Measurement of the wear rate of cast grinding balls using radioactive tracers

Abstract

The wear rate of grinding balls is usually difficult to determine under operational conditions, and little is known about the factors determining ball life. Radioactive tracers have been used successfully to mark cast steel balls to obtain information on their life under various operating conditions, in comparison with balls of different type or composition. A batch of marked steel balls has been followed through a mill operation over several weeks, and statistics on wear and loss of weight have been obtained. In earlier test runs using Fe -59 , techniques were established and qualitative observations made on wear rate. In the present experiments, Co was used as the tracer, which was added to the molten metal prior to casting. The cast balls were used in a mill at an iron mine. The radioactive batch was added to the ball mill which had a normal charge of about 77.3 tons (metric). The charge was sampled at weekly intervals to pick out some of the radioactive balls. These balls were inspected and weighed, and the wear rate has been calculated. This procedure has proved to be a practical way of investigating grinding behaviour under plant operating conditions