Blending systems and control technologies for cement raw materials

In a cement plant, the preparation of on-target, uniform kiln feed requires certain tasks to occur in unison. Typically, this involves stockpiling/preblending, proportioning, grinding, and stocking/blending. The raw-mix logic of a plant describes the type and layout of equipment used to perform these tasks. The capital and operating cost vary, in part, according to the choice of raw-mix logic. Many factors, especially the reliability of the supply and chemistry and the handling characteristics of raw materials, will affect the choices made in conceiving a raw-mix logic. The increasing availability of the sensors discussed gives plant designers and operators opportunities to reduce capital and operating cost and/or improve, as indicated by the regularity of kiln feed, system performance. Diminishing the size and complexity of blending and stocking equipment before and after the raw mill represents a common strategy for reduction of capital and operating cost. The paper discusses the choice between X-ray fluorescence (XRF) and γ-ray analysis sensors. Cross belt analysers used in the stockyard are also discussed