WO2016041717A1 - Method for producing a material - Google Patents

Abstract

The invention relates to a method for producing a material from multiple pre-products. A first pre-product and at least one second pre-product are mixed so as to form the material. The invention is characterized in that the first pre-product, the second pre-product, and/or the material are analyzed in order to ascertain the reactivity and temporarily stored depending on the ascertained reactivity, and the material is produced with defined properties by drawing the first pre-product, the second pre-product, and/or the material from the temporary storage in a controlled manner and by mixing the drawn quantities.

Description

 Process for the production of a material

The invention relates to a method for producing a material from a plurality of precursors. In particular, the invention relates to a process for the production of cement from raw meal and at least one second precursor.

Cements are hydraulic binders made of the components clinker, gypsum in its function as setting regulator and composite materials. As composite materials latent-pozzolanic materials, such as pozzolans, fly ash or granulated blastfurnace as well as fabric-improving materials, in particular limestone, can be used.

In the production of cement, raw materials, in particular limestone, clay or marl and optionally correction materials, such as e.g. Quartz sand, ground to raw meal and then fired in a clinker kiln to clinker. In this case, the constituents of the raw materials form high-temperature phases, such as in particular C3S, C2S, C3A, or C4AF, as well as further subordinate crystalline and, only in exceptional cases, also amorphous phases (for example, in US Pat

White cement clinker). By rapid cooling in a clinker cooler adjacent to the clinker furnace, these phases are metastable under normal conditions.

After its preparation, the clinker is placed in a warehouse and then withdrawn from it again, by common or separate grinding with a sulfate carrier (as solidification regulator) and possibly further

Composite materials (especially limestone, fly ash, blastfurnace slag, pozzolans) are ground into cement.

Typical physical properties of cements are

Strength development, the setting behavior and the hydration heat.

National standards, such as EN 197, EN 196, ASTM C150, ASTM C595 and ASTM Cl 157, regulate the composition of cements and the minimum and maximum performance to be provided in certain categories of performance

Maximum requirements. These standards also determine the repetition frequencies of the physical examinations of the cements in the context of self-inspections in the cement works. For example, according to EN 196-1, two physical tests per week are required.

Due to the sampling, the staffing of the laboratories used for the evaluation and the duration of the investigations, in particular with regard to the strength values after one day, two days, seven days or 28 days, important parameters for the properties of produced cements only become apparent after a considerable delay the production and often only after a successful delivery of these cements known.

In order to defuse this problem, costly chemical and mineralogical test procedures are regularly used in cement plants in order to

Deviations of the properties of the produced cement from target properties promptly to recognize and correct if possible.

Within the chemical and mineralogical analyzes, free-lime analysis is of particular importance. Through this, the degree of implementation of the

Raw materials displayed in the clinker oven. A free lime content of less than two to three wt .-% indicates, if other target values, such as in particular the

Kalkstandard (KST), the silicate module (SM) and the aluminate module (AM), adhered to a clinker normal quality and thus sufficient formation of high-temperature phases. On the other hand, a free lime content of more than three% by weight proves incomplete conversion of the raw meal to the reactive

Mineral phases. Clinkers with increased free lime content are on the one hand because of increased pre-hydration by absorption of moisture from the air

problematic to store. With an increased free lime content, the reactivity of the clinker is also reduced by missing clinker phases. Basically, such a clinker is due to the volume stability of cement with high free lime content not or only partially suitable for cement production. It may, however, be provided Clinker, which exceeds a defined depending on the intended use of the cement to be produced limit for the free lime content, store it in a so-called bypass silo (low-fire silo) and then add small quantities of subsequently fired clinker lying below the limit free Lalkgehalt for further processing to cement. The free lime content is just one of several quality criteria for clinker.

For example, trace elements can positively or negatively affect the reactivity of clinker. Examples of such trace elements are phosphorus from animal meal, sulfur from, for example, petcoke and fluorine from raw materials or addition to the raw material. These elements affect both the

Clinker phase formation as well as the reactivity of the cement:

The stable phase C3P formed in the clinker furnace under increased phosphorus content is isotypic with the clinker mineral C2S. C3P and C2S appear submicroscopically grown within the belite crystals. Both are not individually detectable at conventional low trace element contents. Clinker, which includes a relatively high proportion of phosphorus, usually have an unfavorable

Strength development and are characterized by a lower C3S content

features.

Sulfur is introduced into the manufacturing process by sulfur-rich coal or petcoke or sulfur-rich raw materials. By coupled substitution, sulfur partially replaces Ca-Si compounds with Al-S compounds in the C2S phase. Due to the additional incorporation of sulfur and aluminum, therefore, the C2S content increases in the clinker. The increased formation of C2S consumes additional free lime and reduces the C3S content without the formation of free lime. Such clinker are often characterized by an increased grinding resistance. A clinker with high-sulfur C2S has a lower reactivity due to the lower C3S contents.

Fluorine improves C3S phase formation in the clinker process. For this reason, fluorine is occasionally added during clinker production to produce a clinker to produce improved C3S content. Even such a clinker usually has no free lime. However, in a wrong dosage of fluorine, the physical properties of strength and setting behavior are disturbed.

From DE 103 44 040 Al a method for producing a hydraulic binder and in particular of cement is known, in which the raw meal and / or the clinker is differentiated by chemical and mineralogical analyzes differentiated according to the chemical or mineralogical composition. From the interim storage, the intermediate products are deducted targeted to produce cement with defined properties.

A chemical / mineralogical composition determined in particular by a free-lime measurement only indirectly indicates an actual reactivity of the clinker. Rather, reactivity of the clinker can only be anticipated from the phase inventory. As a result, chemical and mineralogical investigations can only be used to a limited extent for the prognosis of the actual cement properties, since only material differences are determined which, however, do not necessarily correlate with reactivity differences. A disadvantage of the sole determination of the chemical / mineralogical composition of cement or its precursors is consequently the lack of a measured value for determining the actual reactivity of the cement or the precursors used to produce the cement. Based on this prior art, the present invention seeks to provide a method for the production of cement, which allows the most advantageous adjustability of properties of the cement.

This object is achieved by a method according to claim 1.

Advantageous embodiments of the method according to the invention are

Objects of the further claims and will become apparent from the following description of the invention.

A method for producing a material from a plurality of precursors, wherein a first precursor and at least one second precursor to the material are mixed, according to the invention is characterized in that the first precursor, the second precursor and / or the material itself is analyzed to determine the reactivity and stored differentiated according to the reactivity. This is followed by a (quantity-) controlled withdrawal of the first intermediate product, of the second intermediate product and / or of the material from the storage and a mixing of the quantities withdrawn in order to produce material with defined properties and in particular a defined reactivity. In this case, the defined properties in particular in a constant as possible, a desired value corresponding reactivity of the material in a continuous

Production lie. Also possible is the successive production of batches of the material with defined different reactivity.

In the method according to the invention, in particular the hydraulic

Reactivity, i. the nature of one or more of the precursor (s) and / or material to undergo a chemical reaction with water.

The material may in particular be cement, since the reactivity of the material, which can advantageously be set by the process according to the invention, represents a relevant quality feature, in particular in the case of cement. In addition, aligning the analysis of the precursors and / or the material with their reactivity allows for a relatively rapid assessment that may allow for deviations from one or more set points relatively quickly

(For example, within a maximum of 24 hours, possibly even within seven hours) to react to the manufacturing process

adjust accordingly. In particular, it can be avoided that the actual reactivity of an already prepared batch of cement and thus, if appropriate, a deviation from a desired reactivity only after a

Delivery of this batch of cement is known.

If the method according to the invention is used for the production of cement, the first precursor can be (cement) raw meal, which in the context of a thermal treatment in a clinker kiln, for example as Rotary kiln can be formed, is fired to clinker. The clinker and the second precursor may then be ground (together or separately) in a cement mill and mixed with or subsequently to cement. The second precursor may in particular be gypsum in its function as setting regulator or a composite material. As a composite material, a latent-pozzolanic material, such as a pozzolan, fly ash or granulated blastfurnace, as well as a Gefügeverbesserndes material, such as limestone, are used.

In addition to the production of cement, the inventive method can also be used, for example, in the production of other binders, such as geopolymers. Further possible fields of application are fermentation processes and microbiological processes.

A thermal treatment of at least the first precursor may also be advantageously provided in such an application of the method according to the invention.

In a preferred embodiment of the method according to the invention can also be provided that the first precursor, the second precursor and / or the material is analyzed calorimetrically, which represent a relatively simple, rapid and / or advantageous for other reasons procedure for determining the reactivity can. Calorimetric methods allow a direct determination of the reactivity of one or both of the precursors and / or the material. The calorimetric methods which can be used in accordance with the invention include the basically known solution calorimetry, the basically known semi-adiabatic calorimetry and the likewise basically known isothermal heat flow calorimetry (see Wadsö (1995): Evaluation of calorimetry for characterization of very early and early cement reactions, Report TVBM). 7094, Lund).

In these calorimetric method is a precursor or the material itself with water and optionally one or more other additives ("Quality Improver", "Performance Enhancer" and / or sulfate carrier) mixed. The addition of water triggers a hydration reaction, releasing heat. In the context of calorimetry, the heat energy released over time is then determined, which represents a measure of the intensity of the hydration reaction and thus a measure of the hydraulic reactivity of the sample in this application.

Preferably, it may be provided that the analysis of the reactivity based on at intervals in time a flow of the first precursor, the second

Pre-product and / or the material taken samples. As a result, a considerable effort, which would be associated with a continuous analysis, can be avoided. The time intervals can be predefined (for example at fixed time intervals of one to three hours). It is also possible that the time intervals are changed depending on external influences. For example, it can be provided that when changing the first feedstock and / or second feedstock to be fed to the process from one first batch to a second batch as promptly as possible on this change, an analysis of this feedstock or of the material is carried out on the basis of a sampled material sample in order to detect possible changes be recognized in the reactivity, which are due to the batch change, and to be able to take into account in the production of the material.

In the calorimetric analysis of individual substance samples may be provided in particular to determine the time of the maximum heat flow, the cumulative heat flow, the maximum and / or cumulative heat flow in a first (heat flow) peak and / or the time of a defined end of reaction to a useful for comparison purposes, deduce the reactivity reproducing result.

Furthermore, it can be provided that a sulfate carrier is added to the substance sample (s) for controlling (and in particular delaying) the solidification behavior. This can be done, for example, in amounts of> 0 wt .-% to about 5 wt .-%. A thus enabled delay of the solidification behavior and thereby the Release of heat energy can improve the readability of the achieved

Improve analysis result.

In a further preferred embodiment of the method according to the invention can be provided that the first precursor, the second precursor and / or the material are analyzed tempered. As a result, if necessary, an acceleration of the reaction and thus the analysis can be achieved. Especially in a calorimetric analysis, the speed of the hydration reaction can be influenced by the ambient temperature. A higher temperature accelerates the reaction, a lower ambient temperature delays this. Consequently, in particular, an analysis can take place at a surrounding temperature above ambient temperature. Depending on the type of calorimeter used, the ambient temperature can be set externally or internally (isothermal).

Furthermore, it can preferably be provided that the first precursor and / or the second precursor are ground for analysis until a defined grinding fineness is achieved in, for example, a laboratory mill or an automated mill. This can influence the later to be determined

calorimetric result can be minimized by different sized available for hydration surfaces milled powder.

The fineness of grinding may preferably be defined by a defined grinding time and / or by a specifically defined operation of a mill used for grinding (for example the total number of revolutions of the mill intended for grinding a sample), given the same grinding time (and otherwise

constant operating parameters of the mill) sufficiently similar

Fineness levels can be expected.

In a particularly advantageous embodiment of the method according to the invention can also be provided that the first precursor, the second precursor and / or the material (also) in a conventional manner is chemically and / or mineralogically analyzed / are. In particular, an analysis result derived from the chemical and / or mineralogical analysis can be used be compared or otherwise correlated with an analysis result concerning the reactivity. By correlating results from different analyzes of the first precursor, the second precursor and / or the material, a classification of the ultimately produced material can be further improved.

Furthermore, it can be provided that one of the chemical and / or

mineralogical analysis is used to produce a defined first precursor and / or second precursor of raw materials. As a result, the process of producing the material can already be based on the raw materials used with regard to a defined reactivity of the first precursor, the second precursor and / or the

Material are influenced.

In one embodiment of the method according to the invention, provision can be made for the first precursor, the second precursor and / or the material to be temporarily stored during the analysis (n) and after the conclusion of the analysis (n) in

Dependence of the analysis result (s) on different bearings (e.g.

separate silos, multi-chamber silos, multi-cell silos or well storage) are distributed. The distribution to the various warehouses may be made with the aim of combining subsets of the first precursor, of the second precursor and / or of the material for which analysis results obtained in successive analyzes have been combined, or subsets of the first precursor, the second precursor and / or or of the material for which different analysis results were determined in successive analyzes, in order to obtain a defined average value for the reactivity of the first precursor, of the second precursor and / or of the individual bearings (if appropriate in each case)

Adjust material.

Furthermore, it can be provided in the inventive method that subsets of the first precursor, the second precursor and / or the

Material, each assigned to one of successive analyzes be stored in various warehouses, with a deduction from the various camps and a mixing of subtracted subsets depending on the defined characteristics of the first precursor, the second precursor and / or the cement takes place. In this case, therefore, there is no sorting of the individual, successively performed analyzes associated subsets in the camps, but these are classified only in terms of the analysis result to specifically in the subsequent deduction of precursors with the aim to produce the material with defined properties the

classified subsets in the different stores. In a further preferred embodiment of the method according to the invention, provision may also be made for grinding the first precursor and / or the second precursor to be adjusted as a function of the analysis result (s). In particular, it can be provided that the (for example electrical) energy used for the grinding, depending on the reactivity of the straight

processed precursor or material depending on the /

 Analysis result (sen) is controlled. In particular, it may be provided to finely grind a precursor having a relatively high reactivity than one having a relatively low reactivity.

In a further preferred embodiment of the method according to the invention can also be provided that the first precursor and / or the second

 Precursor be preselected in terms of reactivity. This can,

in particular for clinker in the implementation of the method according to the invention for the production of cement, for example by a fractionation after

Grain size and / or density. The invention will be described below with reference to the drawings

Embodiments explained in more detail. In the drawings shows:

1 shows schematically the implementation of a method according to the invention in a first embodiment and 2 shows schematically the implementation of a method according to the invention in a second embodiment;

1 shows in a block diagram individual steps in the implementation of a first embodiment of a method according to the invention for the production of cement having a defined hydraulic reactivity in and the devices used therein.

In the context of the method, raw materials 1 are first ground in a raw mill 2 and the raw meal 3 thus produced is fed to a clinker kiln 4, in which it is burned into clinker 5 while supplying thermal energy. The clinker 5 is then, after cooling in a clinker cooler 6, fed to a buffer bearing 7.

At defined times, a small part of the clinker 5 from the

Clinker cooler 6 (or behind the clinker cooler 6) taken as a clinker sample 8, milled in a (manually or automatically operated) fine mill 9 to a defined fineness and transferred to a calorimeter 10 to a means

calorimetric analysis to determine an actual value 12 for the reactivity of the clinker 5 of the clinker sample 8.

It can be provided that the milled clinker sample 8 by itself or together with a sulfate carrier, which serves to regulate the solidification behavior, and / or one or more other additives 11 in a container with a defined amount of water and homogenize. The addition of the sulfate carrier can be dry or in solution or in suspension. The

Quantity ratio (mass or volume ratio) of the water and the other constituents of the paste thus formed may be in particular between 0.25 and 1. In the calorimeter 10 can then be released from the sample

Heat flow determined and compared with a reference value. Of the

Reference value may come from another measurement of the same plant or another plant (in particular the same cement plant). The preparation, execution and evaluation of the analysis can be at least partially manual or fully automated. To accelerate the analysis, the ambient temperature in the calorimeter 10 compared to the

Ambient temperature can be increased. The result of the calorimetric analysis is a heat flow, i. the release of heat energy over time. From this, different results can be derived. These are u.a. the time of the maximum heat flow, the cumulative total heat flow, the cumulative heat flow in the so-called first peak (characterized by a strong increase and then a sharp decrease in the heat flow immediately after the start of the hydration reaction) and the time of completion of the hydration reaction or the thereof in Compound with a beginning-derived duration of the hydration reaction.

The actual value 12 determined by the calorimetric analysis becomes that in the

Buffer bearing 7 stored intermediate charge of the clinker 5. Then, the clinker 5 is transferred from the buffer bearing 7 in one or more clinker bearing 13. In this case, the transfer of the clinker 5 or subsets thereof from the

Buffer bearing 7 in the clinker or the clinker 13 carried out with the aim of the clinker 5 with a previously prepared batch of clinker 5, for the same or similar actual value 12 was determined in a related analysis for the reactivity merge. In this way, a sorting of clinker 5 from several batches and with different reactivities in different clinker bearings 13 can be achieved. It is also possible, the clinker 5 with one or more previously prepared batches of clinker 5, each of which was assigned its own actual value 12 for the reactivity by a calorimetric analysis, specifically to mix in one, several and possibly all

Klinkerlagern 13 clinker 5 with a defined target value for the reactivity corresponding (average) actual value form. In this case, the target value for the individual clinker bearing 13 may be identical or (partially) different.

For the production of cement 16 with defined reactivity clinker 5 is then controlled from one or more of the clinker bearing 13, ie in defined Subsets, subtracted and ground together with a second precursor 14 in a cement mill 15 and mixed it.

In an alternative embodiment of the method according to FIG. 1 it can be provided that the batches of the clinker 5 are stored at separate locations of the individual clinker bearings 13 or in separate clinker bearings 13, without a specific mixing of different batches for setting a defined (middle ) Value for the reactivity in the individual clinker bearings 13 is provided. By a controlled withdrawal of subsets of the various batches of clinker 5 as a function of the actual values assigned to them 12 for the reactivity and by mixing these subsets before, in or behind the cement mill 15 can then also cement 16 are produced with defined reactivity.

In a further development of one of the methods according to FIG. 1, it can also be provided that the (for example electrical) energy supplied to the cement mill 15 for grinding the cement 16 is dependent on the reactivity of the cement

Cement mill 15 milled clinker 5 is controlled. In particular, it may be provided that clinker 5 having relatively high reactivity is less finely ground than that having relatively low reactivity. This makes it possible to optimally control the energy consumption of the cement mill 15 and thus of the entire method for producing the cement 16, taking into account a desired reactivity of the cement 16, and in particular to keep it as low as possible. This optional development of a method according to the invention is applicable to the two embodiments of the method according to the invention described above with reference to FIG. 1, in which the clinker 5 is analyzed calorimetrically.

In alternative, shown in the Fig. 2 embodiments of the

According to the invention, instead of the clinker 5, cement 16a, which has already been formed from the clinker 5 and at least the second precursor 14, is calorimetrically analyzed on the basis of cement samples 18 in a calorimeter 10 and batchwise, each with an associated actual Intermediate value 12 for the reactivity in several cement storage 17 to then produce by a controlled withdrawal of subsets of the batches of cement 16a from these cement stocks 17 a cement 16 with defined reactivity. The possibilities of intermediate storage of the batches of the cement 16a in the cement bearings 17 correspond to those already with reference to FIG. 1

In this embodiment of the method according to the invention, it is also possible to temporarily store the batches of the cement 16a in a buffer storage 7 during the calorimetric analysis.

The calorimetric analyzes of the clinker 5 and of the cement 16a, which are alternatively described with reference to FIGS. 1 and 2, are also possible combined in a method according to the invention, so that both the clinker 5 and the cement 16a are analyzed accordingly.

Furthermore, the calorimetric analysis of clinker 5 and / or cement 16a may optionally be combined with additional chemical and / or mineralogical analysis of clinker samples 8 and / or cement samples 18 carried out in corresponding analysis device (s) 19 become. This can serve to improve the results of the respective calorimetric analysis (s) by correlation with the results of the chemical and / or mineralogical analysis (s). Additionally or alternatively, the results of the chemical and / or mineralogical analysis (s) can also be used to influence the raw meal 3 by a corresponding adjustment of the raw materials 1 fed to the raw mill 2, for example little or no

To achieve deviations from target values for the raw meal 3. The nominal values may relate in particular to the lime standard, the silicate module and / or the aluminate module.

Claims

Claims: 1. A method for producing a material from a plurality of precursors, wherein a first precursor and at least one second precursor are mixed to the material, characterized in that the first precursor, the second precursor and / or the material analyzed to determine the reactivity, depending is interposed by the determined reactivity and the material with defined properties by a controlled withdrawal of the first precursor, the second precursor and / or the material from the intermediate storage and by mixing the deducted amounts is generated. 2. The method according to claim 1, characterized in that the first  Precursor, the second precursor and / or the material for determining the reactivity is calorimetrically analyzed. 3. The method according to claim 1 or 2, characterized in that the  Analysis of the reactivity on the basis of at intervals a stream of the first precursor, the second precursor and / or the material taken substance samples takes place. 4. The method according to claim 2 and 3, characterized in that in the  Analysis of a substance sample the time of maximum heat flow, the cumulative total heat flow, the maximum and / or cumulative heat flow in a first peak and / or the time of a reaction end is determined. 5. The method according to claim 3 or 4, characterized in that a  Substance is added to a sulfate carrier to control the solidification behavior. 6. The method according to any one of the preceding claims, characterized characterized in that the first precursor, the second precursor and / or the material are tempered analyzed. 7. The method according to any one of the preceding claims, characterized  characterized in that the first precursor and / or the second precursor for the analysis is ground to reach a defined grinding fineness. 8. The method according to claim 7, characterized in that the fineness of grinding is defined by a grinding time and / or by a specific operation of a mill used for grinding. 9. The method according to any one of the preceding claims, characterized  in that the first precursor, the second precursor and / or the material is analyzed chemically and / or mineralogically. 10. The method according to claim 9, characterized in that one of the  chemical analysis and / or mineralogical analysis is related to a reactivity related analysis result. 11. The method according to claim 9 or 10, characterized in that a derived from the chemical and / or mineralogical analysis analysis result for producing a defined first and / or second precursor of raw materials is used. 12. The method according to any one of the preceding claims, characterized  in that the first precursor, the second precursor and / or the material are temporarily stored during the analysis (n) and after the  Conclusion of the analysis (s) depending on the analysis result (s) is distributed to different camps. 13. The method according to claim 12, characterized in that the distribution of the first precursor, the second precursor and / or the material takes place on the various bearings with the aim of subsets of the first Pre-product, the second precursor and / or the material for which similar analysis results were determined in successive analyzes, merge or subsets of the first precursor, the second Pre-product and / or the material, for in successive  Analyzes different analysis results were determined to mix defined. 14. The method according to any one of the preceding claims, characterized  characterized in that subsets of the first precursor, the second  Pre-product and / or the material, which are each assigned to one of successive analyzes are stored in different camps, with a deduction from the various camps and mixing the deducted subsets depending on the defined characteristics of the first precursor, the second precursor and / or of the material. 15. The method according to any one of the preceding claims, characterized  characterized in that a grinding of the first precursor and / or the second precursor depending on the / the analysis result (sen) is adjusted. 16. The method according to any one of the preceding claims for the production of cement (16), characterized in that raw meal (1) as a first precursor in a clinker furnace (4) burned to clinker (5) and the clinker (5) and at least the second precursor (14) ground and mixed into cement (16a, 16).