EFFICIENT USE OF ELECTRIC ENERGY WHEN OPERATING A BALL MILL WITH A CONSTANT ROTATION SPEED

Abstract

Link for citation: Zakamaldin A.A., Perevoshchikov F.V., Shilin A.A. Efficient use of electric energy when operating a ball mill with a constant rotation speed. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 9, рр. 115-127. In Rus. The relevance. Ball mills are widely used in industry for grinding bulk materials, as well as in the last stages of ore crushing, where the required optimal particle sizes are achieved for enrichment. Although ball mills have a relatively simple design and cover extensive research, the industry is still struggling with the very low energy efficiency of the grinding process. As the retrofitting heavy equipment is the costliest approach, process optimization through control system is the most suitable for energy consumption reduction. As a rule, the feed rate is the main control variable for a mill with a constant rotation speed. Due to insufficient information content, outdated methods of analysis and control of the internal dynamics of the mill, control systems keep the target value of feed rate at a deliberately low level in order not to overload the mill. This article provides an explanation of how, in such a case, an increase in mill feed rate could affect the energy efficiency of grinding. The main aim: study of energy efficient modes of operation of stations; verification of models and confirmation of experimental data: the relationship between door loading and power consumption indicators; construction of buildings for energy efficient control of ball towers. Objects: the process of grinding in a ball tower with a constant rotation speed. Methods: mathematical description of the behavior of the electromechanical part of a machine that consumes current and works on a load in the form of spherical furniture; simulation modeling of the operation of the door electric drive; statistical analysis of production indicators. Results. The paper demonstrate the tendency to increase electricity consumption with a decrease in feed rate and vice versa, respectively for ball mills with a synchronous drive of 2500 kW based on modeling and experimental data. Increase in feed rate in the range of 10–40 t/h, there is a drop in active power by 0,48–1,57 %. The values of the specific power consumption of ~5–8 kWh/t during the grinding of apatite ore were obtained. An increase in productivity by 5 t/h on average leads to a decrease in the specific power consumption by 0,12 kWh/t. It is necessary to increase productivity in the operation of ball mills only after integrating measuring instruments into the control system of the mill, which allow an accurate assessment of the state of loading of the mill drum.

Keywords

• mineral processing
• grinding
• ball mill
• mill loading
• productivity
• energy efficiency