839
A Computational Method to Determine the Real Time Wear Rate
of Grinding Media in Ball Mill
Kumar Abhishek, Sujit Jagnade, Jose Martin Korath,
Navin Kumar Srivastav, Indrajit Paul, Surajit Sinha
Automation Dept., Tata Steel Ltd., Jamshedpur
ABSTRACT: A model for real-time estimation of the wear of grinding media in a ball mill of a pelletising plant
is developed considering the key mechanisms of collision(catracting) and abrasion(cascading). The model takes
feed characteristics and operating parameters of the mill and calculates rate of wear (in kg/ton of feed material).
Said model predicts wear of media in real time are in range of 0.25 to 0.73 Kg/ton and is validated on an
operating ball mill (550 tph) through plant trials and reverse predicted motor power. The solution deployed and
entailed savings on account of media consumption and energy reduction.
INTRODUCTION
The ball-mill is a hollow steel cylindrical chamber partially
filled with grinding media (steel balls) along with inner
peripheral liner and lifter, stands as a cornerstone in mod-
ern iron ore pellet manufacturing. Its pivotal role lies in the
reduction of raw materials like iron ore fines to the required
particle size for pelletization through impact and attrition.
This process ensures uniformity in particle size distribution,
crucial for subsequent iron ore pelletization. Additionally,
the ball mill facilitates material homogenization, blending
iron ore fines with additives and flux materials to achieve
a consistent mixture, optimizing the final pellet product’s
quality and performance. Crucial operational parameters
encompass the drum’s rotation speed, media size, feed rate,
mill liner design, media filling level, and moisture content,
all meticulously controlled to achieve efficient grinding,
ideal particle distribution, and the production of high-
quality iron ore pellets. The Tata Steel Ltd, Jamshedpur pel-
let plant, operational since 2012 with an 8 MTPA capacity,
incorporates various essential units, including raw mate-
rial drying and a grinding unit housing two ball mills in a
closed-circuit configuration with a dry classifier as shown
in Figure 1. These ball mills were initially designed with
a primary parameter, the Bond Work Index of iron ore in
range of 6–9 KWH/short T, crucial in achieving a through-
put capacity of 550 tph. However, since last few years, the
plant encountered a shift in the quality of the incoming
iron ore, presenting a higher Bond Work Index exceeding
11. This alteration, where the introduction of hard iron
ore into the grinding mill has led to a notable escalation
in the recirculation rate of the ground product. This surge
in recirculation has correspondingly caused a reduction in
mill throughput by approximately 15 to 20 percent as well
as heightened power consumption, and other operational
inefficiencies. Notably, the presence of this harder ore has
led to increased wear and tear on the media used within the
ball mill, further complicating operations. The prediction
and management of this accelerated wearing rate of grind-
ing media and quantity of top-up of media have emerged
as a paramount challenge during the ongoing operation
of the ball mill. Media used in ball mill operation plays
pivotal role to produce desired ground product of iron ore
and the media wear rate is one of dominant factor for ball
mill efficiency as it optimizes media usage, sustaining ideal
mill filling level in ball mill. The different zones of ball
mill operation and grinding phenomenon is represented in
Figure 1.
A Computational Method to Determine the Real Time Wear Rate
of Grinding Media in Ball Mill
Kumar Abhishek, Sujit Jagnade, Jose Martin Korath,
Navin Kumar Srivastav, Indrajit Paul, Surajit Sinha
Automation Dept., Tata Steel Ltd., Jamshedpur
ABSTRACT: A model for real-time estimation of the wear of grinding media in a ball mill of a pelletising plant
is developed considering the key mechanisms of collision(catracting) and abrasion(cascading). The model takes
feed characteristics and operating parameters of the mill and calculates rate of wear (in kg/ton of feed material).
Said model predicts wear of media in real time are in range of 0.25 to 0.73 Kg/ton and is validated on an
operating ball mill (550 tph) through plant trials and reverse predicted motor power. The solution deployed and
entailed savings on account of media consumption and energy reduction.
INTRODUCTION
The ball-mill is a hollow steel cylindrical chamber partially
filled with grinding media (steel balls) along with inner
peripheral liner and lifter, stands as a cornerstone in mod-
ern iron ore pellet manufacturing. Its pivotal role lies in the
reduction of raw materials like iron ore fines to the required
particle size for pelletization through impact and attrition.
This process ensures uniformity in particle size distribution,
crucial for subsequent iron ore pelletization. Additionally,
the ball mill facilitates material homogenization, blending
iron ore fines with additives and flux materials to achieve
a consistent mixture, optimizing the final pellet product’s
quality and performance. Crucial operational parameters
encompass the drum’s rotation speed, media size, feed rate,
mill liner design, media filling level, and moisture content,
all meticulously controlled to achieve efficient grinding,
ideal particle distribution, and the production of high-
quality iron ore pellets. The Tata Steel Ltd, Jamshedpur pel-
let plant, operational since 2012 with an 8 MTPA capacity,
incorporates various essential units, including raw mate-
rial drying and a grinding unit housing two ball mills in a
closed-circuit configuration with a dry classifier as shown
in Figure 1. These ball mills were initially designed with
a primary parameter, the Bond Work Index of iron ore in
range of 6–9 KWH/short T, crucial in achieving a through-
put capacity of 550 tph. However, since last few years, the
plant encountered a shift in the quality of the incoming
iron ore, presenting a higher Bond Work Index exceeding
11. This alteration, where the introduction of hard iron
ore into the grinding mill has led to a notable escalation
in the recirculation rate of the ground product. This surge
in recirculation has correspondingly caused a reduction in
mill throughput by approximately 15 to 20 percent as well
as heightened power consumption, and other operational
inefficiencies. Notably, the presence of this harder ore has
led to increased wear and tear on the media used within the
ball mill, further complicating operations. The prediction
and management of this accelerated wearing rate of grind-
ing media and quantity of top-up of media have emerged
as a paramount challenge during the ongoing operation
of the ball mill. Media used in ball mill operation plays
pivotal role to produce desired ground product of iron ore
and the media wear rate is one of dominant factor for ball
mill efficiency as it optimizes media usage, sustaining ideal
mill filling level in ball mill. The different zones of ball
mill operation and grinding phenomenon is represented in
Figure 1.