The magnesia composite materials were prepared using fused magnesia, used magnesia chrome bricks, magnesium aluminate spinel, alumina powder and chrome oxide powder as starting materials. In order to improve the perfo...The magnesia composite materials were prepared using fused magnesia, used magnesia chrome bricks, magnesium aluminate spinel, alumina powder and chrome oxide powder as starting materials. In order to improve the performance of magnesia composite material, the influence of chrome oxide concentrate powder on the properties of magnesia composite material was re-searched. The apparent porosity, bulk density, cold crushing streugth, linear expausion and thermal shock resistance of the specimens were determined. The results show that adding chrome oxide concentrate promotes the formation of the composite phases of three kinds of spi-nel, which is beneficial to the thermal shock resistance.The magnesia chrome spbwl can not be .[brined at high temperatures theoreticalby, but can dissolve in the mag-nesia composite material. Comprehensively, the optimal addition of chrome oxide concentrate is 10. 0 mass% for the magnesia composite materials.展开更多
In order to reduce the thermal energy loss of high temperature kilns and furnaces and lower the surface temperature of the kiln body,magnesia insulation materials were prepared using self-made magnesia porous aggregat...In order to reduce the thermal energy loss of high temperature kilns and furnaces and lower the surface temperature of the kiln body,magnesia insulation materials were prepared using self-made magnesia porous aggregates(using high purity magnesia powder as starting material and potassium oleate as the foaming agent),middle grade magnesia powder,calcium aluminate cement,and SiO_(2) micropowder as starting materials,introducing walnut shell powder impregnated with silica sol(short for Sws)as a pore-forming agent.The effects of the Sws addition(0,10%,15%,and 20%,by mass)and the sintering temperature(1300,1350,1400,and 1480℃)on the properties of magnesia insulation materials were studied.The results show that(1)for the specimens fired at 1480℃,when the Sws addition is 10%,the cold compressive strength is 22 MPa;when the Sws addition is 20%,the thermal conductivity is 0.368 W·m^(-1)·K^(-1)(350℃);(2)nano-silica in the silica sol reacts with MgO in the matrix to form forsterite,which encapsulates the pores volatilized from the walnut shell powder and forms closed pores.展开更多
Magnesia（MgO） is widely used in the production of refractory materials due to its high melting point,high thermal shock,and excellent slag resistance.The properties of refractory materials depend upon magnesia sourc...Magnesia（MgO） is widely used in the production of refractory materials due to its high melting point,high thermal shock,and excellent slag resistance.The properties of refractory materials depend upon magnesia sources and processing parameters.In this work,three different magnesium sources,namely,magnesium hydroxide concentrate,magnesium carbonate concentrate,and intermediate flotation concentrate,were obtained from the Zinelbulak talc-magnesite,Uzbekistan,by causticization-hydration and flotation processes,respectively.A series of refractory materials were prepared on the basis of these magnesium sources,and their effects on physico-mechanical properties and microstructures were investigated as a function of sintering temperature,molding pressure,and the particle size of magnesium sources.The experimental results showed that a refractory material obtained from the magnesium hydroxide concentrate at 1600℃ for 4 h demonstrated favorable parameters due mainly to a higher degree of contact among fine particles.The results obtained from X-ray diffraction and optical microscopy confirmed the presence of periclase and forsterite as the predominant phases in refractory specimens.The prepared refractory materials meet the requirements of the State Standards（Nos.4689-94 and 14832-96） for magnesia and forsterite refractories,respectively.It is,therefore,suggested herein that the use of different magnesium sources derived from the Zinelbulak talc-magnesite will offer the potential to provide economic benefits in the refractory industry.展开更多
基金supported by the Industrial Special Resource Protecting Office of Liaoning Province
文摘The magnesia composite materials were prepared using fused magnesia, used magnesia chrome bricks, magnesium aluminate spinel, alumina powder and chrome oxide powder as starting materials. In order to improve the performance of magnesia composite material, the influence of chrome oxide concentrate powder on the properties of magnesia composite material was re-searched. The apparent porosity, bulk density, cold crushing streugth, linear expausion and thermal shock resistance of the specimens were determined. The results show that adding chrome oxide concentrate promotes the formation of the composite phases of three kinds of spi-nel, which is beneficial to the thermal shock resistance.The magnesia chrome spbwl can not be .[brined at high temperatures theoreticalby, but can dissolve in the mag-nesia composite material. Comprehensively, the optimal addition of chrome oxide concentrate is 10. 0 mass% for the magnesia composite materials.
文摘In order to reduce the thermal energy loss of high temperature kilns and furnaces and lower the surface temperature of the kiln body,magnesia insulation materials were prepared using self-made magnesia porous aggregates(using high purity magnesia powder as starting material and potassium oleate as the foaming agent),middle grade magnesia powder,calcium aluminate cement,and SiO_(2) micropowder as starting materials,introducing walnut shell powder impregnated with silica sol(short for Sws)as a pore-forming agent.The effects of the Sws addition(0,10%,15%,and 20%,by mass)and the sintering temperature(1300,1350,1400,and 1480℃)on the properties of magnesia insulation materials were studied.The results show that(1)for the specimens fired at 1480℃,when the Sws addition is 10%,the cold compressive strength is 22 MPa;when the Sws addition is 20%,the thermal conductivity is 0.368 W·m^(-1)·K^(-1)(350℃);(2)nano-silica in the silica sol reacts with MgO in the matrix to form forsterite,which encapsulates the pores volatilized from the walnut shell powder and forms closed pores.
基金the Fulbright Program for the award of a research fellowship
文摘Magnesia（MgO） is widely used in the production of refractory materials due to its high melting point,high thermal shock,and excellent slag resistance.The properties of refractory materials depend upon magnesia sources and processing parameters.In this work,three different magnesium sources,namely,magnesium hydroxide concentrate,magnesium carbonate concentrate,and intermediate flotation concentrate,were obtained from the Zinelbulak talc-magnesite,Uzbekistan,by causticization-hydration and flotation processes,respectively.A series of refractory materials were prepared on the basis of these magnesium sources,and their effects on physico-mechanical properties and microstructures were investigated as a function of sintering temperature,molding pressure,and the particle size of magnesium sources.The experimental results showed that a refractory material obtained from the magnesium hydroxide concentrate at 1600℃ for 4 h demonstrated favorable parameters due mainly to a higher degree of contact among fine particles.The results obtained from X-ray diffraction and optical microscopy confirmed the presence of periclase and forsterite as the predominant phases in refractory specimens.The prepared refractory materials meet the requirements of the State Standards（Nos.4689-94 and 14832-96） for magnesia and forsterite refractories,respectively.It is,therefore,suggested herein that the use of different magnesium sources derived from the Zinelbulak talc-magnesite will offer the potential to provide economic benefits in the refractory industry.
