WO2010060855A1

WO2010060855A1 - Method and plant for the production of cement

Info

Publication number: WO2010060855A1
Application number: PCT/EP2009/065485
Authority: WO
Inventors: Sebastian Frie; Wilfried Kreft
Original assignee: Polysius Ag
Priority date: 2008-11-28
Filing date: 2009-11-19
Publication date: 2010-06-03
Also published as: DE102008059370B4; DE102008059370A1

Abstract

The invention relates to a method and a plant for producing cement by blending hydraulic clinker and a latently hydraulic mixture of minerals, the hydraulic clinker being burned separately from the latently hydraulic mixture of minerals. The latently hydraulic mixture of minerals is produced by combining desired raw materials, then burning and/or melting said raw materials, and cooling the same. The waste gases produced during the production of the latently hydraulic mixture of minerals are fed to a CO₂ processing stage in which the waste gases are compressed.

Description

Process and plant for the production of cement

The invention relates to a method for the production of cement by cutting hydraulic clinker and a latent hydraulic mineral mixture, wherein the hydraulic clinker is fired separately from the latent hydraulic mineral mixture.

The production of cements by blending hydraulic clinker with latent hydraulic materials from the steel industry, such as blast furnace slag, blastfurnace slag, trass or oil shale ash, is a well-known technique which, compared to the production of cements made from pure Portland cement clinker, a significant saving of heat energy and a Reduction of the CO ₂ emission causes.

In EP-A2-1 741 683, for the production of cement clinker, first a lime component is mixed with converter slag and / or electro-steelworks slag and optionally further ingredients, in order then to burn the mixture thus obtained. However, this method has the disadvantage that the slag is burned again with energy expenditure, although it is already latently hydraulic without burning.

Nevertheless, this method is compared to a production of pure Portland cement clinker both energetically and in terms of CO ₂ emission significantly cheaper.

The DE-Al-42 35 125 also discloses a process for the production of synthesis gas, wherein CO 2 -containing exhaust gases are used in the burning of lime in the cement production.

In order to achieve a further energy saving, it is also known to admit the blast furnace slag or another latent hydraulic material only after the burning of the hydraulic clinker and to ground together on In this way, a further energy saving and a reduced CO 2 emission can be achieved.

DE-C2-33 10 129 describes a process for producing different hydraulic binders from common raw materials in a firing process, wherein a partial flow of the gas / solid stream in the region of the calciner is indicated.

From DE-Al-34 12 357 a binder composition is known in which deacidified cement raw meal with a latent hydraulic hardening substance, such as blast furnace slag, in particular blast furnace slag, is mixed.

A fast-curing hydraulic binder is also known from DE-T2-693 15 078, which is formed by a mixture of natural cement with natural or artificial pozzolans, such as industrial waste, in particular silicic acid fumes.

However, unfortunately, there are not everywhere sufficiently large quantities of latent hydraulic substances available, which make it possible to produce such cements.

The invention is therefore based on the object of specifying a method and a plant for the production of cement, which allow a saving of heat energy and a reduction of the CO ₂ emission even in such cases.

According to the invention, this object is solved by the features of claims 1 and 16.

In the method according to the invention for producing cement by cutting hydraulic clinker and a latent hydraulic mineral mixture, the hydraulic clinker is fired separately from latent hydraulic mineral mixture. The latent hydraulic mineral mixture is doing by compilation desired raw materials and subsequent firing and / or melting of these raw materials and cooling, wherein the resulting in the preparation of the latent hydraulic mineral mixture exhaust gases are fed to a CO ₂ - treatment, wherein the exhaust gases are compressed.

Since considerably less heat energy has to be used for firing the latent hydraulic mineral mixture than when firing pure Portland cement clinker, a reduction in the energy requirement and a reduction in C (-E emissions can be achieved even if no blast furnace slag or other latent hydraulic substances are present.

The plant according to the invention for the production of cement according to the method described above consists essentially of at least one furnace for burning the hydraulic clinker and a reactor for burning and / or melting the latent hydraulic mineral mixture, means for combining the hydraulic clinker and the latent separately prepared therefrom hydraulic mineral mixture, a comminuting device for the common or separate comminution of the hydraulic clinker and the latent hydraulic mineral mixture and a CO ₂ -Aufbereitungseinrichtung for the resulting in the production of the latent hydraulic mineral mixture exhaust gas, wherein the CO ₂ -Aufbereitungseinrichtung comprises a compressor.

Further embodiment of the invention are the subject of the dependent claims.

According to a preferred embodiment of the invention, the raw materials for the latent hydraulic mineral mixture are preheated separately from the raw materials for the hydraulic clinker before the firing and / or melting process. Furthermore, at least a subset of the preheated raw materials is precalcined. The hydraulic clinker and the latent hydraulic mineral mixture can be crushed either separately or together. Depending on whether they are mixed together after or before shredding.

During the firing and melting process of the latently hydraulic mineral mixture, it is possible in particular to burn the mineral mixture in a manner similar to the hydraulic clinker, but other temperatures are used or, as in the known blast furnace process, a melt is used over which Floating slag forms. In this case, however, slag-forming raw material is supplied. In addition, as the main product of the melting process, not the melt, but the slag is withdrawn, while the melt is retained to more than 50%, preferably more than 90%.

In this way, the latent hydraulic mineral mixtures can be produced very economically on an industrial scale. This in turn allows for a higher proportion of blastfurnace slag in the cement, which can reduce C (^ emissions in cement production.

According to the invention, therefore, industrial waste is not used, but the latent hydraulic mineral mixture is produced by targeted composition of desired raw materials and subsequent firing or melting of these raw materials and cooling. In this way, the proportion of the latent hydraulic mineral mixture in the cement can be increased, wherein in addition to a saving of heat energy, a corresponding reduction of the CO ₂ - emission is achieved. In that the exhaust gas in the preparation of the latent hydraulic mineral mixture is also supplied to a CO ₂ treatment, the CO ₂ emissions can be reduced even further.

Another potential for C (^ reduction is provided by the process for preparing the latent hydraulic mineral mixture. As combustion air during the firing and / or melting process and / or during precalcination, air, in particular cooler exhaust air, can be used. However, air has a high nitrogen content, so a large amount of air is required for combustion. Separate disposal of these amounts of exhaust gas is not economically feasible. It is therefore desirable to increase the CO ₂ concentration in the exhaust gas, thereby enabling economical treatment, storage or utilization / utilization.

One way of increasing the CO ₂ concentration in the exhaust gas is to use combustion air which has an oxygen content of at least 75 mol%, preferably at least 90 mol%, in the production of the latently hydraulic mineral mixture. Such a combustion air can be used both during precalcining and during the firing and / or melting process. Only by the measure, the CO ₂ concentration in the exhaust gas can be increased to more than 70%.

The energy required to maintain the melt is supplied by adding fuel to the melt. In the method described above, about 60% of the CO ₂ emissions are produced from the raw material-containing limestone, while about 40% result from the combustion. In order to reduce the C (^ emissions caused by the fuel, one measure may be that hydrogen is used as fuel during the firing and / or melting process.

The CO ₂ -containing exhaust gas produced during the production of the latently hydraulic mineral mixture can furthermore be subjected to CO ₂ scrubbing or is dehumidified and compacted and, if appropriate, subjected to a low-temperature phase separation.

Another possibility is to supply the CO 2 -containing exhaust gas as a nutrient to a bioreactor by using plants, in particular algae. The plants used can then be used as fuel in the firing or melting process.

If the latent hydraulic mineral mixture is produced by means of melting, the slag removed is cooled down so rapidly that at least the major part of the slag solidifies glassy. It is conceivable that the cooling takes place in two stages, being cooled first with a liquid cooling medium and then with a gaseous cooling medium.

Subsequently, the cooled slag is finely crushed, wherein at least a portion of the cooled slag is crushed to a fineness of at least 3,500 to 8,000 Blaine, preferably at least 10,000 Blaine.

For the process of producing cement containing at least clinker and blast furnace slag as constituents, at least part of the latent hydraulic mineral mixture prepared by the above process is used, at least part of the total latent hydraulic mineral mixture having the fineness given in the preceding paragraph.

The melting process is operated according to a preferred embodiment under a reducing atmosphere and with a metallic melt, wherein the melting process is fed slag-forming raw material and the main product of the melting process, the slag is withdrawn, while the melt is largely retained.

Conveniently, the resulting in the production of hydraulic clinker exhaust gases are either separately or together with the exhaust gases of the latent hydraulic mineral mixture of a CO ₂ treatment, a CO ₂ storage and / or a CO ₂ use / recovery supplied. Further advantages and embodiments of the invention will be explained in more detail below with reference to the description of some embodiments and the drawings.

In the drawing show

1 is a block diagram of a plant for the production of cement by blending of hydraulic clinker and a latent hydraulic mineral mixture,

2 is a block diagram of a plant for the production of latent hydraulic mineral mixture according to a first embodiment,

3 is a block diagram of a plant for the production of latent hydraulic mineral mixture according to a second embodiment,

Fig. 4 is a block diagram of a plant for the production of latent hydraulic mineral mixture according to a third

exemplary embodiment,

Fig. 5 is a block diagram of a plant for the production of latent hydraulic mineral mixture according to a fourth exemplary embodiment and

Fig. 6 is a block diagram of a plant for the production of latent hydraulic mineral mixture according to a fifth embodiment.

The plant shown in Fig. 1 consists essentially of a first process sträng 100 for producing a hydraulic clinker 21 and a second process strand 200 for producing a latent hydraulic In particular, the first process line 100 comprises a furnace 101 for burning the hydraulic clinker and a downstream cooler 102. The raw materials 104 required for the production of the hydraulic clinker 21 are supplied to the furnace 101 in suitable form. Before the actual firing process, the raw materials are preheated in the usual manner and / or precalcined.

Also in the second process string 200, a reactor 3 for firing and / or melting is provided to produce the latent hydraulic mineral mixture 20 by assembling desired raw materials 6, then firing or melting these raw materials and subsequently cooling.

Furthermore, means 103 for merging the hydraulic clinker 21 and latent hydraulic mineral mixture 20 are provided. These means can be formed for example by dosing belt cars. The ratio of the two components can thereby be adapted to the corresponding requirements. The proportion of the hydraulic clinker is preferably in the range from 30 to 40% by weight, preferably in the range from 20 to 30% by weight. The resulting mixture is optionally crushed with the addition of other additives 22, such as gypsum and other ingredients in a crushing plant 5 to cement 23.

In the context of the invention, it is of course also possible that the two components, d. H. the hydraulic clinker and latent hydraulic mineral mixture, comminuted separately and then mixed together in the desired composition.

The provision of two combustion units (furnace 101 or reactor 3) has the advantage that they can be adapted to the material to be fired. In particular, the energy expenditure for firing the raw materials 6 for the latent hydraulic mineral mixture is much lower than when firing the raw materials of the hydraulic clinker 21, since for the deacidification of the lime-poor raw materials. 6 less heat input is required. The latent hydraulic mineral mixture preferably has a constituent of 30 to 40% by weight of CaO, while the corresponding constituent of CaO in the case of the hydraulic clinker is preferably between 60 to 70% by weight.

If the hydraulic clinker 21 and the latent hydraulic mineral mixture 20 are mixed together in a ratio of 1: 3, the heat requirement can be reduced by about 30% compared to a cement made from pure hydraulic clinker. The emission of CO ₂ from CaCO ₃ and CO ₂ from fuel combustion is reduced even more. This results in great benefits for the heat industry and a significantly reduced environmental impact.

In order to further reduce the CO ₂ emissions, additional measures can be taken in the two process strands 100 and 200, which are explained in more detail below with reference to the process strand 200 for the production of the latently hydraulic mineral mixture. Although the reactor 3 for firing and / or melting of the latent hydraulic mineral mixture in FIGS. 2 to 6 is designed as a melt reactor 3, a furnace of a completely different design may also be used instead.

The plant shown in Fig. 2 for the production of latent hydraulic mineral mixture contains a preheater 1 and a calciner 2 for slag-forming, fine-grained raw material, a melt reactor 3, a cooling device 4 and a crushing plant. 5

The slag-forming raw material 6 is fed to the preheater 1, then passes as preheated raw material 7 in the calciner 2 and is finally registered as precalcined raw material 8 in the melt 9 of the melt reactor 3. The exhaust gases 10 of the melt reactor 3 are fed to the calciner 2, which also fuel 11 and combustion air 12 is supplied as the warm Exhaust air from the cooling device 4 can come. The exhaust gases 13 of the calciner enter the preheater 1.

The melt reactor 3, fuel 15 and combustion air 16 is supplied, which in turn can come as a warm exhaust air from the cooling device 4. The combustion air in the calciner or the combustion air 16 in the melt reactor is preferably formed by pure oxygen or oxygen-enriched combustion air.

The forming in the melt reactor, floating slag 17, which separates due to different density of the metallic melt 9 is withdrawn as actual useful product from the melt reactor 3 (arrow 18), while the melt 9 to more than 50%, preferably more than 90 % remains behind in the melt reactor 3, whereby any smaller melt losses or excesses of melt which may occur are compensated by suitable material supply and removal.

The withdrawn from the melt reactor liquid slag 17 is cooled in the cooling device 4 so quickly that at least the majority of the slag solidifies glassy. The withdrawn slag can be cooled in two stages, wherein first with a liquid cooling medium 19, for example water, and then with a gaseous cooling medium 24, in particular air, is cooled.

The thus produced, predominantly amorphous, latent hydraulic mineral mixture 20 is then finely comminuted in the comminution plant 5, wherein the comminution of the latent hydraulic mineral mixture can be carried out either separately or together with the comminution of clinker 21 and other additives 22. From the crushing plant 5 standard cement 23 is removed with the desired particle size distribution and with a high proportion of latent hydraulic mineral mixture. In the case of separate comminution, the constituents of the cement are homogenized in a mixer to give cement. The plant shown in Fig. 2 for the production of latent hydraulic mineral mixture further provides an air separation plant 25 and a CO ₂ - treatment device 26 before. Furthermore, it comprises a return of a part 14 'of the exhaust gases of the preheater 1 into the calciner 2 and / or the melt reactor 3.

The air separation plant 25 serves to produce oxygen, which can be used as combustion air 12 in the calciner 2 and / or as combustion air 16 in the melt reactor 3. It is conceivable that the combustion air consists of pure oxygen or has an oxygen content of at least 75 mol%, preferably at least 95 mol%.

The use of oxygen or oxygen enriched air significantly reduces the amount of combustion air required for combustion, as the proportion of nitrogen is reduced accordingly. Alone by this measure, the CO ₂ concentration in the exhaust gas 14 after the preheater 1 can be increased from about 25% to 70 to 75% compared to a plant operated with normal combustion air.

If the calciner 2 is designed as a flow current calciner, a minimum amount of carrier gas is required, which is usually composed of the exhaust gas 10 of the melt reactor and the combustion air 12. If, however, the amount of combustion air is reduced by the high oxygen content, it may be necessary to recirculate a partial quantity 14 'of the exhaust gas of the preheater 1 or also a partial amount of the exhaust gas of the calciner to the calciner 2 in order to provide a sufficient amount of carrier gas there.

However, if the calciner 2 is designed as a fluidized-bed reactor, the amount of carrier gas can be reduced so far that no recirculation of calciner and / or preheater exhaust gases is required. This would have the advantage that the Recarbonatisierung caused by the recirculation can be prevented. The preheater 1 is expediently formed by a cyclone heat exchanger, in which, however, it inevitably leads to significant amounts of false air during preheating. Nevertheless, in this variant, a CO ₂ concentration in the exhaust gas 14 of about 70 to 75% can be achieved. At the current state of development, however, CO ₂ storage / storage only makes sense from concentrations of at least 96%.

For this purpose, the exhaust gas 14 is supplied to a CO ₂ treatment device 26, the exhaust gas successively passing through a device 26a for dehumidification, a device 26b for compression and a device 26c for degassing. Further concentration of the exhaust gas could be achieved with a means 26d for cryogenic phase separation. The CO 2 -containing gas present at the end of this process is so highly concentrated that economic storage and / or other use / utilization is possible. The remaining residual gas 27 is vented to the atmosphere or otherwise used.

In the second exemplary embodiment (FIG. 3), two preheaters 1a, 1b are provided, one preheater 1a being connected to the exhaust gas line of the calciner 2 and the other preheater 1b being connected to the exhaust gas line of the melt reactor 3. The preheater Ib is thus only flowed through by the exhaust gases 10 of the melt reactor 3, while the preheater Ia is acted upon by the exhaust gases 13 of the calciner 2. Accordingly, the slag-forming raw material in two subsets 6a and 6b is the two preheaters Ia and Ib abandoned. While the preheater Ib preheated portion of the raw material 7b is passed directly into the melt reactor 3, the preheater Ia preheated partial amount 7a is first precalcined in calciner 2 and passes as precalcined raw material portion 8a in the melt reactor. 3 If, in this variant, the calciner 2 is also operated with pure oxygen or at least with an oxygen-enriched combustion air, a very high CO ₂ concentration is formed in the already exhaust gas 13 of the calciner or in the exhaust gas 14 of the preheater _{1 a} . Since the raw material is divided into two preheaters, resulting in correspondingly smaller preheater, so that the false air intake is about halve. This has the consequence that set at approximately the same thermal energy consumption higher CO ₂ concentrations, which can be over 80%.

The use of pure oxygen or an oxygen-enriched combustion air again reduces the amount of combustion air due to the high oxygen content, so that a partial amount 14 'of the exhaust gas of the preheater 1 or also a partial amount of the exhaust gas of the calciner can be recirculated to the calciner 2 to provide a sufficient amount of carrier gas there.

However, in the exemplary embodiment according to FIG. 3, the exhaust gas 28 of the preheater Ib flowing through the exhaust gases of the melt reactor 3 escapes unhindered. The proportion of CO ₂ in the exhaust gas of the preheater Ib could however be reduced by heat treatment of preferably no carbonates in the preheater Ib, but only Al ₂ O ₃ , FeO ₃ and SiO ₂ carriers. In addition, there is the further possibility to operate the melt reactor 3 with hydrogen, thereby avoiding the CO 2 content due to the fuel.

The hydrogen can be produced in a steam reformer 29 by means of natural gas and in a device 30 of pyrolyzed coal 31. The steam reformer is expediently operated with the waste heat 32 of the cooling device. In a subsequent CO ₂ separator 33, the hydrogen is separated from the carbon dioxide. 4 shows an alternative system with two preheaters 1a and 1b, wherein the preheater 1a flows through the exhaust gas 13 of the calciner 2 and the preheater 1b flows through the exhaust gases 10 of the melt reactor 3. In contrast to the exemplary embodiment according to FIG. 3, however, the partial quantity 7b of the raw material preheated in the preheater 1b does not pass directly into the melt reactor 3, but is first precalcined in the calciner 2 together with the other partial quantity 7a of the raw material preheated in the preheater 1a.

In Fig. 4, the possibility is further shown that the combustion air used in the calciner 2 can be preheated with the waste heat 32 of the cooling device 4 in a heat exchanger 34. The recirculated exhaust gas 14 'can be used both as combustion air 12 in the calciner (as shown), as well as cooling air in the cooling device 4.

The principle of preheating the combustion air 12 for the calciner 2 is also maintained in the embodiment of FIG. 5. Here again, however, only one preheater 1 is provided, which, however, in contrast to the first two embodiments, only flows through the exhaust gas 10 of the melt reactor 3. The raw material 6 fed to the preheater 1 is supplied as preheated raw material 7 to the calciner 2, which is supplied with preheated combustion air 12, fuel 11 and a recirculated part 13 'of the calciner exhaust gas 13. In this variant, the exhaust gas 13 of the calciner is fed immediately after the calciner of the CO ₂ -Aufbereitungseinrichtung 26, so that any false air inlet is avoided in the preheater for this exhaust. Since there is no cooling of the exhaust gas through a preheater, it may be necessary that a cooling device 37, for example in the form of a steam reformer, is interposed. The cooling device can then be used for example for power generation or hydrogen production. As a result, CO ₂ concentrations in the exhaust gas 13 of 96% and more can be achieved, so that only dehumidification and subsequent compression is required if the CO _{2 is to be} stored. Of course, the gas can also be used for other purposes or recovery. However, one must consider in this variant, that part of the amount of CO ₂ after the preheater 1 escapes undiminished. In order to reduce these CO ₂ emissions, the melt reactor 3 can be operated with hydrogen. This fuel would also be in the embodiment of FIG. 4 is a good way to avoid the CO ₂ - share due to the fuel. However, the high temperatures of the exhaust gas 28 cause a significantly increased heat consumption.

Finally, FIG. 6 shows a system in which the CO ₂ treatment device 26 is formed by a device 26e for scrubbing CO _{2 of} the exhaust gas 14 and a device 26f for regenerating the solvent used. The device 26f can be operated by the waste heat 32 of the cooling device 4. Conveniently, the device 26e for CO ₂ scrubbing is preceded by a device 38 for desulfurization.

Since the production of latent hydraulic mineral mixture produces significantly less CO ₂ emissions than clinker production, an increase in the latent hydraulic mineral mixture content in the cement already leads to a significant reduction in CO ₂ emissions. Moreover, if the possibilities shown in the various exemplary embodiments are used individually or in combination with one another, the CO ₂ emissions in the production of the latently hydraulic mineral mixture can be additionally reduced. In highly concentrated form, the CO ₂ -containing gas can be stored in appropriate deposits.

But it is also possible to use the CO ₂ -containing exhaust gas for the production of fuel, which is ideally used as fuel in the production of latent hydraulic mineral mixture. This can be done with plants, In particular algae, equipped bioreactor can be provided, through which the CO ₂ - containing exhaust gases are passed. In combination with light, the algae convert the CO ₂ into biomass and oxygen through photosynthesis. The biomass can then be used as fuel in the fuel or smelting reactor 3. In this type of use of CO ₂ -containing exhaust gases, in principle, a CO ₂ treatment is not required, so that the exhaust gas can be passed directly after the calciner or the preheater in the bioreactor. In Fig. 2, such a bioreactor 35 is indicated by dashed lines. But it can also be used in the other embodiments.

Optionally, the exhaust gas can be freed from dust by a dedusting device 36 before entering the bioreactor 35. Since the algae naturally have a high moisture content after harvesting, optionally the heat of the gaseous cooling medium heated in the cooler 24 can be used to dehumidify the algae in a drier 39.

Claims

Claims:

Anspruch [en] A process for producing (23) cement by blending of hydraulic clinker (21) and a latent hydraulic mineral mixture (20), the hydraulic clinker being fired separately from the latent hydraulic mineral mixture,

characterized in that the latent hydraulic mineral mixture (20) is produced by combining desired raw materials (6) and then firing and / or melting these raw materials and cooling, and the exhaust gases (14) produced during the preparation of the latent hydraulic mineral mixture undergo CO ₂ treatment be fed, the exhaust gases are compressed.

2. The method according to claim 1, characterized in that the raw materials (6) for the latent hydraulic mineral mixture (20) before the firing and / or melting process separately from the raw materials (104) for the hydraulic clinker (21) are preheated and at least a subset is precalcined.

3. The method according to claim 1, characterized in that the hydraulic clinker and the latent hydraulic mineral mixture (20) comminuted separately from each other and then mixed into cement (23) or comminuted together.

4. The method according to claim 2, characterized in that the preheated and at least in a subset precalcined raw material (8) is fed in fine-grained form the firing and / or melting process.

5. The method according to claim 1, characterized in that in the preparation of the latent hydraulic mineral mixture (20) and / or the hydraulic Clinker (21) combustion air is used, which has an oxygen content of at least 75 mol%.

6. The method according to claim 1, characterized in that during the combustion and / or melting process hydrogen is used as the fuel (15).

7. The method according to claim 2, characterized in that the raw materials (6) for the latent hydraulic mineral mixture (20) in at least two subsets (6a, 6b) are preheated separately and at least one of the subsets (7a) is precalcined before the Raw material is supplied to the burning and / or melting process.

8. The method according to claim 7, characterized in that the one subset (6a) with exhaust gases (10) from the combustion and / or melting process and the other subset (6b) is preheated with exhaust gases (13) of Vorcalcination.

9. The method according to claim 1, characterized in that the exhaust gas (14) dehumidified in the CO ₂ treatment.

10. The method according to claim 1, characterized in that the exhaust gas (14) is subjected in the CO ₂ treatment of a CO ₂ scrubbing.

11. The method according to claim 1, characterized in that the exhaust gas (14) is subjected in the CO ₂ preparation of a low-temperature phase separation.

12. The method according to claim 1, characterized in that in the production of the latent hydraulic mineral mixture (20) resulting CO2-containing exhaust gas is fed as nutrient a bioreactor (35), are used in the plants, especially algae.

13. The method according to claim 12, characterized in that the plants so used are used as fuel in the firing and / or melting process.

14. The method according to claim 1, characterized in that for the preparation of the latent hydraulic mineral mixture (20) required combustion air (12, 16) is preheated by means of emerging process gases.

15. The method according to claim 1, characterized in that the resulting in the production of both substances exhaust gases (14) are supplied together or separately from the CO ₂ treatment.

16. plant for the production of cement according to the method of claim 1, characterized by at least one furnace (101) for firing the hydraulic clinker (21) and a reactor (3) for burning and / or melting the latent hydraulic mineral mixture (20) Means (103) for combining the hydraulic clinker (21) and the latent hydraulic mineral mixture (20) prepared separately thereof, a comminution device (5) for the common or separate comminution of the hydraulic clinker and the latent hydraulic mineral mixture and a CO ₂ preparation device (26) for the resulting in the production of the latent hydraulic mineral mixture exhaust gas, wherein the CO ₂ -aufbereitungseinrichtung (26) comprises a compressor.

17. Plant according to claim 16, characterized in that a preheater (1) and a calciner (2) for preheating and precalcination of the preparation of the latent hydraulic mineral mixture (20) required raw materials (6) is provided.

18. Plant according to claim 16, characterized in that the calciner (2) and / or the furnace (101) for burning the hydraulic clinker and / or the Reactor (3) for burning and / or melting the latent hydraulic mineral mixture comprises means for supplying combustion air (12, 16) having an oxygen content of at least 75 mol%.

19. Plant according to claim 16, characterized in that at least two preheaters (Ia, Ib) are provided for the preparation of the latent hydraulic mineral mixture (20), wherein the preheater (Ib) to an exhaust pipe of the reactor (3) for firing and / or melting the latent hydraulic mineral mixture (20) and the other preheater (Ia) is connected to an exhaust pipe of the calciner (2).

20. Plant according to claim 16, characterized in that the plant for the production of cement with a bioreactor (35) is in connection, are used in the plants, especially algae, and of CO ₂ -containing exhaust gases of the plant for the production of cement is flowed through.

21. Plant according to claim 16, characterized in that the CO ₂ - treatment device (26) comprises means (26 a) for dehumidification.

22. Plant according to claim 16, characterized in that the CO ₂ - treatment device (26) further comprises a degasser (26 c).

23. Plant according to claim 16, characterized in that the CO ₂ - treatment device (26) comprises means (26 e) for CO ₂ - laundry.

24. Plant according to claim 16, characterized in that the combustion and / or melt reactor (3) comprises means for supplying hydrogen.