ULTRASONİK SES DALGALARININ KÖMÜR TANE BOYUTU ÜZERİNE ETKİSİNİN ARAŞTIRILMASI

Yıl 2020, Sayı: 002, 39 - 54, 31.12.2020

Uğur Demir

Öz

İnsan kulağı tarafından duyulamayan, 20 kHz frekanstan daha yüksek olan sese, ultrasonik ses dalgaları denilmektedir. Ultrasonik ses dalgaları cevher ve kömür hazırlamanın birçok alanından özellikle son 10-15 yıl içerisinde yaygın olarak kullanılmaya başlanmıştır. Ultrasonik sesin kavitasyon olarak tanımlanan mekanik etkisi, başta fiziksel olmak üzere kimyasal olarak ta mineral ve kömür üzerinde etkilere neden olmaktadır. Bu çalışmada önce ultrasonik ses dalgaları ve özellikleri hakkında bilgi verilecek, ardından kavitasyon etkinin kömür (yüksek oranda pirik kükürt içeren) tane boyutu üzerinde meydana getirdiği değişimler belirtilecektir. Deneysel çalışmalarda 20kHz frekans ile çalışmakta olan 200W güce sahip prob tipi ultrasonik ses üreteci kullanılmıştır. Ultrasonik ses dalgalarının farklı güç (%10-30) seviyesi ve süresinin (5-30 dakika) kömür numunesi boyutunda meydana getirdiği etki, referans tane boyutu olan 0,038 mm boyuttaki tane miktarı dikkate alınarak belirlenmiştir. Elde edilen sonuçlar ayrı ayrı ve beraber değerlendirildiğin de ultrasonik ses dalgalarının uygulama süresi ve güçteki artış tane boyutunda belirgin değişmelerin meydana gelmesine neden olduğu tespit edilmiştir. -4+2 mm tane boyutu içerisindeki -0,038 mm boyutlu malzeme miktarı ultrasonik işlemden sonra %1,86’dan %6,97’ye yükselmiştir. Yapılan mikroskobik incelemeler de ultrasonik ses dalgalarının kömür yüzeyinde yeni kırık ve çatlakların oluştuğunu göstermektedir.

Anahtar Kelimeler

Ultrasonik ses dalgaları, kömür, tane boyut değişimi

INVESTIGATION OF THE EFFECTS OF ULTRASONIC ENERGY ON COAL PARTICLE SIZE

Öz

Sound that cannot be heard by the human ear, which is higher than the 20 kHz frequency, is called ultrasonic waves. Ultrasonic waves have been widely used in many areas of ore and coal preparation, especially in the last 10-15 years. The mechanical effect of ultrasonic waves, defined as cavitation, causes various effects on mineral and coal, both physical and chemical. In this study, firstly information will be given about ultrasonic waves and properties, and then the changes caused by cavitation effect on coal (included high pyritic sulfur) particle size will be specified. In experimental studies, a probe type ultrasonic wave generator with a power of 200W operating at a frequency of 20 kHz was used. The effect of ultrasonic waves at different power level (10-30%) and application time (5-30 minutes) on coal sample size was determined by considering the particle size of the reference particle size of 0.038 mm. When the obtained results were evaluated separately and together, it was found that the increase in power and application time of ultrasonic waves caused significant changes in particle size. The amount of material in the -4 + 2 mm size group increased from 1.86% before applying ultrasonic treatment to the grain size of -0.038 mm to 6.97%. Microscopic examinations also show that ultrasonic waves have formed new fractures and cracks on the coal surface.

Anahtar Kelimeler

Ultrasonic wave, coal, particle size reduction

Kaynakça

• [1] Pesic B., (1996), Application of ultrasound in solvent extraction of nickel and gallium, Idaho National Engineering Laboratory, Idaho Falls, Idaho
• [2] Alp İ., (1998), Yüksek frekanslı ses dalgalarının cevher zenginleştirmede kullanabilirliliğinin araştırılması, Doktora tezi, Osmangazi Üniversitesi Fen Bilimleri Enstitüsü, Eskişehir
• [3] Önal G., Özer M., Arslan F., (2003), Sedimentation of clay in ultrasonic medium, Minerals Engineering, vol:16, pp129-134
• [4] Aditya S., Nandi Tapas K., Pal Samir K., Majumder Arun K. (2017), Pre-treatment of rocks prior to comminution – A critical review of present practices, International Journal of Mining Science and Technology 27 339–348
• [5] Kyllönen, H. Pirkonen, P. Hintikka, V. Parvinen, P. Grönroos, A. Sekki, H. (2004), Ultrasonically aided mineral processing technique for remediation of soil contaminated by heavy metals, Ultrasonics Sonochemistry 11 211–216
• [6] Teipel, U. Leisinger, K. Mikonsaari I. (2004), Comminution of crystalline material by ultrasonics, Int. J. Miner. Process. 74S p183–190
• [7] Suslick K. S., Price G. J., (1999), Application of ultrasound to materials chemistry, Annual Reviews Materials Scinece, vol:29, pp295-326
• [8] Farmer A.D., Collings A.F., Jameson G.J., (2000), Effect of ultrasound on surface cleaning of silica particles, İnternation Journal of Mineral Processing, vol:60, pp101-113
• [9] Farmer, A.D. Collings, A.F. Jameson, G.J. (2000), The application of power ultrasound to the surface cleaning of silica and heavy mineral sands, Ultrasonics Sonochemistry 7 243–247
• [10] Kang W., Xun H., Kong X., Lı M. (2009), Effects from changes in pulp nature after ultrasonic conditioning on high-sulfur coal flotation” Mining Science and Technology 19 0498–0502
• [11] Küncek, İ. Sener S. (2010), Adsorption of methylene blue onto sonicated sepiolite from aqueous solutions, Ultrasonics Sonochemistry 17 250–257
• [12] Bang, J., H., ve S. Suslick K., S., (2010), Applications of Ultrasound to the Synthesis of Nanostructured Materials, Adv. Mater. 22, 1039–1059
• [13] Seidi, S., Yamini Y., (2012), Analytical sonochemistry; developments, applications, and hyphenations of ultrasound in sample preparation and analytical techniques, Cent. Eur. J. Chem.10(4) 938-976
• [14] Leonelli, C. Mason, T.J. (2010), Microwave and ultrasonic processing: Now a realistic option for industry, Chemical Engineering and Processing 49 885–900
• [15] Turan Ö., (2007), Boraks çözeltilerinden probertit çökmesine ultrases dalgalarının etkisinin incelenmesi, Yüksek Lisans Tezi, İTÜ Fen Bilimleri Enstitüsü, İstanbul
• [16] Mao Y., Xia W., Peng Y., Xie G., (2019), Ultrasonic-assisted flotation of fine coal: A review, Fuel Processing Technology 195 106150
• [17] Mao Y., Chen Y., Bu X., Xie G., (2019), Effects of 20 kHz ultrasound on coal flotation: The roles of cavitation and acoustic radiation force, Fuel 256 115938
• [18] Demir U., (2019) Ultrasonik ses dalgalarının gümüş liçi performansına etkisinin araştırılması, DPU Bilimsel Araştırma Projeleri Birimi, Proje No: 2016-60, Proje Sonuç Raporu
• [19] Ambedkar B., Nagarajan R., Jayanti S., (2011), Investigation of high-frequency, high-intensity ultrasonics for size reduction and washing of coal in aqueous medium, Industrial and Engineering Chemistry Research 50 13210–13219.
• [20] Şahinoğlu, E., Uslu, T., (2013), Increasing coal quality by oil agglomeration after ultrasonic treatment, Fuel Processing Technology 116 332–338
• [21] Şahinoğlu, E., Uslu, T., (2015) Effects of various parameters on ultrasonic comminution of coal in water media, Fuel Processing Technology 137 48–54
• [22] Ambedkar, B. Chintala,T.N. Nagarajan, R. Jayanti, S. (2011), Feasibility of using ultrasound-assisted process for sulfur and ash removal from coal, Chemical Engineering and Processing 50 236–246
• [23] Gartner W. (1953), Über die Möglichkeit der zerkleinerung suspendierter stoffe durch ultrashall, Acustica 3 124–128.
• [24] Fleischhauer,W.J. Kröger,C. (1969), Forschungsberichte des Landes, Nordrhein Westfallen No. 2081,
• [25] Graff, K.F. In: (1979) Ultrasonic Comminution, Ultrasonics International ’79 Proc., May, Graz, Austria 171–175.
• [26] Kang W, Xun H, Hu J, (2008) Study of the effect of ultrasonic treatment on the surface composition and the flotation performance of high-sulfur coal, Fuel Progessing Technology 89 1337-1344
• [27] Raman V., Abbas A., (2008) Experimental investigations on ultrasound mediated particle breakage, Ultrasonics Sonochemistry 15 55–64
• [28] Raman, V. Abbas, A. Zhu, W. (2011) Particle grinding by high-intensity ultrasound: kinetic modeling and identification of breakage mechanisms, AICHE J. 57
• [29] Gaete-Garreto´n L.F., Vargas-Herma´ndez Y.P., Velasquez-Lambert C., (2000) Application of ultrasound in comminution, Ultrasonics 38 345–352
• [30] Ambedkar B., Nagarajan R., Jayanti S., (2011) Ultrasonic coal-wash for de-sulfurization, Ultrason. Sonochem. 18 718–726. 2025–2035.