Method and system for operating a comminution process in a ball mill

A system comprising:

• a tumbling mill configured to perform a comminution process, the tumbling mill being a ball mill having a shell that is rotatable around an axis at a speed of rotation for grinding a charge of material by tumbling the material together with a number of grinding balls in the rotating shell so as to generate product particles;
• said shell having an internal shell surface including a first number of protrusions configured to engage material and/or grinding balls when the shell rotates about the axis, thereby causing a vibration having a first repetition frequency dependent on said speed of rotation;
• the ball mill comprising:
• a first feed inlet for receiving, at a solid material feed rate, a solid feed material for grinding;
• said solid material feed rate being an amount of solid material feed particles per time unit that is being fed into an input of the tumbling mill thereby influencing an internal state of said comminution process;
• said solid material feed rate being controlled or set by a solid material feed rate set point value;
• the solid feed material feed particles having a feed particle size distribution;
• a ball feed inlet for receiving, at a ball feed rate, said grinding balls for enhancing said grinding;
• said ball feed rate being an amount of grinding balls per time unit that is being fed into a feed ball inlet of the tumbling mill thereby influencing said internal state of said comminution process;
• said ball feed rate being controlled or set by a ball feed rate set point value;
• a mill output for delivery of said product particles;
• said product particles having a product particle size distribution;
• said product particle size distribution being different from said feed particle size distribution;
• a vibration sensor for generating a signal indicative of said vibration;
• a position sensor for generating a signal indicative of a rotational position of said rotating shell;
• and
• a monitoring module being configured to receive data indicative of said vibration signal;
• and data indicative of said position signal;
• the monitoring module including:
• a status parameter extractor configured to generate at least one status parameter value indicative of an internal state of said comminution process based on said vibration signal and said position signal;
• said at least one status parameter value including a toe position value;
• and
• a product analyser configured to analyse at least a portion of said product particles;
• said analyser being configured to generate at least one product measurement value based on the analysing of said at least a portion of said product particles;
• said at least one product measurement value being indicative of a product particle median size;
• the system further comprising:
• a reference value generator having an input configured to receive data indicative of a desired product particle size distribution, said reference value generator being configured to generate at least one status parameter reference value based on said data indicative of said desired product particle size distribution, and
• correlation data indicative of a causal relationship between said at least one status parameter value, and
• said at least one product measurement value and/or
• correlation data indicative of a causal relationship between
• said internal state of said comminution process and
• said product particle size distribution;
• said at least one status parameter reference value including a toe position reference value;
• and
• a regulator for controlling said product particle size distribution based on
• said at least one status parameter reference value,
• said at least one status parameter value, and
• at least one status parameter error value,
• wherein
• said at least one status parameter error value depends on said at least one status parameter reference value, and
• said at least one status parameter value.