Variation of Feed Chemical Composition and Its Effect on Clinker Formation–Simulation Process

Abstract

The raw materials for Portland cement production are the mixture (as fine powder in the 'Dry process') of minerals containing calcium oxide, silicon oxide, aluminum oxide, ferric oxide, and magnesium oxide. The raw materials are usually quarried from local rocks which are found in some places have already practically the desired composition and in other places require addition of the clay and limestone, as well as iron ore, or recycled materials such as CKD]. The homogeneity of feed chemical composition has an important relationship to fuel consumption, kiln operation, clinker formation and cement performance. The raw materials for Portland cement production are the mixture (as fine powder in the 'Dry process') of minerals containing calcium oxide, silicon oxide, aluminum oxide, ferric oxide, and magnesium oxide. The raw materials are usually quarried from local rocks which are found in some places have already practically the desired composition and in other places require addition of the clay and limestone, as well as iron ore, or recycled materials such as CKD]. The homogeneity of feed chemical composition has an important relationship to fuel consumption, kiln operation, clinker formation and cement performance. Cement quality is typically assessed by its compressive strength development in mortar and concrete. The basis for this property is a well-burned clinker with consistent chemical composition and free lime. The main reason for the clinker free lime to change in a situation with stable kiln operation is variation in the chemical composition of the kiln feed. This variation in chemical composition is related to raw mix control and the homogenization process. To ensure a constant quality of the product and maintain a stable and continuous operation of the kiln, the attention must be paid to storage and homogenization of raw materials and kiln feed. This article focuses to study the role of raw mix composition control and the homogenization process. The study have been done by computer simulation (Fortran 90) to make calculations to estimate quantities of the raw materials (limestone, clay, iron ore,.. ) required to prepare kiln feed. These calculations have been done based on knowing composition of raw materials, these field data obtained from Al-Mergheb cement plant. Due to variations in the kiln feed chemical compositions that affect its burnability and eventually the fuel consumption, so the simulation done to give a suitable composition of kiln feed to allow soft burning inside kiln. A simulation of the mixing raw materials process and estimate composition of kiln feed, as well as formed clinker were done successful through fitting of the results obtained with field data of one of the plants operating in Libya.