skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Energy efficiency of cement finish grinding in a dry batch ball mill

Abstract

Dry grinding experiments on cement clinker were carried out using a laboratory batch ball mill equipped with torque measurement. The specific energy was found to be dependent on operating parameters and clinker environment. Additional compounds such as gypsum and pozzolanic tuff improve energy efficiency. The optimal parameters allowing maximising the energy efficiency factor were determined. Energy efficiency factors were obtained both on the crude material (size minus 2.8 mm) and on a sieved fraction (1-0.71 mm). They demonstrate that a low initial rate of breakage implies higher energy efficiency. On the contrary, conditions ensuring an initial maximal rate of breakage lead to an increase of the energy consumption.

Authors:
 [1];  [2];  [3]
  1. Laboratoire de Genie Chimique, UMR CNRS 5503, ENSIACET, 5 rue Paulin Talabot, 31106 Toulouse Cedex 01 (France)
  2. Department of Industrial Chemistry, USTHB, BP 32 El-Alia, 16000 Algiers (Algeria)
  3. Laboratoire de Genie Chimique, UMR CNRS 5503, ENSIACET, 5 rue Paulin Talabot, 31106 Toulouse Cedex 01 (France). E-mail: Christine.Frances@ensiacet.fr
Publication Date:
OSTI Identifier:
20793276
Resource Type:
Journal Article
Resource Relation:
Journal Name: Cement and Concrete Research; Journal Volume: 36; Journal Issue: 3; Other Information: DOI: 10.1016/j.cemconres.2005.12.005; PII: S0008-8846(05)00313-3; Copyright (c) 2005 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CEMENTS; ENERGY CONSUMPTION; ENERGY EFFICIENCY; GRINDING; GYPSUM; SURFACE AREA; TORQUE; TUFF

Citation Formats

Touil, D., Belaadi, S., and Frances, C. Energy efficiency of cement finish grinding in a dry batch ball mill. United States: N. p., 2006. Web. doi:10.1016/J.CEMCONRES.2005.1.
Touil, D., Belaadi, S., & Frances, C. Energy efficiency of cement finish grinding in a dry batch ball mill. United States. doi:10.1016/J.CEMCONRES.2005.1.
Touil, D., Belaadi, S., and Frances, C. Wed . "Energy efficiency of cement finish grinding in a dry batch ball mill". United States. doi:10.1016/J.CEMCONRES.2005.1.
@article{osti_20793276,
title = {Energy efficiency of cement finish grinding in a dry batch ball mill},
author = {Touil, D. and Belaadi, S. and Frances, C.},
abstractNote = {Dry grinding experiments on cement clinker were carried out using a laboratory batch ball mill equipped with torque measurement. The specific energy was found to be dependent on operating parameters and clinker environment. Additional compounds such as gypsum and pozzolanic tuff improve energy efficiency. The optimal parameters allowing maximising the energy efficiency factor were determined. Energy efficiency factors were obtained both on the crude material (size minus 2.8 mm) and on a sieved fraction (1-0.71 mm). They demonstrate that a low initial rate of breakage implies higher energy efficiency. On the contrary, conditions ensuring an initial maximal rate of breakage lead to an increase of the energy consumption.},
doi = {10.1016/J.CEMCONRES.2005.1},
journal = {Cement and Concrete Research},
number = 3,
volume = 36,
place = {United States},
year = {Wed Mar 15 00:00:00 EST 2006},
month = {Wed Mar 15 00:00:00 EST 2006}
}
  • Machinery and equipment suitable for retrofits in existing finish grinding systems and for new installations are described: adjustable diaphragms for ball mills to control the material transfer from the first to the second compartment; static separators for product separation from the mill vent air; dynamic high-efficiency separators for product separation, with and without recirculation of separation air; and high-pressure grinding rolls for pregrinding or for use in a closed circuit. For all equipment, operating results are given with respect to capacity and energy efficiency. These results clearly demonstrate that considerable improvements in existing grinding systems, as well as higher energymore » efficiencies of new grinding systems, can be accomplished with these features.« less
  • Residence time distributions (RTDs) were estimated by water tracing in a number of wet overflow ball mills (diameters 0.38 to 4.65 m) producing dense, coal-water slurries. In open-circuit mills of 0.38 m diameter and various length-diameter (LID) ratios, the mean residence times of solid were also determined from measured mill holdups. Holdup increased with increased mill feed rate, but the mean residence times of coal and water were still equal to each other. The experimental residence time distributions were fitted to the Mori-Jimbo-Yamazaki semi-infinite, axial mixing model, and the dimensionless mixing coefficient was determined for each of 25 tests inmore » single- and two-compartment mills. This coefficient was found to be independent to the feed rate but linearly proportional to the D/L ratio. The mixing coefficient was smaller for two-compartment mills than for single-compartment mills, showing that there was reduced mixing introduced by the diaphragm separating the compartments. Equations are given to scale residence time distributions for changes in mill diameter and length.« less
  • Conventional closed-circuit ball mill systems for the finish grinding of portland cement produces product particle size distributions (PSDs) which indicate poor reduction of topsize and excessive production of fines. Optimization of ball mill systems should improve energy efficiency while meeting or exceeding typical cement performance requirements. Pilot scale continuous grinding systems, including a closed-circuit ball mill with a conventional classifier, a high-efficiency classifier, or a vertical roller mill were used to determine operating conditions and configurations which would lead to narrowing of the cement PSD. Closed-circuit ball mill results suggest that several opportunities exist to increase particle breakage efficiencies whilemore » minimizing unnecessary fines generation by means such as: modification of mill recirculation rates, optimal selection of ball size distribution, and use of highly efficient particle size classifiers. Mill system design philosophies common worldwide which favor long mill lengths, fine ball charges, and low circulating loads are called into question. In order to produce cements with acceptable early mortar strengths by sole use of a roller mill, products must be ground to finenesses similar to those of conventional cements.« less
  • The inert gas atomised prealloyed copper powders containing 3.5 wt.% Al were milled up to 20 h in the planetary ball mill in order to oxidize aluminium in situ with oxygen from the air. In the next procedure compacts from milled powder were synthesized by hot-pressing in argon atmosphere. Compacts from as-received Cu-3.5 wt.% Al powder and electrolytic copper powder were also prepared under the same conditions. Microstructural and morphological changes of high energy milled powder as well as changes of thermal stability and electrical conductivity of compacts were studied as a function of milling time and high temperature exposuremore » at 800 deg. C. Optical, scanning electron microscopy (SEM) and X-ray diffraction analysis were performed for microstructural characterization, whereas thermal stability and electrical conductivity were evaluated by microhardness measurements and conductometer Sigmatest, respectively. The prealloyed 5 h-milled and compacted powder showed a significant increase in microhardness reaching the value of 2600 MPa, about 4 times greater than that of compacts synthesized from as-received electrolytic copper powder (670 MPa). The electrical conductivity of compacts from 5 h-milled powder was 52% IACS. The results were discussed in terms of the effect of small grain size and finely distributed alumina dispersoids on hardening and thermal stability of compacts.« less
  • Fine grinding of taconite for the liberation of iron-containing minerals is very energy-intensive. This investigation has shown that a high-pressure roll mill is significantly more energy-efficient than the traditional ball mill. Further energy efficiency can be achieved by grinding taconite in a hybrid mode, whereby the material is first ground in a high-pressure roll mill and then in a ball mill. However, optimal partitioning of energy between the two mills is necessary for attaining maximum efficiency. 10 refs., 5 figs.