1. MECHANOCHEMICAL PHENOMENONS TAKE PLACE DURING COMMINUTIONS OF CONVENTIONAL BRICK CLAYS ON PAN MILL Dr. László A. Gömze associated professor UNIVERSITY OF MISKOLC FACULTY OF MATERIAL SCIENCE AND ENGINEERING Dept. of Ceramics and Silicate Engineering http://keramia.uni-miskolc.hu femgomze@uni-miskolc.hu Habilitációs tudományos kollokvium Miskolc, 2011. január 20.

2. THEMES 1.Our goals 2.Properties of clay minerals and conventional brick clays 3.The aims of crushing and fine comminution of brick clays 4.Mechano-chemical processes during fine comminution 5.Mechano-chemical phenomenons take place during grinding clay materials on laboratory pan mill 6.Conclusions MECHANOCHEMICAL PHENOMENONS TAKE PLACE DURING COMMINUTIONS OF CONVENTIONAL BRICK CLAYS ON PAN MILL

3. OUR GOALS 1.Understand the essence of mechano-chemical processes take place during grinding and fine comminution of clay minerals. 2. Understand the effects of mechano-chemical activation on the physico-chemical and technological properties of the main components of conventional brick clays and clay minerals. 3. Increase the efficiency of crushing of conventional brick clays and clay minerals through understanding the mechano-chemical processes take place during their fine comminutions. MECHANOCHEMICAL PHENOMENONS TAKE PLACE DURING COMMINUTIONS OF CONVENTIONAL BRICK CLAYS ON PAN MILL

4. PROPERTIES OF CLAY MINERALS AND CONVENTIONAL BRICK CLAYS THE CLAY MINERALS Clay minerals are hydrous aluminium phylosilicates, sometimes contain Fe +2, Mg +2, Na +, K + and other cations; Clay minerals are products of common weathering and low temperature hydrothermal alteration; Generally they are built of tetrahedral (t) and octahedral (o) sheets; Clay minerals are ultra fine grained, d max < 2 µm; Typical t-o clay is kaolinite AS 2 H 2  Al 2 O 3 *2SiO 2 *2H 2 O; t-o-t clays are illite, smectite and others. Octahedral structureTetrahedral structure

5. The conventional brick clays are mix of minerals like: Quartz: SiO 2 and its modifications Feldspars: Albite: NAS 6  Na 2 O*Al 2 O 3 *6SiO 2 Orthoclas: KAS 6  K 2 O*Al 2 O 3 *6SiO 2 Anorthite: CAS 2  CaO*Al 2 O 3 *2SiO 2 Clay minerals of the following groups: Kaolin group: AS 2 H 2  Al 2 O 3 *2SiO 2 *2H 2 O Kaolinite and their modifications(dickite, halloysit, nacrite) Smectite group: Montmorillonite (Na, Ca) 0,33 (Al,Mg) 2 (Si 4 O 10 )(OH)*nH 2 O Montronite (CaO 0,5,Na) 0,3 Fe 3+ 2 (Si,Al) 4 O 10 (OH) 2 *nH 2 O SaponiteCaO 0,25 (Mg, Fe) 3 ((Si,Al) 4 O 10 )(OH) 2 *nH 2 O Illite group:illite and clay micas Chlorite group:wide variety of similar minerals Other minerals:carbides, oxides and organic materials and pollutions THE CONVENTIONAL BRICK CLAYS PROPERTIES OF CLAY MINERALS AND CONVENTIONAL BRICK CLAYS

6. THE TYPICAL STRUCTURES OF CONVENTIONAL BRICK CLAYS Magnification: 1000X Magnification: 2000X Magnification: 3000X Magnification: 1000X Magnification: 10 000X 60. évf. 4. szám 2008/4 építőanyag

7. STRUCTURE AND TOTAL VOLUME OF PORES IN CLAY MINERALS Where: A and B – the total numbers of opened and closed pores C and D – the total numbers of capillares and gaps between the grains V – Volume V npi – the volume of „i-th” open pore V zpj – the volume of „j-th” closed pore V kpk – the volume of „k-th” capillary V htl – the volume of „l-th” void (gap)

8. 1.Decrease the sizes and volumes of grains, individual pores, gaps (voids) and capillaries through grinding. 2. To get the required grain sizes and their distributions of the clay minerals as raw materials. 3.Increase the chemical reactivity of the grains and particles of clay minerals throught obtaining the required values of surface and specific surface areas. 4.Use mechanical energy to change physico-mechanical properties of clay minerals as raw materials. 5. Change the chemical and mineralogical compositions of clay minerals through mechanical activation of their atoms and ions. THE AIMS OF CRUSHING AND FINE COMMINUTION OF CLAYS

9. The tensile stress (p k ) in water-droppes generated by surface stress: α – contact wetting angle; [°] σ - surface tension (N/m); r – radius of water drop (m) Radius of the pore, (the radius of water drop) The required mechanical stress to overtake the surface tension of water MPa MPa MPa MPa RELATIONSHIPS BETWEEN THE VOLUMES OF INDIVIDIUAL PORES AND WATERS IN THEM

10. Atoms and ions at the surface have less neighbouring atoms and ions as inside of the body  They have extra energy and activity at the surfaces. During grinding the total volume of grain surfaces are increasing, because of which the surfaces become chemically activated. These chemically activated states of clays are appeared in: increased adsorption activity, aggregation and agglomeration phenomenons, mechano-chemical processes and phase transformations, increased volume of amorphous phases. MECHANO-CHEMICAL PROCESSES DURING FINE COMMINUTIONS TheoreticalPractical

11. THE INITIAL MODEL OF MECHANO- CHEMICAL PROCESSES (Taken from Jushchenko, V. S, Grivtsov, A. G., and Shchukin, E. D.) DAN, SSSR 215 148 (1974) (Taken from Jushchenko, V. S, Grivtsov, A. G., and Shchukin, E. D.) DAN, SSSR 219 162 (1974) Cavity wall adsorbed with alien atoms (medium) Cavity is not adsorbed Propagation of brittle crack with deformation at low temperature; Formation of dislocation with deformation of high temperature Formation of dislocation with deformation of high temperature Formation of crack through penetration of alien atoms (medium) into the stressed and deformed system

12. C ch – Chemical composition and structure; C cm – Mineralogical composition and structure; C cr – Crystal structures of mineralogical components; D gs – Grain sizes and structures of components; F cr – Crushing forces and their loadings; F ib – Interatomic bonding forces; P oc – Porosity, pore sizes and structures; R mc – Mechanical properties, strength and hardnesses. SOME IMPORTANT FACTORS INFLUENCE ON MECHANO-CHEMICAL PROCESSES DURING FINE COMMINUTIONS M cp =f(C ch, C cm, C cr, D gs, F cr, F ib, P oc, R mc )

13. USED EQUIPMENT AND TESTING INSTRUMENTS a.Used equipment for crushing and comminution Hosokawa mechanofusior Pan grinder b. Used instruments for testing Bruker D8 Advance X-ray diffractometer Hitachi TM 1000 Scanning Electronmicroscope Tristar 3000 Specific surface tester Derivatograph

14. INFLUENCE OF CRUSHING TIMES ON SPECIFIC SURFACES OF CLAY MINERALS USED IN CERAMIC BRICK INDUSTRY

15. MINERAL CONTENTS OF MINED CLAY RAW MATERIALS USED IN CERAMIC ROOF-TILES INDUSTRY IN LENTI, HUNGARY

16. INFLUENCE OF CRUSHING TIME ON MINERAL CONTENTS OF „LENTI” MINED CLAY RAW MATERIALS

17. CHANGES IN MINERAL CONTENTS OF MINED CLAY RAW MATERIALS USED IN CERAMIC ROOF-TILES INDUSTRY IN LENTI, HUNGARY

18. CHANGES IN MINERAL CONTENTS OF „LENTI” CLAY RAW MATERIALS AS FUNCTION OF MOISTURE AND CRUSHING TIME

19. INFLUENCE OF CRUSHING TIMES ON MINERAL CONTENTS AND SPECIFIC SURFACE OF MINED CLAYS USED IN CERAMIC BRICK INDUSTRY IN TISZAVASVÁRI, HUNGARY

20. INFLUENCE OF GRINDING TIME ON THERMO-ANALYTICAL PROPERTIES OF CONVENTIONAL BLUE CLAY FROM TISZAVASVÁRI

21. MODELING OF CHEMICAL ACTIVITY OF FINE QUARTZ GRAINS IN WET CLAY MINERALS OF CERAMIC BRICKS AND ROOF-TILES a: adsorption layer b: diffusion layer of cations m: number of molecules in the core n: number of molecules in the colloid outside of the core R 1 : radius of the core R 2 : radius of the colloid particle R 3 : radius of the micell [(SiO 2 ) m *nSiO 3 2- *2(n-x)H + ]*2x*H + (SiO 2 *4H 2 O) m

22. CONCLUSIONS Clay minerals of ceramic brick and roof-tile industries having high values of specific surface area are mechano-chemically very actives during crushing on pan grinder. Clay minerals of ceramic brick and roof-tile industries having high values of specific surface area are mechano-chemically very actives during crushing on pan grinder. Because of the dissipation of minerals, like Muscovite 2M and significant growth of volumes of Quartz, the specific surfaces of Lenti clay decrease considerably, depending on crushing times. Because of the dissipation of minerals, like Muscovite 2M and significant growth of volumes of Quartz, the specific surfaces of Lenti clay decrease considerably, depending on crushing times. During the fine comminution of clay minerals of brick and roof-tile industries the Muscovite 2M and Illite are the most instable components, meanwhile the quantity of Albite and Quartz can be formed. During the fine comminution of clay minerals of brick and roof-tile industries the Muscovite 2M and Illite are the most instable components, meanwhile the quantity of Albite and Quartz can be formed. The free moisture – water – in mined clay minerals and dehydration and dissociation of sum of their components can mechano-chemically activate the fine Quartz crystals, generating colloids and micells. These micells are chemically very active and can participate in forming new minerals of Illite or Muscovite 2M, as well. The free moisture – water – in mined clay minerals and dehydration and dissociation of sum of their components can mechano-chemically activate the fine Quartz crystals, generating colloids and micells. These micells are chemically very active and can participate in forming new minerals of Illite or Muscovite 2M, as well. During grinding conventional brick clays on laboratory pan grinder a considerably volume of amorphous phase can be formed.During grinding conventional brick clays on laboratory pan grinder a considerably volume of amorphous phase can be formed.

23. ACKNOWLEDGEMENT The author acknowledge to the colleagues and PhD students at : The author acknowledge to the colleagues and PhD students at : Dept. of Mineralogy and Petrology for XRD examinations, Dept. of Metallurgical and Foundry Engineering for specific surface measurements, and to the colleagues, PhD students and technicians at Dept. of Ceramics and Silicate Engineering for the collaboration in laboratory tests and measurements.

24. Thank you very much for your time and kind attention ! Habilitációs tudományos kollokvium Miskolc, 2011. január 20. Dr. László A. Gömze associated professor University of Miskolc FACULTY OF MATERIAL SCIENCE AND ENGINEERING Dept. of Ceramics and Silicate Engineering