| Controlled object characteristics of the closed-circuit grinding process of ball mill with spiral classifiers are described in detail in this paper. Based on the specially designed control scheme and some common control algorithms, a JS- 872 type control system is developed, which includes the self-adjusting set-point control system of feed rate for grinding mills, and the constant value control system of classifier overflow density and flow rate, providing all the relevant data and operating records. The system has been applied in a medium scale mineral processing plant for more than five years, and has obtained beneficial results both in technology and economics. |