ULTRASONİK SES DALGALARININ KÖMÜR TANE BOYUTU ÜZERİNE ETKİSİNİN ARAŞTIRILMASI

Abstract

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.

Keywords

• Ultrasonik ses dalgaları
• kömür
• tane boyut değişimi

INVESTIGATION OF THE EFFECTS OF ULTRASONIC ENERGY ON COAL PARTICLE SIZE

Abstract

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.

Keywords

• Ultrasonic wave
• coal
• particle size reduction

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