Cold grinding of feedstock

Abstract

The invention relates to a method for processing feedstock (8), in particular ores, rocks and / or industrial minerals. The method comprises grinding the feedstock (8) in a processing device (4) to form ground grinding stock (10), and discharging at least some of the ground grinding stock (10) from the processing device (4) by means of a process air flow (11). The temperature of the air in the process air flow is at most 15 degrees Celsius, in particular at most 10 degrees Celsius, above the dew point temperature. The invention further relates to a processing plant (1) and to the use of a cyclone (28) in combination with a downstream filter (17) or the use of a filter (17) for discharging ground grinding stock (10) from a process air flow during the cold grinding of ores, rocks and / or industrial minerals.

Description

[0001] Cold milling

[0002] Cold milling of feed material

[0003] The present invention relates to a method for preparing feed material, a processing plant for preparing feed material in the form of ores, rocks and / or industrial minerals and the use of a filter or a cyclone in combination with a downstream filter for the discharge of ground material from a process air stream during the cold grinding of ores, rocks and / or industrial minerals.

[0004] Processing equipment, such as grinding and separation devices, is a commonly used means of grinding and processing raw materials, particularly ores, rocks, and / or industrial minerals. A feed material is introduced into the grinding device and reduced to a fine, granular product. This product contains different fractions, for example, fractions of varying particle sizes. The granulated product, or a portion thereof, is then discharged from the processing equipment by means of a process air stream. The granulated product can be separated from the process air stream by means of separation devices, such as a filter. The processing equipment can be part of a processing plant.

[0005] The relative humidity in the process air stream is influenced, among other things, by the moisture content of the feed material and should be significantly below 100 percent, as otherwise condensation can occur in the processing plant and, in particular, the separator can become clogged. Especially in processing plants with a large proportion of recirculated air / process air stream, there is an increased risk of condensation, since relatively little (relatively dry) fresh air is supplied. This risk of condensation is generally counteracted by a hot gas supply or heat source. An increased temperature of the process air stream leads to lower relative humidity, as the heated air can hold more absolute humidity.

[0006] In practice, the so-called dew point distance is used as a key parameter instead of relative humidity. The dew point corresponds to the temperature at which the relative humidity is 100 percent and the water content in the air condenses. The dew point distance is defined as the temperature difference between the process airflow and the dew point.

[0007] In known processing methods, a dew point difference of at least 20 Kelvin is maintained to prevent condensation. This is achieved, for example, by a high proportion of (dry) fresh air in the process air stream to keep the absolute humidity low and thus the dew point temperature low. Depending on the cold milling process and region, this can lead to significant fluctuations in the process air temperature between day and night. Alternatively or additionally, the process air stream can be heated, for example, by means of a hot gas supply or heating elements, to increase the dew point difference. However, this is associated with high energy consumption.

[0008] The object of the present invention is to reduce the aforementioned disadvantages of the processing methods known from the prior art.

[0009] A first aspect of the present invention provides a method for processing feed material, in particular ores, rocks and / or industrial minerals. The method comprises grinding the feed material in a processing device to produce ground material and discharging at least a portion of the ground material from the processing device by means of a process air stream.

[0010] The temperature of the air in the process air stream can be a maximum of 15 Kelvin, preferably a maximum of 10 Kelvin, preferably a maximum of 5 Kelvin, above the dew point temperature.

[0011] The relative humidity of the air in the process air stream can be at least 35 percent, preferably at least 50 percent, preferably at least 75 percent.

[0012] The processing device can comprise a grinding device and a separation device. The processing device is also referred to as a grinding and separation device. The grinding device can be configured to grind the feed material into ground material. The grinding device can be a vertical roller mill or a roller press. The separation device can be configured to separate the ground material into coarse material and fine material. The separation device can be a classifier, for example, a rotary classifier. The fine material, in particular, has a smaller particle size on average than the coarse material. The relevant temperature of the air in the process air stream can be the temperature of the air in the process air stream after the separation device.

[0013] The grinding device can have one or more grinding rollers. The grinding device can have a grinding plate. The separation device can have classifier lamellae and classifier wheel sails.

[0014] The grinding device and the separating device can be designed as described in WO2021144358A1, WO2021099396A1 or EP3909682A1.

[0015] The grinding of the feed material can take place in the grinding unit, and the ground material can then be separated into fines and coarse material in the separation unit. The fines can be discharged from the separation unit by means of the process airflow. The discharge of at least a portion of the ground material from the processing unit by means of the process airflow (cold grinding) includes, in particular, the discharge of the fines. Additionally, the coarse material can also be discharged via the same discharge unit or a separate discharge unit, for example, a coarse material discharge unit. Alternatively, the coarse material can be fed back into the grinding unit after the separation unit. The coarse material discharge unit can be a screw conveyor.

[0016] The relevant location for relative humidity can be the process airflow downstream of the classifier outlet (or the outlet of the separation device) or at the blower inlet. The relevant location for temperature can also be the process airflow downstream of the classifier outlet or at the blower inlet. The classifier outlet is specifically defined as the point where the ground material, particularly the fines, is discharged from the processing device.

[0017] The dew point temperature is defined, in particular, as the temperature at which the relative humidity of the air in the process air stream is 100 percent. The dew point temperature is defined, in particular, as the temperature at which the air in the process air stream is completely saturated with water vapor.

[0018] The air pressure in the process air stream can roughly correspond to the ambient pressure, in particular standard atmospheric pressure of 1013 mbar (1013 hPa). Ambient pressure is specifically defined as the air pressure outside the treatment equipment. Depending on the weather conditions and the location of the treatment equipment, the ambient pressure may be lower or higher.

[0019] The processing device or the entire processing plant can be operated under negative pressure. This means, in particular, that the air pressure in the process air stream is lower than the ambient pressure. The air pressure in the process air stream can be between 800 mbar and 1015 mbar, especially between 860 mbar and 1000 mbar. The air pressure in the process air stream can be between 5 mbar and 120 mbar, especially between 15 mbar and 110 mbar, and especially between 40 mbar and 100 mbar, lower than the ambient pressure. The air pressure in the process air stream at the blower inlet and / or classifier outlet can be between 15 mbar and 120 mbar, especially between 40 mbar and 100 mbar, lower than the ambient pressure.

[0020] The relative humidity in the process air stream can be at least 35 percent, preferably at least 50 percent, preferably at least 90 percent, preferably at least 95 percent, preferably at least 99 percent.

[0021] The process airflow temperature is preferably 0°C to 60°C, preferably 5°C to 50°C, preferably 10°C to 30°C. The process airflow temperature can be between 0°C and 30°C, preferably between 5°C and 20°C, above the ambient temperature during cold grinding. The ambient temperature is specifically defined as the air temperature outside the processing equipment.

[0022] Specifically, at a process airflow temperature of 20 degrees Celsius and a relative humidity of 35 percent, the dew point temperature is approximately 4.1 degrees Celsius, corresponding to a dew point difference of 15.9 Kelvin. Specifically, at a process airflow temperature of 20 degrees Celsius and a relative humidity of 37.2 percent, the dew point temperature is approximately 5 degrees Celsius, corresponding to a dew point difference of 15 Kelvin. Specifically, at a process airflow temperature of 20 degrees Celsius and a relative humidity of 50 percent, the dew point temperature is approximately 9.3 degrees Celsius, corresponding to a dew point difference of 10.7 Kelvin. Specifically, at a process airflow temperature of 20 degrees Celsius and a relative humidity of 90 percent, the dew point temperature is approximately 18.3 degrees Celsius, corresponding to a dew point difference of 1.7 Kelvin.In particular, at a process airflow temperature of 20 degrees Celsius and a relative humidity of 95 percent, the dew point temperature is approximately 19.2 degrees Celsius, which corresponds to a dew point difference of 0.8 Kelvin.

[0023] Specifically, at a process airflow temperature of 25 degrees Celsius and a relative humidity of 35 percent, the dew point temperature is approximately 8.5 degrees Celsius, corresponding to a dew point difference of 16.5 Kelvin. Specifically, at a process airflow temperature of 25 degrees Celsius and a relative humidity of 38.7 percent, the dew point temperature is approximately 10 degrees Celsius, corresponding to a dew point difference of 15 Kelvin. Specifically, at a process airflow temperature of 25 degrees Celsius and a relative humidity of 50 percent, the dew point temperature is approximately 13.9 degrees Celsius, corresponding to a dew point difference of 11.1 Kelvin. Specifically, at a process airflow temperature of 25 degrees Celsius and a relative humidity of 90 percent, the dew point temperature is approximately 23.2 degrees Celsius, corresponding to a dew point difference of 1.8 Kelvin.In particular, at a process airflow temperature of 25 degrees Celsius and a relative humidity of 95 percent, the dew point temperature is approximately 24.1 degrees Celsius, which corresponds to a dew point difference of 0.9 Kelvin.

[0024] The process can be carried out without the addition / supply of hot gas, in particular without adding hot gas to the process air stream and / or the grinding device. The process can be carried out without the external addition of hot gas, in particular without externally adding hot gas to the process air stream and / or the grinding device. Hot gas is defined in particular as air or gas with a temperature above 50 degrees Celsius, preferably above 75 degrees Celsius, preferably above 100 degrees Celsius.

[0025] The process can be carried out without the use of a heating device. The process can be carried out without the use of a heating device, with the exception of one or more heating elements in the cold milling unit.

[0026] The process can be carried out without the use of one or more heating elements, in particular without the use of heating elements to introduce heat into the process air stream. For the purposes of this document, a heating element is understood to be, for example, a heating coil, an electric heater, a gas burner, a radiant heater, or the like. The process can be carried out without the use of a heating device (and / or a heating element) and without the addition / supply of hot gas. The process can be carried out without the use of one or more heating elements, with the exception of one or more heating elements at the filter body, the rotary valve, and / or the cyclone outlet.

[0027] The operation of the grinding device, for example, the friction between the individual particles of the material being ground or between the material being ground and the grinding device, can cause the process airflow to heat up. However, this is specifically not understood as a heating device, heating element, or addition of hot gas within the meaning of the present application. The operation of the separation device, for example, by rotating the classifier, can cause the process airflow to heat up. However, this is specifically not understood as a heating device, heating element, or addition of hot gas within the meaning of the present application. The operation of an air movement device, for example, by rotating a fan, can cause the process airflow to heat up. However, this is specifically not understood as a heating device, heating element, or addition of hot gas within the meaning of the present application.The method may include heating machine parts, such as the filter housing, rotor, and / or cyclone outlet. However, this is specifically not understood as a heating device, heating element, or hot gas supply device within the meaning of the present application.

[0028] The process is operated, in particular, without a heating device or hot gas supply device designed to heat the process air stream to over 100 degrees Celsius, in particular over 75 degrees Celsius, and in particular over 50 degrees Celsius. A heating device designed only to heat the process air stream by a few Kelvin is specifically excluded.

[0029] The air in the process air stream can be at a maximum temperature of 80 degrees Celsius, preferably at a maximum temperature of 50 degrees Celsius, preferably at a maximum temperature of 35 degrees Celsius, immediately after the treatment device, in particular immediately after the separation device.

[0030] The ground material, especially the fines, in the process air stream immediately after the processing device, particularly the separation device, can be a maximum of 10 Kelvin, preferably a maximum of 5 Kelvin, preferably 2 Kelvin, below the temperature of the air in the process air stream. Cold grinding

[0031] A portion of the process airflow can be recirculated to the processing device, in particular the grinding device. At least 50 percent, preferably at least 70 percent, and preferably at least 90 percent of the process airflow can be recirculated to the processing device, in particular the grinding device.

[0032] At least 50 percent, preferably at least 70 percent, and preferably at least 90 percent of the air supplied to the processing device, in particular the grinding device, is recirculated air. Recirculated air is, in particular, process air that is supplied back to the processing device, in particular the grinding device, after discharge from the processing device, in particular the separation device. The remaining portion of the air supplied to the processing device, in particular the grinding device, is ambient air, also referred to as fresh air. Ambient air can include both ambient air supplied intentionally (for example, via a supply line) and ambient air supplied unintentionally (for example, due to leaks in the processing device, such as from gaps and holes).The latter is specifically referred to as false air in the present application. Fresh air, in the present application, specifically refers to ambient air that is deliberately / intentionally supplied (for example, via a supply line).

[0033] In particular, a maximum of 50 percent, preferably a maximum of 30 percent, preferably a maximum of 10 percent, of the air supplied to the processing device, especially the grinding device, is ambient air. The ratio of ambient air to intentionally supplied fresh air is in particular a maximum of 20 percent, preferably a maximum of 5 percent.

[0034] At least a first part of the process airflow can be fed to a first separation device, in particular in the form of a filter. The process airflow comprises in particular air and ground material, especially fines. In the first separation device, at least a portion of the ground material, in particular the fines, can be separated from the process airflow.

[0035] The remaining process airflow can then be discharged via a process air discharge device, in particular by being released into the ambient air. For example, the entire process airflow can be discharged via the chimney. The process air discharge device can be a chimney. Alternatively, only a portion of the process airflow, for example, a maximum of 50 percent, a maximum of 30 percent, or a maximum of 10 percent, can be discharged via the process air discharge device. The remaining portion of the process airflow, for example, at least 50 percent, at least 70 percent, or at least 90 percent, can be returned to the processing device, in the case of cold grinding, in particular the grinding device. Fresh air can be added to the remaining portion of the process airflow before it is fed to the processing device, in particular the grinding device.

[0036] A second separation device, in the form of a cyclone separator or centrifugal separator, can be arranged upstream of the first separation device. The second separation device is positioned, in particular, in the direction of the process airflow between the processing device, especially the grinding device, and the first separation device. The terms "first separation device" and "second separation device" serve only to name and distinguish the two separation devices from one another, but do not imply any sequence or arrangement of their components. The process airflow can first be directed to the second separation device, and at least a portion of the material being ground, especially the fines, can be separated from the process airflow within the second separation device.Subsequently, a first part of the process airflow can be fed to the first separation device and a second part of the process airflow can be fed back to the processing device, in particular the grinding device.

[0037] The temperature of the air in the process air stream is in particular the temperature of the air in the process air stream between the separation device and the first separation device, in particular the second separation device.

[0038] The feed material may have a natural moisture content. The feed material may have a moisture content of less than 12% by mass, preferably less than 8% by mass, preferably less than 5% by mass.

[0039] The regrind separated from the process airflow in the first separation device, particularly fines, can represent the finished product or a portion thereof. The regrind separated from the process airflow in the second separation device, particularly fines, can represent the finished product or a portion thereof. The finished product can be composed of the regrind separated from the first and second separation devices, particularly fines.

[0040] The material separated by the first and / or second separating device, particularly fines, can be discharged as a finished product. The moisture content in the feed material and the moisture content in the finished product differ from each other by a maximum of 3% by mass, preferably a maximum of 2% by mass, and preferably a maximum of 1% by mass.

[0041] The finished product refers in particular to the ground material separated from the process air stream, especially fines, immediately after the first and / or second separation device. The moisture content in the finished cold-ground product

[0042] The term "product" refers in particular to the moisture content of the ground material, especially fines, separated from the process air stream immediately after the first and / or second separation device. The term "moisture content of the feed material" refers in particular to the moisture content of the feed material immediately before the processing device, especially the grinding device.

[0043] The finished product can be a combination of separated fines, in particular fines separated from the process air stream by the first and / or second separation device, and separated coarses, in particular coarses discharged via the coarses discharge device. The moisture content in the finished product is then, in particular, the moisture content averaged over the mass fractions of fines and coarses.

[0044] The moisture content in the feed material can be higher than the moisture content in the finished product. For example, the moisture content in the finished product can be a maximum of 3% by mass lower, preferably a maximum of 2% by mass lower, and preferably a maximum of 1% by mass lower than the moisture content in the feed material.

[0045] The moisture content in the finished product can be a maximum of 10% by mass, preferably a maximum of 5% by mass, preferably a maximum of 4% by mass, preferably a maximum of 3% by mass.

[0046] The moisture content in the finished product can be at least 1% by mass, preferably at least 1.5% by mass, preferably at least 2% by mass, preferably at least 5% by mass.

[0047] The air in the process air stream may have a carbon dioxide (CO2) content of less than 0.5% by volume, in particular less than 0.25% by volume, and in particular less than 0.1% by volume. The air in the process air stream supplied to the processing device, in particular the grinding device and / or the separation device, may have a carbon dioxide (CO2) content of less than 0.5% by volume, in particular less than 0.25% by volume, and in particular less than 0.1% by volume. The air in the process air stream discharged from the processing device, in particular the separation device, may have a carbon dioxide (CO2) content of less than 0.5% by volume, in particular less than 0.25% by volume, and in particular less than 0.1% by volume.The processing device, in particular the grinding device, can be supplied with process air containing less than 0.5% by volume, in particular less than 0.25% by volume, and in particular less than 0.1% by volume. Cold grinding.

[0048] A second aspect of the present invention comprises a processing plant for preparing feed material in the form of ores, rocks, and / or industrial minerals. The processing plant includes a grinding device for grinding the feed material into ground material and a separation device for separating the ground material into fines and coarse material. The grinding device and the separation device are collectively referred to as the processing plant. The processing plant comprises a first separation device and a second separation device. The processing plant also includes a process air discharge device, in particular in the form of a chimney. The second separation device is connected to the separation device via a first line and to the first separation device via a second line.The second separation device is arranged in the direction of process air flow, specifically between the separation device and the first separation device. The process air discharge device is connected to the first separation device via a third line and is designed to discharge process air from the treatment plant.

[0049] The ratio of the minimum cross-sectional area of ​​the first pipe to the minimum cross-sectional area of ​​the third pipe can be at least three, preferably at least five, preferably at least ten. In particular, the minimum cross-sectional area of ​​the first pipe is at least three, preferably at least five, preferably at least ten times the minimum cross-sectional area of ​​the third pipe. Alternatively or additionally, the ratio of the minimum cross-sectional area of ​​the first pipe to the minimum cross-sectional area of ​​the process air discharge device is at least three, preferably at least five, preferably at least ten.

[0050] The minimum cross-sectional areas are determined, in particular, in a plane orthogonal to the longitudinal axis of the first or third duct. The minimum cross-sectional areas are also determined, in particular, in a plane orthogonal to the process airflow direction.

[0051] The minimum cross-sectional area is defined in particular as the smallest cross-sectional area along the first or third line.

[0052] The minimum cross-sectional area can be limited by valves, especially in the form of flaps, and cross-sectional changes.

[0053] The process airflow runs from the grinding device to the separation device, to the second separator, to the first separator, and finally to the process air discharge device. A portion of the process airflow can be recirculated to the grinding device between each stage. The first, second, and / or third lines can be pipelines. Cold grinding

[0054] The first separation device can be a filter. The first separation device, in particular the filter, can be designed to separate at least a portion of the ground material, especially the fines, from the process airflow.

[0055] The second separation device can be a cyclone separator or a centrifugal separator. The second separation device, in particular the cyclone separator or centrifugal separator, is designed to separate at least a portion of the ground material, especially the fines, from the process airflow.

[0056] Because a second separator is installed upstream of the first, the first separator can be significantly smaller. This also reduces the frequency of maintenance required for the first separator. The smaller size of the first separator is also reflected in the dimensions, particularly the cross-sectional area, of the third pipe. Especially in processing plants operating near the dew point temperature, condensation can impair the first separator, particularly the filter. Filters are generally very sensitive to moisture. This can be mitigated by using a second upstream separator, especially a cyclone separator or centrifugal separator. Cyclone and centrifugal separators are generally less susceptible to moisture damage.

[0057] The ratio of the cross-sectional area, in particular the nominal cross-sectional area, of the first pipe to the cross-sectional area, in particular the nominal cross-sectional area, of the third pipe can be between 3 and 50, preferably between 5 and 20, preferably between 10 and 15. The ratio of the cross-sectional area, in particular the nominal cross-sectional area, of the first pipe to the cross-sectional area, in particular the nominal cross-sectional area, of the process air discharge device can be between 3 and 50, preferably between 5 and 20, preferably between 10 and 15.

[0058] The processing plant, in particular the processing device, may include a vertical roller mill with a classifier. The vertical roller mill may constitute the grinding device. The classifier may constitute the separation device. The classifier may be a rotary classifier.

[0059] The processing plant does not have a heating device or hot gas supply system. The processing plant does not have a heating device or hot gas supply system. The processing plant does not have a heating device, with the exception of one or more heating elements on the filter body, the rotary valve, and / or the cyclone outlet, and does not have a hot gas supply system. Cold grinding

[0060] Hot gas is defined in particular as air or gas with a temperature above 50 degrees Celsius, preferably above 75 degrees Celsius, preferably above 100 degrees Celsius. The processing plant does not include a heating element, in particular no heating element for introducing heat into the process air stream. For the purposes of this document, a heating element is understood to be, for example, a heating coil, an electric heater, a gas burner, a radiant heater, or the like.

[0061] The operation of the grinding device, for example, the friction between the individual particles of the material being ground or between the material being ground and the grinding device, can cause the process airflow to heat up. However, this is specifically not understood as a heating device, heating element, or hot gas supply device within the meaning of this application. The operation of the separation device, for example, by rotating the classifier, can cause the process airflow to heat up. However, this is specifically not understood as a heating device, heating element, or hot gas supply device within the meaning of this application. The operation of an air movement device, for example, by rotating a fan, can cause the process airflow to heat up. However, this is specifically not understood as a heating device, heating element, or hot gas supply device within the meaning of this application.The processing plant may include a heating element for machine parts, such as the filter housing, rotor, and / or cyclone outlet. However, this is specifically not understood as a heating device, heating element, or hot gas supply device within the meaning of the present application.

[0062] The processing plant does not include, in particular, a heating device or hot gas supply device designed to heat the process air stream to over 100 degrees Celsius, especially over 75 degrees Celsius, and especially over 50 degrees Celsius. A heating device designed only to heat the process air stream by a few Kelvin is specifically excluded.

[0063] The processing plant can comprise a first air movement device, in particular in the form of a first fan, and a second air movement device, in particular in the form of a second fan. The first air movement device can be arranged between the second separation device and the first separation device. The term "between" is to be understood in particular with regard to the process airflow. For example, the process airflow is conveyed from the second separation device via the first air movement device to the first separation device. The first air movement device can be configured to move a process airflow from the second separation device to the first separation device or to contribute to the movement of the process airflow. The second air movement device can be arranged between the first separation device and the process air discharge device.The second air handling device can be configured to discharge a process air stream from the treatment plant or to contribute to the discharge of the process air stream. In particular, the second air handling device is configured to discharge the process air stream from the first separation device via the process air discharge device. The second air handling device can also be arranged within the process air discharge device. In particular, such an arrangement is also included in the term "between". The ratio of the installed power of the first air handling device to the installed power of the second air handling device can be at least 10, preferably at least 25, and preferably at least 50.The installed power of the first air movement device can be, in particular, at least 10, preferably at least 25, preferably at least 50, times greater than the installed power of the second air movement device.

[0064] The installed power is, in particular, the power of a drive unit for the first or second air movement device. The installed power is specifically defined as the theoretical maximum power.

[0065] The ratio of the nominal capacity of the second separating device to the nominal capacity of the first separating device can be at least 5, preferably at least 10, preferably at least 20. The nominal capacity of the second separating device can be 5 times greater, in particular 10 times greater, preferably 20 times greater, than the nominal capacity of the first separating device.

[0066] Capacity is specified primarily in process air flow rate per unit of time, for example, cubic meters per hour. Nominal capacity refers specifically to the capacity achieved under normal conditions.

[0067] The ratio of the maximum capacity of the second separation device to the maximum capacity of the first separation device can be at least 5, preferably at least 10, preferably at least 20. The maximum capacity of the second separation device can be 5 times greater, in particular 10 times greater, preferably 20 times greater, than the maximum capacity of the first separation device.

[0068] The processing plant may include a process airflow dividing device. The process airflow dividing device may be arranged between the second separator and the first separator. In particular, the process airflow dividing device may be arranged between a first section of the second line and a second section of the second line. The first section of the second line is arranged, in particular, between the second separator and the process airflow dividing device. The second section of the second line is arranged, in particular, between the process airflow dividing device and the first separator. The processing plant may also include a fourth line. The fourth line may connect the process airflow dividing device to the processing equipment, in particular the grinding equipment. The fourth line may be a pipeline.The process airflow dividing device can be configured to direct a first portion of the process airflow to the first separation device and a second portion of the process airflow, in particular the portion complementary to the first portion, to the grinding device.

[0069] The processing plant may include a fresh air supply line. The fresh air supply line may connect to the fourth line. The fresh air supply line may be located between the process air flow dividing device and the grinding device. The fresh air supply line may be configured to supply ambient air, in particular fresh air, to the grinding device, especially via the fourth line. The ratio of the cross-sectional area of ​​the fourth fresh air supply line to the cross-sectional area of ​​the fourth line may be a maximum of 50 percent, preferably a maximum of 30 percent, and preferably a maximum of 10 percent.

[0070] The air purification system may include a sensor. The sensor may be configured to detect the humidity, in particular the relative humidity, in the process air stream. The sensor may be arranged between the separation device and the first separation device, in particular the second separation device. The sensor may be arranged in the first line. The air purification system may include a control unit. The control unit may be a microprocessor. The control unit may be configured to control the ratio between the first and second portions of the process air stream split by the air stream dividing device, in particular based on the detected humidity.

[0071] The sensor can be located in the first, second, third, or fourth duct. The control unit can be configured to regulate the ratio between recirculated air and fresh air supplied to the grinding device, particularly based on the humidity level detected by the sensor.

[0072] A third aspect of the present invention may include the use of a filter for discharging ground material from a process air stream during the cold grinding of ores, rocks, and / or industrial minerals. Alternatively, the third aspect of the present invention may include the use of a cyclone in combination with a downstream filter for discharging ground material from a process air stream during the cold grinding of ores, rocks, and / or industrial minerals. The discharged ground material may have a moisture content of a maximum of 10% by mass, in particular a maximum of 5% by mass, and in particular a maximum of 3% by mass, for cold grinding. The air in the process air stream, in particular the process air stream supplied to the cold grinding process, may have a carbon dioxide content of less than 0.5% by volume, in particular less than 0.25% by volume, and in particular less than 0.1% by volume.

[0073] The material to be ground can first be ground in a grinding device and then discharged from the grinding device or a separation device downstream of the grinding device by means of the process airflow.

[0074] Examples of industrial minerals include corundum, quartz, diamond, feldspar, calcite, kaolin, talc, wollastonite, mica, phosphate, potash, barite and / or bentonite.

[0075] Examples of ores include, in particular, ores of copper, lead, zinc, aluminum, magnesium, titanium, gold, silver, platinum, uranium, radium, beryllium, chromium, vanadium, molybdenum, tungsten and / or iron.

[0076] Examples of rocks include in particular rock, coal, oil shale, oil sand, concrete gravel, asphalt gravel, rockfill and / or industrial sand.

[0077] The use according to the third aspect of the present invention may in particular exclude the cold grinding of limestone and / or dolomite.

[0078] Cold grinding means in particular that the material being ground or the process air stream does not exceed a temperature of 20 degrees Celsius, preferably 40 degrees Celsius, preferably 60 degrees Celsius.

[0079] The processing plant according to the second aspect of the invention can be used with process steps of the process according to the first aspect of the invention. The process according to the first aspect of the invention can be carried out with a processing plant according to the second aspect of the invention. The use according to the third aspect of the invention can be carried out with a processing plant according to the second aspect of the invention or using process steps of the process according to the first aspect of the invention.

[0080] The terms "first," "second," "third," and "fourth" are simply to be understood as designations for a specific element or component and do not necessarily indicate a particular order of the components or elements mentioned. For example, the presence of a fourth element / component does not necessarily imply the presence of a first, second, or third element / component, and vice versa.

[0081] The invention is defined in the claims. However, the following is a non-exhaustive list of exemplary embodiments. Each or more of the features of these embodiments can be combined with one or more cold milling processes.

[0082] Features of another embodiment, example, or aspect described here may be combined.

[0083] Embodiment AF1: Method for processing feed material, in particular ores, rocks and / or industrial minerals, comprising grinding the feed material in a processing device to produce ground material, and discharging at least a part of the ground material from the processing device by means of a process air stream, wherein the temperature of the air in the process air stream is a maximum of 15 degrees Celsius, in particular a maximum of 10 degrees Celsius, above the dew point temperature.

[0084] Embodiment AF2: Method for processing feed material in the form of rocks, comprising grinding the feed material in a processing device to produce ground material, and discharging at least a part of the ground material from the processing device by means of a process air stream, wherein the temperature of the air in the process air stream is a maximum of 15 degrees Celsius, in particular a maximum of 10 degrees Celsius, above the dew point temperature.

[0085] Embodiment AF3: Method for processing feed material in the form of rocks, comprising grinding the feed material in a processing device to produce ground material, and discharging at least a part of the ground material from the processing device by means of a process air stream, wherein the temperature of the air in the process air stream is a maximum of 15 degrees Celsius, in particular a maximum of 10 degrees Celsius, above the dew point temperature.

[0086] Embodiment AF4: Method for processing feed material in the form of industrial minerals, comprising grinding the feed material in a processing device to produce ground material, and discharging at least a part of the ground material from the processing device by means of a process air stream, wherein the temperature of the air in the process air stream is a maximum of 15 degrees Celsius, in particular a maximum of 10 degrees Celsius, above the dew point temperature.

[0087] Embodiment AF5: Method for processing feed material in the form of construction waste, such as concrete rubble, comprising grinding the feed material in a processing device to ground material, and discharging at least a part of the ground material from the processing device by means of a process air stream, wherein the temperature of the air in the process air stream is a maximum of 15 degrees Celsius, in particular a maximum of 10 degrees Celsius, above the dew point temperature.

[0088] Embodiment AF6: Method for processing feed material, in particular ores, rocks and / or industrial minerals, comprising grinding the feed material in a processing device to produce ground material, and discharging at least a part of the ground material from the processing device by means of cold grinding.

[0089] process air stream, wherein the temperature of the air in the process air stream is a maximum of 15 degrees Celsius, in particular a maximum of 10 degrees Celsius, above the dew point temperature, wherein at least a first part of the process air stream is fed to a first separation device, in particular in the form of a filter, and in the first separation device at least a part of the ground material, in particular the fines, is separated from the process air stream, wherein the ground material, in particular fines, separated by the first separation device is discharged as a finished product, wherein the moisture content in the feed material and the moisture content in the finished product differ from each other by a maximum of 3 mass percent, in particular a maximum of 2 mass percent, in particular a maximum of 1 mass percent.

[0090] Embodiment AF7: Method for processing feed material, in particular ores, rocks and / or industrial minerals, comprising grinding the feed material in a processing device to produce ground material, and discharging at least a portion of the ground material from the processing device by means of a process air stream, wherein the temperature of the air in the process air stream is at most 10 degrees Celsius above the dew point temperature, wherein at least a first portion of the process air stream is fed to a first separation device in the form of a filter and in the first separation device at least a portion of the fine material is separated from the process air stream, wherein the fine material separated by the first separation device is discharged as a finished product, wherein the moisture content in the feed material and the moisture content in the finished product is at most 3% by mass, in particular at most 2% by mass, in particular at most 1% by mass.differ from each other.

[0091] Embodiment AF8: Method for processing feed material, in particular ores, rocks and / or industrial minerals, comprising grinding the feed material in a processing device to produce ground material, and discharging at least a portion of the ground material from the processing device by means of a process air stream, wherein the temperature of the air in the process air stream is at most 15 degrees Celsius, in particular at most 10 degrees Celsius, above the dew point temperature, wherein at least a first portion of the process air stream is fed to a first separation device, in particular in the form of a filter, and in the first separation device at least a portion of the ground material, in particular the fines, is separated from the process air stream, wherein a second separation device, in particular in the form of a cyclone separator or centrifugal separator, is arranged upstream of the first separation device.and the process air stream is initially fed to the second separation device and at least a portion of the ground material, in particular the fines, is separated from the process air stream in the second separation device, wherein subsequently, in cold grinding, a first portion of the process air stream is fed to the first separation device and a second portion of the process air stream is fed back to the processing device, in particular the grinding device, wherein the ground material separated by the first separation device and / or the second separation device, in particular fines, is discharged as the finished product, wherein the moisture content in the feed material and the moisture content in the finished product differ from each other by a maximum of 3% by mass, in particular a maximum of 2% by mass, in particular a maximum of 1% by mass.

[0092] Embodiment AF9: Method according to one of the preceding embodiments, wherein the method is carried out without the addition of hot gas, in particular into a grinding device and / or the process air stream, and without the use of a heating device, with the exception of one or more heating elements on the filter body, at the cyclone outlet and / or on the rotary valve.

[0093] Embodiment AF10: Method according to one of the preceding embodiments, wherein the method is carried out without the addition of hot gas to a grinding device, without the addition of hot gas to the process air stream, and without the use of a heating device, with the exception of one or more heating elements on the filter body, at the cyclone outlet and / or on the rotary valve.

[0094] Embodiment AF11: Method according to one of the preceding embodiments, wherein the processing device comprises a grinding device and a separation device, wherein the grinding of the feed material takes place in the grinding device and the ground material is subsequently separated into fines and coarse material in the separation device, wherein the fines are discharged from the separation device by means of the process air stream.

[0095] Embodiment AF12: Method according to one of the preceding embodiments, wherein a portion of the process airflow, in particular at least 50 percent, in particular at least 70 percent, in particular at least 90 percent, is returned to the processing device.

[0096] Embodiment AF13: Method according to one of the preceding embodiments, wherein a portion of the process airflow, in particular at least 50 percent, in particular at least 70 percent, in particular at least 90 percent, is returned to the grinding device.

[0097] Embodiment AF14: Method according to one of the preceding embodiments, wherein at least a first part of the process airflow is fed to a first separation device, in particular in the form of a filter, and in the first separation device at least a part of the ground material, in particular the fines, is separated from the process airflow. Cold grinding

[0098] Embodiment AF15: Method according to embodiment AF14, wherein the first separation device is a filter and at least a part of the fine material is separated from the process air stream in the filter.

[0099] Embodiment AF16: Method according to one of the embodiments AF14 or AF15, wherein a second separation device, in particular in the form of a cyclone separator or centrifugal separator, is arranged upstream of the first separation device, and the process airflow is initially supplied to the second separation device and at least a part of the ground material, in particular the fine material, is separated from the process airflow in the second separation device, wherein subsequently a first part of the process airflow is supplied to the first separation device and a second part of the process airflow is supplied back to the processing device, in particular the grinding device.

[0100] Embodiment AF17: Method according to embodiment AF16, wherein the second separation device is a cyclone separator, wherein a part of the fines is separated from the process air stream in the cyclone separator and subsequently a first part of the process air stream is fed to the first separation device and a second part of the process air stream is fed back to the grinding device.

[0101] Embodiment AF18: Method according to embodiment AF16, wherein the second separation device is a centrifugal separator, wherein a part of the fines is separated from the process air stream in the centrifugal separator and subsequently a first part of the process air stream is supplied to the first separation device and a second part of the process air stream is supplied back to the grinding device.

[0102] Embodiment AF19: Method according to one of the preceding embodiments AF14 to AF18, wherein the ground material separated by the first separation device, in particular fine material, is discharged as a finished product, wherein the moisture content in the feed material and the moisture content in the finished product differ from each other by a maximum of 3 mass percent, in particular a maximum of 2 mass percent, in particular a maximum of 1 mass percent.

[0103] Embodiment AF20: Method according to one of the preceding embodiments AF16 to AF18, wherein the ground material separated by the second separation device, in particular fine material, is discharged as a finished product, wherein the moisture content in the feed material and the moisture content in the finished product differ from each other by a maximum of 3 mass percent, in particular a maximum of 2 mass percent, in particular a maximum of 1 mass percent.

[0104] Embodiment AF21: Method according to one of the preceding embodiments

[0105] AF16 to AF18, wherein the first separation device and the second cold grinding

[0106] The separated material, especially fines, is discharged as a finished product by the separating device, wherein the moisture content in the feed material and the moisture content in the finished product differ from each other by a maximum of 3 mass percent, in particular a maximum of 2 mass percent, in particular a maximum of 1 mass percent.

[0107] Embodiment AF22: Method according to one of the preceding embodiments, wherein the feed material has a natural moisture content.

[0108] Embodiment AF23: Method according to one of the preceding embodiments, wherein the feed material has a moisture content of less than 12% by mass, in particular less than 8% by mass, in particular less than 5% by mass.

[0109] Embodiment AF24: Method according to one of the preceding embodiments, wherein the finished product has a moisture content of at least 1% by mass, in particular at least 1.5% by mass, in particular at least 2% by mass, in particular at least 5% by mass.

[0110] Embodiment AF25: Method according to one of the preceding embodiments, wherein the air in the process air stream has a carbon dioxide content of less than 0.5% by volume, in particular less than 0.25% by volume, in particular less than 0.1% by volume.

[0111] Embodiment AF26: Method according to one of the preceding embodiments, wherein the air in the process air stream supplied to the processing device, in particular the grinding device and / or separation device, has a carbon dioxide content of less than 0.5% by volume, in particular less than 0.25% by volume, in particular less than 0.1% by volume.

[0112] Embodiment AF27: Method according to one of the preceding embodiments, wherein the air in the process air stream which is discharged from the treatment device, in particular the separation device, has a carbon dioxide content of less than 0.5 by volume percent, in particular less than 0.25 by volume percent, in particular less than 0.1 by volume percent.

[0113] Embodiment AF28: Method according to one of the preceding embodiments, wherein process air with a carbon dioxide content of less than 0.5% by volume, in particular less than 0.25% by volume, in particular less than 0.1% by volume, is supplied to the processing device.

[0114] Embodiment AF29: A method according to one of the preceding embodiments, wherein the moisture content in the feed material and the moisture content of the ground material discharged from the processing device, in particular the separation device, differ from each other by a maximum of 3% by mass, in particular by a maximum of 2% by mass, in particular by a maximum of 1% by mass. Cold grinding

[0115] Embodiment AF30: Method according to one of the preceding embodiments, wherein the moisture content in the feed material and the moisture content of the fines discharged from the processing device, in particular the separation device, differ from each other by a maximum of 3% by mass, in particular by a maximum of 2% by mass, in particular by a maximum of 1% by mass.

[0116] Embodiment AF31: Method according to embodiment AF29 or AF30, wherein the moisture content in the feed material is higher than the moisture content in the ground material or fines.

[0117] Embodiment AF32: Method according to one of the preceding embodiments, wherein at least a first part of the process air stream is supplied to a first separation device, where at least a part of the ground material is separated from the process air stream, wherein the process air stream is previously supplied to a second separation device in the form of a cyclone separator or centrifugal separator, which is arranged between the processing device and the first separation device, where at least a part of the ground material is separated from the process air stream.

[0118] Embodiment AF33: Method according to embodiment AF32, wherein the processing device comprises a grinding device and a separation device.

[0119] Embodiment AF34: Processing plant for processing feed material in the form of ores, rocks and / or industrial minerals, comprising a grinding device for grinding feed material into ground material, a separation device for separating the ground material into fines and coarse material, a first separation device, a second separation device, and a process air discharge device, in particular in the form of a chimney, wherein the second separation device is connected to the separation device via a first line and to the first separation device via a second line, and the process air discharge device is connected to the first separation device via a third line and is configured to discharge a process air stream from the processing plant.wherein the ratio of the minimum cross-sectional area of ​​the first pipe to the minimum cross-sectional area of ​​the third pipe and / or the process air discharge device is at least three, in particular at least five, in particular at least ten.

[0120] Embodiment AF35: Processing plant according to embodiment AF34, wherein the processing plant does not include a heating device, with the exception of one or more heating elements on the filter body, on the cyclone outlet and on the rotor, and does not include a hot gas supply device.

[0121] Embodiment AF36: Processing plant according to embodiment AF34, wherein the processing plant does not have a heating device, with the exception of one or more cold mills

[0122] Heating elements on the filter body, at the cyclone outlet or on the rotor, and does not include a hot gas supply device.

[0123] Embodiment AF37: Processing plant according to one of the embodiments AF34 to AF36, wherein the processing plant does not include a heating device or hot gas supply device designed to heat the process air stream to over 100 degrees Celsius, in particular over 75 degrees Celsius, in particular over 50 degrees Celsius.

[0124] Embodiment AF38: Processing plant according to one of embodiments AF34 to AF37, wherein the processing plant comprises a first air movement device, in particular in the form of a first fan, and a second air movement device, in particular in the form of a second fan, wherein the first air movement device is arranged between the second separator and the first separator and is configured to move the process airflow from the second separator to the first separator or to contribute to the movement of the process airflow, wherein the second air movement device is arranged between the first separator and the process air discharge device and is configured to discharge the process airflow from the processing plant or to contribute to the discharge of the process airflow.wherein the ratio of the installed power of the first air movement device to the installed power of the second air movement device is at least 10, preferably at least 25, preferably at least 50.

[0125] Embodiment AF39: Processing plant according to embodiment AF38, wherein the first air movement device is a first fan and the second air movement device is a second fan.

[0126] Embodiment AF40: Processing plant according to one of the embodiments AF34 to AF39, wherein the ratio of the nominal capacity of the second separator to the nominal capacity of the first separator is at least 5, in particular at least 10, in particular at least 20.

[0127] Embodiment AF41: Processing plant according to one of embodiments AF34 to AF40, wherein the processing plant comprises a process airflow dividing device arranged between the second separating device and the first separating device, in particular between a first section of the second line and a second section of the second line, wherein the processing plant comprises a fourth line connecting the process airflow dividing device to the grinding device, wherein the process airflow dividing device is configured to perform a first cold grinding

[0128] to direct a portion of the process airflow to the first separation device and a second portion of the process airflow to the grinding device.

[0129] Embodiment AF42: Use of a cyclone in combination with a downstream filter for the discharge of ground material from a process air stream during the cold grinding of ores, rocks and / or industrial minerals.

[0130] Embodiment AF43: Use of a filter for the discharge of ground material from a process air stream during the cold grinding of ores, rocks and / or industrial minerals.

[0131] Embodiment AF44: Use according to embodiment AF42 or AF43, wherein air in the process air stream, in particular the process air stream supplied to the cold grinding, has a carbon dioxide content of less than 0.5 by volume percent, in particular less than 0.25 by volume percent, in particular less than 0.1 by volume percent.

[0132] Embodiment AF45: Use according to one of the embodiments AF42 to AF44, wherein the use is without the addition of hot gas, in particular into a grinding device and / or the process air stream, and in particular without the use of a heating device, with the exception of one or more heating elements on the filter body, on the cyclone outlet and / or on the rotary valve.

[0133] Embodiment AF46: Use according to one of the embodiments AF42 to AF45, wherein a part of the process air stream, in particular at least 50 percent, in particular at least 70 percent, in particular at least 90 percent, is fed back into a processing device from which the process air stream was previously discharged.

[0134] Embodiment AF47: Use according to one of the embodiments AF42 to AF46, wherein the discharged ground material has a moisture content of a maximum of 10 mass percent, in particular a maximum of 5 mass percent, in particular a maximum of 3 mass percent.

[0135] Advantageous embodiments of the invention are explained in more detail below with reference to the accompanying figures.

[0136] Figure 1 shows a schematic representation of a processing plant for operating a process according to the invention for processing feed material.

[0137] Figure 2 shows a schematic representation of a further processing plant for operating a process according to the invention for processing feed material.

[0138] Figure 3 shows a schematic representation of a processing plant according to the invention for operating a process according to the invention for processing feed material. Cold grinding

[0139] Fig. 1 shows a processing plant 1 according to the invention. The processing plant comprises a grinding device 2 and a separation device 3. Fig. 1 is to be understood merely as a system diagram. The devices and features shown are not necessarily to scale. The grinding device 2 and the separation device 3 together form the processing plant 4. In this case, the grinding device 2 is a vertical roller mill and the separation device 3 is a classifier arranged above the grinding device 2.

[0140] The grinding device 2 comprises a grinding plate 5 and grinding rollers 6. Feed material 8 is supplied to a material feed opening 9 of the processing device 4 via a rotary valve 7. The feed material 8 is fed to the grinding plate 5, where it is ground into milled material 10 by the interaction of the grinding plate 5 and the grinding rollers 6. The milled material 10 is conveyed to the separation device 3 by means of the process air stream 11, where it is separated into fines 12 and coarses 13. The coarses 13 fall back to the grinding device 2 and / or are discharged from the processing device 4 via a coarse discharge device 14, for example, in the form of a screw conveyor. The fines 12 are discharged from the processing device 4, in particular the separation device 3, by means of the process air stream 11. The processing device 4 shown in Fig. 1 is merely an example.The processing device 4 can, for example, also have only a grinding device 2 without a separation device 3.

[0141] The material to be ground 10, in particular the fines 12, is conveyed in the process air stream 11 via a first line 15 to a first separation device 17. In this embodiment, the first line 15 also constitutes the second line 16. The conveyance is effected, in particular, by a first air movement device 18, which is arranged between the processing device 4 and the first separation device 17, in particular in the first line 15 or the second line 16. The first air movement device 18 can be designed as a fan. The first separation device 17 can be designed as a filter. The first separation device 17 is designed to separate at least a portion of the material to be ground 10, in particular the fines 12, from the process air stream 11. The separated material to be ground 10 or fines 12 is discharged from the processing plant 1 as the finished product 19.

[0142] The process air stream 11 is fed to a process air discharge device 21 via a third line 20 after passing through the first separator 17. This is accomplished by means of a second air movement device 22. The second air movement device 22 is arranged between the first separator 17 and the process air discharge device 21, specifically within the third line 20. The second air movement device 22 can be designed as a fan. The process air discharge device 21 can be designed as a chimney. At least a portion of the process air stream 11 is discharged from the processing plant 1 via the process air discharge device 21 and, in particular, released into the ambient air.

[0143] A process air flow dividing device 23 is arranged between the first separation device 17 and the process air discharge device 21, in particular in the third line 20. The processing plant 1 further comprises a fourth line 24. The process air flow dividing device 23 is configured to direct a first portion of the process air flow 11 to the process air discharge device 21 and a second portion of the process air flow 11 via the fourth line 24 to the processing device 4, in particular the grinding device 2.

[0144] A fresh air supply line 25 opens into the fourth line 24. The fresh air supply line 25 is arranged between the process air flow dividing device 23 and the processing device 4, in particular the grinding device 2. The fresh air supply line 25 is designed to supply ambient air, in particular fresh air 26, to the grinding device 2, in particular via the fourth line 24. Due to leakage in the processing device 4 or the grinding device 2, false air 27 enters the processing device 4, in particular the grinding device 2. False air 27 is also ambient air.

[0145] The processing plant 1 shown in Fig. 1 is operated in recirculation mode. A portion of the process air flow 11 is recirculated from the processing device 4, in particular from the grinding device 2. The process air flow 11 supplied to the processing device 4 or grinding device 2 consists partly of recirculated process air 11 and partly of fresh air 26 or ambient air 27.

[0146] In contrast, Fig. 2 shows a processing plant 1 according to the invention without recirculated air operation. Fig. 2 is to be understood merely as a system diagram. The devices and features shown are not necessarily to scale. Compared to the processing plant 1 shown in Fig. 1, the processing plant 1 of Fig. 2 has no process air flow dividing device 23 and no fourth line 24. The entire process air flow 11 is discharged from the processing plant 1 via the process air discharge device 21. The fresh air supply line 25 opens directly into the processing device 4, in particular the grinding device 2. The process air flow 11 supplied to the processing device 4 or grinding device 2 consists exclusively of ambient air, namely mostly fresh air 26 and a smaller part of ambient air 27. Cold grinding

[0147] Fig. 3 shows another processing plant 1 according to the invention. Fig. 3 is to be understood merely as a system diagram. The devices and features shown are not necessarily to scale. The processing device 4, in particular the grinding device 2 and the separation device 3, is designed identically to the embodiments shown in Figs. 1 and 2. The material to be ground 10, in particular the fines 12, is fed from the processing device 4 to a second separation device 28 via a first line 15 using the process air 11. The second separation device 28 is arranged between the processing device 4 and the first separation device 17. The second separation device 28 can be designed as a cyclone separator or a centrifugal separator. The second separation device 28 is designed to separate at least a portion of the material to be ground 10, in particular the fines 12, from the process air stream 11. The separated milled material 10 orFine material 12 is discharged as finished product 19 from the processing plant 1.

[0148] The process airflow 11, including the ground material 10 or fines 12, is subsequently fed to the first separation device 17 via the second line 16. This is done by means of a first air movement device 18, which is arranged between the second separation device 28 and the first separation device 17. The first air movement device 18 can be designed as a fan. The first air movement device 18 is, in particular, arranged in the second line 16. The first separation device 17 can be designed as a filter. Compared to the embodiments of Figures 1 and 2, the separation device 17 can be significantly smaller due to the upstream second separation device 28. The first separation device 17 is designed to separate at least a portion of the ground material 10, in particular the fines 12, from the process airflow 11. The separated ground material 10 or fines 12 is then transferred to the second separation device 17.Fine material 12 is discharged as finished product 19 from the processing plant 1.

[0149] After the first separation device 17, the process air stream 11 is conveyed by means of a second air movement device 22 via a third line 20 to a process air discharge device 21. The process air discharge device 21 can be designed as a chimney. The process air stream 11, or a portion thereof, is discharged from the treatment plant 1 via the process air discharge device 21 and, in particular, released into the ambient air. The second air movement device 22 can be designed as a fan. The second air movement device 22 can be arranged in the third line 20.

[0150] A third air movement device 29 can be arranged between the processing device 4 and the second separation device 28, particularly in the first line 15. The third air movement device 29 can be designed as a fan. Cold grinding

[0151] The third air movement device 29 can be configured to convey or contribute to the process airflow 11.

[0152] A process airflow dividing device 23 is arranged between the second separating device 28 and the first separating device 17.

[0153] The process airflow dividing device 23 is arranged between a first section 30 of the second line 16 and a second section 31 of the second line 16. The first section 30 of the second line 16 is specifically arranged between the second separator 28 and the process airflow dividing device 23. The second section 31 of the second line 16 is specifically arranged between the process airflow dividing device 23 and the first separator 17.

[0154] The processing plant 1 also includes a fourth line 24. The fourth line 24 connects the process air flow dividing device 23 to the processing device 4, in particular the grinding device 2. The process air flow dividing device 23 is designed to direct a first portion of the process air flow 11 to the first separation device 17 and a second portion of the process air flow 11 to the processing device 4, in particular the grinding device 2.

[0155] The first line 15, the second line 16, the third line 20 and / or the fourth line 24 can be pipelines.

[0156] The processing plant 1 may have a fresh air supply line 25. The fresh air supply line 25 opens into the fourth line 24. The fresh air supply line 25 is arranged between the process air flow dividing device 23 and the processing device 4, in particular the grinding device 2. The fresh air supply line 25 is designed to supply ambient air, in particular fresh air 26, to the grinding device 2, in particular via the fourth line 24. Due to leakage in the processing device 4 or the grinding device 2, false air 27 enters the processing device 4, in particular the grinding device 2. False air 27 is also ambient air.

[0157] The processing plant 1 shown in Fig. 3 is operated in recirculation mode. A portion of the process air flow 11 is recirculated from the processing device 4, in particular from the grinding device 2. The process air flow 11 supplied to the processing device 4 or grinding device 2 consists partly of recirculated process air 11 and partly of fresh air 26 or false air 27.

Claims

Cold milling Claims 1. Method for processing feed material (8), in particular ores, rocks and / or industrial minerals, comprising: - Grinding the feed material (8) in a processing device (4) to ground material (10), and - Discharge at least a part of the ground material (10) from the processing device (4) by means of a process air stream (11), wherein the temperature of the air in the process air stream (11) is a maximum of 15 degrees Celsius, in particular a maximum of 10 degrees Celsius, above the dew point temperature, wherein at least a first part of the process air stream (11) is fed to a first separation device (17), in particular in the form of a filter, and in the first separation device (17) at least a part of the ground material (10) is separated from the process air stream (11), wherein the ground material (10) separated by the first separation device (17) is discharged as the finished product (19), wherein the moisture content in the feed material (8) and the moisture content in the finished product (19) differ from each other by a maximum of 3 percent by mass.

2. Method according to claim 1, wherein the method is carried out without the addition of hot gas, in particular into a grinding device (2) and / or the process air stream (11), and without the use of a heating device, with the exception of one or more heating elements on the filter body, at the cyclone outlet and / or on the rotary valve.

3. Method according to claim 1 or 2, wherein the processing device (4) comprises a grinding device (2) and a separation device (3), wherein the grinding of the feed material (8) takes place in the grinding device (2) and the ground material (10) is subsequently separated in the separation device (3) into fine material (12) and coarse material (13), wherein the fine material (12) is discharged from the separation device (3) by means of the process air stream (11).

4. Method according to claim 3, wherein in the first separation device (17) at least a part of the fine material (12) is separated from the process air stream (11).

5. Method according to one of the preceding claims, wherein a portion of the process airflow (11), in particular at least 50 percent, in particular at least 70 Cold milling percent, in particular at least 90 percent, is returned to the processing device (4), in particular the grinding device (2).

6. Method according to one of the preceding claims, wherein a second separation device (28), in particular in the form of a cyclone separator or centrifugal separator, is arranged upstream of the first separation device (17), and the process air stream (11) is first fed to the second separation device (28) and at least a part of the ground material (10), in particular the fine material (12), is separated from the process air stream (11) in the second separation device (28), wherein subsequently a first part of the process air stream (11) is fed to the first separation device (17) and a second part of the process air stream (11) is fed back to the processing device (4), in particular the grinding device (2).

7. Method according to claim 6, wherein the ground material (10), in particular fine material (12), separated by the first separation device (17) and the second separation device (28) is discharged as a finished product (19).

8. Method according to one of the preceding claims, wherein the feed material (8) has a natural moisture content, in particular a moisture content of less than 12% by mass, in particular less than 8% by mass, in particular less than 5% by mass.

9. Processing plant (1) for processing feed material (8) in the form of ores, rocks and / or industrial minerals, comprising: a grinding device (2) for grinding feed material (8) into ground material (10), a separation device (4) for separating the ground material (10) into fine material (12) and coarse material (13), a first separation device (17), a second separation device (28), and a process air discharge device (21), in particular in the form of a chimney, wherein the second separation device (28) is connected to the separation device (4) via a first line (15) and to the first separation device (17) via a second line (16), and the process air discharge device (21) is connected to the first separation device (17) via a third line (20) and is configured to discharge a process air stream (11) from the processing plant (1). to carry out Cold grinding wherein the ratio of the minimum cross-sectional area of ​​the first line (15) to the minimum cross-sectional area of ​​the third line (20) and / or the process air discharge device (21) is at least three, in particular at least five, in particular at least ten.

10. Processing plant according to claim 9, wherein the processing plant (1) does not include a heating device, with the exception of one or more heating elements on the filter body, on the cyclone outlet and / or on the rotor, and does not include a hot gas supply device.

11. Processing plant according to claim 9 or 10, wherein the processing plant (1) does not include a heating device or hot gas supply device designed to heat the process air stream (11) to over 100 degrees Celsius, in particular over 75 degrees Celsius, in particular over 50 degrees Celsius.

12. Processing plant according to one of claims 9 to 11, wherein the processing plant (1) comprises a first air movement device (18), in particular in the form of a first fan, and a second air movement device (22), in particular in the form of a second fan, wherein the first air movement device (18) is arranged between the second separator device (28) and the first separator device (17) and is configured to move the process air flow (11) from the second separator device (28) to the first separator device (17) or to contribute to the movement of the process air flow (11), wherein the second air movement device (22) is arranged between the first separator device (17) and the process air discharge device (21) and is configured to discharge the process air flow (11) from the processing plant (1) or to contribute to the discharge of the process air flow (11).wherein the ratio of the installed power of the first air movement device (18) to the installed power of the second air movement device (22) is at least 10, preferably at least 25, preferably at least 50.

13. Processing plant according to one of claims 9 to 12, wherein the ratio of the nominal capacity of the second separating device (28) to the nominal capacity of the first separating device (17) is at least 5, in particular at least 10, in particular at least 20. Cold milling 14. Processing plant according to one of claims 9 to 13, wherein the processing plant (1) comprises a process airflow dividing device (23) arranged between the second separating device (28) and the first separating device (17), in particular between a first section (30) of the second line (16) and a second section (31) of the second line (16), wherein the processing plant (1) comprises a fourth line (24) connecting the process airflow dividing device (23) to the grinding device (2), wherein the process airflow dividing device (23) is configured to direct a first portion of the process airflow (11) to the first separating device (17) and a second portion of the process airflow (11) to the grinding device (2).

15. Use of a cyclone (28) in combination with a downstream filter (17) or a filter (17) for the discharge of ground material (10) from a process air stream (11) in the cold grinding of ores, rocks and / or industrial minerals, wherein the discharged ground material (10) has a moisture content of a maximum of 10% by mass, in particular a maximum of 5% by mass, in particular a maximum of 3% by mass.

16. Use according to claim 16, wherein air in the process air stream (11), in particular the process air stream (11) supplied to the cold grinding process, has a carbon dioxide content of less than 0.5 by volume percent, in particular less than 0.25 by volume percent, in particular less than 0.1 by volume percent.

17. Method according to any one of claims 1 to 8, wherein the air in the process air stream (11) has a carbon dioxide content of less than 0.5% by volume, in particular less than 0.25% by volume, in particular less than 0.1% by volume.

18. Method according to one of claims 1 to 8 or 17, wherein process air with a carbon dioxide content of less than 0.5% by volume, in particular less than 0.25% by volume, in particular less than 0.1% by volume, is supplied to the processing device (4).

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