Mechano-chemical activation of mineral materials
The described process and device for mechano-chemical activation address the issue of excessive heating by continuous circulation and high gas flow, ensuring efficient temperature control and effective activation of mineral materials below 250 °C, facilitating continuous operation.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- THYSSENKRUPP POLYSIUS GMBH
- Filing Date
- 2026-01-12
- Publication Date
- 2026-07-23
AI Technical Summary
The challenge in mechano-chemical activation of mineral materials is the excessive heating caused by high energy input, which can lead to undesirable properties due to the removal of water of crystallization, necessitating effective temperature control below 300 °C.
A process involving stepwise mechano-chemical activation with continuous circulation and high gas flow to dissipate heat, combined with a device design that allows complete filling and emptying without size-selective separation, ensuring homogeneous residence time and temperature control.
Achieves efficient temperature control below 250 °C, even with high energy inputs, maintaining effective activation while avoiding thermal degradation, and enabling continuous operation.
Smart Images
Figure EP2026050547_23072026_PF_FP_ABST
Abstract
Description
[0001] Mechano-chemical activation of mineral materials
[0002] The invention relates to a method for simplified temperature control of the mineral material during mechano-chemical activation.
[0003] During mechanochemical activation, a very high amount of energy is introduced into the material in a suitable unit, for example, a mill, especially a high-energy mill. This energy input goes far beyond the energy required for comminution, reaching a phase where a renewed increase in particle size can be observed. Simultaneously, however, the crystalline structure is also altered in such a way that the material is activated.
[0004] From DE 102023 106210 A1 a process for grinding and pozzolanic activation in a stirred ball mill is known.
[0005] From DE 102023 106217 A1 a process for grinding and pozzolanic activation in two separate stages of a stirred ball mill is known.
[0006] From DE 102023 106221 A1, the combination of mechano-chemical and thermal activation in at least one stirred ball mill is known.
[0007] Color optimization in the mechano-chemical activation of clays is known from DE 102023 106222 A1.
[0008] A cement additive made from recycled concrete is known from DE 102023 123525 A1.
[0009] From the subsequently published DE 102023 133379, a mechano-chemical activation of mineral materials is known.
[0010] From the subsequently published DE 102023 133383, a device and a method for temperature-optimized mechano-chemical activation are known. From the subsequently published DE 102023 133386, a method for the optimized operation of a mill for mechano-chemical activation is known.
[0011] From the subsequently published DE 102023 133387, a mechano-chemical activation with thermal coupling is known.
[0012] One challenge is that the large amount of energy input causes the mineral material to heat up. However, excessive heating is detrimental, as it can lead to the removal of water of crystallization from the mineral material, which in turn creates undesirable properties during setting. Therefore, the challenge lies in keeping the mineral material consistently well below 300 °C throughout the activation process. Cooling via the components of the activation device is limited by their surface area. Heat dissipation is also possible, particularly by increasing the gas flow. However, this also affects the residence time and thus the effective activation.
[0013] The object of the invention is to propose a process for mechano-chemical activation in which simplified temperature control of the mineral material to be activated takes place.
[0014] This problem is solved by the method with the features specified in claim 1 and by the device with the features specified in claim 10. Advantageous embodiments are described in the dependent claims, the following description, and the drawings.
[0015] The process according to the invention serves for the mechano-chemical activation of a mineral material. In particular, clays are mechano-chemically activated to enable their use as artificial pozzolans in cement substitutes. Other mineral materials, such as recycled concrete, can also be mechano-chemically activated. The process is carried out using an activation device. A stirred ball mill is particularly suitable as an activation device because it can efficiently transfer the high energy input required for mechano-chemical activation into the mineral material. However, since it is not used for comminution in this case, as the term "mill" might suggest, the term "activation device" is more appropriate, especially since not every mill is suitable as an activation device. The process according to the invention comprises the following steps:
[0016] a) Filling an activation circuit containing the activation device with the material to be activated,
[0017] b) Mechano-chemical, stepwise activation of the mineral material, wherein the material is circulated out of the activation device and completely back into the activation device,
[0018] c) Emptying the activation circuit.
[0019] The advantage of the process according to the invention is that the activation device can be operated with a significantly larger gas flow, making it much easier to dissipate excess heat. Furthermore, the cycle in step b) enables further heat removal from the mineral material, allowing for very efficient temperature control of the mineral material. The resulting disadvantage is that the continuous process becomes a batch process. This distinguishes the process according to the invention significantly from processes in which finished product is removed from the cycle and only incomplete material is returned, as complete recycling takes place. The effect is that the residence time in the process chamber remains much more homogeneous, since the number of passes for the material (neglecting the residence time distribution occurring per pass) remains the same for the entire material.In contrast, for example, with size-selective separation before recycling, the residence time distribution of the entire amount of material would become very broad.
[0020] Therefore, the filling in step a) and the emptying in step c) are complete, as a person skilled in the art understands this to mean in normal operation. Residues remain in the activation device, but these are negligible. Such residues do not preclude complete filling or emptying according to the invention. When grinding a material, three stages are observed depending on the energy input. In the first stage, the particle size decreases (more or less linearly) with increasing energy input (Rittinger zone). Put simply, the more one grinds, the finer the product becomes. However, there is a limit to this, a particle size that can hardly be reduced further. From this point on, a second stage begins, in which the particle size cannot be changed further with additional energy input (aggregation zone).For economic reasons, the transition from the first to the second stage is avoided during milling, as the increased effort yields no further reduction in size. If the energy input is increased even further, a third stage can be reached, in which an increase in particle size is again observed (agglomeration zone). This zone is therefore avoided even more during milling, as a better result in terms of particle size distribution can be achieved with less effort.
[0021] However, it has been shown that at high energy inputs, i.e., in the third stage, changes occur in the material itself. In the case of clays, for example, this leads to activation, i.e., reactivity, similar to thermal activation, which enables their use in a binder (and thus as a clinker substitute). This third stage is therefore mechanochemical activation and differs from the milling carried out in the first stage. Thus, milling according to the state of the art is not mechanochemical activation, and not every mill is suitable for mechanochemical activation according to the state of the art.
[0022] The process also differs from conventional comminution or mechanochemical activation processes in that size-selective separation typically occurs after a single pass, with one fraction being recycled back into the process and the other fraction being removed as product. For example, in comminution, the coarse fraction is usually recycled and the fine fraction removed as product, whereas in mechanochemical activation, the fine fraction can be recycled and the coarse fraction removed as product. This is not the case with the process according to the invention, since in step b) the material, preferably completely, is fed back into the activation device and in step c) is completely removed without size-selective separation taking place.
[0023] In a further embodiment of the invention, the mineral material passes through the activation device 2 to 20 times, preferably 5 to 12 times, in step b). The more frequently the mineral material passes through the activation device, the more effective the heat dissipation and the lower the maximum temperature increase within the mineral material. At the same time, the cycle consumes energy to circulate the material, so a lower number of cycles is advantageous for efficiency reasons. Therefore, experimental data have shown the aforementioned range to be optimal.
[0024] In a further embodiment of the invention, all steps are carried out in parallel, so that a portion of fresh material to be activated is always supplied, a portion of the activated material is recirculated, and the remaining portion is removed. This results in a distribution over the residence time in the activation device, but the process can again be operated continuously.
[0025] In a further embodiment of the invention, a cooling gas is supplied to the activation circuit downstream of the activation device in step b). This enables additional cooling in the activation circuit in a very efficient manner. Since the mineral material is already separated from the gas stream in a separation device within the activation circuit in order to return only the mineral material, the direct cooling by means of additional cooling gas does not constitute an additional process step.
[0026] In a further embodiment of the invention, the activation level of the mineral material in the activation cycle is determined during step b). This can be done by sampling, but preferably within the activation cycle, for example by X-ray diffraction. Step b) is terminated when a predetermined target activation level is reached. Since the mineral material regularly exits the activation device, analysis is significantly simpler than if the activation were performed in a single pass through the activation device, as in that case only the finished product could be analyzed, and thus control would only affect subsequent material.
[0027] In a further embodiment of the invention, the temperature of the mineral material is detected during step b). This allows the residence time and / or the supply of cooling gas to be controlled depending on the detected temperature.
[0028] The temperature of the mineral material is kept significantly below 300 °C, preferably below 250 °C, particularly preferably below 170 °C, and most preferably below 130 °C. The aim is a purely mechano-chemical activation that avoids all the disadvantages of thermal activation. Using the process according to the invention, temperatures between 100 and 120 °C can even be achieved with very high energy inputs of 500 to 700 kWh / t.
[0029] In a further embodiment of the invention, during step b) the activation device is supplied with a gas flow between 0.5 and 10 Nm 3 / kg (standard cubic meters per kilogram) of material. As already explained, the inventive method allows a comparatively high gas flow through the activation device, so that a large amount of heat can be dissipated directly by the comparatively large quantity of gas. A comparable gas flow in a conventional mechano-chemical activation would lead to an insufficient residence time and thus to inadequate activation.
[0030] In a further embodiment of the invention, during step b) the activation device is supplied with a gas flow, based on the free cross-sectional area through which the activation device flows, of between 1000 and 20,000 Nm². 3 / m 2h (standard cubic meters per square meter per hour). As already explained, the inventive method allows a comparatively high gas flow through the activation device, so that a large amount of heat can be dissipated directly due to the comparatively large quantity of gas. A comparable gas flow in a conventional mechano-chemical activation would lead to an insufficient residence time and thus to inadequate activation. In a further embodiment of the invention, during step b), the activation device is loaded with a gas mixture of 5 to 500 kg / m³ in the activation chamber. 3 operated.
[0031] In a further embodiment of the invention, at least 300 kWh / t of material are introduced via the activation device during step b). Such a high energy input has the disadvantage with simple conventional mechano-chemical activation that the heat generated during the process may overheat the material, potentially reaching temperatures of 300 °C or more, and thus negatively altering the material.
[0032] In a further aspect, the invention relates to a device for the mechanochemical activation of a mineral material. The device is preferably configured to carry out the process according to the invention. The device comprises a material feed, an activation device, a separation device, and a material outlet. The activation device has an activator inlet and an activator outlet for feeding and removing the mineral material. The separation device has a separation inlet and a separation outlet. The separation outlet is provided for the solid material. Additionally, the separation device has a gas outlet. The material feed is switchably connected to the activator inlet. This means that during step a), the material feed is connected to the activator inlet for filling, and is disconnected in steps b) and c). The material outlet is connected to the separation inlet.The separating outlet is switchably connected to either the activator inlet or the material outlet. In steps a) and b), the separating outlet is connected to the activator inlet, and in step c), the separating outlet is connected to the material outlet. This allows the device to be switched between filling (step a)), recirculation (step b)), and emptying (step c)).
[0033] This distinguishes the device from conventional devices in which size-selective separation takes place downstream of the activation device, with one fraction being returned to the activation device and another fraction being directed to the material outlet. The separation device serves solely to separate the solid from the gaseous components.
[0034] In a further embodiment of the invention, the device includes a raw material storage unit. The raw material storage unit is arranged upstream of the material feed. The device also includes a product storage unit. The product storage unit is arranged downstream of the material outlet. This serves to integrate the inventive method, which is characterized by discontinuous operation, into a continuous operation. Furthermore, the raw material storage unit enables rapid loading, and the product storage unit enables rapid unloading, thus reducing non-productive time.
[0035] In another embodiment of the invention, the separation device is a cyclone, a dust filter or a combination thereof.
[0036] In a further embodiment of the invention, an intermediate storage unit is arranged between the separation outlet and the activator inlet, as well as the material outlet. This allows the amount of material in the cycle to be increased. The residence time of the material in the intermediate storage unit enables further heat dissipation. This intermediate storage unit can also be designed as a heat exchanger.
[0037] In a further embodiment of this design, an additional intermediate storage unit is arranged between the separation outlet and the activator inlet, as well as the material outlet. The activation circuit can be switched between this intermediate storage unit and the additional intermediate storage unit. For example, in a first cycle, the activation circuit can run through the intermediate storage unit. After the end of the cycle, the activation circuit runs through the additional intermediate storage unit (step b)), while the intermediate storage unit is connected to the material outlet and emptied (step c)). This allows for parallelization and a reduction in dead time.
[0038] In a further development of this embodiment, the intermediate storage and the additional intermediate storage can be connected to the material supply. This allows, for example, the intermediate storage to be filled by the material supply while the intermediate storage is operating in the activation cycle and thus in step b), thereby further reducing the dead time.
[0039] The method according to the invention is explained in more detail below with reference to an embodiment shown in the drawings.
[0040] Fig. 1 first example
[0041] Fig. 2 second example
[0042] Fig. 3 third example
[0043] Fig. 4 fourth example
[0044] Fig. 5 fifth example
[0045] Figure 1 shows a first example. Mineral material to be activated is fed from the material feed 10 into the activation device 20 via the activator inlet 22, activated there, and then fed into the separation device 30 via the activator outlet 24 and the separation inlet 32. The separation device 30 can preferably be a two-stage unit consisting of a separation cyclone and a filter to achieve good separation performance and efficiency. The gas is discharged via the gas outlet 34, and the mineral material is returned to the activator inlet 22 via a switching element 50. Once the desired fill level of the activation device 20 is reached, the material feed 10 is stopped. Thus, the mineral material is circulated within the activation cycle consisting of the activation device 20 and the separation device 30.After sufficient activation, the switching element 50 is switched so that the activated mineral material is directed from the separation outlet 34 to the material outlet 40. This completes the three steps of the process, and the process begins again.
[0046] Fig. 2 shows a second example, which differs from the first example shown in Fig. 1 by an additional cooling gas supply 60 behind the activator outlet 24, thus enabling additional cooling.
[0047] The third example shown in Fig. 3 differs from the example shown in Fig. 2 in that a raw material storage 12 is arranged before the material feed 10 and a product storage 42 is arranged after the material outlet 40. This allows for easy integration into a larger continuous process.
[0048] Fig. 4 shows a fourth example, which differs from the third example shown in Fig. 3 in that an intermediate storage tank 70 is arranged after the separating outlet 34.
[0049] Figure 5 shows a fifth example, which differs primarily from the fourth example shown in Figure 4 in that a further intermediate storage unit 72 is arranged in parallel to the intermediate storage unit 70. Additionally, the material feed 10 can now be connected to the activator inlet 22 via the intermediate storage unit 70 or the further intermediate storage unit 72. For this purpose, four switching elements 50 are connected to form either the activation circuit consisting of the activation device 20, the separating device 30, and the intermediate storage unit 70, or the activation device 20, the separating device 30, and the further intermediate storage unit 72. The other intermediate storage unit 70, 72, which is not connected in the activation circuit, can then be emptied (step c)) and subsequently refilled (step a)) in parallel with the activation step b) taking place in the activation circuit. This avoids downtime.
[0050] Reference sign
[0051] 10 Material supply
[0052] 12 raw material storage
[0053] 20 Activation device
[0054] 22 Activator inlet
[0055] 24 Activator outlet
[0056] 30 separating device
[0057] 32 Separation inlet
[0058] 34 Separating outlet
[0059] 36 Gas outlet
[0060] 40 Material outlet
[0061] 42 product storage
[0062] 50 Switching element Cooling gas supply Intermediate storage further intermediate storage
Claims
Patent claims 1. A method for the mechano-chemical activation of a mineral material, wherein the method is carried out with an activation device (20), the method comprising the following steps: a) Filling an activation circuit containing the activation device (20) with the mineral material to be activated, b) Mechano-chemical activation of the mineral material, whereby the material in the circuit is taken out of the activation device (20) and completely returned to the activation device (20), c) Emptying the activation circuit.
2. Method according to claim 1, characterized in that the mineral material passes through the activation device (20) 2 to 20 times, preferably 5 to 12 times, in step b).
3. Method according to one of the preceding claims, characterized in that a cooling gas is supplied in the activation circuit downstream of the activation device (20) in step b).
4. Method according to one of the preceding claims, characterized in that the activation level of the material in the activation cycle is detected during step b) and step b) is terminated when a predetermined target activation level is reached.
5. Method according to one of the preceding claims, characterized in that during step b) the temperature of the material is detected and the residence time and / or the supply of cooling gas is controlled depending on the detected temperature.
6. Method according to one of the preceding claims, characterized in that during step b) the activation device (20) is supplied with a gas flow between 0.5 and 10 Nm 3 / kg (standard cubic meters per kilogram) of material is operated.
7. Method according to one of the preceding claims, characterized in that during step b) the activation device (20) is supplied with a gas flow, based on the free cross-sectional area through which the activation device flows, between 1000 and 20000 Nm 3 / m 2 h (standard cubic meters per square meter and hour) is operated.
8. Method according to one of the preceding claims, characterized in that during step b) the activation device (20) is loaded with a load of 5 to 500 kg / m² in the activation chamber. 3 is operated.
9. Method according to one of the preceding claims, characterized in that during step b) at least 300 kWh / t of material are introduced via the activation device (20).
10. Device for the mechano-chemical activation of a mineral material, wherein the device comprises a material feed (10), an activation device (20), a separation device (30) and a material outlet (40), wherein the activation device (20) comprises an activator inlet (22) and an activator outlet (24), wherein the separation device (30) comprises a separation inlet (32) and a separation outlet (34), wherein the material feed (10) is switchably connected to the activator inlet (22), wherein the activator outlet (24) is connected to the separation inlet (32), and wherein the separation outlet (34) is switchably connected to the activator inlet (22) or the activator outlet (24).
11. Device according to claim 10, characterized in that the device has a raw material storage (12), wherein the raw material storage (12) is arranged in front of the material supply (10), wherein the device has a product storage (42), wherein the product storage (42) is arranged behind the material outlet (40).
12. Device according to one of claims 10 to 11, characterized in that the separation device (30) is a cyclone, a dust filter or a combination thereof.
13. Device according to one of claims 10 to 11, characterized in that an intermediate storage unit (70) is arranged between the separation outlet and the activator inlet (22) and the material outlet (40).