Characteristics of Glass Beads from Molten Slag Produced by Rotary Cup Atomizer

Abstract

Steelmaking is well known to be one of the highest energy-consuming industries, where high temperature molten slag is discharged without any heat recovery. This paper describes the hot experiments where a Rotary Cup Atomizer (RCA) is used to produce dry glassy slag without water impingement. In this, the properties for granulated slag were chiefly investigated. Molten slag was first poured onto the center of the rotating cup at various rotating speeds. Slag granulation was then observed using a video camera, and finally, the particles were collected for physical and chemical analyses. The results of XRD and DSC analyses demonstrate that all slag drops obtained by the RCA method are undoubtedly glassy. The particle size of the granulated slag is strongly controlled by both the diameter of the cup and the speed of rotation. The relationship between the particle size and the two parameters is expressed as D p ¼ 16:86=r!. Smaller particles that produced at a higher rotating speed seem to be more transparent or glassy and have compression strength twice higher in comparison with water granulated slag. The data obtained will provide valuable information not only for producing glassy slag, but also for exchanging energy between gas and molten slag efficiently.

Heat Recovery Process from Packed Bed of Hot Slag Plates

“…One promising heat resource that can be recovered is the waste heat of steelmaking slag, which has both a higher temperature and a higher calorific value than other types of waste heat and is unused in the current process. Although many slag heat recovery processes, including air atomizing [3][4][5][6] and mechanical atomizing, [7][8][9][10] were tried previously, 11,12) most were not successful at the industrial scale due to the instability of the physical properties of slag, such as viscosity, which changes drastically depending on both the temperature and the chemical composition of the slag. Furthermore, the heat conductivity of slag is also relatively low compared with that of other materials like coke, from which heat is recovered by coke dry quenching (CDQ), and this reduces the efficiency of heat recovery from a packed bed of slag particles.…”

Prediction of Granulated Slag Properties Produced from Spinning Disk Atomizer by Mathematical Model

“…A comparison of the calculated data and experimental one 15) shows the validity of the model for predicting the drop diameter. The agreement is reasonably good, except for experimental condition below 16.6 s À1 of rotating speed.…”

“…The number of the ligaments around the disk, K, was estimated using Kitamura's eqs. (13) to (15) under the operation conditions; additionally, the physical properties of the liquid slag and then the film thickness were also calculated. Accordingly, by substituting eq.…”

Effect of Solidification and Cooling Methods on the Efficacy of Slag as a Feedstock for CO₂ Mineralization

“…These theoretical results are consistent with the result of Purwanto et al which found fracture of RCA slag (amorphous) required ~1.82 times more energy than water-impinged slag (ostensibly a mixture of IG, GB, and IP fractures). 36) In slags solidified moderately quickly (e.g., water impinged, pit cooled), the polycrystalline structure results in the potential for IP, GB, and IG fractures. Though grain boundaries are plentiful, there is a random distribution in the alignment of grain boundaries to the application of force.…”