LU103050B1 - Device for color optimization of activated tones - Google Patents

Abstract

The present invention relates to a device for the thermal activation of mineral materials, wherein the device comprises a calciner 40, a reduction device and a material cooler 70, wherein the calciner 40 and the reduction device are connected to one another for the transfer of calcined material, wherein the reduction device is connected to the material cooler 70 for the transfer of color-optimized material, characterized in that the reduction device is a fluidized bed reactor 50.

Description

thyssenkrupp Industrial Solutions AG 222226P00LU thyssenkrupp AG 14.12.2022 LU103050 1/18

Device for color optimization of activated tones

The invention relates to a device and a method for color optimization of activated clays.

The cement industry is a major emitter of carbon dioxide. One important point is the carbon dioxide released from limestone. In order to reduce carbon dioxide emissions, clinker substitutes are used, which preferably do not release carbon dioxide during activation. An important product is therefore activated clay.

The problem with clays, however, is that they often contain iron, for example, which is usually (at least partially) oxidized when activated under oxidizing conditions and gives the clay a strong red color as Fe"!. However, this is usually not accepted by the customer. In order to achieve a cement or clinker-like

To obtain a color that is acceptable to the customer, the activated clay is often treated under reducing conditions to reduce the oxidized iron again and thus give the activated clay a cement-like color.

DE 10 2016 104 738 A1 discloses a method and a device for thermal

Treatment of granular solids.

DE 102008 020600B4 describes a method and a system for

Heat treatment of fine-grained mineral solids.

A clinker substitute is known from DE 10 2011 014 498 A1.

A process for producing synthetic pozzolans is known from US 2012 / 160 135 A1.

WO 2021 / 224 055 A1 describes a colour optimization in the production of activated

Tone known.

However, there are two problems with color optimization. Firstly, a longer residence time of the already activated clays at high temperatures is bad, as this can lead to deactivation. This effect also depends on the particle size. With smaller particles, deactivation occurs more quickly. On the other hand, the reduction and thus the color optimization also depends on the particle size. The smaller the particles, the faster the decolorization, the larger the

The smaller the particles are, the longer it takes for the reduction. This means that an optimum must be found where the smallest particles are not deactivated and the largest particles are still decoloured. This optimum is achieved by choosing the narrowest possible particle size distribution, i.e. the

difference between the smallest particle and the largest particle is kept small.

This in turn is complex and energy-intensive, which in turn creates a new potential

carbon dioxide source, since renewable energy is only available to a limited extent for the processes required to produce a narrow grain size band.

The object of the invention is to provide a device and a method in which color optimization is also possible with a significantly broader particle size distribution.

This object is achieved by a device having the features specified in claim 1

Features. Advantageous further developments emerge from the subclaims, the following description and the drawings.

The device according to the invention serves for the thermal activation of mineral

materials, especially clays. The device comprises a calciner, a

reduction device and a material cooler. The calciner and the

Reduction device are connected to each other for the transfer of calcined material. The reduction device is connected to the material cooler for the transfer of color-optimized material. According to the invention, the reduction device is a

Fluidized bed reactor. This fluidized bed reactor has proven to be

Reduction device can prove extremely advantageous when a wide

particle size distribution (a broad grain range). On the one hand, extremely small

Particles are carried away very quickly with the fluidizing gas. On the other hand, the

Particle size also influences the transport speed in the

Fluidized bed reactor. The fluidized bed reactor enables color optimization thyssenkrupp Industrial Solutions AG 222226P00LU thyssenkrupp AG 14.12.2022 LU103050 3/18 in a simple way, since small particles, which are quickly color-optimized, are also discharged more quickly, whereas large particles, which require a longer treatment time, also have a longer residence time. This makes it possible to significantly

To save energy during comminution and fractionation of the particle size distribution.

In addition, a preheater can be arranged in front of the calciner, for example.

This allows the heat carried out of the calciner with the gas stream to be transferred to the material to be thermally activated.

In a further embodiment of the invention, the reduction device has a first material outlet and a second material outlet. In particular, the first material outlet and the second material outlet are arranged at different heights. For example, the first material outlet can be located on the underside of the

fluidized bed. This creates a

Coarse fraction of the color-optimized material is discharged. For example, the second

Material discharge should be arranged at the top of the fluidized bed. This means that a fine fraction of the color-optimized material is discharged through the second material outlet. In this way, in addition to the targeted color optimization, a separation according to size can also be carried out. The two fractions can then be processed separately or together.

In a further embodiment of the invention, the first material outlet and the second material outlet are each connected to the material cooler for transferring color-optimized material. In this case, the first material flow from the first material outlet and the second material flow from the second

Material outlet preferably at different points in the material cooler. This also allows for customized cooling, especially if the first material flow and the second material flow have different

particle size distribution.

In a further embodiment of the invention, the device has a

Deagglomeration device. The deagglomeration device is connected to the thyssenkrupp Industrial Solutions AG 222226P00LU thyssenkrupp AG 14.12.2022 LU103050 4/18

Calciner for transferring deagglomerated material. For example and preferably, the deagglomeration device is connected to the calciner for transferring deagglomerated material via a riser dryer. More preferably, the deagglomeration device is a hammer mill,

Vertical roller mill, impact mill, pendulum roller mill or agitator mill. The deagglomeration device is particularly preferably a hammer mill.

In a further embodiment of the invention, the device has a

Color detection device. The color detection device is designed to detect the

colour of the product. The colour detection device is arranged in or along the

product flow after the material cooler. By detecting the color, a reduction and thus a color optimization can be carried out to the necessary extent, but also limited to the necessary extent, whereby

reducing agent can be saved.

In a further embodiment of the invention, the device has a

Reducing agent supply. The reducing agent supply is connected to the

Reduction device for supplying reducing agent. As

Various gaseous, liquid or solid substances can be used as reducing agents. Typical gaseous reducing agents are methane, hydrogen or

Carbon monoxide. Examples of liquid reducing agents are liquid hydrocarbons.

An important example of a solid reducing agent is coal, especially

Coal dust or biomass. If the reducing agent is a fuel, combustion usually takes place in a deficiency of oxygen, so that a reducing atmosphere is created, for example and in particular carbon monoxide.

The device further comprises a control device. The control device is designed to

Control of the amount of reducing agent supplied by the reducing agent supply

reducing agent. For this purpose, the control device is designed in a corresponding manner for the transmission of control commands or by directly controlling, for example,

Servomotors are connected to the reducing agent supply. The control device is also designed to regulate the amount of reducing agent depending on the

The color detection device detects the color. For this purpose, the

Control device in particular has a data connection to the color detection device thyssenkrupp Industrial Solutions AG 222226P00LU thyssenkrupp AG 14.12.2022 LU103050 5/18 in order to obtain the color of the product detected by the color detection device.

The control device also has, for example, a colour threshold value.

If the color threshold is exceeded, for example if the sample is too reddish, the

The supply of reducing agent is increased to achieve a stronger decolorization. If the

If the color threshold is exceeded, the supply of reducing agent is reduced in order to avoid unnecessary consumption. For example, the

The color threshold can also be specified in the form of a range. Alternatively, the

Control device may have an allocation table in which the amount of

Reducing agent is specified for different color value ranges. Overall, the minimum amount of reducing agent required to achieve sufficient decolorization and thus market acceptance can be used.

It can be provided that both a reducing agent and a fuel are provided. For example, biomass is used as the fuel, whereby an approximately stoichiometric combustion takes place. This means that after the

After combustion, the residual oxygen content is usually low. Hydrogen is then added as a reducing agent. This has a small

Molecule has excellent diffusion properties, but would be more expensive as a fuel than biomass.

In a further embodiment of the invention, a gas-sealing material lock is arranged between the reduction device and the material cooler.

In a further embodiment of the invention, between the calciner and the

A gas-sealing material lock is arranged in the reduction device.

In a further embodiment of the invention, the device has a

Gas supply to the reduction device. The gas supply is

Volume flow and gas speed adjustable. The device has a

control device. The device further comprises a

Particle size specification device. The particle size specification device can be designed, for example, in that the particle size distribution is determined by a particle size measuring device and passed on to the particle size specification device thyssenkrupp Industrial Solutions AG 222226P00LU thyssenkrupp AG 14.12.2022 LU103050 6/18. Alternatively, the particle size specification device can be a

Input device in the traditional sense, where an operator

Particle size distribution either directly or via a selection of predefined

distributions. The particle size specification device can also be used as an interface to a central database system, which, for example, stores data from the

laboratory analysis or supplied products and thus the

Particle size distribution can be transferred, for example, based on the material supplied. The control device is designed to control the gas supply in such a way that the control device controls the volume flow and gas speed depending on the particle size of the material specified by the particle size setting device. The particle size distribution has an influence on the

Loosening speed (loosening point), i.e. the point at which the gas flow just begins to fluidize the solid. The device with a

Fluidization speed of the gas flow, which corresponds to 5 to 15 times the loosening speed, it is helpful to record a size, such as the particle size, so that a changed

The loosening speed of the fluidized bed can be easily recognized.

In a further embodiment of the invention, the

Particle size setting device has a particle size measuring device on or connected to it. For example, the particle size measuring device can be

Light scattering in or before the calciner can determine the particle size and particle size distribution. Alternatively, samples can be taken before or after the reduction device and fed to the particle size measuring device.

In a further alternative embodiment of the invention, the

Particle size specification device an input device via which the

Information can be entered by the plant personnel. Another alternative is the

Particle size specification device an interface through which information on the

Particle size distribution can be taken from an analytical laboratory system, for example.

thyssenkrupp Industrial Solutions AG 222226P00LU thyssenkrupp AG 14.12.2022 LU103050 7/18

In a further embodiment of the invention, the reduction device

Guide elements to guide the material flow. For example, these can be arranged in the lower part of the fluidized bed to extend the path of the largest particles and thereby reduce the residence time of these largest particles in the

To extend the reduction device.

In a further embodiment of the invention, the reduction device

Guide elements for guiding the gas flow. This serves in particular to keep the gas flow that has already emerged from the fluidized bed and the finest particles carried away with the gas flow in the reduction device for a minimum time and thus ensure reliable reduction and color optimization. This can be achieved, for example, by means of a labyrinth guide.

In a further embodiment of the invention, the reduction device has a

Gas outlet. The gas outlet is connected to a filter device. In the

The finest fraction of the activated and color-optimized material is separated in a filter device. This fraction is usually also the most active fraction. This can either be recombined with the other activated and color-optimized material. This finest fraction can also be processed separately, for example for particularly demanding applications.

In a further embodiment of the invention, the fluid flow behind the

A gas sensor is arranged at the gas outlet, which is designed to detect the

Concentration of one or more substances selected from the list comprising

Carbon monoxide, carbon dioxide, hydrogen, methane. These substances can either be used directly as reducing agents or are formed in the

reducing device. Therefore, the concentration detected at the outlet can be used as an indicator for an excess of reducing agent.

Carbon dioxide concentration is preferably combined with the

Carbon monoxide concentration is recorded, in particular to determine the ratio.

In a further embodiment of the invention, the device has a bypass between the calciner and the material cooler to bypass the reduction device.

thyssenkrupp Industrial Solutions AG 222226P00LU thyssenkrupp AG 14.12.2022 LU103050 8/18

This bypass is preferably used exclusively for starting and shutting down the

The activated material can be fed to the

reduction device directly into the material cooler.

In a further embodiment of the invention, the reduction device comprises a

Dip tube for feeding activated material. The dip tube preferably extends into the fluidized bed. This allows the activated material to be fed directly into the

The fluidized bed is introduced into the interior of the fluidized bed, so that the residence time is slightly extended, especially for the finest particles, and thus also for the finest particles a

Color optimization is guaranteed.

In a further aspect, the invention relates to a method for color optimization of an activated material using a device according to the invention. For the color optimization in the reduction device, a broad particle size distribution is selected, wherein the broad particle size distribution is characterized in that at least 10% by weight of the particles are smaller than 50 µm and at least 10% by weight of the particles are larger than 250 µm. Such a broad grain range (particle size distribution) is unusual and cannot be processed by the existing systems. In previous

Systems would deactivate the very small particles before the very large

The use of a fluidized bed reactor allows the use of this broad particle size distribution. This allows

By crushing or deagglomerating a lot of energy can be saved and/or a size separation step can be omitted.

In a further embodiment of the invention, the particle size distribution is selected so that all particles are smaller than 2 mm.

In a further embodiment of the invention, the particle size distribution is selected such that at least 5 wt.% of the particles are larger than 900 µm.

In a further embodiment of the invention, the particle size distribution is selected such that at least 5 wt.% of the particles are smaller than 20 µm.

thyssenkrupp Industrial Solutions AG 222226P00LU thyssenkrupp AG 14.12.2022 LU103050 9/18

In a further embodiment of the invention, at least 10 wt.% of the

Material flow from the reduction device via the gas flow through the

Gas outlet and separated in the filter device. This means that the finest fraction with a particularly small particle size of at least

% by weight. This fraction would most likely lose activity in the reduction device in a conventional process. In a fluidized bed reactor according to the invention, however, this fraction is

Fluidization gas is discharged very quickly, so that the color is optimized but not deactivated. This effect of the fluidized bed also results in the separation of the finest fraction.

In a further embodiment of the invention, the fluidization speed in the reduction device is selected so that the fluidization speed is 5 times to 15 times the loosening speed. The

The loosening speed or the loosening point is the

Flow velocity of the fluidizing gas at which fluidization of the

material, i.e. the theoretically lowest speed for the formation of the

Fluidized bed. This higher fluidization speed significantly supports the different residence time of the particles depending on their size, which means that the finest particles in particular, which are color-optimized very quickly and which would also lose activity again quickly, are very quickly carried away with the gas, thus only having a comparatively short residence time.

In a further embodiment of the invention, the fluidization gas supplied to the reduction device has a temperature of at least 700°C.

For example and in particular, an exhaust gas with an oxygen content of less than 15 vol.% can be used as the gas. The lower the oxygen content and the higher the temperature of the exhaust gas used, the less it needs to be heated further, which means that less fuel (and thus reducing agent) is required.

Preferably, however, the exhaust gas has an oxygen content of more than 0.5 vol.% to enable combustion and thus energy release. The process of color optimization, for example the reduction of trivalent iron, is endothermic,

thyssenkrupp Industrial Solutions AG 222226P00LU thyssenkrupp AG 14.12.2022 LU103050 10/18 so that the temperature would drop. In addition, the

reduction device heat. In particular, to achieve these two effects in the

reduction device and no cooling in the

reduction device, the gas preferably has a corresponding

residual oxygen content.

In a further embodiment of the invention, a reducing agent is introduced directly into the

reduction device. For example, coal, especially

Coal dust or biomass can be fed into the reduction device via a direct feed. This creates the reducing atmosphere directly in the

On the one hand, heat is generated in a fluidized bed, and on the other hand, heat is also made available directly through combustion, thus maintaining a constant temperature. Alternatively, hydrogen or methane, for example, can be introduced directly into the reduction device.

In a further embodiment of the invention, a reducing agent is used with the

Gas stream is introduced into the reduction device. Gaseous reducing agents such as hydrogen and methane are particularly suitable for this purpose, but also liquid

Reducing agents, such as liquid hydrocarbons.

In a further embodiment of the invention, a reducing agent is used with the

Material flow is introduced into the reduction device. This is preferred for solid

Reducing agents such as coal, especially coal dust. Here, a

Mixing of reducing agent with activated material before introduction into the reduction device, so that the reducing atmosphere is safe for all particles of

is given in the same way from the beginning.

In a further embodiment of the invention, in the case of iron-containing minerals, in particular clays, with an Fe,O; content of more than 20% by weight, a reduction of at least 80% of the iron is carried out.

In a further embodiment of the invention, for iron-containing minerals, in particular clays, with an Fe,O3 content between 10 wt.% and 20 wt.%, a thyssenkrupp Industrial Solutions AG 222226P00LU thyssenkrupp AG 14.12.2022 LU103050 11/18

Reduction of 50 to 80% of the iron is carried out. The proportion of iron to be reduced is increased from 50% at 10% by weight to 80% at 20% by weight. This can be done linearly or in stages, for example.

In a further embodiment of the invention, in the case of iron-containing minerals, in particular clays with an Fe,O3 content of less than 10 wt.%, only a reduction of up to 50% of the iron is carried out.

The device according to the invention is explained in more detail below using an embodiment shown in the drawings.

Fig. 1 first embodiment

Fig. 2 second embodiment

Fig. 3 third embodiment

In Fig. 1 is shown a first embodiment of a device according to the invention for

Production of color-optimized activated materials, especially clays, is presented.

The material first goes into a hammer mill where it is deagglomerated.

This results in a comparatively broad particle size distribution. The deagglomerated material is then lifted and dried in a riser dryer. The material then passes through a preheater into a calciner and is thermally activated there. During activation under oxidizing conditions, however, oxidation of iron to Fe! also occurs, so that the

Material turns reddish. The oxidation does not necessarily occur quantitatively, i.e. not all iron atoms on the fur are necessarily oxidized. To reverse this, the thermally activated material is introduced into a fluidized bed reactor 50. To fluidize the fluidized bed, the fluidized bed reactor 50 is

Fluidizing gas is supplied from a fluidizing gas supply 100 via a combustion chamber 90, wherein the combustion chamber 90 is supplied via a reducing agent supply 110 with, for example, coal dust in excess of the fluidizing gas supplied

Oxygen is supplied, so that carbon monoxide is produced in the combustion chamber.

For example, a low-oxygen exhaust gas from a process, for example from the preheater 30, can be used as fluidization gas. The fluidized bed reactor is operated, for example, in such a way that the fluidization speed corresponds to 5-15 times the loosening speed. As a result, the finest particles, which also reduce the fastest and are thus color-optimized, are quickly discharged through the gas outlet and reach the filter device 60, in which they are then separated. The fluidized bed reactor also has two outlets for the color-optimized material. One of these outlets is located on the underside and is used to remove the largest particles, the second outlet is in the upper area of the

fluidized bed and serves to remove the middle particle fraction. All three

Fractions of the color-optimized material are fed to a material cooler 70.

After cooling, the color is determined in the color detection device 80.

As a result, the addition of reducing agent via the reducing agent supply 110 can be regulated in such a way that as little reducing agent as possible is added, but sufficient decolorization is still achieved.

Fig. 2 shows a second embodiment, which differs from the first embodiment shown in Fig. 1 in that the reducing agent is mixed with the activated material before the fluidized bed reactor 50 and is introduced together with it into the fluidized bed reactor 50. For example,

Coal dust is fed via the reducing agent feed 110. This also reduces the

Heat supply directly in the fluidized bed of the fluidized bed reactor 50 by

combustion. This embodiment is preferred if the gas produced by the

Fluidization gas supply 100 supplied fluidization gas is already close to (just below) the treatment temperature.

In Fig. 3 a third embodiment is shown, which differs from the first embodiment shown in Fig. 1 in that, on the one hand, behind the

A gas sensor 120 is arranged at the gas outlet, so that in addition to the color detection in the

Color detection device 80 also the reducing substances still present in the exhaust gas

Components can be used as control variables. For example, the

Gas sensor 120 can be a carbon monoxide sensor. In addition, the finest

Material fraction is separated from the filter device 60. This often has the highest reactivity and can therefore be used for particularly high-quality products.

thyssenkrupp Industrial Solutions AG 222226P00LU thyssenkrupp AG 14.12.2022 LU103050 13/18

Reference symbols

Hammer mill

Riser dryer s 30 preheater

Calciner

Fluidized bed reactor 60 Filter device 70 Material cooler 10 80 Color detection device 90 Combustion chamber 100 Fluidizing gas supply 110 Reducing agent supply 120 Gas sensor

Claims (26)

thyssenkrupp Industrial Solutions AG 222226P00LU thyssenkrupp AG 14.12.2022 LU103050 14/18 Patent claims 1. Device for thermal activation of mineral materials, wherein the device comprises a calciner (40), a reduction device and a material cooler (70), wherein the calciner (40) and the reduction device are connected to one another for transferring calcined material, wherein the reduction device is connected to the material cooler (70) for transferring color-optimized material, characterized in that the reduction device is a fluidized bed reactor (50) is. 2. Device according to claim 1, characterized in that the reduction device has a first material outlet and a second material outlet, wherein the first material outlet and the second material outlet are each connected to the material cooler (70) for transferring color-optimized material. 3. Device according to one of the preceding claims, characterized in that the device comprises a deagglomeration device, wherein the deagglomeration device is connected to the calciner (40) for transferring deagglomerated material. 4. Device according to claim 3, characterized in that the deagglomeration device is connected via a riser dryer (20) to the calciner (40) for transferring deagglomerated material. 5. Device according to one of claims 3 to 4, characterized in that the deagglomeration device is a hammer mill (10), vertical roller mill, impact mill, pendulum roller mill or agitator mill. 6. Device according to claim 5, characterized in that the deagglomeration device is a hammer mill (10). 7. Device according to one of the preceding claims, characterized in that the device has a color detection device (80), wherein the thyssenkrupp Industrial Solutions AG 222226P00LU thyssenkrupp AG 14.12.2022 LU103050 15/18 color detection device (80) is designed to detect the color of the product, wherein the color detection device (80) is arranged in or along the product flow after the material cooler (70). 8. Device according to claim 7, characterized in that the device has a reducing agent supply, wherein the reducing agent supply is connected to the reduction device for supplying reducing agent, wherein the device has a control device, wherein the control device is designed to regulate the amount of reducing agent supplied by the reducing agent supply, wherein the control device is designed to regulate the amount of reducing agent depending on the color detected by the color detection device (80). 9. Device according to one of the preceding claims, characterized in that a gas-sealing material lock is arranged between the reduction device and the material cooler (70). 10. Device according to one of the preceding claims, characterized in that the device has a gas supply to the reduction device, wherein the gas supply is controllable with regard to volume flow and gas velocity, wherein the device has a control device, wherein the device has a particle size specification device, wherein the control device is designed to control the gas supply, wherein the control device controls volume flow and gas velocity depending on the particle size of the material specified by the particle size specification device. 11. Device according to claim 10, characterized in that the particle size setting device is a particle size measuring device. 12. Device according to one of the preceding claims, characterized in that the reduction device has guide elements for guiding the material flow. thyssenkrupp Industrial Solutions AG 222226P00LU thyssenkrupp AG 14.12.2022 LU103050 16/18 13. Device according to one of the preceding claims, characterized in that the reduction device has a gas outlet, wherein the gas outlet is connected to a filter device (60). 14. Device according to claim 13, characterized in that a gas sensor (120) is arranged fluidically behind the gas outlet, wherein the gas sensor (120) is designed to detect the concentration of one or more substances selected from the list comprising carbon monoxide, carbon dioxide, hydrogen, methane. 15. Device according to one of the preceding claims, characterized in that the device has a bypass between the calciner (40) and the material cooler (70) for bypassing the reduction device. 16. Device according to one of the preceding claims, characterized in that the reduction device has a dip tube for the supply of activated material. 17. A method for color optimization of an activated material with a device according to one of the preceding claims, wherein a broad particle size distribution is selected for the color optimization in the reduction device, wherein the broad particle size distribution is characterized in that at least 10 wt.% of the particles are smaller than 50 µm and at least 10 wt.% of the particles are larger than 250 µm. 18. The method according to claim 17, characterized in that at least 5 wt.% of the particles are larger than 900 µm. 19. Method according to one of claims 17 to 18, characterized in that at least 10 wt. % of the material flow from the reduction device is discharged via the gas flow through the gas outlet and separated in the filter device (60). 20. Method according to one of claims 17 to 19, characterized in that the fluidization speed in the reduction device is selected so that thyssenkrupp Industrial Solutions AG 222226P00LU thyssenkrupp AG 14.12.2022 LU103050 17/18 that the fluidization rate is 5 to 15 times the loosening rate. 21. Method according to one of claims 17 to 20, characterized in that the gas supplied to the reduction device has a temperature of at least 700 °C. 22. Method according to one of claims 17 to 21, characterized in that a reducing agent is introduced directly into the reduction device. 23. Method according to one of claims 17 to 21, characterized in that a reducing agent is introduced into the reduction device with the gas stream. 24. Method according to one of claims 17 to 21, characterized in that a reducing agent is introduced into the reduction device with the material flow. 25. Process according to one of claims 17 to 24, characterized in that in the case of iron-containing minerals with an Fe,O3 content of more than 20% by weight, only a reduction of at least 80% of the iron is carried out. 26. Process according to one of claims 17 to 24, characterized in that in the case of iron-containing minerals with an Fe,O3 content of less than 10% by weight, only a reduction of up to 50% of the iron is carried out.