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EP-4642744-B1 - MECHANOCHEMICAL ACTIVATION OF CLAYS

EP4642744B1EP 4642744 B1EP4642744 B1EP 4642744B1EP-4642744-B1

Inventors

  • WILCZEK, MICHAEL
  • HINDER, DANIEL
  • FYLAK, Marc
  • NEUMANN, THOMAS
  • MAIER, OLIVER
  • LAMPE, KARL
  • SACHSE, CARSTEN
  • STROTMANN, Jan
  • WILLMS, EIKE
  • RUDOWSKI, LUC
  • MÖLLER, Hendrik
  • HAMM, ANDREAS

Dates

Publication Date
20260513
Application Date
20240311

Claims (15)

  1. A method for the mechanochemical activation of mineral material, wherein the method has the following steps: a) drying and coarse comminution of the mineral material, b) transfer of the mineral material to a first high-energy mill (40), c) dry grinding and mechanochemical activation of the mineral material in the first high-energy mill (40), and d) removal of the activated mineral material from the first high-energy mill (40), wherein in step c) the grinding is carried out with an energy input per mill volume of at least 100 kW/m 3 , wherein the first high-energy mill (40) is an agitator bead mill and wherein the agitator bead mill is operated at a peripheral speed of 2 m/s to 8 m/s.
  2. The method according to claim 1, characterized in that in step c) the grinding and mechanochemical activation is carried out with an energy input per mill volume of at least 200 kW /m 3 .
  3. The method according to one of the preceding claims, characterized in that an agitator bead mill with a length-to-diameter ratio of 2.5 to 5 is selected.
  4. The method according to one of the preceding claims, characterized in that the first high-energy mill (40) is filled with a grinding media fill level of from 50% by volume to 95% by volume, preferably from 50% by volume to 80% by volume, particularly preferably from 60% by volume to 70% by volume, wherein the bulk volume of the grinding media relates to the grinding chamber volume of the first high-energy mill (40).
  5. The method according to one of the preceding claims, characterized in that grinding media are selected from iron or an iron alloy or from aluminum or an aluminum alloy or from ceramics.
  6. The method according to one of the preceding claims, characterized in that grinding media with a diameter of from 1 mm to 10 mm are selected.
  7. The method according to one of the preceding claims, characterized in that the agitator bead mill is operated at a peripheral speed of from 2 m/s to 6 m/s, preferably from 3 m/s to 5 m/s, particularly preferably from 3.5 m/s to 4.5 m/s.
  8. The method according to one of the preceding claims, characterized in that the agitator bead mill is operated with a gas volume flow and a material flow, wherein the ratio of gas volume flow to material flow is set such that the ratio of gas volume flow to material flow is between 0.0001 m 3 /kg and 5 m 3 /kg, preferably between 0.1 m 3 /kg and 2 m 3 /kg.
  9. The method according to one of the preceding claims, characterized in that the drying and comminution in step a) is carried out to a residual moisture content of less than 1% by weight and a particle size of less than 2 mm.
  10. The method according to one of the preceding claims, characterized in that after removal of the activated mineral material in step d), the removed material is analyzed to determine the activation, one or more methods being selected for the examination from the group comprising IR spectroscopy, RAMAN spectroscopy, X-ray diffraction analysis, heat flow calorimetry, thermogravimetry, scanning electron microscopy, particle size and/or particle shape analysis, and NMR spectroscopy.
  11. The method according to claim 10, characterized in that after removal of the activated mineral material in step d), the removed material is analyzed to determine the activation, wherein for the analysis, one or more methods are selected from the group comprising IR spectroscopy, RAMAN spectroscopy, X-ray diffraction analysis, and heat flow calorimetry.
  12. The method according to one of the preceding claims, characterized in that the gas selected and used is a gas that comprises one or more gases selected from the group comprising nitrogen, argon, carbon dioxide, water vapor, carbon monoxide, hydrogen, and hydrocarbons, in particular methane, ethane, propane, and butane.
  13. The method according to one of the preceding claims, characterized in that in step c), the mineral material is ground with a liquid or solid reducing agent and mechanochemically activated.
  14. The method according to one of the preceding claims, characterized in that the grinding and mechanochemical activation in step c) takes place at 100 °C to 200 °C.
  15. The method according to one of the preceding claims, characterized in that after step d) in a step e), the activated mineral material is separated into a first fraction and a second fraction, wherein the first fraction is recycled in step b) and the second fraction is removed as a product.

Description

The invention relates to a method for the mechano-chemical activation of clays. Activated clays have become established as an additive, particularly in the cement industry. The current standard method involves drying and calcining the clays, i.e., thermal activation. This requires a two-stage process: 1) Amorphization of clay minerals by thermal activation (calcination) including pre-drying and 2) Increase in the surface area of amorphous clay minerals through grinding. The aim of thermal activation is to disrupt the crystalline structure of the clay minerals and transform them into an amorphous structure, enabling the individual chemical components, such as aluminum oxide and silica, to react chemically with the ground clinker during cement hydration. The second step aims for further mechanical activation through grinding to increase the surface area of the thermally activated clays and ultimately enhance the kinetics of the cement hydration reaction. The new mechano-chemical activation process combines the two activation steps - amorphization and mechanical activation - in a single-stage process using a high-energy-density mill that uses only mechanical energy. Thermal activation requires energy for heating, and the high temperature can also cause further material changes, which may be undesirable. Furthermore, the thermal process necessitates flue gas cleaning to remove the resulting nitrogen oxide and sulfur oxide emissions. In addition, the thermal process will require, in the future, the use of methods for capturing and, if necessary, purifying the generated or released carbon dioxide. From the WO 2017 / 008 863 A1 A process and a plant arrangement for processing and activating a raw material are known. From the EP 3 909 682 A1 A method and a roller mill for the thermomechanical activation of a clay mixture are known. From the DE 10 2015 106 109 A1 A method for the tribochemical activation of binders and additives is known. From the US 8 783 589 B2 A grinding process is known. From the RU 2 209 824 C2 A method for producing sludge powders is known. From the CN 109 954 485 A A method for producing activated clay is known. With Martin Reformat: "Cement Grinding", September 16, 2020 (2020-09-16), XP93163189, Found on the Internet: URL:https://e-pub.uni-weimar.de/opus4/files/4279/Dissertation_Reformat_Martin.pdf A dissertation on cement grinding has been published. From the VIZCAYNO C ET AL: "Pozzolan obtained by mechanochemical and thermal treatments of kaolin", APPLIED CLAY SCIENCE, ELSEVIER, AMSTERDAM, NL, Vol. 49, No. 4, August 1, 201 O (2010-08-01), • Pages 405-413, XP027198140, ISSN: 0169-1317 [found on 2009-10-03 The production of a pozzolan by mechano-chemical and thermal treatment of kaolin is known. From the TOLE ILDA ET AL: "Mechanochemical activation of natural clay minerals: an alternative to produce sustainable cementitious binders - review", MINERALOGY AND PETROLOGY, SPRINGER VIENNA, VIENNA, Vol. 113, No. 4, May 8, 2019 (2019-05-08), pages 449-462, XP036833323, ISSN: 0930-0708, DOI: 10.1007/S00710-019-00666-Y [found on 2019-05-08 The mechano-chemical activation of clay is known. Since clay is a complex system (especially compared to the burning of limestone), different activation methods lead to Different products (activated clays) with different properties are used. While kaolinite, in particular, can be easily activated by thermal activation, other clay minerals such as muscovite cannot be thermally activated, or only insufficiently, even at high temperatures. Similarly, the diversity of usable clays means that not every method is suitable for every clay. The object of the invention is to provide an alternative activation process in order to use clay qualities other than those currently considered suitable for clay calcination or to achieve different product properties. In particular, it should be possible to expand the range of possible raw materials to include, in particular, muscovite, illitic, or chloritic clays. This problem is solved by the method with the features specified in claim 1. Advantageous further developments are described in the dependent claims, the following description, and the drawing. The process according to the invention serves for the mechano-chemical activation of mineral material, in particular clay. In contrast to conventional thermal activation, a thermal treatment step after comminution is thus omitted. The process according to the invention comprises the following steps: a) Drying and coarse crushing of the mineral material, b) Transferring the mineral material to a first high-energy mill, c) Dry milling and mechano-chemical activation of the mineral material in the first high-energy mill, d) Extraction of the activated mineral material from the first high-energy mill. In step a), initial drying and coarse grinding take place. The order of drying and coarse grinding can be arbitrary; they can even be carried out (partially) simultaneously. This is well kno