Effect of milling speed on the iron mill scale particle size

Abstract

Iron mill scale is a waste of steel processing and physically is flakes in shape. Milling is a process to reduce iron mill scale into a fine powder. The purpose of this study is to find the best milling speed to produce the average particle size of 300 µm and below 75 µm. To achieve the objective, different of milling speeds were used and start with lowest speed and followed by highest speed. Then, the middle speed between these two points was determined. This process was repeated for the second and third stage. Two types of sample were used which were from Southern Steel Berhad (SSB) and Perwaja Steel Berhad (PSB). There were eleven milling speed which were 40, 105, 170, 235, 300,430, 560 rpm for SSB sample and 137.5, 202.5, 365 rpm, 495 rpm for PSB sample. After milling process, samples undergo sieving for particle size of 1100, 600, 300, 150, 75 and below 75 µm. Then, the samples were analyzed and selected for powder analysis. The powder analysis provide the iron mill scale properties such as phase identification by XRD, morphology by SEM, composition by EDS, surface area by BET and particle distribution by particle size analyzer. For SSB sample, the best milling speed to produce the average particle size 300 µm was 105 rpm and < 75 µm was 170 rpm. For PSB sample, the best milling speed was 202.5 rpm for both size of 300 µm dan < 75 µm.