Mgo-Cao refractories are widely used in the iron and steel metalurgy industry due to their advantages of purifying molten steel,high refractoriness,good thermal shock resistance,and excellent corrosion resistance to b...Mgo-Cao refractories are widely used in the iron and steel metalurgy industry due to their advantages of purifying molten steel,high refractoriness,good thermal shock resistance,and excellent corrosion resistance to basic slags.However,hydration occurs during the manufacturing,storage,and transportation of refractories,which severely limits their application.Mgo-CaO clinker is the main raw material for Mgo-Cao refractories,and its hydration resistance determines the development of the latter case.Herein,the Mgo-Cao clinker was modified using myristic acid as the modifying agent by the liquid-phase deposition method.The effects of the particle size of the raw materials,concentration of myristic acid,treatment temperature and time on the phase composition and hydration resistance of the modified Mgo-Cao clinkers were investigated in detail.The results show that the samples with an agent concentration of 0.25 mol L^(-1) and treated at 25℃ for 1 h exhibit the optimal hydration resistance properties,namely a low hydration mass gain rate(0.23%)and a large water contact angle(152.9).展开更多
MgO-CaO ceramics with enhanced microhardness and hydration resistance were successfully prepared by doping Y_(2)O_(3)in this work.The effects of introducing Y_(2)O_(3)on the microstructure and properties of MgO-CaO ce...MgO-CaO ceramics with enhanced microhardness and hydration resistance were successfully prepared by doping Y_(2)O_(3)in this work.The effects of introducing Y_(2)O_(3)on the microstructure and properties of MgO-CaO ceramics were investigated.The microstructural regulation effects of Y_(2)O_(3)additive on MgO,CaO,and MgO-CaO ceramics were analyzed comparatively.The results show that Y_(2)O_(3)dissolves into the CaO lattice to form solid solution in CaO ceramics,and no obvious intergranular phase forms.While the Y_(2)O_(3)additive leads to the micro structural reconstruction in MgO and MgO-CaO ceramics.By adding Y_(2)O_(3),SiO_(2)impurity from magnesium source reacts with CaO to form the silicate phases containing Y^(3+)ions in MgO-CaO ceramics.The increase in the MgO/CaO interface and the microstructural reconstruction synergistically improves the microhardness and hydration resistance of MgO-CaO ceramics markedly.展开更多
MgO-CaO(40 wt.%CaO)refractory aggregates were prepared using the calcined dolomite and light-burned magnesia fine powder as raw materials and TiO_(2) as additive.The effect of TiO_(2) on their phase composition,micros...MgO-CaO(40 wt.%CaO)refractory aggregates were prepared using the calcined dolomite and light-burned magnesia fine powder as raw materials and TiO_(2) as additive.The effect of TiO_(2) on their phase composition,microstructures and properties was investigated by X-ray diffraction and scanning electron microscopy.The properties such as bulk density,apparent porosity,relative aggregate tube strength and hydration resistance were also investigated.The results showed that the CaTiO_(3) generated by the reaction between CaO and TiO_(2) was distributed around the CaO grain boundaries and intermittently distributed with MgO,which formed an isolation layer around CaO and greatly improved the hydration resistance.Meanwhile,the introduction of TiO_(2) promoted sintering and increased the grain size,further improving the strengths and hydration resistance of the materials.In addition,the most significant enhancement in the hydration resistance and strengths of the samples was achieved when 1.0-2.0 wt.%TiO_(2) was added.In this case,the relative strength of aggregate increased from 33.3% to 37.3%-43.1%,and the mass gain after the hydration test decreased from 3.13% to 1.26%-1.45%.展开更多
The grain growing dynamics including the growing process, the growing exponent and the growing activation energy is obtained for the MgO-CaO composite ceramics with the additions of Fe2O3, CeO2 and/or ZrO2 as fluxes b...The grain growing dynamics including the growing process, the growing exponent and the growing activation energy is obtained for the MgO-CaO composite ceramics with the additions of Fe2O3, CeO2 and/or ZrO2 as fluxes by measuring the size of grains with the method of Straight Line Across. The results show that all of the additions, in which Fe2O3 is the strongest, have notable effects on the grain growing dynamics by reducing the growing activation energy and promoting the grain growing. The research gives a good reference for the additions of fluxes to the matrix of ceramic filter.展开更多
基金National Natural Science Foundation of China(Grants 52202025 and U23A20559)Natural Science Foundation of Hubei Province(Grant 2022CFB629)+1 种基金"The 14^(th)Five-Year Plan"Hubei Provincial Advantaged Characteristic Disciplines(Groups)Project of Wuhan University of Science and Technology(2023A0307).
文摘Mgo-Cao refractories are widely used in the iron and steel metalurgy industry due to their advantages of purifying molten steel,high refractoriness,good thermal shock resistance,and excellent corrosion resistance to basic slags.However,hydration occurs during the manufacturing,storage,and transportation of refractories,which severely limits their application.Mgo-CaO clinker is the main raw material for Mgo-Cao refractories,and its hydration resistance determines the development of the latter case.Herein,the Mgo-Cao clinker was modified using myristic acid as the modifying agent by the liquid-phase deposition method.The effects of the particle size of the raw materials,concentration of myristic acid,treatment temperature and time on the phase composition and hydration resistance of the modified Mgo-Cao clinkers were investigated in detail.The results show that the samples with an agent concentration of 0.25 mol L^(-1) and treated at 25℃ for 1 h exhibit the optimal hydration resistance properties,namely a low hydration mass gain rate(0.23%)and a large water contact angle(152.9).
基金Project supported by the National Natural Science Foundation of China(U20A20239,U21A2057)the Key Research and Development Project of Hubei Province(2021BAD002)。
文摘MgO-CaO ceramics with enhanced microhardness and hydration resistance were successfully prepared by doping Y_(2)O_(3)in this work.The effects of introducing Y_(2)O_(3)on the microstructure and properties of MgO-CaO ceramics were investigated.The microstructural regulation effects of Y_(2)O_(3)additive on MgO,CaO,and MgO-CaO ceramics were analyzed comparatively.The results show that Y_(2)O_(3)dissolves into the CaO lattice to form solid solution in CaO ceramics,and no obvious intergranular phase forms.While the Y_(2)O_(3)additive leads to the micro structural reconstruction in MgO and MgO-CaO ceramics.By adding Y_(2)O_(3),SiO_(2)impurity from magnesium source reacts with CaO to form the silicate phases containing Y^(3+)ions in MgO-CaO ceramics.The increase in the MgO/CaO interface and the microstructural reconstruction synergistically improves the microhardness and hydration resistance of MgO-CaO ceramics markedly.
基金the Key Project of the National Natural Science Foundation of China(Grant Nos.U21A2058 and 51802235)the Hubei Science and Technology Innovation Talent Project(Grant No.2023DJC087).
文摘MgO-CaO(40 wt.%CaO)refractory aggregates were prepared using the calcined dolomite and light-burned magnesia fine powder as raw materials and TiO_(2) as additive.The effect of TiO_(2) on their phase composition,microstructures and properties was investigated by X-ray diffraction and scanning electron microscopy.The properties such as bulk density,apparent porosity,relative aggregate tube strength and hydration resistance were also investigated.The results showed that the CaTiO_(3) generated by the reaction between CaO and TiO_(2) was distributed around the CaO grain boundaries and intermittently distributed with MgO,which formed an isolation layer around CaO and greatly improved the hydration resistance.Meanwhile,the introduction of TiO_(2) promoted sintering and increased the grain size,further improving the strengths and hydration resistance of the materials.In addition,the most significant enhancement in the hydration resistance and strengths of the samples was achieved when 1.0-2.0 wt.%TiO_(2) was added.In this case,the relative strength of aggregate increased from 33.3% to 37.3%-43.1%,and the mass gain after the hydration test decreased from 3.13% to 1.26%-1.45%.
文摘The grain growing dynamics including the growing process, the growing exponent and the growing activation energy is obtained for the MgO-CaO composite ceramics with the additions of Fe2O3, CeO2 and/or ZrO2 as fluxes by measuring the size of grains with the method of Straight Line Across. The results show that all of the additions, in which Fe2O3 is the strongest, have notable effects on the grain growing dynamics by reducing the growing activation energy and promoting the grain growing. The research gives a good reference for the additions of fluxes to the matrix of ceramic filter.
