Calcined kaolin/TiO2 composite particle material （CK/TCPM） was prepared with TiO2 coating on the surfaces of calcined kaolin particles by the mechano-chemical method. X-ray diffraction （XRD） and scanning electron ...Calcined kaolin/TiO2 composite particle material （CK/TCPM） was prepared with TiO2 coating on the surfaces of calcined kaolin particles by the mechano-chemical method. X-ray diffraction （XRD） and scanning electron microscope （SEM） were used to investigate the microstructures and morphologies, respectively. The mechanism of the mechano-chemical reaction between calcined kaolin and TiO2 was studied by infrared spectra （IR）. The results show that TiO2 coats evenly on the surfaces of calcined kaolin particles by Si-O-Ti and Al-O-Ti bonds on their interfaces. The hiding power and whiteness of CK/TCPM are 17.12 g/m^2 and 95.7%, respectively, presenting its similarity to TiO2 in pigment properties.展开更多
Lithium–sulfur batteries have great potential for high energy applications due to their high capacities,low cost and eco-friendliness. However, the particularly rapid capacity decay owing to the dissolution and diffu...Lithium–sulfur batteries have great potential for high energy applications due to their high capacities,low cost and eco-friendliness. However, the particularly rapid capacity decay owing to the dissolution and diffusion of polysulfide intermediate into the electrolyte still hamper their practical applications.And the reported preparation procedures to sulfur based cathode materials are often complex, and hence are rather difficult to produce at large scale. Here, we report a simple mechano-chemical sulfurization methodology in vacuum environment applying ball-milling method combined both the chemical and physical interaction for the one-pot synthesis of edge-sulfurized grapheme nanoplatelets with 3D porous foam structure as cathode materials. The optimal sample of 70%S–Gn Ps-48 h(ball-milled 48 h) obtains 13.2 wt% sulfur that chemically bonded onto the edge of Gn Ps. And the assembled batteries exhibit high initial discharge capacities of 1089 mAh/g at 0.1 C and 950 mAh/g at 0.5 C, and retain a stable discharge capacity of 776 mAh/g after 250 cycles at 0.5 C with a high Coulombic efficiency of over 98%. The excellent performance is mainly attributed to the mechano-chemical interaction between sulfur and grapheme nanoplatelets. This definitely triggers the currently extensive research in lithium–sulfur battery area.展开更多
Core-shell wollastonite@ TiO2(WOT)composite particles are prepared by a mechano-chemical method (MCM)to improve the dispersion of TiO2and reduce its dosage,and to achieve synergistic effects with the wollastonite mine...Core-shell wollastonite@ TiO2(WOT)composite particles are prepared by a mechano-chemical method (MCM)to improve the dispersion of TiO2and reduce its dosage,and to achieve synergistic effects with the wollastonite mineral.The crystal structure,morphology,functional groups,and pigment properties of the as-prepared composite powders are determined.The W@T composite particles are formed by van der Waals force in addition to electrostatic attraction and chemical bonding.The anatase TiO2coating is anchored on the woUastonite surface by Si-O-Ti and Ca-O-Ti bonds.The W@T powders possess excellent characteristics such as whiteness of 96.6%,hiding power of 17.97g/m^2,and oil absorption of 22.72g/100g.The properties of the W@T composite are similar to those of TiO2and the former,which is much cheaper,can potentially substitute the latter as a white paint in many applications.展开更多
A novel, high-temperature, mechano-chemical（HTMC） method was developed to synthesise singlephase Sr_2CeO_4：Eu^（3＋）phosphor. Phosphors were characterised by X-ray diffraction（XRD）, scanning electron microscopy...A novel, high-temperature, mechano-chemical（HTMC） method was developed to synthesise singlephase Sr_2CeO_4：Eu^（3＋）phosphor. Phosphors were characterised by X-ray diffraction（XRD）, scanning electron microscopy（SEM）, and luminescence spectra. Compared with phosphors prepared by the traditional hightemperature solid state method and citric acid gel method, single-phase Sr_2CeO_4：Eu^（3＋）powders by using the HTMC method, with small average particle sizes of about 5 μm, a narrow size distribution range and uniform dispersion, were prepared at 800 ℃, and reached their maximum luminescent intensity at 900 ℃.Under ultraviolet excitation at 298 nm, the sample showed good luminescence with the strongest red light of 616 nm. However, Sr_2CeO_4：Eu^（3＋）was prepared at the higher temperature of 1100 ℃ by solid state method and citric acid gel method. The particle size was too large and uneven with phosphor agglomeration by high-temperature solid state method. The luminescent intensity reached a maximum for Sr_2CeO_4：Eu^（3＋）phosphor at a synthesis temperature of 1100 ℃ by using the high-temperature solid state method, and at 1200 ℃ by both citric acid gel and chemical precipitation methods. Furthermore, the advantages of the Sr_2CeO_4：Eu^（3＋）powder prepared by HTMC method were discussed compared with that prepared using traditional high-temperature solid state and citric acid gel methods.展开更多
Gold-tailings are one of the major mine wastes which is dramatically damaging the environment.With low reactivity in an alkaline medium,gold-tailings are rarely utilized in the geopolymer production.In this work,we in...Gold-tailings are one of the major mine wastes which is dramatically damaging the environment.With low reactivity in an alkaline medium,gold-tailings are rarely utilized in the geopolymer production.In this work,we investigated the effects of mechano-chemical activation on physical-mechanical properties and structure of gold-tailings and/with geopolymer samples.The structures of the gold-tailings and the geopolymer samples were researched by Fourier transform infrared spectroscopy and X-ray diffraction;the morphology was examined using scanning electron microscopy.All results suggested that mechano-chemical activation increases with the amorphous phase content,then promotes the compressive strength of geopolymer samples from 11.6 to 17.2 MPa.However,the compressive strength decreased when the milling time over than 20 min due to higher water demand and lower packing density.展开更多
The preparation of a new mineral composite material, calcium carbonate particles coated with titanium dioxide, was studied. The mechanism of the preparation process was proposed. The new mineral composite material was...The preparation of a new mineral composite material, calcium carbonate particles coated with titanium dioxide, was studied. The mechanism of the preparation process was proposed. The new mineral composite material was made by the mechanoehemieal method under the optimum condition that the mass ratio of calcium carbonate particles to titanium dioxide was 6.5：3.5. The mass ratios of two different types of titanium dioxide （anatase to rutile） and grinding media to grinded materials were 8：2 and 4：1 respectively, and the modified density was 60%. Under this condition, the new material was capable of forming after 120-min modification. The hiding power and oil absorption of this new material were 29.12 g/m^2 and 23.30%, respectively. The results show that the modification is based on surface hydroxylation. After coating with titanium dioxide, the hiding power of calcium carbonate can be improved greatly. The new mineral composite materials can be used as the substitute for titanium dioxide.展开更多
The mixture of(2NaBH4+ MnCl2) was ball milled in a magneto-mill. No gas release was detected. The XRD patterns of the ball milled mixture exhibit only the Bragg diffraction peaks of the Na Cl-type salt which on the ba...The mixture of(2NaBH4+ MnCl2) was ball milled in a magneto-mill. No gas release was detected. The XRD patterns of the ball milled mixture exhibit only the Bragg diffraction peaks of the Na Cl-type salt which on the basis of the present X-ray diffraction results and the literature is likely to be a solid solution Na(Cl)x(BH4)(1-x), possessing a cubic Na Cl-type crystalline structure. No presence of any crystalline hydride was detected by powder X-ray diffraction which clearly shows that NaBH4in the initial mixture must have reacted with MnCl2forming a Na Cl-type by-product and another hydride that does not exhibit X-ray Bragg diffraction peaks. Mass spectrometry(MS) of gas released from the ball milled mixture during combined MS/thermogravimetric analysis(TGA)/differential scanning calorimetry(DSC) experiments, confirms mainly hydrogen(H2) with a small quantity of diborane gas, B2H6. The Fourier transform infra-red(FT-IR) spectrum of the ball milled(2NaBH4+ MnCl2) is quite similar to the FT-IR spectrum of crystalline manganese borohydride, c-Mn(BH4)2, synthesized by ball milling, which strongly suggests that the amorphous hydride mechano-chemically synthesized during ball milling could be an amorphous manganese borohydride. Remarkably, the process of solvent filtration and extraction at 42 °C, resulted in the transformation of mechano-chemically synthesized amorphous manganese borohydride to a nanostructured,crystalline, c-Mn(BH4)2hydride.展开更多
Copper ion conducting solid electrolyte Rb_(4)Cu_(16)I_(6.5)Cl_(13.5)was prepared by means of mechano-chemical method.The structure and morphology of the powder was investigated by x-ray diffraction and scanning elect...Copper ion conducting solid electrolyte Rb_(4)Cu_(16)I_(6.5)Cl_(13.5)was prepared by means of mechano-chemical method.The structure and morphology of the powder was investigated by x-ray diffraction and scanning electron microscopy.The grain size was estimated to be 0.2-0.9μm and the ionic conductivity at room temperature was approximately 0.206 S/cm.The solid electrolyte Rb_(4)Cu_(16)I_(6.5)Cl_(13.5)was exploited for copper ion beam generation.The copper ion emission current of several nA was successfully obtained at acceleration voltages of 15 kV and temperature of 197℃in vacuum of 2.1×10^(-4)Pa.A good linear correlation between the logarithmic ion current(logI)and the square root of the acceleration voltage(U_(acc))at high voltage range was obtained,suggesting the Schottky emission mechanism in the process of copper ion beam generation.展开更多
The ceramic setting binders obtained by means of the raw mix mechano-chemical processing(mechanical dispersion and chemical interaction processes combination), used for bonding refractory concretes, become more availa...The ceramic setting binders obtained by means of the raw mix mechano-chemical processing(mechanical dispersion and chemical interaction processes combination), used for bonding refractory concretes, become more available with a subsequent increased interest in their properties because they develop initial strength during a heat up of the units within 8-10 h, in contrast to 24 h after placement for high Al_2O_3 cements(HAC). This strength development enables high temperature processing units to be relined with minimum turnaround time, thus providing a favored cost/performance ratio. The present paper identifies the predominant phosphate phases responsible for developing good mechanical-strength properties of zirconia and alumina concretes bonded with mechano-chemical binders. It sets out the colloid and crystalline phases resulted from interphase interaction that provide the basis for high concentrated bonding suspensions(HCBS) technology useful to the refractory industry.展开更多
Barite/TiO2 composite particle (B/TCP) was prepared by coating TiO2 on the surfaces of barite particles through mechano-chemical method. The preparation parameters and pigment properties of B/TCP as well as the intera...Barite/TiO2 composite particle (B/TCP) was prepared by coating TiO2 on the surfaces of barite particles through mechano-chemical method. The preparation parameters and pigment properties of B/TCP as well as the interaction mechanism between barite and TiO2 were studied. The results indicated that the mechanical co-grinding process and the proportion of TiO2 affected the properties of B/TCP significantly. B/TCP prepared under optimal conditions was similar to TiO2 in pigment properties. It was mainly the strong electrostatic attraction between barite and TiO2 in water that combined them firmly and then formed B/TCP.展开更多
基金Funded by the National Key Technology R&D Program of China(No.2008BAE60B06)Beijing Municipal Science&Technology Commission (No.Z080003032208015)
文摘Calcined kaolin/TiO2 composite particle material （CK/TCPM） was prepared with TiO2 coating on the surfaces of calcined kaolin particles by the mechano-chemical method. X-ray diffraction （XRD） and scanning electron microscope （SEM） were used to investigate the microstructures and morphologies, respectively. The mechanism of the mechano-chemical reaction between calcined kaolin and TiO2 was studied by infrared spectra （IR）. The results show that TiO2 coats evenly on the surfaces of calcined kaolin particles by Si-O-Ti and Al-O-Ti bonds on their interfaces. The hiding power and whiteness of CK/TCPM are 17.12 g/m^2 and 95.7%, respectively, presenting its similarity to TiO2 in pigment properties.
基金the Link Project of the National Natural Science Foundation of China and Guangdong Province(Grant no.U1301244)the National Natural Science Foundation of China(Grant nos.51573215,21506260)+2 种基金Guangdong Province Science&Technology Foundation(2011B050300008)Guangdong Natural Science Foundation(Grant nos.2014A030313159,2016A030313354)Guangzhou Scientific and Technological Planning Project(2014J4500002,201607010042)for financial support of this work
文摘Lithium–sulfur batteries have great potential for high energy applications due to their high capacities,low cost and eco-friendliness. However, the particularly rapid capacity decay owing to the dissolution and diffusion of polysulfide intermediate into the electrolyte still hamper their practical applications.And the reported preparation procedures to sulfur based cathode materials are often complex, and hence are rather difficult to produce at large scale. Here, we report a simple mechano-chemical sulfurization methodology in vacuum environment applying ball-milling method combined both the chemical and physical interaction for the one-pot synthesis of edge-sulfurized grapheme nanoplatelets with 3D porous foam structure as cathode materials. The optimal sample of 70%S–Gn Ps-48 h(ball-milled 48 h) obtains 13.2 wt% sulfur that chemically bonded onto the edge of Gn Ps. And the assembled batteries exhibit high initial discharge capacities of 1089 mAh/g at 0.1 C and 950 mAh/g at 0.5 C, and retain a stable discharge capacity of 776 mAh/g after 250 cycles at 0.5 C with a high Coulombic efficiency of over 98%. The excellent performance is mainly attributed to the mechano-chemical interaction between sulfur and grapheme nanoplatelets. This definitely triggers the currently extensive research in lithium–sulfur battery area.
基金the Fundamental Research Funds for the Central Universities of China (No. 2011PY0169)National Natural Science Foundation of China (NSFC) (Nos.51144011and 51474194)City University of Hong Kong Applied Research Grants (ARG),China,Nos.9667104and 9667122.
文摘Core-shell wollastonite@ TiO2(WOT)composite particles are prepared by a mechano-chemical method (MCM)to improve the dispersion of TiO2and reduce its dosage,and to achieve synergistic effects with the wollastonite mineral.The crystal structure,morphology,functional groups,and pigment properties of the as-prepared composite powders are determined.The W@T composite particles are formed by van der Waals force in addition to electrostatic attraction and chemical bonding.The anatase TiO2coating is anchored on the woUastonite surface by Si-O-Ti and Ca-O-Ti bonds.The W@T powders possess excellent characteristics such as whiteness of 96.6%,hiding power of 17.97g/m^2,and oil absorption of 22.72g/100g.The properties of the W@T composite are similar to those of TiO2and the former,which is much cheaper,can potentially substitute the latter as a white paint in many applications.
文摘A novel, high-temperature, mechano-chemical（HTMC） method was developed to synthesise singlephase Sr_2CeO_4：Eu^（3＋）phosphor. Phosphors were characterised by X-ray diffraction（XRD）, scanning electron microscopy（SEM）, and luminescence spectra. Compared with phosphors prepared by the traditional hightemperature solid state method and citric acid gel method, single-phase Sr_2CeO_4：Eu^（3＋）powders by using the HTMC method, with small average particle sizes of about 5 μm, a narrow size distribution range and uniform dispersion, were prepared at 800 ℃, and reached their maximum luminescent intensity at 900 ℃.Under ultraviolet excitation at 298 nm, the sample showed good luminescence with the strongest red light of 616 nm. However, Sr_2CeO_4：Eu^（3＋）was prepared at the higher temperature of 1100 ℃ by solid state method and citric acid gel method. The particle size was too large and uneven with phosphor agglomeration by high-temperature solid state method. The luminescent intensity reached a maximum for Sr_2CeO_4：Eu^（3＋）phosphor at a synthesis temperature of 1100 ℃ by using the high-temperature solid state method, and at 1200 ℃ by both citric acid gel and chemical precipitation methods. Furthermore, the advantages of the Sr_2CeO_4：Eu^（3＋）powder prepared by HTMC method were discussed compared with that prepared using traditional high-temperature solid state and citric acid gel methods.
文摘Gold-tailings are one of the major mine wastes which is dramatically damaging the environment.With low reactivity in an alkaline medium,gold-tailings are rarely utilized in the geopolymer production.In this work,we investigated the effects of mechano-chemical activation on physical-mechanical properties and structure of gold-tailings and/with geopolymer samples.The structures of the gold-tailings and the geopolymer samples were researched by Fourier transform infrared spectroscopy and X-ray diffraction;the morphology was examined using scanning electron microscopy.All results suggested that mechano-chemical activation increases with the amorphous phase content,then promotes the compressive strength of geopolymer samples from 11.6 to 17.2 MPa.However,the compressive strength decreased when the milling time over than 20 min due to higher water demand and lower packing density.
文摘The preparation of a new mineral composite material, calcium carbonate particles coated with titanium dioxide, was studied. The mechanism of the preparation process was proposed. The new mineral composite material was made by the mechanoehemieal method under the optimum condition that the mass ratio of calcium carbonate particles to titanium dioxide was 6.5：3.5. The mass ratios of two different types of titanium dioxide （anatase to rutile） and grinding media to grinded materials were 8：2 and 4：1 respectively, and the modified density was 60%. Under this condition, the new material was capable of forming after 120-min modification. The hiding power and oil absorption of this new material were 29.12 g/m^2 and 23.30%, respectively. The results show that the modification is based on surface hydroxylation. After coating with titanium dioxide, the hiding power of calcium carbonate can be improved greatly. The new mineral composite materials can be used as the substitute for titanium dioxide.
基金supported by the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery grant to Prof. R.A. Varin
文摘The mixture of(2NaBH4+ MnCl2) was ball milled in a magneto-mill. No gas release was detected. The XRD patterns of the ball milled mixture exhibit only the Bragg diffraction peaks of the Na Cl-type salt which on the basis of the present X-ray diffraction results and the literature is likely to be a solid solution Na(Cl)x(BH4)(1-x), possessing a cubic Na Cl-type crystalline structure. No presence of any crystalline hydride was detected by powder X-ray diffraction which clearly shows that NaBH4in the initial mixture must have reacted with MnCl2forming a Na Cl-type by-product and another hydride that does not exhibit X-ray Bragg diffraction peaks. Mass spectrometry(MS) of gas released from the ball milled mixture during combined MS/thermogravimetric analysis(TGA)/differential scanning calorimetry(DSC) experiments, confirms mainly hydrogen(H2) with a small quantity of diborane gas, B2H6. The Fourier transform infra-red(FT-IR) spectrum of the ball milled(2NaBH4+ MnCl2) is quite similar to the FT-IR spectrum of crystalline manganese borohydride, c-Mn(BH4)2, synthesized by ball milling, which strongly suggests that the amorphous hydride mechano-chemically synthesized during ball milling could be an amorphous manganese borohydride. Remarkably, the process of solvent filtration and extraction at 42 °C, resulted in the transformation of mechano-chemically synthesized amorphous manganese borohydride to a nanostructured,crystalline, c-Mn(BH4)2hydride.
基金supported by Shenzhen Municipal Science and Technology Innovation Commission(Grant Nos.JCYJ20170818112901473 and GJHZ20200731095604015)the Department of Science and Technology of Guangdong Province,China(Grant Nos.2020A0505100059,2020A1515011531,and 2020A1515011451)by the Ministry of Education and Science of the Russian Federation in the frame of the state assignment(Grant No.FSSN-2020-0003)。
文摘Copper ion conducting solid electrolyte Rb_(4)Cu_(16)I_(6.5)Cl_(13.5)was prepared by means of mechano-chemical method.The structure and morphology of the powder was investigated by x-ray diffraction and scanning electron microscopy.The grain size was estimated to be 0.2-0.9μm and the ionic conductivity at room temperature was approximately 0.206 S/cm.The solid electrolyte Rb_(4)Cu_(16)I_(6.5)Cl_(13.5)was exploited for copper ion beam generation.The copper ion emission current of several nA was successfully obtained at acceleration voltages of 15 kV and temperature of 197℃in vacuum of 2.1×10^(-4)Pa.A good linear correlation between the logarithmic ion current(logI)and the square root of the acceleration voltage(U_(acc))at high voltage range was obtained,suggesting the Schottky emission mechanism in the process of copper ion beam generation.
文摘The ceramic setting binders obtained by means of the raw mix mechano-chemical processing(mechanical dispersion and chemical interaction processes combination), used for bonding refractory concretes, become more available with a subsequent increased interest in their properties because they develop initial strength during a heat up of the units within 8-10 h, in contrast to 24 h after placement for high Al_2O_3 cements(HAC). This strength development enables high temperature processing units to be relined with minimum turnaround time, thus providing a favored cost/performance ratio. The present paper identifies the predominant phosphate phases responsible for developing good mechanical-strength properties of zirconia and alumina concretes bonded with mechano-chemical binders. It sets out the colloid and crystalline phases resulted from interphase interaction that provide the basis for high concentrated bonding suspensions(HCBS) technology useful to the refractory industry.
基金National Key Technology R&D Program of China (2008BAE60B06)Beijing Municipal Science & Technology Commission (Z080003032208015)
文摘Barite/TiO2 composite particle (B/TCP) was prepared by coating TiO2 on the surfaces of barite particles through mechano-chemical method. The preparation parameters and pigment properties of B/TCP as well as the interaction mechanism between barite and TiO2 were studied. The results indicated that the mechanical co-grinding process and the proportion of TiO2 affected the properties of B/TCP significantly. B/TCP prepared under optimal conditions was similar to TiO2 in pigment properties. It was mainly the strong electrostatic attraction between barite and TiO2 in water that combined them firmly and then formed B/TCP.
