overall homogeneous fluidization regime of Geldart-A magnetizable particles became composed of two parts:inherent homogeneous fluidization and newly-created magnetic stabilization.Since the former remained almost unchanged whereas the latter became broader as the magnetic field intensity increased,the overall homogeneous fluidization regime could be extended remarkably.As for Geldart-A nonmagnetizable particles,certain amount of magnetizable particles had to be premixed to transmit the magnetic stabilization.Among others,the mere addition of magnetizable particles could broaden the homogeneous fluidization regime.The added content of magnetizable particles had an optimal value with smaller/lighter ones working better.The added magnetizable particles might raise the ratio between the interparticle force and the particle gravity.After the magnetic field was exerted,the homogeneous fluidization regime was further expanded due to the formation of magnetic stabilization flow regime.The more the added magnetizable particles,the better the magnetic performance and the broader the overall homogeneous fluidization regime.Smaller/lighter magnetizable particles were preferred to maximize the magnetic performance and extend the overall homogeneous fluidization regime.This phenomenon could be ascribed to that the added magnetizable particles themselves became more Geldart-A than-B type as their density or size decreased.

Preparation of a high-performance synthetic pitch from aromatic hydrocarbons containing N/Cl

The preparation of a synthetic pitch from aromatic monomers could easily regulate structure orientation at the molecu-lar level,which would be useful in fabrication.An isotropic synthetic pitch was prepared by a chlorine-and/or nitrogen-induced sub-stitution polymerization reaction method using aromatic hydrocarbon precursors containing Cl and N,which for this study were chloromethyl naphthalene and quinoline.This method was verified by investigating the structural changes under different synthesis conditions,and the synthesis mechanism induced by aromatics containing Cl was also probed.The result shows that the pyridinic N in quinoline contains a lone pair of electrons,and is an effective active site to induce the polymerization reaction by coupling with aromatic hydrocarbons containing Cl.The reaction between such free radicals causes strong homopolymerization and oligomeriza-tion.A higher reaction temperature and longer reaction time significantly increased the degree of polymerization and thus increased the softening point of the pitch.A linear molecular structure was formed by the Cl substitution reaction,which produced a highly spinnable pitch with a softening point of 258.6℃,and carbon fibers with a tensile strength of 1163.82 MPa were obtained.This study provides a relatively simple and safe method for the preparation of high-quality spinnable pitch.

Electrochemical behavior of gold and its associated minerals in alkaline thiourea solutions

Electrochemical measurements were conducted to study the electrochemical behavior of gold （Au） and its commonly associated minerals in alkaline thiourea solutions. The results indicated that without addition of any stabilizer, selective dissolution of Au from stibnite and pyrite was only possible at relatively low thiourea concentrations. As Na2SiO3 was added, pyrite started to become active and an oxida- tion peak appeared; the oxidation peaks of axsenopyrite and chalcocite appeared earlier thaxl that of Au. The chalcocite peak shifted in the positive direction and the peak current increased. Stibnite did not show an oxidation peak and its current was nearly zero. Adding Na2SiO3 favored the selective dissolution of Au when its minerals were associated with chalcocite and stibinte. At pH 12, the Au anode dissolution peak current increased with stabilizer concentration. At 0.38 and 0.42 V and for Na2SiO3 concentration below 0.09 M, the current density continuously increased with Na2SiO3 concentration. The Na2SiO3 concentration had to be adequate to stabilize thiourea. When the potential was higher than 0.42 V, the surface of the Au electrode started to passivate. With an additional increase in potential, the presence of Na2SiO3 could not stop the inevitable decomposition of thiourea.

A Comparative Study of Electrochemical Capacitance of Graphene Oxide Affected by Oligomers of p-phenylenediamine and Hydrazine Hydrate in Solvothermal Condition

A systematic investigation of the graphene oxide composite reduced by either p-phenylenediamine oligomers or hydrazine hydrate was performed with field emission scanning electron microscopy,high resolution transmission electron microscopy,X-ray diffraction,fourier transform infrared,and X-ray photoelectron spectroscopy analyses.The electrical capacitance of the composite was evaluated by a cyclic voltammetry technique,while the properties of these prototype supercapacitors were measured by a chronopotentiometry technique.It was found that,under the solvothermal condition,the graphene oxide reduced by p-phenylenediamine oligomers was observed to have higher electrical capacitance than that reduced by hydrazine.The improved electrical capacitance can be attributed to that p-phenylenediamine oligomers are the more effective spacers for graphene layers;and they could also provide some pseudo-capacitance to the graphene oxide composite based on their conjugate structure.The results imply that graphene oxide modified by diamine oligomers has a good potential in energy storage devices.

Activation mechanism of ammonium oxalate with pyrite in the lime system and its response to flotation separation of pyrite from arsenopyrite

The activation properties of ammonium oxalate on the flotation of pyrite and arsenopyrite in the lime system were studied in this work.Single mineral flotation tests showed that the ammonium oxalate strongly activated pyrite in high alkalinity and high Ca^(2+)system,whereas arsenopyrite was almost unaffected.In mineral mixtures tests,the recovery difference between pyrite and arsenopyrite after adding ammonium oxalate is more than 85%.After ammonium oxalate and ethyl xanthate treatment,the hydrophobicity of pyrite increased significantly,and the contact angle increased from 66.62°to 75.15°and then to 81.21°.After ammonium oxalate treatment,the amount of ethyl xanthate adsorption on the pyrite surface significantly increased and was much greater than that on the arsenopyrite surface.Zeta potential measurements showed that after activation by ammonium oxalate,there was a shift in the zeta potential of pyrite to more negative values by adding xanthate.X-ray photoelectron spectroscopy test showed that after ammonium oxalate treatment,the O 1s content on the surface of pyrite decreased from 44.03%to 26.18%,and the S 2p content increased from 14.01%to 27.26%,which confirmed that the ammonium oxalatetreated pyrite surface was more hydrophobic than the untreated surface.Therefore,ammonium oxalate may be used as a selective activator of pyrite in the lime system,which achieves an efficient flotation separation of S-As sulfide ores under high alkalinity and high Ca2+concentration conditions.

Adsorption characteristics of Pb(Ⅱ)ions on sulfidized hemimorphite surface under ammonium sulfate system

In this work,the effect of ammonium sulfate on the adsorption characteristics of low-concentration Pb(Ⅱ)ions on the sulfidized hemimorphite surface was comprehensively investigated.The results showed that ammonium sulfate could increase the maximum recovery of hemimorphite from 69.42%to 88.24%under a low concentration of Pb(Ⅱ)ions.On the hemimorphite surface pretreated with ammonium sulfate,the adsorption of Pb(Ⅱ)ions was enhanced and the main species of Pb adsorbed was changed from Pb―O/OH to PbS.This was due to the larger amount of ZnS providing more effective adsorption sites for Pb components to generate Pb S.Meanwhile,the intensity of ZnS decreased with the formation of PbS,demonstrating that ZnS was covered by PbS which formed later on the mineral surface.It was beneficial for the adsorption of butyl xanthate on the hemimorphite surface to form more hydrophobic substances.As a result,ammonium sulfate played a crucial role in realizing the efficient recovery of hemimorphite.

Elucidating the diffusion pathway of lithium ions in superionic halide solid electrolytes Li_(2+x)Hf_(1-x)In_(x)Cl_(6) for all-solid-state lithium-metal based batteries

All-solid-state batteries(ASSBs) with inorganic solid-state-electrolytes(SSEs) have been regarded as the promising candidate for next-generation energy storage due to their high energy density and outstanding safety performance.However,the representative oxide and sulfide electrolytes suffer from low ionic conductivity and poor(electro)chemical stability,respectively.Herein,we report a series of new halide superionic conductors Li_(2+x)Hf_(1-x)In_(x)Cl_(6) with high ionic conductivity up to 1.05 mS cm^(-1) at 30 ℃ that are simultaneously stable to high voltage.By means of the characterization techniques and bond-valence site energy(BVSE) calculation,insights into the effect of the phase transformation and underlying ionic transport mechanism by In substitution for Hf in Li_(2)HfCl_(6) are provided.Importantly,with the increased amount of aliovalent substitution in Li_(2+x)Hf_(1-x)In_(x)Cl_(6) microcrystal framework,a gradual structure evolution from trigonal to monoclinic phase has been observed,which is accompanied by the redistribution of Li-ions to generate two dimensionally(2D) preferable diffusion pathways through octahedral-tetrahe dral-octahedral sites in In^(3+)-substituted Li_(2)HfCl_(6).Additionally,due to the oxidative stability of Insubstituted Li_(2)HfCl_(6),the bulk-type ASSBs with bare LiCoO_(2) deliver distinguished electrochemical performance.

Flotation and adsorption of novel Gemini decyl-bishydroxamic acid on bastnaesite:Experiments and density functional theory calculations

Rare earth element is an important strategic metal,but the supply of high purity rare earth ores is growing slowly,which is in sharp contradiction with the rapidly growing demand.Froth flotation has been confirmed to be an effective method to separate bastnaesite from its gangue minerls.However,the traditional collectors are facing serious problems in flotation separation of minerals,requiring the addition of excess depressant and regulator in the flotation process.Herein,we proposed and synthesized novel Gemini hydroxamic acids Octyl-bishydroxamic acid(OTBHA),Decyl-bishydroxamic acid(DCBHA)and Dodecyl-bishydroxamic acid(DDBHA)as the collectors in bastnaesite-barite flotation system.The effect of different carbon chain lengths on the molecular properties were explored by density functional theory(DFT)calculations.DCBHA possessed a stronger reactivity compared with OCBHA and DDBHA.The flotation results verified the consistency of the computational calculation about the performance prediction of Gemini hydroxamic acids.Compared with OCBHA and DDBHA,DCBHA displayed superior collecting affinity toward bastnaesite,and did not float barite.Zeta potential results showed that the presence of DCBHA increased the potential of bastnaesite,while it had almost no effect on barite,indicating DCBHA had a stronger affinity for bastnaesite.Then,Fourier transform infrared(FTIR)and X-ray photoelectron spectroscopy(XPS)analyses indicated that the adsorption mechanism was due to two hydroxamate groups of DCBHA co-anchored on bastnaesite surface by forming five-membered hydroxamic―(O―O)―Ce complexes.In addition,atomic force microscopy(AFM)clearly observed that DCBHA uniformly aggregated on bastnaesite surface,which increased surface contact angle and improved the hydrophobicity of bastnaesite.

Discussion on the Teaching of“Metallic Mineral Processing”for Mineral Processing Engineering

Social economic growth and the increasing demand for mineral resources have promoted the development of metallic mineral processing technology.Therefore,in order to satisfy the demands for development in mining,cultivating comprehensive mineral processing engineering professionals with strong innovative practical skills has become the top priority in current education.We have established a new course,“Metallic Mineral Processing,”for students majoring in mineral processing engineering in universities,with coal and other sources of energy as the main focus.This paper analyzes the purpose and significance of setting up this course and the exploration of the reform of the teaching mode,with the aim of improving the teaching quality and ensuring the cultivation of mineral processing engineering undergraduates.

A three-dimensional co-continuous network structure polymer electrolyte with efficient ion transport channels enabling ultralong-life all solid-state lithium metal batteries

Solid polymer electrolytes(SPEs)have emerged as one of the most promising candidates for the construction of solid-state lithium batteries due to their excellent flexibility,scalability,and interface compatibility with electrodes.Herein,a novel all-solid polymer electrolyte(PPLCE)was fabricated by the copolymer network of liquid crystalline monomers and poly(ethylene glycol)dimethacrylate(PEGDMA)acts as a structural frame,combined with poly(ethylene glycol)diglycidyl ether short chain interspersed serving as mobile ion transport entities.The preparaed PPLCEs exhibit excellent mechanical property and out-standing electrochemical performances,which is attributed to their unique three-dimensional cocontinuous structure,characterized by a cross-linked semi-interpenetrating network and an ionic liquid phase,resulting in a distinctive nanostructure with short-range order and long-range disorder.Remarkably,the addition of PEGDMA is proved to be critical to the comprehensive performance of the PPLCEs,which effectively modulates the microscopic morphology of polymer networks and improves the mechanical properties as well as cycling stability of the solid electrolyte.When used in a lithiumion symmetrical battery configuration,the 6 wt%-PPLCE exhibites super stability,sustaining operation for over 2000 h at 30 C,with minimal and consistent overpotential of 50 mV.The resulting Li|PPLCE|LFP solid-state battery demonstrates high discharge specific capacities of 160.9 and 120.1 mA h g^(-1)at current densities of 0.2 and 1 C,respectively.Even after more than 300 cycles at a current density of 0.2 C,it retaines an impressive 73.5%capacity.Moreover,it displayes stable cycling for over 180 cycles at a high current density of 0.5C.The super cycle stability may promote the application for ultralong-life all solid-state lithium metal batteries.

柠檬酸协同黄铁矿对煤矸石硅缓释及土壤砷稳定性的影响研究

煤矸石是煤炭开采和加工过程中产生的固体废弃物,通常由硅酸盐组成。其在提升硅的生物可利用性方面具有显著潜力,因此可作为农业用硅肥的潜在来源。然而,煤矸石硅的缓释性不足与植物的慢吸收速率存在天然矛盾,限制了煤矸石作为硅肥的应用。本研究探讨了柠檬酸和黄铁矿对煤矸石中硅的缓释效果,以及由此制备的复合物(C@PC-10)对土壤中砷的固化与稳定化作用。研究结果显示,C@PC-10能有效减缓煤矸石中硅的释放速率,在30 d的实验周期内,土壤中水溶态砷和有效态砷的去除效率分别达到71.3%和55.9%。此外,酸溶态砷的比例降低,而残渣态砷的比例增加。模拟酸雨实验进一步表明C@PC-10能够抑制土壤中砷的溶出。通过X射线衍射(XRD)、X射线光电子能谱(XPS)和傅里叶变换红外光谱(FT-IR)分析,本研究证实了球磨过程中黄铁矿的氧化及其向黄钾铁矾和FeOOH的转化。这些发现揭示了氧化黄铁矿对砷的吸附能力显著增强,表明C@PC-10复合物是一种高效的修复材料,能够调控硅酸盐的释放并有效阻碍土壤中砷的迁移。

Determination of Fe and Zn contents and distributions in natural sphalerite/marmatite by various analysis methods

The contents of Fe and Zn in natural sphalerite samples were determined by chemical titration and spectroscopic techniques(portable X-ray fluorescence(P-XRF) spectrometry, electron probe microanalysis with energy dispersive spectroscopy(EPMA-EDS), electron probe microanalysis with wavelength dispersive spectroscopy(EPMA-WDS), and time-of-flight secondary ion mass spectrometry(To F-SIMS)). Besides, the distribution of Fe and Zn in sphalerite samples was analyzed by imaging EPMA-WDS and imaging To F-SIMS. The results show that Fe and Zn contents determined by each spectroscopic technique have good linearity with those determined by chemical titration(R^2>0.77), and the R^2 values of Fe are generally greater than those of Zn. The imaging analysis results revealed that Fe and Zn are not uniformly distributed in the sphalerite.

Enhancement of corrosion resistance of AZ31 Mg alloys by one-step in situ synthesis of ZnAl-LDH films intercalated with organic anions(ASP, La)

Inserting corrosion inhibitors into a lamellar protective coating is an effective way to improve the corrosion resistance of metal substrates.In this work,two kinds of environmentally friendly organic acid anions,aspartic acid(ASP)and lauric acid(La),were explored as corrosion inhibitors to in situ intercalate into the Zn Al-layered double hydroxides(Zn Al-LDHs)on AZ31 magnesium alloys by a facile one-step hydrothermal method.The morphology,composition,structure and the corrosion resistance of these two LDHs coating before and after corrosion experiment were investigated.It is found that both the two kinds of Zn Al-LDHs films consist of uniform and dense layered nanosheets(NSs),and the NSs of ZnAl-ASP-LDHs films grow vertically,but those of ZnAl-La-LDHs films exhibit a staggered tilted structure.The corrosion current density of the two Zn Al-LDHs films are two orders of magnitude lower than that of Mg alloy substrate.After one week’s immersion in NaCl solution,the NSs structure of two kind of ZnAl-LDHs films still remains the uniform and densely coverage on Mg alloy.Owing to the larger d(003)spacing,the ZnAl-La-LDHs have better ability to absorb Cl-and release interlayer anions than Zn Al-ASP-LDHs.These results indicate that the Zn Al-LDHs films intercalated with organic anions,specially La anions,can significantly improve the corrosion resistance of Mg alloy.

Resource utilization of slag from desulphurization and slag skimming:A comprehensive recycling process of all components

In order to make the slag from desulphurization and slag skimming(SDSS)to be comprehensively recycled and utilized,a combined process of beneficiation and building materials preparation was proposed to recover iron from SDSS,meanwhile to apply the remaining slag tailings as cement admixture.From this process,three iron-rich products were recovered in stages by clean gravity-magnetic separation,slag tailings were left.Slag powder was prepared by ultrafine grinding of slag tailings.The stability,setting time and cement mortar strength of the slag tailings cements(STC)which were mixed with Portland cement and slag powder were studied respectively.The results showed that a proper overall performance still could be obtained at the slag powder content of 30%.Chemical composition analysis,X-ray diffraction(XRD)analysis,metallographic microscope and scanning electron microscope(SEM)analysis were employed to assess the characteristics of the SDSS and the products obtained from the whole process.The results indicated that the three iron-rich products could be used as a raw material for steelmaking and ironmaking and the relatively large amount of calcium silicate(C_(2)S)and tricalcium silicate(C_(3)S)in the slag tailings make the addition of slag powder into the Portland cement feasible.

Synthesis,Structure and Thermal Stability of a New Lead Coordination Polymer:[Pb(L1)(L2)]·1.25H2O

A new Pb（Ⅱ） coordination polymer [Pb（L1）（L2）]·1.25H2O has been synthesized with 2-（4-fluorophenyl）-1H-imidazo[4,5-f][1,10]phenanthroline （L1） and sebacic acid （H2L2） under hydrothermal conditions. Crystallographic data： triclinic, space group Pī with a=8.4890（17）, b=12.471（3）, c=14.604（3）, α=67.04（3）, β=74.08（3）, γ=85.80（3）°, V=1368.0（5）3 , Z=1, C58H59F2N8O10.5Pb2 , Mr=1488.51, Dc=1.807g/cm3 , F（000）=729, μ（MoKa）=6.221mm-1 , R=0.0283 and wR=0.0564. The L2 dianions bridge neighboring Pb（Ⅱ） atoms to form a two-dimensional layer structure. The π-π interactions between the L1 ligands of neighboring layers led to a three-dimensional supramolecular architecture. The IR and TGA of the complex have been studied in detail.

Vegetation dynamics of coal mining city in an arid desert region of Northwest China from 2000 to 2019

Coal mining has led to serious ecological damages in arid desert region of Northwest China.However,effects of climatic factor and mining activity on vegetation dynamics and plant diversity in this region remain unknown.Wuhai City located in the arid desert region of Northwest China is an industrial city and dominated by coal mining.Based on Landsat data and field investigation in Wuhai City,we analyzed the vegetation dynamics and the relationships with climate factors,coal mining activity and ecological restoration projects from 2000 to 2019.Results showed that vegetation in Wuhai City mostly consisted of desert plants,such as Caragana microphylla,Tetraena mongolica and Achnatherum splendens.And the vegetation fractional coverage(VFC)and greenness rate of change(GRC)showed that vegetation was slightly improved during the study period.Normalized difference vegetation index(NDVI)was positively correlated with annual mean precipitation,relative humidity and annual mean temperature,indicating that these climate factors might play important roles in the improved vegetation.Vegetation coverage and plant diversity around the coal mining area were reduced by coal mining,while the implementation of ecological restoration projects improved the vegetation coverage and plant diversity.Our results suggested that vegetation in the arid desert region was mainly affected by climate factors,and the implementation of ecological restoration projects could mitigate the impacts of coal mining on vegetation and ecological environment.

Designing and optimizing a parallel neural network model for predicting the solubility of diosgenin in n-alkanols

Accurate estimation of the solubility of a chemical compound is an important issue for many industrial proce sses.To overcome the defects of some thermodynamic models and simple correlations,a parallel neural network(PNN) model was conceived and optimized to predict the solubility of diosgenin in seven n-alkanols(C_(1)-C_(7)).The linear regression analysis of the parity plots indicates that the PNN model can give more accurate descriptions of the solubility of diosgenin than the ordinary neural network(ONN) model.The comparison of the average root mean square deviation(RMSD) shows that the suggested model has a slight advantage over the thermodynamic NRTL model in terms of the calculating precision.Moreover,the PNN model can reflect the effects of the temperature and the chain length of the alcohol solvent on the solution behavior of diosgenin correctly and can estimate its solubility in the n-alkanols with more carbon atoms.