Method and installation for calcining cement raw meal in a calciner whereby fuel and a calciner oxidant having an oxygen content of at least 30% vol are introduced into the calciner so as to generate either an oxidant-lean zone or a fuel-lean zone in the calciner located between the lowermost fuel inlet level and the lowermost oxidant inlet level of the calciner, between 50% and 100% by weight of the raw meal being supplied to the calciner upstream of and/or within the oxidant-lean, respectively the fuel-lean zone.

Method and installation for calcining cement raw meal in a calciner whereby fuel and a calciner oxidant having an oxygen content of at least 30% vol are introduced into the calciner so as to generate either an oxidant-lean zone or a fuel-lean zone in the calciner located between the lowermost fuel inlet level and the lowermost oxidant inlet level of the calciner, between 50% and 100% by weight of the raw meal being supplied to the calciner upstream of and/or within the oxidant-lean, respectively the fuel-lean zone.

A material heating device comprises a rotary kiln, a plurality of heat exchange tubes, a hot air hood, a high-temperature gas input mechanism, an exhaust-gas collecting chamber, and an exhaust-gas output pipeline. The rotary kiln is provided with a material feed end and a material discharge end. The heat exchange tubes are in the rotary kiln. The hot air hood is outside the rotary kiln. The air inlet ends of the heat exchange tubes communicate with the hot air hood, and the air outlet ends of the heat exchange tubes communicate with the exhaust-gas collecting chamber. The exhaust-gas collecting chamber communicates with the exhaust-gas output pipeline. The hot air hood communicates with the high-temperature gas input mechanism, and the cavity between the heat exchange tubes and the heat insulation layer of the rotary kiln is a material channel. The heat exchange tubes are directly in contact with the material.

The invention relates to multi-stage cement calcining plant suspension preheater of the kind mentioned in the introduction, wherein the preheater comprises a top separator comprising a central tube entering the top separator in a lowermost part of the separator housing whereas the central tubes of the bottom separators enters the separator housing in an upper part of the separator housing.

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.

Dust Da containing zinc and iron is charged in a rotative cylindrical kiln base body 11 of an indirect-heating rotary kiln 10 and is subjected to heat treatment in the kiln base body so that zinc contained in the dust is volatilized. The volatilized zinc is guided to a treatment device 30 through an exhaust pipe 31 disposed at a discharge part 16 of the rotary kiln and is recovered. A residue Db resulting from the treatment in the kiln base body is transferred from a residue outlet 16b disposed at the discharge part 16 of the rotary kiln to a burner device 40, in which the residue is combusted and heated.

A system for measuring temperatures of a preheater of a rotary kiln can include: at least one infrared imaging sensor for each level of the preheater; and an imaging analysis computer operably coupled with the at least one infrared imaging sensor of each level of the preheater. The imaging analysis computer can be configured to: obtain a 3D model of a preheater level of the preheater; obtain at least one infrared image of a fixed field of view of the preheater level of the preheater; analyze all pixels in the fixed field of view of the at least one infrared image for each pixel temperature; generate a 2D temperature model of the preheater level; overlaying the 2D temperature model over the 3D model to generate a virtual 3D preheater level temperature model; and providing a visual representation of the virtual 3D preheater level temperature model.

A system for measuring temperatures of a preheater of a rotary kiln can include: at least one infrared imaging sensor for each level of the preheater; and an imaging analysis computer operably coupled with the at least one infrared imaging sensor of each level of the preheater. The imaging analysis computer can be configured to: obtain a 3D model of a preheater level of the preheater; obtain at least one infrared image of a fixed field of view of the preheater level of the preheater; analyze all pixels in the fixed field of view of the at least one infrared image for each pixel temperature; generate a 2D temperature model of the preheater level; overlaying the 2D temperature model over the 3D model to generate a virtual 3D preheater level temperature model; and providing a visual representation of the virtual 3D preheater level temperature model.

In methods of and/or plants for manufacturing cement clinker, the amount of chloride bypass exhaust gas 79 can be substantially decreased, when using previously cooled chloride bypass exhaust gas 81 and/or cooled kiln exhaust gas as coolant for the chloride bypass exhaust gas 39 prior to deducting the chloride bypass exhaust gas 39.