Continuous grinding mill simulation using Austin's model

Abstract

Comminution is a frequently-required step in mineral processing and is responsible for almost 90% of all energy consumption in a mineral processing plant. Tumbling mill design has been studied since the middle of the XIX century. There are many comminution models in the literature, with preponderance, however, of Austin’s model (2002) for mineral impact breakage. In this paper, Austin’s model was applied to tubular tumbling mills. Once Austin’s model was proposed for batch processing of narrowly-distributed fraction sizes, an artifice has allowed it to be used in continuous grinding mill processes with widely-distributed fraction sizes. Interesting results were obtained with errors less than 0.005 for mills with sharp residence time distributions.

Coal Sampe Preparation Strategy using the TENCAN GQM series Ball Milling device.

“…Because ball milling operates at charge capacity range between [65% − 80%] of the total milling Jar volume, it is vital to select the correct grinding medium percentage loading limits for all the experimental involved such that when selecting a maximum ball load percentage at [20%], feedstock amount must occupy about [60%] the mill Jar volumetric capacity. High density balls should be selected when grinding large and hard coal aggregates in feed materials while small sized grinding media must be included in small quantities to aid breakage contact region between large grinding media therefore achieving upgraded liberation in minimum grinding duration [1], [12]. A larger feed size distribution [−40mm, +14mm] needs a heterogeneous ball mix of large balls, intermediate size to small diameter grinding media to accommodate coal particles residing in void between larger grinding media.Table 2 and Table 3 highlight the ball filling combination activity in our modelling trials which were nominated between the minimum and maximum ball charge loading percentage range of [20%−35%] such that central composite design (CCD) strategies a proper combination will was identified in a randomized design of experiment combining featuring all possible ball-mix ratio of large balls, medium size balls and small balls [5], [57].…”

“…Figure 2 illustrates the charge material displacement from resting position to the ultimate height position labeled at point P, such that both the kinetic energy and gravitational energy exerted onto the charge material are at equilibrium and further linear energy increments will cause the charge or feed material to spin into complete mill circle without cascading or cataracting and failing the tumbling effect that cause particle fragmentation. The critical speed equation development can thus be traced mathematically through this model adaptation in accordance to the (Equations 1) through to (Equation 5), in chronological steps [1], [9], [12], [19], [20], [21], [22]. Where; (m) is the mass in (kg) of the grinding medium, (V) is the linear velocity (m/s) while (ℊ) is the acceleration due to gravity (m/s 2 ).…”

“…However, product size distribution can be altered by changing grinding conditions in an optimization design for which configure to the semi-autogenous grinding mill setup, therefore based on the mass recovery of products data response function equations can be estimated which precisely describe the ideal experimental settings that connect input parameter data to generated response output [1], [9], [10], [11], [12].…”

“…Nonetheless most customized cylindrical mill designs are constructed with liners of tungsten carbide high-grade matrix alloys or other exceptional composite rubber liners capable of withstanding accelerated wear rates and highly scratch resistant. Liners are waved in structure while others are grid shape manufactured to aid industrial milling cylinders comminute various material at minimum effort because they prolonged the lifespan of mill equipment while affording maximum grinding efficacy achieved through liner grids and an added hard surface [12], [13], [14], [15].…”

Coal Sample Preparation Strategy using the TENCAN GQM series Ball Milling device.

“…However, product size distribution can be altered by changing grinding conditions in an optimization design for which configure to the semi-autogenous grinding mill setup, therefore based on the mass recovery of products data response function equations can be estimated which precisely describe the ideal experimental settings that connect input parameter data to generated response output [1], [9], [10], [11], [12]. In our study an attempt to maximize coal mass recovery at specific size ranges between [−600μm, +38μm] will be investigated by mimicking the grinding time, grinding media load and the coal feed amount per session at constant operation speed (Nc) of the TANCAN roll ball milling machinery.…”