A multitubular rotary heat exchanger has a stationary shielding unit. The shielding unit is positioned in close proximity to a tube plate outside a heating or cooling region. A stationary surface of the shielding unit is positioned in opposition to and in close proximity to an end opening of a heat transfer tube moving in an upper zone of the heating or cooling region, thereby transiently reducing or restricting the flow rate of the thermal medium fluid flowing through the heat transfer tube moving in the upper zone.

A first radiance meter is directed toward an object to be measured, radiance is measured through a space where dust is present with the use of at least two wavelengths by the first radiance meter, second radiance meters which are equal in number to one or more objects having temperatures different from that of the object to be measured are directed toward the objects, radiances are measured through the space with the use of at least two wavelengths by the second radiance meters respectively, and a temperature of the object to be measured, a temperature of the dust, and concentration of the dust are measured from the radiances measured by the first radiance meter and the second radiance meters.

A porous and easy water soluble amorphous silica which does not contain tar, crystal, residual agrichemicals, and carcinogens, and method and apparatus to produce same, by using only one burning treatment from a plant including abundant silica, including a method of manufacturing the amorphous silica wherein rice family plants are burned while stirring and introducing into the furnace an atmospheric gas having a mass of 6.7 or more and 20 or less of the weight of the rice family plants, or oxygen gas having a weight of 1.4 or more and 4 or less with respect to the weight of the rice family plants, and at the same time as burning, combustion gas generated at the time of combustion is discharged.

A porous and easy water soluble amorphous silica which does not contain tar, crystal, residual agrichemicals, and carcinogens, and method and apparatus to produce same, by using only one burning treatment from a plant including abundant silica, including a method of manufacturing the amorphous silica wherein rice family plants are burned while stirring and introducing into the furnace an atmospheric gas having a mass of 6.7 or more and 20 or less of the weight of the rice family plants, or oxygen gas having a weight of 1.4 or more and 4 or less with respect to the weight of the rice family plants, and at the same time as burning, combustion gas generated at the time of combustion is discharged.

A process and an apparatus are disclosed for improved recovery of metal from hot and cold dross, wherein a dross-treating furnace is provided with a filling material with good capacity to store heat. This filling material is preheated to a desired temperature by injection of an oxidizing gas to burn non-recoverable metal remaining in the filling material after tapping of the recoverable metal contained in the dross and discharging of the treatment residue. When dross is treated in such furnace, the heat emanating by conduction from the filling material is sufficient to melt and separate the recoverable metal contained in the dross, without addition of an external heat source, such as fuel or gas burners, plasma torches or electric arcs and without use of any salt fluxes. Furthermore, the recovered metal being in the molten state can be fed to the molten metal holding furnace without cooling the melt; in addition, the non-use of fluxing salt for the treatment means that the non-contaminated residue can be used as a cover for the electrolytic cells in the case of aluminum. In the case of zinc dross, the residue is a valuable zinc oxide by-product very low in contaminants.

A process and an apparatus are disclosed for improved recovery of metal from hot and cold dross, wherein a dross-treating furnace is provided with a filling material with good capacity to store heat. This filling material is preheated to a desired temperature by injection of an oxidizing gas to burn non-recoverable metal remaining in the filling material after tapping of the recoverable metal contained in the dross and discharging of the treatment residue. When dross is treated in such furnace, the heat emanating by conduction from the filling material is sufficient to melt and separate the recoverable metal contained in the dross, without addition of an external heat source, such as fuel or gas burners, plasma torches or electric arcs and without use of any salt fluxes. Furthermore, the recovered metal being in the molten state can be fed to the molten metal holding furnace without cooling the melt; in addition, the non-use of fluxing salt for the treatment means that the non-contaminated residue can be used as a cover for the electrolytic cells in the case of aluminum. In the case of zinc dross, the residue is a valuable zinc oxide by-product very low in contaminants.

The method for recycling carbon dioxide according to the present invention includes: injecting a reaction gas containing carbon dioxide and a carbon raw material into a rotary heating furnace; reacting the reaction gas and the carbon raw material with each other in the rotary heating furnace to generate a hydrocarbon precursor containing carbon monoxide; and converting the hydrocarbon precursor into a hydrocarbon compound, thereby exhibiting excellent conversion rate of carbon dioxide.

The method for recycling carbon dioxide according to the present invention includes: injecting a reaction gas containing carbon dioxide and a carbon raw material into a rotary heating furnace; reacting the reaction gas and the carbon raw material with each other in the rotary heating furnace to generate a hydrocarbon precursor containing carbon monoxide; and converting the hydrocarbon precursor into a hydrocarbon compound, thereby exhibiting excellent conversion rate of carbon dioxide.

The device for drying or heating and cooling bulk material in accordance with the invention consists of a rotatable drum comprising means for receiving the bulk material in a first region and means for discharging the bulk material from a second region, wherein a central region is arranged between the first and second regions, said central region consisting of an annular structure with a first and a second diaphragm with central diaphragm apertures each, which form substantially two diaphragm planes parallel to each other, and comprise a plurality of transport channels closed toward the central region for transporting the bulk material from the first region to the second region of the rotatable drum through the central region, wherein the transport channels extend from the first to the second diaphragms at a non-90 angle relative to the two diaphragm planes.

The device for drying or heating and cooling bulk material in accordance with the invention consists of a rotatable drum comprising means for receiving the bulk material in a first region and means for discharging the bulk material from a second region, wherein a central region is arranged between the first and second regions, said central region consisting of an annular structure with a first and a second diaphragm with central diaphragm apertures each, which form substantially two diaphragm planes parallel to each other, and comprise a plurality of transport channels closed toward the central region for transporting the bulk material from the first region to the second region of the rotatable drum through the central region, wherein the transport channels extend from the first to the second diaphragms at a non-90 angle relative to the two diaphragm planes.