Automating raw mix control using multifunctional software

The successful preparation of a multi-component mix in the production of raw meal achieving multiple target control results in several benefits in the cement manufacturing process. Obvious advantages include maintaining a quality product, while maximizing the use of lower cost raw materials. An automated mix control program developed by Tarasystem's Inc. and River Cement Co. (USA) is utilized as a quality control tool to proportion an eight component mix to the milling system. Mix control calculations involve a simultaneous solution of up to 8 equations given the chemical composition of the raw materials, the proportions of these materials during a given time interval and the resulting analysis of the mix produced in this time interval. If a solution does not exist, successive modifications are made to the calculation procedure until a solution is found. A Windows-based format allows direct communication with the raw mill PLC via DDE, an interface with the X-ray spectrometer software, which eliminates manual data entry by the operator and a user-friendly interface. This paper discusses the strategies employed in the mix calculations, the implementation of kiln feed and clinker analysis in the mix control of the raw mills and empirically derived adjustable target adjustments to compensate for circulating loads in a ball mill circuit. The use of the program for quarry development at Hercules Cement Co. is also be mentioned.