Magnesium titanate was prepared directly through external coal reduction of seashore titanomagnetite concentrate and magnesium oxide(MgO).The effects of roasting temperature and the type and dosage of reductants on th...Magnesium titanate was prepared directly through external coal reduction of seashore titanomagnetite concentrate and magnesium oxide(MgO).The effects of roasting temperature and the type and dosage of reductants on the purity of generated magnesium titanate particles were systematically investigated.Scanning electron microscopy and energy-dispersive spectroscopy analyses were performed to characterize the magnesium titanate particles and observe their purity under different conditions.Results showed that the roasting temperature remarkably influenced the purity of magnesium titanate.At 1200,1300,and 1400℃,some magnesium ferrite and magnesium aluminate spinel were dissolved in magnesium titanate.However,as the roasting temperature increased to 1500℃,relatively pure magnesium titanate particles were generated because no magnesium ferrite was dissolved in them.The type and dosage of the reductants also remarkably affected the purity of magnesium titanate.The amount of fine metallic iron disseminated in the magnesium titanate particles obviously decreased when lignite was used as a reductant at a dosage of 70wt%.Thus,high-purity magnesium titanate particles formed.At a roasting temperature of 1500℃and with 70wt%lignite,the magnesium titanate product with a yield of 30.63%and an iron content of 3.01wt%was obtained through magnetic separation.展开更多
MgO- Mg2TiO4 composite was prepared by adding chemically pure TiO2（0,1%,2%,5% and 10%,in mass,the same hereinafter） to light-burned magnesia（particle size 〈0.045 mm）,ball milling,dry pressing,and reaction sinteri...MgO- Mg2TiO4 composite was prepared by adding chemically pure TiO2（0,1%,2%,5% and 10%,in mass,the same hereinafter） to light-burned magnesia（particle size 〈0.045 mm）,ball milling,dry pressing,and reaction sintering at 1 400,1 500 and 1 600 ℃ fo3 h,respectively. Apparent porosity,bulk density and corrosion resistance to AlF3- Na3AlF6- K3AlF6 were in vestigated. Phase composition and microstructure wer analyzed. The results show that：（1） MgO- Mg2TiO4 composite can be synthesized by reaction sintering; with TiO2 addition increasing from 0 to 5%,the specimen i denser obviously accompanying with more Mg2TiO4 form ing and MgO grains growing; the specimen with 10%TiO2obtains a slightly lower density than that with 5%TiO2due to larger volume expansion resulting from th formation of more Mg2TiO4;（2）with TiO2 addition in creasing from 0 to 5%,corrosion resistance to AlF3-Na3AlF6- K3AlF6 of the specimens improves gradually owing to the density increase and the Mg2TiO4 possessing good chemical stability distributing along periclas grains; compared with the specimen with 5% TiO2,tha with 10% TiO2 owns a little worse corrosion resistanc because of the lower density.展开更多
Ceramic porous MgTiO3 materials have been prepared by classical solid-state route. The sintered pellets of MgTiO3 with different LiF contents were characterized for humidity-sensing application. The sintered disks of ...Ceramic porous MgTiO3 materials have been prepared by classical solid-state route. The sintered pellets of MgTiO3 with different LiF contents were characterized for humidity-sensing application. The sintered disks of these mixtures were subjected to capacitance measurements at 20℃as function of the relative humidity from which revealed that the Mixture MgTiO3 + 2% LiF (w/w) has the better characteristics. The disks were subjected to DC resistance measurements as a function of relative humidity in the range 15% - 95% RH. The selectivity of this material was discussed and compared to commercial sensor results. The response and recovery characteristics were assessed.展开更多
A novel red phosphor Eu3＋ doped magnesium titanate （MgTiO3） was synthesized via sol-gel method. The X-ray diffraction patterns （XRD） revealed that a pure MgTiO3 phase was obtained. Its excitation spectrum consist...A novel red phosphor Eu3＋ doped magnesium titanate （MgTiO3） was synthesized via sol-gel method. The X-ray diffraction patterns （XRD） revealed that a pure MgTiO3 phase was obtained. Its excitation spectrum consisted of a broad band （〈350nm） and a series of narrow bands in the long wavelength, and the strongest excitation peak at 465nm might be exited by GaN-chip to emit red light for white LED. The phosphors showed strong emission at 614nm which could be attributed to the 5D0→7F2 emission of Eu3＋ . The emission intensity of MgTiO3：Eu3＋ phosphor reached the maximum at the Eu3＋ concentration of 3.5mol.%. The luminescent properties （such as emission intensity and decay times） were further improved by introducing Al3＋ as a charge compensator, demonstrating potential applications in white LED.展开更多
基金This work was financially supported by the National Natural Science Foundation of China(Nos.51874017 and 51674018)the Inner Mongolia University of Science and Technology Innovation Fund(No.2019QDL-B28).
文摘Magnesium titanate was prepared directly through external coal reduction of seashore titanomagnetite concentrate and magnesium oxide(MgO).The effects of roasting temperature and the type and dosage of reductants on the purity of generated magnesium titanate particles were systematically investigated.Scanning electron microscopy and energy-dispersive spectroscopy analyses were performed to characterize the magnesium titanate particles and observe their purity under different conditions.Results showed that the roasting temperature remarkably influenced the purity of magnesium titanate.At 1200,1300,and 1400℃,some magnesium ferrite and magnesium aluminate spinel were dissolved in magnesium titanate.However,as the roasting temperature increased to 1500℃,relatively pure magnesium titanate particles were generated because no magnesium ferrite was dissolved in them.The type and dosage of the reductants also remarkably affected the purity of magnesium titanate.The amount of fine metallic iron disseminated in the magnesium titanate particles obviously decreased when lignite was used as a reductant at a dosage of 70wt%.Thus,high-purity magnesium titanate particles formed.At a roasting temperature of 1500℃and with 70wt%lignite,the magnesium titanate product with a yield of 30.63%and an iron content of 3.01wt%was obtained through magnetic separation.
文摘MgO- Mg2TiO4 composite was prepared by adding chemically pure TiO2（0,1%,2%,5% and 10%,in mass,the same hereinafter） to light-burned magnesia（particle size 〈0.045 mm）,ball milling,dry pressing,and reaction sintering at 1 400,1 500 and 1 600 ℃ fo3 h,respectively. Apparent porosity,bulk density and corrosion resistance to AlF3- Na3AlF6- K3AlF6 were in vestigated. Phase composition and microstructure wer analyzed. The results show that：（1） MgO- Mg2TiO4 composite can be synthesized by reaction sintering; with TiO2 addition increasing from 0 to 5%,the specimen i denser obviously accompanying with more Mg2TiO4 form ing and MgO grains growing; the specimen with 10%TiO2obtains a slightly lower density than that with 5%TiO2due to larger volume expansion resulting from th formation of more Mg2TiO4;（2）with TiO2 addition in creasing from 0 to 5%,corrosion resistance to AlF3-Na3AlF6- K3AlF6 of the specimens improves gradually owing to the density increase and the Mg2TiO4 possessing good chemical stability distributing along periclas grains; compared with the specimen with 5% TiO2,tha with 10% TiO2 owns a little worse corrosion resistanc because of the lower density.
文摘Ceramic porous MgTiO3 materials have been prepared by classical solid-state route. The sintered pellets of MgTiO3 with different LiF contents were characterized for humidity-sensing application. The sintered disks of these mixtures were subjected to capacitance measurements at 20℃as function of the relative humidity from which revealed that the Mixture MgTiO3 + 2% LiF (w/w) has the better characteristics. The disks were subjected to DC resistance measurements as a function of relative humidity in the range 15% - 95% RH. The selectivity of this material was discussed and compared to commercial sensor results. The response and recovery characteristics were assessed.
基金Project supported by National Natural Science Foundation of China (21271139)Tianjin Natural Science Foundation (08JCZDJC18700)
文摘A novel red phosphor Eu3＋ doped magnesium titanate （MgTiO3） was synthesized via sol-gel method. The X-ray diffraction patterns （XRD） revealed that a pure MgTiO3 phase was obtained. Its excitation spectrum consisted of a broad band （〈350nm） and a series of narrow bands in the long wavelength, and the strongest excitation peak at 465nm might be exited by GaN-chip to emit red light for white LED. The phosphors showed strong emission at 614nm which could be attributed to the 5D0→7F2 emission of Eu3＋ . The emission intensity of MgTiO3：Eu3＋ phosphor reached the maximum at the Eu3＋ concentration of 3.5mol.%. The luminescent properties （such as emission intensity and decay times） were further improved by introducing Al3＋ as a charge compensator, demonstrating potential applications in white LED.
