Effects of grinding media shapes on ball mill performance

Student number : 0318567G School of Chemical and Metallurgical Engineering Faculty of Engineering === Comminution is an important process in mineral processing, power plants, cement production and pharmaceutical industries. It is costly and an inefficient process in terms of energy requirements...

Full description

Bibliographic Details
Main Author: Lameck, Niyoshaka Nistlaba Stanley
Format: Others
Language:en
Published: 2006
Subjects:
Online Access:http://hdl.handle.net/10539/1506
id ndltd-netd.ac.za-oai-union.ndltd.org-wits-oai-wiredspace.wits.ac.za-10539-1506
record_format oai_dc
spelling ndltd-netd.ac.za-oai-union.ndltd.org-wits-oai-wiredspace.wits.ac.za-10539-15062019-05-11T03:40:47Z Effects of grinding media shapes on ball mill performance Lameck, Niyoshaka Nistlaba Stanley grinding comminution power load behaviour grinding media breakage kinetics Student number : 0318567G School of Chemical and Metallurgical Engineering Faculty of Engineering Comminution is an important process in mineral processing, power plants, cement production and pharmaceutical industries. It is costly and an inefficient process in terms of energy requirements and steel consumption related to grinding media and liners. Spherical grinding media are predominantly used in final stages of ore grinding. The spherical balls change shape through breakage and wear. Though this is universal in milling, its contribution and effect on milling kinetics, load behaviour and mill power is not fully established. One area that is usually ignored is the relationship between media shape and mill power. The objective of this dissertation was to investigate how media shape affects grinding. Ball size distribution inside an industrial mill was analysed in terms of shapes and sizes. Load behaviour, mill power and breakage as affected by media shapes were studied in a pilot laboratory mill. An inductive proximity probe, light emitting diode, phototransistor and video photographs were used to determine the load orientation in terms of toe and shoulder positions. A load beam was used to measure the torque exerted by the charge. The variation in load orientation and mill power with speed among different media shapes was observed. Higher shoulder positions were noted with cylpebs than with worn and spherical balls. The power increased to a maximum with increasing mill speed for all media shapes reaching its peak at different mill speeds for the three shapes studied. Variations of breakage rates with media shapes were found; higher breakage rates were noted with spherical media but the differences narrows with decreasing feed size and increasing material fractional filling U. Considering that worn balls in an industrial mill charge constitute about 15 to 40 percent and that the highest difference in breakage rate observed being nine percent for purely one shape charge; it is very doubtful whether it is worthwhile in attempting to develop techniques for removing worn balls from the mill. 2006-10-31T06:53:13Z 2006-10-31T06:53:13Z 2006-10-31T06:53:13Z Thesis http://hdl.handle.net/10539/1506 en 1073957 bytes application/pdf application/pdf
collection NDLTD
language en
format Others
sources NDLTD
topic grinding
comminution
power
load behaviour
grinding media
breakage kinetics
spellingShingle grinding
comminution
power
load behaviour
grinding media
breakage kinetics
Lameck, Niyoshaka Nistlaba Stanley
Effects of grinding media shapes on ball mill performance
description Student number : 0318567G School of Chemical and Metallurgical Engineering Faculty of Engineering === Comminution is an important process in mineral processing, power plants, cement production and pharmaceutical industries. It is costly and an inefficient process in terms of energy requirements and steel consumption related to grinding media and liners. Spherical grinding media are predominantly used in final stages of ore grinding. The spherical balls change shape through breakage and wear. Though this is universal in milling, its contribution and effect on milling kinetics, load behaviour and mill power is not fully established. One area that is usually ignored is the relationship between media shape and mill power. The objective of this dissertation was to investigate how media shape affects grinding. Ball size distribution inside an industrial mill was analysed in terms of shapes and sizes. Load behaviour, mill power and breakage as affected by media shapes were studied in a pilot laboratory mill. An inductive proximity probe, light emitting diode, phototransistor and video photographs were used to determine the load orientation in terms of toe and shoulder positions. A load beam was used to measure the torque exerted by the charge. The variation in load orientation and mill power with speed among different media shapes was observed. Higher shoulder positions were noted with cylpebs than with worn and spherical balls. The power increased to a maximum with increasing mill speed for all media shapes reaching its peak at different mill speeds for the three shapes studied. Variations of breakage rates with media shapes were found; higher breakage rates were noted with spherical media but the differences narrows with decreasing feed size and increasing material fractional filling U. Considering that worn balls in an industrial mill charge constitute about 15 to 40 percent and that the highest difference in breakage rate observed being nine percent for purely one shape charge; it is very doubtful whether it is worthwhile in attempting to develop techniques for removing worn balls from the mill.
author Lameck, Niyoshaka Nistlaba Stanley
author_facet Lameck, Niyoshaka Nistlaba Stanley
author_sort Lameck, Niyoshaka Nistlaba Stanley
title Effects of grinding media shapes on ball mill performance
title_short Effects of grinding media shapes on ball mill performance
title_full Effects of grinding media shapes on ball mill performance
title_fullStr Effects of grinding media shapes on ball mill performance
title_full_unstemmed Effects of grinding media shapes on ball mill performance
title_sort effects of grinding media shapes on ball mill performance
publishDate 2006
url http://hdl.handle.net/10539/1506
work_keys_str_mv AT lameckniyoshakanistlabastanley effectsofgrindingmediashapesonballmillperformance
_version_ 1719082595091742720