Centrifugal mill charge motion and power draw: comparison of DEM predictions with experiment

2000 ◽  
Vol 59 (2) ◽  
pp. 131-148 ◽  
Author(s):  
Paul W. Cleary ◽  
David Hoyer
Keyword(s):  
Charge Motion ◽  
Centrifugal Mill ◽  
Power Draw ◽  
Mill Charge

scholarly journals EXPLORING THE DESIGN AND DEVELOPMENT OF AN "ON-THE-SHELL" TUMBLING MILL ACOUSTING MONITORING SYSTEM

2011 ◽  
Author(s):  
Suda Martins ◽  
Joachim Zepeda ◽  
Benoit Picard ◽  
Peter Radziszewski
Keyword(s):  
Data Acquisition System ◽  
Trial Data ◽  
Acoustic System ◽  
Charge Motion ◽  
Acoustic Data ◽  
Tumbling Mills ◽  
Toe Angle ◽  
Tumbling Mill ◽  
Mill Charge

In the mineral processing industry, tumbling mills are used in the size reduction or comminution of ore to a target size distribution. As the tumbling mill environment is quite violent it is difficult to monitor mill charge motion. One way is to develop an “on-the-shell” acoustic system. This system will be used in the determination of the charge toe angle of an operating tumbling mill. The instrument, microphone system with the appropriate data acquisition system, collects the acoustic data. An analysis of the signal determines the location of the toe. The results of this development along with some trial data are presented.

Autogenous grinding mill process control practices

2021 ◽  
pp. 38-42
Author(s):  
S. S. Khaymovskiy
Keyword(s):  
Control System ◽  
Process Control ◽  
Estimation Accuracy ◽  
Stable Operation ◽  
Motor Power ◽  
Ball Mills ◽  
Power Draw ◽  
Mill Charge ◽  
Mill Control ◽  
Grinding Mill

This paper considers pre-requisite conditions for developing grinding mill control systems and describes the main problems of control and existing constraints. The author selected a set of grinding equipment that consists of autogenous grinding mills and ball mills. The paper considers the selected mill types as control objects. It is shown that there exists a good correlation between the mill charge and its acoustic and vibration noise. The paper examines the relationship between the level of vibroacoustic noise and the mill motor power draw and defines what can be considered an extreme dependence, as well as the conditions in which a stable operation of the automatic system can be maintained excluding the mill overload mode. The paper specifies what hardware and software means would be necessary to implement such system and describes the mill charge analyzer VAZM-1M developed by Soyuztsvetmetavtomatika that was selected for this application. The author looks at certain downsides typical of the conventional control scheme when the head mill feed rate changes as the mill motor power draw changes without allowing for changing physical and mechanical properties of the ore material. The author also considers the capability of the VAZM-1M analyzer in terms of mill load estimation accuracy. This laid the basis for developing mill protection and optimization algorithms for the AG and Ball Mill comminution circuit. The paper features a block diagram of the control algorithm and its brief description. The algorithm consists of blocks, which are responsible for the following actions: they receive key process parameters from the process control system database, check them for validity, perform initial processing and filtering; after that they analyze the trends of the measured parameters and analyze if an overload condition is probable. As decided by the mill operator, the ore flow rate can be adjusted. The paper describes a case study of running an AG mill control system on the basis of the above described algorithm and using the VAZM-1M analyzer. It is noted that this algorithm can be implemented both as an adviser for the operator and for automatic control of the mill when running in overload mode.

scholarly journals INSTRUMENTED BALL DESIGN AND DEVELOPMENT

2011 ◽  
Author(s):  
Suda Martins ◽  
Wei Li ◽  
Peter Radziszewski
Keyword(s):  
Motion Simulation ◽  
Charge Motion ◽  
Ball Mills ◽  
Processing Industry ◽  
Tumbling Mills ◽  
Simulation Results ◽  
The Relationship ◽  
Instrument Package ◽  
Tumbling Mill ◽  
Mill Charge

In the mineral processing industry, tumbling mills are used in the size reduction or comminution of ore to a target size distribution. As the tumbling mill environment is quite violent it is difficult to monitor mill charge motion let alone single ball or particle motion. An effort was initiated to investigate the development of an instrumented ball that includes data collection capabilities. A variety of sensors, including accelerometers and gyros, form the instrument package. The data collected by the instruments allow the calculation of a number of dynamic and kinematic quantities as a function of time. Using instrumented ball data, the error model of the instrument can be found. Finally, the importance of the data with respect to ball mills is discussed along with the relationship between the instrumented ball data and charge motion simulation results is discussed.

Charge Motion Effects in Ionic Clusters

1991 ◽  
Author(s):  
Isidore Last ◽  
Thomas F. George
Keyword(s):  
Charge Motion ◽  
Ionic Clusters

Charge motion on silicon oxide surfaces

1967 ◽  
Vol 6 (4) ◽  
pp. 440-460 ◽  
Author(s):  
P. Ho ◽  
K. Lehovec ◽  
L. Fedotowsky
Keyword(s):  
Silicon Oxide ◽  
Oxide Surfaces ◽  
Charge Motion

MACROSCOPICALLY QUANTIZED HOLE STATES IN La2-χSrχCuO4-δ FILM CRYSTAL OBSERVABLE UP TO ROOM TEMPERATURE

2001 ◽  
Vol 15 (09) ◽  
pp. 1239-1252 ◽  
Author(s):  
M. SUGAHARA ◽  
S. OGI ◽  
K. ARAKI ◽  
R. SUGIURA
Keyword(s):  
Doping Level ◽  
Low Frequency ◽  
Side Surface ◽  
Life Time ◽  
Cell Number ◽  
Polarization Property ◽  
Dielectric Measurement ◽  
Charge Motion ◽  
Macroscopic Quantum ◽  
Macroscopic Quantum Effects

Theoretical study of multi-layered CuO 2 surfaces with localization potential shows that (i) special stable macroscopic quantum states appear when [Formula: see text], where χ is the doping level and G is the unit-cell number, and that (ii) the physical phenomena related to ‖c charge motion takes place just as expected in the fictitious situation where whole uniformly doped holes concentrate in one-side surface. In the dielectric measurement of doping-level dependence and film-thickness dependence on c-oriented La 2-χ Sr χ CuO 4-δ film, we find that (a) anomalous low-frequency polarization is enhanced when a scaling parameter χG is near to [Formula: see text], that (b) quasi-static measurement of the polarization property in low doped film shows two typical characteristics explicable by the fictitious charge concentrations, and that (c) ‖c small-voltage conduction measurement on low doped film also shows two types of characteristic which are switched each other triggered by laser irradiation. Since these macroscopic quantum effects with plural levels with very long life time are observable even up to room temperatures, they may be useful in quantum computing application.

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