The importance of specific surface area in the geopolymerization of heated illitic clay

Abstract Geopolymers are inorganic binders formed by adding alkaline (hydroxide) solution to silicates such as blast furnace slag, fly ash or calcined clay to dissolve Si and Al that polymerizes and precipitates while hardening. The most common clay used as geopolymer raw material is kaolin. The aim of this study was to investigate the suitability of clays dominated by 2:1 dioctahedral layer silicates using the example of Friedland clay as a cheaper alternative to kaolin and determine the necessary preparation steps required to produce an effective geopolymer binder material. After a Rietveld-based quantification of the raw clay, the successive thermal modifications of the mineral phases were analyzed using simultaneous thermal analysis coupled with mass spectrometer (STA-MS), temperature-resolved X-ray diffraction (TXRD), and 27 Al solid-state nuclear magnetic resonance spectroscopy (NMR) measurements. Friedland clay heated to 875 °C was found to produce a geopolymer with the highest compressive strength, but in contrast to the literature, the Si:Al ratio and the amount of 5-fold coordinated Al were not found to be the key parameters that determined the success of geopolymer synthesis. The specific surface area and the amount of Si and Al dissolved are here reported to be the key factors determining the suitability of clays dominated by 2:1 dioctahedral layer silicates as raw materials for geopolymer production.

[1]  Waltraud M. Kriven,et al.  The effect of alkali and Si/Al ratio on the development of mechanical properties of metakaolin-based geopolymers , 2007 .

[2]  G. Hoatson,et al.  Modelling one‐ and two‐dimensional solid‐state NMR spectra , 2002 .

[3]  K. Emmerich.  Thermal Analysis in the Characterization and Processing of Industrial Minerals , 2010 .

[4]  K. MacKenzie.  Applications of solid state NMR spectroscopy to ceramic research , 2000 .

[5]  G. Corder,et al.  Costs and carbon emissions for geopolymer pastes in comparison to ordinary portland cement , 2011 .

[6]  Y. S. Zhang,et al.  Hydration process of interfacial transition in potassium polysialate (K-PSDS) geopolymer concrete , 2005 .

[7]  Siv Olsson,et al.  Mineralogy and sealing properties of various bentonites and smectite-rich clay materials , 2007 .

[8]  J. Bai,et al.  Metakaolin and calcined clays as pozzolans for concrete: a review , 2001 .

[9]  K. Knight,et al.  Calibration of excess thermodynamic properties and elastic constant variations associated with the alpha beta phase transition in quartz , 1998 .

[10]  R. Dohrmann,et al.  Rietveld Refinement of Disordered Illite-Smectite Mixed-Layer Structures by a Recursive Algorithm. I: One-Dimensional Patterns , 2012, Clays and Clay Minerals.

[11]  R. J. Ackermann,et al.  Thermal expansion and the high–low transformation in quartz. I. High-temperature X-ray studies , 1974 .

[12]  F. Liebau,et al.  Structural Chemistry of Silicates: Structure, Bonding, and Classification , 1985 .

[13]  E. Galán,et al.  Genesis of Clay Minerals , 2013 .

[14]  Efraím Mendelovici.  Comparative study of the effects of thermal and mechanical treatments on the structures of clay minerals , 1997 .

[15]  Ilaria Capasso,et al.  Thermally treated clay sediments as geopolymer source material , 2015 .

[16]  A. Buchwald,et al.  The suitability of thermally activated illite/smectite clay as raw material for geopolymer binders , 2009 .

[17]  K. MacKenzie,et al.  Geopolymer synthesis using silica fume and sodium aluminate , 2007 .

[18]  J. Davidovits.  Geopolymers : inorganic polymeric new materials , 1991 .

[19]  L. Warr,et al.  The influence of alkali activator type, curing temperature and gibbsite on the geopolymerization of an interstratified illite-smectite rich clay from Friedland , 2017 .

[20]  J. Klinowski,et al.  29Si and 27Al magic-angle-spinning NMR studies of the thermal transformation of kaolinite , 1990 .

[21]  S. Guggenheim,et al.  The Dehydroxylation of Chlorite and the Formation of Topotactic Product Phases , 1995 .

[22]  R. Dohrmann,et al.  Rietveld Refinement of Disordered Illite-Smectite Mixed-Layer Structures by a Recursive Algorithm. II: Powder-Pattern Refinement and Quantitative Phase Analysis , 2012, Clays and Clay Minerals.

[23]  G. Lecomte‐Nana,et al.  Kaolin-based geopolymers: Effect of mechanical activation and curing process , 2013 .

[24]  H. Eckert,et al.  Site Connectivities in Amorphous Materials Studied by Double-Resonance NMR of Quadrupolar Nuclei: High-Resolution 11B ↔ 27Al Spectroscopy of Aluminoborate Glasses , 1999 .

[25]  Raffaele Cioffi,et al.  Optimization of geopolymer synthesis by calcination and polycondensation of a kaolinitic residue , 2003 .

[26]  M. E. Smith,et al.  Solid-state NMR characterisation of the thermal transformation of a Hungarian white illite. , 2005, Solid state nuclear magnetic resonance.

[27]  Emil Makovicky,et al.  Pozzolanic reactions of six principal clay minerals: Activation, reactivity assessments and technological effects , 1995 .

[28]  K. MacKenzie,et al.  Formation of inorganic polymers (geopolymers) from 2:1 layer lattice aluminosilicates , 2008 .

[29]  S. Ashbrook,et al.  27Al multiple-quantum MAS and 27Al{1H} CPMAS NMR study of amorphous aluminosilicates , 2001 .

[30]  G. Brindley,et al.  Crystal Structures of Clay Minerals and their X-ray Identification , 1982 .

[31]  Robert C. Reynolds,et al.  X-Ray Diffraction and the Identification and Analysis of Clay Minerals , 1989 .

[32]  J. Provis,et al.  Designing Precursors for Geopolymer Cements , 2008 .

[33]  Hua Xu,et al.  The effect of alkali metals on the formation of geopolymeric gels from alkali-feldspars , 2003 .

[34]  Grant C. Lukey,et al.  Physical evolution of Na-geopolymer derived from metakaolin up to 1000 °C , 2007 .

[35]  Meirong Wang,et al.  Influence of calcination temperature of kaolin on the structure and properties of final geopolymer , 2010 .