LIGHTWEIGHT AGGREGATE PRODUCTION by RAPID SINTERING TERRA ROSSA-NaOH MIXTURES in MICROWAVE OVEN

Abstract

In this study, the use of microwave ovens (MO) in the production of lightweight aggregates (LWA) with rapid sintering method was investigated. Sintering temperatures up to 1200 C° was obtained by using SiC coated microwave kiln in MO. LWA were produced by rapid sintering terra rossa (TR)-NaOH mixtures at MO. Alkali amount (2.5, 5 and 7.5% NaOH by weight of TR), drying type (no drying, drying in laboratory at 20 ₒC or in oven at 80 ₒC for one day) and sintering time (8, 12 and 18 min) on the physical, mechanical and microstructure of aggregates were investigated. The aggregate pellets dried in oven were stronger than those dried in the laboratory. Thus the sintering cracks diminished and the compressive strengths were enhanced for aggregates. The highest compressive strength (36.96 kg/cm2) was obtained in aggregates using 2.5% NaOH by weight of TR, dried in oven and rapid sintered for 18 minutes. When more alkali (5% NaOH) was used, due to the increase in flux content; the aggregate shell formed earlier and had more time to expand up to 127%. Thus the unit weight (0.67 g/cm3) and compressive strength (4.74 kg/cm2) of the aggregate were decreased.

Keywords

• Rapid sintering
• Microwave
• Terra rossa
• Lightweight aggregate
• Compressive strength

References

1. [1] Ceramic history., (2016, 10 February). Access Address: https://hititterra.com/seramik-tarihcesi.
2. [2] Cengiz, O. and Kuşçu, M., (2010), Usability of Anamas Mountains-Isparta terra rossa in brick-tile production (Unpublished Master Thesis). Süleyman Demirel University, Institute of Science and Technology, Isparta.
3. [3] Rice, P.M., (1987), Pottery analysis, Chicago: The University of Chicago Press.
4. [4] Rashad, A.M., (2018), Lightweight expanded clay aggregate as a building material-An overview, Construction and Building Materials, 170, 757-775.
5. [5] Roces, E., Menéndez, M.M, Galindo, J.G, Estaire J., (2021), Lightweight expanded clay aggregate properties based on laboratory testing, Construction and Building Materials, 313, 125486, https://doi.org/10.1016/j.conbuildmat.2021.125486.
6. [6] Rattanachan, S., Lorprayoon C., (2005) Korat clays as raw materials for lightweight aggregates. Sci. Asia., 31, 277-281. doi: 10.2306/scienceasia1513-1874.2005.31.277.
7. [7] Kowalenko, W., Mojsiejenko, J., Roszak, W., (1972), Artificial Lightweight Aggregate, Production and Application, Arkady; Warsaw, Poland, 120-283.
8. [8] Piasecki, J., (1992), Structure of Grains of Lightweight Expanded Clay Aggregate a Model Approach. Scientific Works of Szczecin University of Technology, Institute of Civil Engineering; Szczecin, Poland, 69-77.

9. [9] Osiecka, E., (2000) Selected Issues on the Technology of Mineral Construction Composite Materials. Warsaw University of Technology; Warsaw, Poland, 98-184.
10. [10] de’Gennaro R., Cappelletti, P., Cerri, G., de’Gennar, M., Dondi, M., Langella, A. (2004), Zeolitic tuffs as raw materials for lightweight aggregates. Appl. Clay Sci., 25, 71-81. doi: 10.1016/j.clay.2003.08.005.
11. [11] Latosińska, J, Żygadło, M, Czapik, P., (2021), The Influence of Sewage Sludge Content and Sintering Temperature on Selected Properties of Lightweight Expanded Clay Aggregate. Materials, 14-3363, 1-17. doi: 10.3390/ma14123363.
12. [12] Kang, J., Wang, J., Zhou, X., Yuan, J., Hou, Y., Qian, S., Li, S., Yue, Y., (2018), Effects of alkali metal oxides on crystallization behaviour and acid corrosion resistance of cordierite based glass-ceramics, J. Non-Cryst. Solids, 481, 184-190.
13. [13] Ge, X., Zhou, M., Wang, H., Chen, L., Li, X., & Chen, X., (2019), Effects of flux components on the properties and pore structure of ceramic foams produced from coal bottom ash, Ceramics International, 45-9, 12528-12534.
14. [14] Avcı, M., (2018, 25 May, Microwave, Access Address: https://www.foodelphi.com/mikrodalga-teknolojisi/.
15. [15] Nabi, G., (2018, 5 February), Microwave sintering method, Access Address: https://docplayer.biz.tr/109511016-Mikrodalga-sinterleme-yontemi.html.
16. [16] Li, Q., Ye, R., Jin, R., Chen, H., Xia, G., & Li, T., (2020), Experimental study on dielectric properties of SiC material and temperature distribution of rubber materials containing silicon carbide coated metal via microwave heating. IOP Conference Series: Materials Science and Engineering, 772(1), 012012. https://doi.org/10.1088/1757-899x/772/1/012012.
17. [17] Wu, R., Zhou, K., Yue, C. Y., Wei, J., & Pan, Y., (2015). Recent progress in synthesis, properties and potential applications of SiC nanomaterials. Progress in Materials Science, 72, 1-60. doi: 10.1016/j.pmatsci.2015.01.003.
18. [18] Çekil, K., (2022), Mikrodalga sinterleme ile agrega üretimi, Yüksek Lisans Tezi, Kütahya Dumlupınar Üniversitesi, Fen Bilimleri Enstitüsü, Kütahya.
19. [19] EN 1097-6, (2015), Tests for mechanical and physical properties of aggregates - Part 6: Determination of particle density and water absorption, Comite European de Normalisation.
20. [20] Kockal N.U, Özturan T. (2011) Characteristics of lightweight fly ash aggregates produced with different binders and heat treatments, Cement and Concrete Composites, Volume 33-1, 61-67. https://doi.org/10.1016/j.cemconcomp.2010.09.007.
21. [21] Hiramatsu, Y., & Oka, Y., (1966), Determination of the tensile strength of rock by a compression test of an irregular test piece. Int. Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 3-2, 89-90. doi:10.1016/0148-9062(66)90002-7.
22. [22] De’ Gennaro, R., Cappelletti, P., Cerri, G., de’ Gennaro, M., Dondi, M., Guarini, G., Naimo, D., (2003), Influence of zeolites on the sintering and technological properties of porcelain stoneware tiles. Journal of the European Ceramic Society, 23-13, 2237-2245.
23. [23] Duvarcı, Ö.Ç., Akdeniz, Y., Özmıhçı, F., Ülkü, S., Balköse, D., Çiftçioğlu, M., (2007), Thermal behaviour of a zeolitic tuff, Ceramics International, 33-5, 795-801.
24. [24] Bhattacharya, M., Basak, T.A., (2016), Review on the susceptor assisted microwave processing of materials. Energy, 97, 306-38. https:// doi.org/10.1016/j.energy.2015.11.034.
25. [25] Lyra, G.P, Santos, V., Pallone, E.M.D.J.A., Herta Goldschmidt, A.K.R., De Santis, B.C., Adriano Rossignolo, J., (2021), Microwave hybrid fast sintering of red clay ceramics. Int. J. Appl. Ceram Technol., 18, 705-715. https://doi.org/10.1111/ijac.13676.
26. [26] Lyra, G.P., Santos, V., De Santis, B.C., Rivaben, R.R., Fisher, C., Pallone, E.M.D.J.A., Adriano Rossignolo, J., (2019), Reuse of sugarcane bagasse ash to produce a lightweight aggregate using microwave oven sintering, Construction and Building Materials, 222-20, 222-228. https://doi.org/10.1016/j.conbuildmat.2019.06.150.