A plate-like alumina powder production method of the present invention comprises placing a transition alumina and a fluoride in a container such that the transition alumina and the fluoride do not come into contact with each other and then performing heat treatment to obtain a plate-like -alumina powder. The transition alumina is preferably at least one selected from the group consisting of gibbsite, boehmite, and -alumina. It is preferable that the amount of the fluoride used is set such that the percentage ration of F in the fluoride to the transition alumina is 0.17% by mass or more. The container preferably has a volume such that a value obtained by dividing the mass of F in the fluoride by the volume of the container is 6.510.sup.5 g/cm.sup.3 or more. The heat treatment is preferably performed at the temperature of 750 to 1,650 C.

A method comprises reacting an aluminum feedstock with an acid in the presence of water to provide an aluminum salt solution comprising an aluminum salt in water, wherein the aluminum salt comprises a reaction product of the acid and aluminum, and spray roasting the aluminum salt solution at a temperature of at least about 450 C. to provide an aluminum oxide powder, wherein the spray roasting is performed in a furnace lined with a refractory comprising alumina that is at least about 99.2% purity alumina, and wherein the aluminum oxide powder is 99.2% pure aluminum oxide or greater.

To provide alumina having excellent electrolytic solution stability and a slurry containing the same, and an alumina porous film using the same, a laminated separator, a nonaqueous electrolyte secondary battery and a method for manufacturing the nonaqueous electrolyte secondary battery.

The first aspect of the present invention provides alumina including one or more selected from the group consisting of K, Mg, Ca, Sr, Ba and La in the total amount of 200 to 50,000 ppm by mass, wherein a surface concentration of one or more elements is 0.5 to 20 at % in total. The second aspect of the present invention provides alumina, in which in an infrared absorption spectrum of the alumina obtained by Fourier-transform infrared spectroscopy, a peak having an intensity larger than that of a baseline defined by a line segment connecting an intensity at 3,400 cm.sup.1 and an intensity at 3,500 cm.sup.1 and having a half width of 90 cm.sup.1 or less, does not exist in a range of 3,400 to 3,500 cm.sup.1.

A system, process and related sintered article are provided. The process includes supporting a piece of inorganic material with a pressurized gas and sintering the piece of inorganic material while supported by the pressurized gas by heating the piece of inorganic material to a temperature at or above a sintering temperature of the inorganic material such that the inorganic material is at least partially sintered forming the sintered article. The inorganic material is not in contact with a solid support during sintering. The sintered article, such as a ceramic article, is thin, has high surface quality, and/or has large surface areas.

Alumina having excellent electrolytic solution stability, a slurry containing the same, an alumina porous film using the same, a laminated separator, a nonaqueous electrolyte secondary battery and a method for manufacturing the nonaqueous electrolyte secondary battery are provided. Alumina is provided including one or more selected from K, Mg, Ca, Sr, Ba and La in the total amount of 200 to 50,000 ppm by mass, wherein a surface concentration of one or more elements is 0.5 to 20 at % in total. Alumina is provided in which in an infrared absorption spectrum of the alumina obtained by Fourier-transform infrared spectroscopy, a peak having an intensity larger than that of a baseline defined by a line segment connecting an intensity at 3,400 cm.sup.1 and an intensity at 3,500 cm.sup.1 and having a half width of 90 cm.sup.1 or less, does not exist in a range of 3,400 to 3,500 cm.sup.1.

An alumina sintered body according to the present invention has a degree of c-plane orientation of 90% or more as determined by Lotgering's method from an X-ray diffraction profile obtained by irradiating a plate surface with X-rays in a range of 2=20 to 70. The alumina sintered body has no pores when a cross-sectional surface formed in a direction perpendicular to the plate surface is polished using an Ar.sup.+ ion beam and a mask and is examined under a scanning electron microscope at a magnification of 5,000 times. The alumina sintered body has a total mass fraction of impurity elements other than Mg and C of 100 ppm or less. This alumina sintered body has a high degree of orientation, high density, and high purity and thus has a higher optical translucency than those known in the art.

A novel alumina gel is described having an elevated dispersibility index, and in particular a dispersibility index greater than 70%, a crystallite size between 1 and 35 nm, and a sulphur content between 0.001% and 2% by weight, and a sodium content between 0.001% and 2% by weight, the weight percentages being expressed in relation to the total mass of alumina gel.

The present invention also discloses the method for preparing said gel comprising at least one step of precipitating at least one aluminium salt, at least one step of heating the suspension obtained and a final heat treatment step for forming the alumina gel.

The present invention provides a resin composition including aluminum oxide (A) containing molybdenum having a size on the order of m or less and a resin (B); and a resin molded body formed by molding the resin composition. Also, the present invention provides a heat-dissipating material containing the resin composition; and a heat-dissipating member containing the resin molded body. The heat-dissipating member of the present invention can be used for electronic parts such as electronic devices, electric devices, OA devices or for LED illumination.

An improved apparatus for steam calcining aluminium trihydroxide (Al(OH).sub.3) to produce alumina (Al.sub.2O.sub.3) is disclosed. The apparatus comprises an Al(OH).sub.3 preheater configured to heat an Al(OH).sub.3feedstock by contacting it with steam. The Al(OH).sub.3 preheater comprises at least one gas solid separator for separating preheated Al(OH).sub.3 from carrier steam. The apparatus further comprises a calciner configured to accept preheated Al(OH).sub.3 from the Al(OH).sub.3 preheater and to produce heated Al.sub.2O.sub.3 by steam calcination. The apparatus also comprises an Al.sub.2O.sub.3 cooler configured to remove heat from the heated Al.sub.2O.sub.3 and produce Al.sub.2O.sub.3 product. The Al.sub.2O.sub.3 cooler comprises at least one gas solid separator. The apparatus further comprises a steam compressor in fluid communication with the Al(OH).sub.3 preheater, the calciner and the Al.sub.2O.sub.3 cooler and configured to accept and pressurise carrier steam from the Al(OH).sub.3preheater and to provide pressurised carrier steam to the Al(OH).sub.3 preheater and pressurised carrier steam the Al.sub.2O.sub.3 cooler to transfer Al(OH).sub.3 feedstock to and within the Al(OH).sub.3 preheater, and pressurised carrier steam to transfer preheated Al(OH).sub.3 from the Al(OH).sub.3 preheater to the calciner, and to transfer heated Al.sub.2O.sub.3 from the calciner to and within the Al.sub.2O.sub.3 cooler.

A catalyst support comprising at least 85 wt.-% of alpha-alumina and having a pore volume of at least 0.40 mL/g, as determined by mercury porosimetry, and a BET surface area of 0.5 to 5.0 m.sup.2/g, wherein the catalyst support is a tableted catalyst support comprising, based on the total weight of the catalyst support, less than 500 ppmw of potassium. The invention moreover relates to a process for producing a tableted alpha-alumina catalyst support, which comprises i) forming a free-flowing feed mixture comprising i-a) at least one aluminum compound which is thermally convertible to alpha-alumina, the aluminum compound comprising a transition alumina and/or an alumina hydrate; and i-b) 30 to 120 wt.-%, relative to i-a), of a pore-forming material; ii) tableting the free-flowing feed mixture to obtain a compacted body; and iii) heat treating the compacted body at a temperature of at least 1100? C., to obtain the tableted alpha-alumina catalyst support. The invention further relates to a compacted body obtained by tableting a free-flowing feed mixture which comprises, relative to the total weight of the free-flowing feed mixture, a) at least one aluminum compound which is thermally convertible to alpha-alumina, the aluminum compound comprising a transition alumina and/or an alumina hydrate; and b) 30 to 120 wt.-%, relative to a), of a pore-forming material. The invention moreover relates to a shaped catalyst body for producing ethylene oxide by gas-phase oxidation of ethylene, comprising at least 12 wt.-% of silver, relative to the total weight of the catalyst, deposited on the tableted alpha-alumina catalyst support. The invention also relates to a process for producing ethylene oxide by gas-phase oxidation of ethylene, comprising reacting ethylene and oxygen in the presence of the shaped catalyst body. The invention allows for the use of specific pore-forming materials that are particularly suitable for obtaining an advantageous pore structure while allowing for a catalyst support having high purity.