Firing installation and method for producing a sintered material at least from one aluminum-containing raw material, preferably nepheline, which is in the form of a raw meal

Abstract

The invention relates to a firing installation and to a method for producing a sintered material at least from one aluminum-containing raw material, preferably nepheline, which is in the form of a raw meal.

Description

[0001] Firing plant and method for producing a sintered material from at least one aluminum-containing raw material, preferably nepheline, which is present as raw meal.

[0002] The invention relates to a firing plant and a method for producing a sintered material from at least one aluminum-containing raw material, preferably nepheline, which is present as raw meal.

[0003] To produce aluminum oxide from aluminum-containing raw materials, such as nepheline (Na,K)[AISiC>4], the aluminum-containing raw material, especially nepheline, is ground with limestone, treated with soda as an additive, among other things, to reduce the sintering temperature, and combined into a homogeneous dry mixture. The homogeneous dry mixture is then fired in a kiln to produce a sintered material. The aluminum oxide is then washed out of the resulting sintered material using alkalis or other chemical compounds in a wet-chemical process. The aluminum oxide is then extracted in a hydrometallurgical process.

[0004] A method for processing aluminum-containing raw materials is known, for example, from WO 2016 / 082827 A1.

[0005] Known firing systems and processes for producing a sintered material from a homogeneous dry mixture include a preheater consisting of several cyclone stages for heating the homogeneous dry mixture, a calciner in which the preheated dry mixture is partially deacidified and which is equipped with a calciner burner, a rotary kiln in which the partially deacidified dry mixture is fired to form the sintered material and which is equipped with a rotary kiln burner, and a sinter cooler for cooling the fired sintered material. Specifically, in the production of sintered material in firing systems operating according to the dry process, an aluminum-containing raw material, such as nepheline, is ground with a calcium-containing raw material, such as limestone, to form a raw meal, treated with soda, and combined to form a homogeneous dry mixture.This dry mix is ​​preheated, dried, calcined, fired to the sintered material and then cooled. The energy for the material conversion in such plants is supplied by feeding fuel into a rotary kiln and a calciner. Air heated in a sinter cooler is fed partly as secondary air to the rotary kiln and partly as tertiary air to the calciner. The exhaust gases from the rotary kiln are led through a rotary kiln inlet chamber to the calciner, flow through it and are discharged together with the exhaust gases generated in the calciner into the preheater, which consists of several cyclone stages. The preheater consists of several, usually 4, 5 or 6 cyclone stages, each of which functions as a suspended gas heat exchanger. The homogeneous dry mix is ​​fed into the riser pipe of the first or uppermost cyclone stage, passes through the cyclone stages from top to bottom and is discharged from the penultimate or third cyclone stages.The dry mixture is then fed from the second lowest cyclone stage into the calciner for partial deacidification. The partially or fully deacidified dry mixture is then fed into the rotary kiln inlet chamber via the last or lowest cyclone stage. The cyclone preheater heats the dry mixture to 850 to 880°C, depending on the number of cyclone stages. The calciner is located between the rotary kiln and the preheater. The dry mixture can be partially deacidified to well over 90% in the calciner. The combustion air is fed from the sinter cooler to the calciner as tertiary air via a tertiary air line. The dry mixture deacidified in the calciner is separated from the gas stream by the last or lowest cyclone stage and slides through the rotary kiln inlet chamber into the rotary kiln. The cylindrical rotary kiln typically comprises an inlet zone, a calcining zone, a transition zone, a sintering zone and an outlet zone.The rotary kiln is slightly inclined longitudinally, creating a gentle gradient from the inlet zone to the outlet zone. The partially deacidified dry meal is fed into the rotary kiln in the inlet zone and then continuously conveyed through the rotating rotary kiln due to the gradient. In the calcining zone, the residual deacidification of the dry mix, previously partially deacidified in the calciner, takes place. The thermal conversion to the sintered material takes place in the sintering zone. The exact process data depend on the specific characteristics of the raw meals or raw materials used, the fuels used, and the various ambient conditions. The sintered material, which is partially cooled in the end area of ​​the rotary kiln, i.e. in the cooling zone of the rotary kiln, is fed to a sinter cooler at a temperature of over 1000 °C for final cooling. Preferably, a modern grate cooler due to the high recuperation rate.

[0006] A disadvantage of the previously described kiln or the previously described process for producing a sintered material from the aforementioned raw materials or raw meal or the homogeneous dry mix is ​​the very high risk of uncontrollable buildup in the calciner, riser, final-stage cyclones, and inlet zone of the kiln's rotary kiln. This buildup can lead to disruptions in the kiln's operation. Therefore, such buildup is usually removed manually during ongoing kiln operation, and the high temperatures present pose a risk to the personnel removing it.

[0007] The following invention is based on the finding that deposit formation is primarily caused by the high temperature in the calciner, or rather in the riser pipe, cyclones of the final stage, and the inlet zone of the rotary kiln of the kiln. This temperature is above the melting point of soda, which is approximately 850 °C. The calciner gas temperature, in contrast, is over 1000 °C.

[0008] Another disadvantage is that, due to the formation of deposits, a complete or high-grade deacidification, also known as calcination or decarbonization, of the dry mixture in the calciner does not appear to be possible in order to achieve or ensure a stable and shock-free process with high leaching capacity of the sintered material.

[0009] The present invention is therefore based on the object of improving a firing system and a method for producing sintered material from at least one aluminum-containing raw material, preferably nepheline, from a calcium-containing raw material, preferably limestone, and from a sodium carbonate-containing raw material, preferably soda, wherein the raw materials are present as raw meals. This object is achieved by a firing system having the features of claim 1 and by a method having the features of claim 14. Further developments and advantageous embodiments emerge from the respective dependent claims.

[0010] The combustion plant according to the invention for producing sintered material from at least one aluminum-containing raw material, preferably nepheline, from a calcium-containing raw material, preferably limestone, and from a sodium carbonate-containing raw material, preferably soda, wherein the raw materials are present as raw meals, comprises

[0011] • a preheater having several cyclone stages for heating a raw meal mixture consisting of the aluminium-containing and the calcium-containing raw material, but not of the sodium carbonate-containing raw material,

[0012] • a calciner which receives the preheated raw meal mixture from the penultimate cyclone stage of the preheater, wherein the preheated raw meal mixture is deacidified in the calciner, preferably at temperatures above 1000 °C, wherein the calciner has a calciner burner,

[0013] • a cyclone separator, which forms the last cyclone stage of the preheater, in which the deacidified raw meal mixture from the calciner is separated from the gas phase,

[0014] • a cooler, to which the deacidified raw meal mixture from the cyclone separator is fed, and in which the deacidified raw meal mixture is cooled to a temperature below the melting temperature of the sodium carbonate-containing raw material,

[0015] • a mixer to which the deacidified raw meal mixture from the cooler and the sodium carbonate-containing raw material in the form of raw meal, preferably from a raw meal silo, are fed, whereby the mixer mixes these to a homogeneous mixture,

[0016] • a rotary kiln to which the homogeneous mixture is fed and in which the homogeneous mixture is fired to form the sintered material, the rotary kiln having a rotary kiln burner,

[0017] • and a sinter cooler to cool the fired sintered material.

[0018] Because the raw meal mixture in the calciner does not contain any raw material containing sodium carbonate, preferably no soda, a high degree or preferably complete deacidification of the raw meal mixture in the calciner can be achieved without the formation of deposits in the calciner or in other areas, in particular in the riser pipe, in the cyclones of the last stage of the preheater or in the inlet zone of the rotary kiln, the firing plant. The calciner can still be operated at temperatures above 1000 °C, for example 1030 °C. The risk of deposits forming no longer exists in particular if the deacidified raw meal mixture, after separation in the last cyclone stage, is first cooled by a cooler to such an extent that the melting temperature of the raw material containing sodium carbonate, preferably the soda, is not reached. The cooled and deacidified orThe sodium carbonate-containing raw material, preferably soda, is then added in a specified amount to the calcined raw meal mixture. This mixture is then homogenized in the mixer and fed as a homogeneous mixture to the rotary kiln for the sintering process. "Homogeneously mixed" means that the mixture has the most homogeneous distribution of the individual substances possible, in order to obtain a high-quality sintered material with high leaching capacity.

[0019] It can be advantageous to install a number of so-called shock blowers at the inlet zone of the rotary kiln. These can be used if deposits should form at the inlet zone. The shock blowers blow away the deposits and thus serve to clean the inlet zone of the rotary kiln.

[0020] It can be advantageous if the cooler is designed as a downpipe or in the manner of a downpipe with a double-walled jacket, whereby the coolant, preferably air, flows through the jacket preferably against the direction of fall of the deacidified raw meal mixture, so that the deacidified raw meal mixture can be cooled to the desired temperature in the interior of the downpipe. The design as a downpipe reduces the risk of buildup. The fact that the downpipe is connected to the outlet of the cyclone separator on a common axis also results in a more compact design of the combustion plant. If air is used as the coolant, a fan arranged outside the jacket to generate the air flow is particularly suitable.

[0021] It may be advantageous if at least one sensor is provided to determine the temperature of the deacidified raw meal mixture upon entry into the cooler and / or in particular upon exit from the cooler.

[0022] It may be advantageous if at least one sensor is provided for determining and / or adjusting the temperature of the coolant when entering the jacket and / or when exiting the jacket.

[0023] The at least one temperature measurement by means of a sensor enables the setting and control of parameters, for example the temperature of the coolant and the flow rate of the coolant, in order to cool the deacidified raw meal mixture in the interior of the downpipe to a desired temperature when leaving the cooler.

[0024] It may be advantageous if the flow path of the coolant within the jacket is predetermined by an arrangement of one or more guide elements within the jacket in order to cool the deacidified raw meal mixture in the interior of the downpipe down to the desired temperature.

[0025] In addition to the flow path, it may also be advantageous to specify the flow velocity and the coolant temperature at the inlet into the jacket in order to cool the deacidified raw meal mixture in the interior of the downpipe to the desired temperature.

[0026] It may be advantageous if the mixer is designed as a downpipe or in the manner of a downpipe, which is preferably connected directly and preferably integrally to the downpipe of the cooler. Designing the mixer as a downpipe reduces the risk of buildup. Furthermore, the fact that the downpipe of the mixer connects to the cooler outlet on a common axis essentially results in a more compact design of the distillation system.

[0027] It can be advantageous to provide baffles within the downpipe of the mixer. These can, for example, be projections, particularly plate-like projections, that protrude from the inner wall of the downpipe in a predetermined arrangement. The baffles prevent the free fall of the cooled, deacidified raw meal mixture emerging from the cooler and the added sodium carbonate-containing raw material, thus achieving the desired mixing of the aforementioned components. The baffles alter the flow paths and cause different flow velocities. Preferably, a turbulent flow is created, which promotes a homogeneous mixture.

[0028] It may be advantageous if the downpipe of the mixer has at least one inlet opening in the upper third of the area facing the cooler, through which in particular the raw material containing sodium carbonate can be fed.

[0029] It may be advantageous to provide an analysis unit that analyzes the deacidified raw meal mixture for its chemical composition and / or grain size, preferably online and preferably continuously as the deacidified raw meal mixture passes through the analysis unit. Such an analysis enables rapid adjustment of process parameters to optimize the process and calculate the required addition quantity of the sodium carbonate-containing raw material, preferably soda, to improve the combustibility of the raw meal mixture at lower sintering temperatures. Furthermore, based on the analysis, adjustments to the composition of the deacidified raw meal mixture can be made by adding additives or supplements, which can also be referred to as admixtures.

[0030] It may be advantageous if the analysis unit is located downstream of the cooler. It may be advantageous if the amount of sodium carbonate-containing raw material added to the deacidified raw meal mixture can be determined based on the analysis data provided by the analysis unit.

[0031] It may be advantageous if further additives, preferably stored in raw meal silos, are provided, for example an aluminum-containing additive, preferably nepheline, or a calcium-containing additive, preferably limestone, preferably in each case as raw meal, which can be added to the deacidified raw meal mixture to produce the homogeneous mixture which is to have a predetermined composition and grain size, wherein the type and quantity of the additive can preferably be determined as a function of the analysis data supplied by the analysis unit.

[0032] It may be advantageous if a dust removal system is provided for dedusting the cooler, wherein the separated dust can preferably be fed directly to the deacidified raw meal mixture leaving the cooler in order to maintain the chemical properties of the deacidified raw meal mixture unchanged and almost constant over the entire process, wherein the dust removal system preferably has a bag filter for separating the dust.

[0033] It may be advantageous if the raw meal mixture can be deacidified up to 100%, preferably from 95% to 100%, in the calciner.

[0034] It may be advantageous if the cooler is designed as a direct cooler and / or indirect cooler, whereby different coolants, for example water and / or air, can be used directly or indirectly.

[0035] It may be advantageous if the cooler is designed as a screw conveyor with a double-walled jacket, wherein the coolant, for example air or water or mixtures of different coolants, flows through the jacket, so that the deacidified raw meal mixture can be cooled to the desired temperature in the interior of the screw conveyor. The invention also relates to a process for producing sintered material from at least one aluminum-containing raw material, preferably nepheline, from a calcium-containing raw material, preferably limestone, and from a sodium carbonate-containing raw material, preferably soda, wherein the raw materials are present as raw meals, wherein

[0036] • a raw meal mixture consisting of the aluminium-containing and the calcium-containing raw material, but not of the sodium carbonate-containing raw material, is heated in a preheater having several cyclone stages,

[0037] • the preheated raw meal mixture from the penultimate cyclone stage of the preheater is transferred to a calciner, whereby the preheated raw meal mixture is deacidified preferably at temperatures above 1000 °C,

[0038] • the deacidified raw meal mixture is transferred from the calciner to a cyclone separator, which forms the last cyclone stage of the preheater, in which the deacidified raw meal mixture is separated from the gas phase,

[0039] • the deacidified raw meal mixture is transferred from the cyclone separator to a cooler in which the deacidified raw meal mixture is cooled to a temperature below the melting temperature of the sodium carbonate-containing raw material,

[0040] • the deacidified raw meal mixture from the cooler and the sodium carbonate-containing raw material, which is taken as an additive, preferably in the form of raw meal, from an additive silo or raw meal silo, are fed to a mixer, whereby the mixer mixes them into a homogeneous mixture,

[0041] • the homogeneous mixture is fed into a rotary kiln in which the homogeneous mixture is fired to form the sintered material, the rotary kiln having a rotary kiln burner,

[0042] • the fired sintered material is transferred to a sinter cooler for cooling.

[0043] It may be advantageous if the deacidified raw meal mixture is analyzed with regard to its chemical composition and / or grain size, preferably online and preferably continuously while it passes through an analysis unit.

[0044] It may be advantageous to analyze the deacidified raw meal mixture after leaving the cooler. It may be advantageous to determine the amount of sodium carbonate-containing raw material added to the deacidified raw meal mixture based on the analytical data, preferably provided by the analytical unit.

[0045] It may be advantageous if one or more additional additives, which are preferably stored in one or more raw meal silos and which can also be referred to as additive for short, for example an aluminum-containing additive, preferably nepheline, or a calcium-containing additive, preferably limestone, preferably in each case as raw meal, are added to the deacidified raw meal mixture to produce the homogeneous mixture which is to have a predetermined composition and grain size, wherein the type and quantity of the additive are preferably determined as a function of the analysis data preferably supplied by the analysis unit.

[0046] It may be advantageous if the cooler is dedusted by means of a dedusting system, whereby the separated dust is preferably fed directly to the deacidified raw meal mixture leaving the cooler in order to ensure that the chemical properties of the deacidified raw meal mixture remain virtually unchanged.

[0047] It can be advantageous if the raw meal mixture is deacidified up to 100% in the calciner.

[0048] Further developments and advantageous embodiments of the invention can also be derived from the following description of the combustion system according to the invention, which is illustrated in the drawing. In this drawing, schematically:

[0049] Fig. 1a is a schematic view of a first part of a combustion plant according to the invention,

[0050] Fig. 1b is a schematic view of a second part of the combustion plant according to the invention adjoining the first part shown in Fig. 1a, and Fig. 2 is a schematic view of an alternative design and arrangement of a cooler and mixer.

[0051] The kiln 10 shown in Figs. 1a and 1b forms a single unit. Fig. 1b is clearly connected to the right side of Fig. 1a. The kiln 10 is used to produce sintered material from nepheline, limestone, and soda, which are used as raw meal.

[0052] The combustion plant 10 comprises a preheater having several cyclone stages 12, 14 for heating a raw meal mixture composed of nepheline and limestone, but not soda. The raw meal mixture is fed via a raw meal feeder (not shown here) to the first or uppermost cyclone stage (not shown here) of the preheater 14. In the preheater, the raw meal mixture is heated to 800°C and more. The preheated raw meal mixture from the penultimate cyclone stage, indicated here by arrow 12, is fed to a calciner 16. In the calciner 16, the raw meal mixture is further heated to temperatures above 1000°C by the exhaust gases from a rotary kiln 28 and by one or more calciner burners 18, thereby almost completely deacidifying or decarbonizing it. The required combustion air is fed as tertiary air via a tertiary air line 46 from the outlet of the rotary kiln 28 and thus from the sinter cooler 32 into the calciner 16.From the calciner 16, the deacidified raw meal mixture is conveyed into the last cyclone stage 14, which is referred to herein as a cyclone separator, where the deacidified raw meal mixture is separated from the gas stream and then fed to a cooler 20.

[0053] In the cooler 20, the deacidified raw meal mixture is cooled to a temperature below the melting point of soda, preferably below 850 °C. The cooler 20 is connected to a dust removal system 44 for dust removal from the cooler 20.

[0054] The cooled, deacidified raw meal mixture next leaves the cooler 20 and passes through an analysis unit 34. Prior to this, the dust separated in the dedusting system 44 can be re-added to the cooled, deacidified raw meal mixture after it leaves the cooler 20. This has no influence on the subsequent analysis. In the analysis unit 34, the cooled, deacidified raw meal mixture is analyzed for its chemical composition and / or grain size, preferably online and preferably continuously as the cooled, deacidified raw meal mixture passes through the analysis unit 34.

[0055] Depending on the analysis data supplied by the analysis unit 34, a predetermined amount of soda 24 is then added to the cooled, deacidified raw meal mixture as an additive, preferably in the form of raw meal, from an additive silo or raw meal silo 26. Depending on the analysis data supplied by the analysis unit 34, deviations in the desired composition can be compensated for by various correction agents 48. The correction agents 48 can be additives stored in raw meal silos 36, 38, in particular nepheline 40 or limestone 42, which are then added in predetermined amounts as an additive to the cooled, deacidified raw meal mixture along with soda 24.

[0056] The cooled, deacidified raw meal mixture is then mixed with the soda 24 and, if necessary, other additives 40, 42 in a mixer 22 to form a homogeneous mixture. "Homogeneously mixed" means that the mixture has the most homogeneous distribution of the individual substances possible in order to obtain a high-quality sintered material.

[0057] The homogeneous mixture is then fed into the rotary kiln inlet chamber of the rotary kiln 28. In the rotary kiln 28, the homogeneous mixture is fired to form the sintered material. The required thermal energy is provided by a rotary kiln burner 30. The fired sintered material leaving the rotary kiln is then cooled in the sinter cooler 32, which is connected to a sinter cooler filter, represented here by an arrow 50 as the path to the sinter cooler filter. In the area of ​​the sinter cooler 32, the rotary kiln head is designed so that the gas velocity is kept below the suspended velocity of the sinter dust particles, thereby minimizing the dust load in the tertiary air. This advantageously prevents dust circulation, which could otherwise negatively impact the sintering process.

[0058] Fig. 2 shows a schematic view of an alternative design and arrangement of a cooler 52 and mixer 54 in contrast to Fig. 1a. Not shown is the raw meal silo 26 shown in Fig. 1a, which is of course present in order to remove soda 24 from it and feed it to the mixer 54.

[0059] The analysis unit 34 shown in Fig. 1a and the correction means 48 shown in Fig. 1a can advantageously also be provided in the alternative design and arrangement of a cooler 52 and mixer 54 shown in Fig. 2, even if these 34, 48 are not explicitly shown.

[0060] A dust removal system 44 can also advantageously be provided in the alternative design and arrangement of a cooler 52 and mixer 54 shown in Fig. 2, even if this 44 is not explicitly shown.

[0061] The cooler 52 shown in Fig. 2 is advantageously designed as a downpipe that has a double-walled jacket at least partially along its length. According to the invention, a coolant 60, preferably air, flows through this jacket counter to the direction of fall of the deacidified raw meal mixture 62, so that the deacidified raw meal mixture 62 is cooled to the desired temperature in the interior of the downpipe.

[0062] The flow path of the coolant 60 is defined within the jacket by an arrangement of one or more guide elements within the jacket in order to cool the deacidified raw meal mixture 62 in the interior of the downpipe to the desired temperature.

[0063] The mixer 54 shown in Fig. 2 is advantageously designed as a downpipe that is directly and preferably integrally connected to the downpipe of the cooler 52. Baffles 56 are provided within the downpipe of the mixer 54. These 56 protrude as plate-like projections from the inner wall of the downpipe in a predetermined arrangement. The baffles 56 prevent the free fall of the cooled, deacidified raw meal mixture 62 emerging from the cooler 52 and the added soda 24, so that the desired mixing of the aforementioned components is achieved. The baffles 56 alter the flow paths and cause different flow velocities, which also creates a turbulent flow, which promotes a homogeneous mixture.

[0064] For the supply of the soda 24, the downpipe of the mixer 54 has an inlet opening 58 in the upper third of the area facing the cooler 52.

[0065] List of reference symbols

[0066] (is part of the description)

[0067] 10 Distillation plant

[0068] 12 penultimate cyclone stage

[0069] 14 last or lowest cyclone stage or cyclone separator

[0070] 16 Calciner

[0071] 18 calciner burners

[0072] 20 coolers

[0073] 22 mixers

[0074] 24 raw material containing sodium carbonate, preferably soda

[0075] 26 raw meal silo

[0076] 28 rotary kilns

[0077] 30 rotary kiln burners

[0078] 32 sinter coolers

[0079] 34 Analysis Unit

[0080] 36 raw meal silo

[0081] 38 raw meal silo

[0082] 40 aluminum-containing aggregate

[0083] 42 calcium-containing supplement

[0084] 44 Dust extraction system

[0085] 46 Tertiary air duct

[0086] 48 correction materials

[0087] 50 sintered cooler filters or the way there

[0088] 52 coolers

[0089] 54 mixers

[0090] 56 chicane

[0091] 58 Inlet opening

[0092] 60 coolant

[0093] 62 raw flour mixture

Claims

Patent claims 1. A combustion plant (10) for producing sintered material from at least one aluminum-containing raw material, preferably nepheline, from a calcium-containing raw material, preferably limestone, and from a sodium carbonate-containing raw material, preferably soda, wherein the raw materials are present as raw meals, comprising • a preheater having several cyclone stages (12, 14) for heating a raw meal mixture consisting of the aluminium-containing and the calcium-containing raw material, but not of the sodium carbonate-containing raw material, • a calciner (16) which receives the preheated raw meal mixture from the penultimate cyclone stage (12) of the preheater, wherein the preheated raw meal mixture is deacidified in the calciner (16), preferably at temperatures above 1000 °C, wherein the calciner (16) has a calciner burner (18), • a cyclone separator, which forms the last cyclone stage (14) of the preheater, in which the deacidified raw meal mixture from the calciner (16) is separated from the gas phase, • a cooler (20, 52) to which the deacidified raw meal mixture from the cyclone separator (14) is fed, and in which the deacidified raw meal mixture is cooled to a temperature below the melting temperature of the sodium carbonate-containing raw material, • a mixer (22, 54) to which the deacidified raw meal mixture from the cooler (20, 52) and the sodium carbonate-containing raw material (24) in the form of raw meal, preferably from a raw meal silo (26), are fed, the mixer (22, 52) mixing them into a homogeneous mixture, • a rotary kiln (28) to which the homogeneous mixture is fed and in which the homogeneous mixture is fired to form sintered material, the rotary kiln (28) having a rotary kiln burner (30), • and a sinter cooler (32) for cooling the fired sintered material.

2. Combustion plant (10) according to claim 1, characterized in that the cooler (52) is designed as a downpipe or in the manner of a downpipe with a double-walled jacket, wherein the coolant, preferably air, is preferably directed against the direction of fall of the deacidified raw meal mixture flows through the jacket so that the deacidified raw meal mixture can be cooled to the desired temperature in the interior of the downpipe.

3. Combustion plant (10) according to claim 1 or 2, characterized in that the mixer (54) is designed as a downpipe or in the manner of a downpipe, which is preferably connected directly and preferably in one piece to the downpipe of the cooler (52).

4. Combustion plant (10) according to claim 3, characterized in that baffles (56) are provided within the downpipe of the mixer (54).

5. Combustion plant (10) according to claim 3 or 4, characterized in that the downpipe of the mixer (54) has at least one inlet opening (58) in the upper third of the area facing the cooler, via which in particular the raw material (24) containing sodium carbonate can be fed.

6. Combustion plant (10) according to one of claims 1 to 5, characterized in that an analysis unit (34) is provided which analyses the deacidified raw meal mixture with regard to its chemical composition and / or grain size, preferably online and preferably continuously during the passage of the deacidified raw meal mixture through the analysis unit (34).

7. Combustion plant according to claim 6, characterized in that the analysis unit (34) is connected downstream of the cooler (20).

8. Combustion plant (10) according to claim 6 or 7, characterized in that the amount of sodium carbonate-containing raw material (24) added to the deacidified raw meal mixture can be determined as a function of the analysis data supplied by the analysis unit (34).

9. Combustion plant (10) according to one of claims 1 to 8, characterized in that further additives are provided, preferably stored in raw meal silos (36, 38), for example an aluminum-containing additive (40), preferably nepheline, or a calcium-containing additive (42), preferably limestone, preferably in each case as raw meal, which can be added to the deacidified raw meal mixture to produce the homogeneous mixture which is to have a predetermined composition and grain size, wherein the type and quantity of the additive (40, 42) can preferably be determined as a function of the analysis data supplied by the analysis unit (34).

10. Combustion plant (10) according to one of claims 1 to 9, characterized in that a dedusting system (44) is provided for dedusting the cooler (20), wherein the separated dust can preferably be fed directly to the deacidified raw meal mixture leaving the cooler (20), wherein the dedusting system (44) preferably has a bag filter for separating the dust.

11. Combustion plant (10) according to one of claims 1 to 10, characterized in that the raw meal mixture can be deacidified up to 100% in the calciner (16).

12. Combustion plant (10) according to one of claims 1 to 11, characterized in that the cooler (20) is designed as a direct cooler and / or indirect cooler, wherein different cooling means, for example water and / or air, can be used directly or indirectly.

13. Combustion plant (10) according to claim 1, characterized in that the cooler (20) is designed as a screw conveyor with a double-walled jacket, wherein the coolant, for example air or water or mixtures of different coolants, flows through the jacket, so that the deacidified raw meal mixture can be cooled to the desired temperature in the interior of the screw conveyor.

14. A process for producing sintered material from at least one aluminium-containing raw material, preferably nepheline, from a calcium-containing raw material, preferably limestone, and from a sodium carbonate-containing raw material, preferably soda, the raw materials being in the form of raw meals, wherein • a raw meal mixture consisting of the aluminium-containing and the calcium-containing raw material, but not of the sodium carbonate-containing raw material, is heated in a preheater having several cyclone stages, • the preheated raw meal mixture from the penultimate cyclone stage of the preheater is transferred to a calciner, whereby the preheated raw meal mixture is deacidified preferably at temperatures above 1000 °C, • the deacidified raw meal mixture is transferred from the calciner to a cyclone separator, which forms the last cyclone stage of the preheater, in which the deacidified raw meal mixture is separated from the gas phase, • the deacidified raw meal mixture is transferred from the cyclone separator to a cooler in which the deacidified raw meal mixture is cooled to a temperature below the melting temperature of the sodium carbonate-containing raw material, • the deacidified raw meal mixture from the cooler and the sodium carbonate-containing raw material, which is taken as raw meal from a raw meal silo, are fed to a mixer, whereby the mixer mixes them into a homogeneous mixture, • the homogeneous mixture is fed into a rotary kiln in which the homogeneous mixture is fired to form the sintered material, the rotary kiln having a rotary kiln burner, • the fired sintered material is transferred to a sinter cooler for cooling.

15. A method according to claim 14, characterized in that the deacidified raw meal mixture is analyzed with regard to its chemical composition and / or grain size, preferably online and preferably continuously, while it passes through an analysis unit.

16. Method according to claim 14 or 15, characterized in that the deacidified raw meal mixture is analyzed after leaving the cooler.

17. Method according to claim 15 or 16, characterized in that the amount of sodium carbonate-containing raw material added to the deacidified raw meal mixture is determined as a function of the analysis data preferably supplied by the analysis unit.

18. Method according to one of claims 14 to 17, characterized in that one or more than one further additive, preferably stored in a raw meal silo, for example an aluminum-containing additive, preferably nepheline, or a calcium-containing additive, preferably limestone, preferably in each case as raw meal, are added to the deacidified raw meal mixture to produce the homogeneous mixture, which is to have a predetermined composition and grain size, wherein the type and quantity of the additive are preferably determined as a function of the analysis data preferably supplied by the analysis unit.

19. Combustion plant according to one of claims 14 to 18, characterized in that the cooler is dedusted by means of a dedusting system, wherein the separated dust is preferably fed directly to the deacidified raw meal mixture leaving the cooler.

20. Process according to one of claims 14 to 19, characterized in that the raw meal mixture is deacidified up to 100%, preferably completely, in the calciner.

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