An apparatus for reducing mercury content of cement kiln exhaust gas 11 comprising: a mixing and heating device 19 for mixing cement kiln dusts D2, D4 included in a cement kiln combustion exhaust gas G1 into a cement raw material R2 withdrawn from a cyclone 4C (or 4B) other than the highest stage cyclone 4D and the lowest stage cyclone 4A of a preheater 4 for preheating cement raw material R1 while heating the cement kiln dusts D2, D4 through sensible heat of the cement raw material R2; a mercury recovery device 21 for recovering mercury Hg vaporized from the cement kiln dusts D2, D4 by the mixing and heating; and a feeder for feeding mercury-removed dusts D5, D6 discharged from the mixing and heating device 19 to a cyclone 4B (or 4A) positioning at a lower stage from the cyclone 4C (or 4B) from which the cement raw material R2 is withdrawn.

Installation including an industrial glass furnace (1) including a tank (2) for molten glass (3), a combustion heating chamber (4) situated above the tank (2), and a duct for evacuation of flue gases in communication with said heating chamber (4), and a stone furnace including a firing zone (21) for stone to be fired, the flue gas evacuation duct including a flue gas outlet that is connected to the firing zone (21) of stone to be fired and supplying the firing zone (21) of stone to be fired with flue gases at high temperature.

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 plant for production of cement clinker from raw meal, having a calciner for deacidification of the raw meal and a rotary furnace for sintering the deacidified raw meal to give cement clinker. The deacidified raw meal flows through a cyclone preheating stage into the rotary furnace. A reactor is provided upstream of the calciner on the flow path of the rotary furnace offgas to the calciner, to which an inlet for the rotary furnace offgas leads. A corresponding method of operating such a plant wherein fuel is added to the reactor in a superstoichiometric amount in relation to the residence time of the offgases in the reactor, such that carbon dioxide present in the offgases is reduced to carbon monoxide. At least one input air conduit for supplying input air, preferably coming from a tertiary air conduit, is provided at at least one point in the reactor.

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.

An improved direct smelting system and process using a smelt reduction vessel (SRV), and optionally, a cyclone converter furnace (CCF). The improved system and process utilizes a fast quench system in which hot process offgas containing molten material is quench-cooled from greater than 1400? C. (2552? F.) to no more than 600? C. (1112? F.) in a time-of-flight of no greater than 1 second. The quenching occurs using water spray injection and vaporization to cool, stress and break solid slag into slag pieces small enough to remove from the quenching system. The improved system eliminates plant availability problems associated with (i) accretion formation in the offgas train as hot process offgas cools down in a conventional (slow) manner to allow for steam-raising for power generation or other heat recovery purposes, and (ii) trigger mechanisms causing slag foaming events in the SRV that propagate up the offgas train.

There is provided a method for operating a cement plant capable of simultaneously optimizing both combustion in a calciner and a heat consumption rate. The method for operating a cement plant includes: feeding first fuel to a calciner; feeding second fuel for maintaining the inside at a burning temperature to a cement kiln along with combustion primary air, and introducing air for cooling cement clinker to a cooler; and feeding a part of the air as secondary air to the cement kiln, feeding as tertiary air to the calciner, and discharging the rest of the air from the cooler, wherein relation between a first oxygen concentration at an exhaust gas outlet of the calciner and a heat consumption rate determined by the first fuel and the second fuel, and relation between a second oxygen concentration at an exhaust gas outlet of the preheater and the heat consumption rate are beforehand obtained, and amounts of the secondary air and the tertiary air are adjusted such that both the first oxygen concentration and the second oxygen concentration fall within a range including values of the oxygen concentrations at which the heat consumption rate becomes at its minimum.

The present invention provides a device for smelting and regenerating phosphogypsum using high-temperature ceramsite and method for using same, where a rotary kiln is used to accept high-temperature ceramic granules that have been calcined and formed. The residual heat of the high-temperature ceramic granules allows them to be fully mixed with the phosphogypsum. On one hand, the high temperature of the ceramic granules achieves high-temperature dehydration of the phosphogypsum. On the other hand, the porous adsorption property of the ceramic granules can facilitate full absorption of some harmful substances in the phosphogypsum, thereby realizing the purification of the phosphogypsum. In addition, because the dehydrated phosphogypsum is generally in a suspended state, the rotary kiln of the present invention is equipped with a discharge outlet at the end. The discharge outlet uses a combination of a cyclone dust aspirator and a baghouse dust collector, which can draw out the phosphogypsum that has been fully dehydrated and is suspended in the rotary kiln, thereby realizing its complete collection without any leakage and achieving zero pollution.