THE EFFECT OF GRINDING MEDIA PERFORMANCE ON WET MILLING OF CALCITE

Abstract

This study aimed to conduct systematic research on the design of high-density zircon (ZrO₂) grinding media (0.2-1 mm) in a laboratory-scale media mill (750 ml) for wet grinding of calcite (CaCO₃, d₅₀= 5.4 µm). Sub-micron grinding experiments were carried out by using different amounts of finer grinding media (25%, 50% and 75%) and different size ratio of finer-coarser media (0.2 and 0.5). Besides, the surface areas (S_bw, m²/kg) of grinding media on grinding performance were investigated. If the best experimental results are compared (M1 and M4), it is found that the S_bw of the bimodal media(M4) is 75% larger compared to that of monosized media (M1). The experimental results were analyzed based on product size (d₅₀, d₈₀), cumulative undersize curves and specific surface area (S_W, m²/g). The findings showed that only the finer grinding media was not very effective at 600 rpm.

Keywords

• Calcite,Media size,Stirred media mill

Kalsitin Yaş Öğütülmesinde Öğütücü Ortam Performansının Etkisi

Öz

Bu çalışmada, kalsitin (CaCO₃, d₅₀=5,4 µm) yaş öğütülmesi üzerine laboratuvar ölçekli bilyalı değirmende (750 ml) yüksek yoğunluğa sahip zirkon (ZrO₂) bilya (0,2-1 mm) tasarımıyla sistematik bir çalışma amaçlanmıştır. Farklı miktarda ince bilya (%25, %50 ve %75) ve farklı ince-iri bilya oranları (0,2 ve 0,5) kullanılarak mikron-altı öğütme gerçekleştirilmiştir. Ayrıca, öğütücü ortamın yüzey alanlarının (S_bw, m²/kg) öğütme performansına etkisi araştırılmıştır. En iyi deney sonuçları karşılaştırıldığında (M1 ve M4), karışık bilya boyut dağılımının (M4) yüzey alanı, tek tip bilya boyut dağılımının (M1) yüzey alanından %75 daha fazladır. Deneysel sonuçlar ürün boyutu (d₅₀, d₈₀), kümülatif elek altı eğrisi ve spesifik yüzey alanı (S_W,m²/g) dikkate alınarak değerlendirilmiştir. Sonuçlar, sadece ince boyutlu öğütücü ortamın 600 devir/dk hızda çok fazla etkili olmadığını gösteriyor.

Anahtar Kelimeler

• Bilya boyutu,Kalsit,Karıştırmalı bilyalı değirmen

Kaynakça

1. Bel Fadhel, H. and Frances, C., 2001, “Wet batch grinding of alumina hydrate in a stirred bead mill”, Powder Technology, 119, (2–3), 257–268.
2. Bilgili, E., Hamey, R., Scarlett, B., 2004, “Production of Pigment Nanoparticles Using a Wet Stirred Mill with Polymeric Media”, China Particuology, 2, 93–100.
3. Breitung-Faes, S. and Kwade, A., 2008, “Nano particle production in high-power-density mills” Chemical Engineering Research and Design, 86, 4, 390–394.
4. Cho, K., Chang, H., Kil, D. S., Kim, B. G., Jang, H. D., 2009, “Synthesis of dispersed CaCO3 nanoparticles by the ultrafine grinding”, Journal of Industrial and Engineering Chemistry, 15, 243–246.
5. Kotake, N., Matsumoto, K., Sekine, Y., Gunjı, S., Kezuka, H., 2014, “Effect of Poly-sized and Mono-sized Grinding Media on Fine Grinding of Limestone in a Bead Mill”, International Journal of the Society of Materials Engineering for Resources, 20, 147-153.
6. Kumar, P., Sahoo, B. K., De, S., Kar, D. D., Chakraborty, S., Meikap, B. C., 2010, “Iron ore grindability improvement by microwave pre-treatment”, Journal of Industrial and Engineering Chemistry, 16, 805-812.
7. Kwade, A., Blecher, L., Schwedes, J., 1996, “Motion and stress intensity of grinding beads in a stirred media mill: Part II. Stress intensity and its effect on comminution”, Powder Technology, 86, 69– 76.
8. Mankosa, M. J., Adel, G. T. and Yoon, R. H., 1986, “Effect of media size in stirred ball mill grinding of coal”, Powder Technology, 4, 75–82.

9. Patel, C. M., Chakraborty, M., Murthy, Z. V. P., 2014, “Enhancement of stirred media mill performance by a new mixed media grinding strategy”, Journal of İndustrial and Engineering Chemistry, 20, 2111-2118.
10. Tüzün, M. A., 1994, “A study of comminution in a vertical stirred ball mill”, Ph.D. Dissertation, Chemical Engineering Department, University of Natal.
11. Vital, A., Zurcher, S., Dittmann, R., Trottmann, M., Lienemann, P., Bommer, B., Graule, T., Fadhel, H. B., Frances, C., 2001, “Wet batch grinding of alumina hydrate in a stirred media mill”, Powder Technology, 119, 257-268.
12. Wang, Y., Forssberg, E., 2007, “Enhancement of energy efficiency for mechanical production of fine and ultra-fine particles in comminution”, China Particuology, 5, 193–201.
13. Yokoyama, T., Huang, C. C., 2005, “Nanoparticle technology for the production of functional materials”, Kona, 23, 7–17.
14. Yue, J., and Klein, B., 2006, “Effects of bead size on ultrafine grinding in a stirred bead mill”, Advances in Comminution, Kawatra S. (ed.), Society for Mining, Metallurgy and Exploration, Inc.