Cement is a hydraulic binding agent to produce concrete. Due in part to the fast growth of the Asian economies, world consumption of cement is currently growing at an annual rate of 8%.
Therefore, cement production is expanding and, at the same time, production processes need to be optimized to ensure maximum efficiency. In this context, process analytics plays an important role: It determines reliable and exact data from the processes and thereby allows their optimization.
S.A.I.E. is a provider of implement analysis systems for cement plants, with services ranging from planning and commissioning through to maintenance.
This case study provides an over-view of the cement production pro-cesses and describes how S.A.I.E. solves defined analysis tasks with its broad portfolio of instruments and systems engineering as well as its experience with applications.
Cement production (Fig. 1) involves the fusing together of precisely controlled blend of calcium, silicon, aluminum, iron and small amounts of other ingredients at high temperatures. Common among the materials used are lime-stone, shells and chalk or marl, combined with clay, silica sand, blast furnace slag, and iron ore. Lime and silica make up about 85% of the mass. The three basic process steps in cement manufacturing are·Preparation, blending and milling of the raw material to raw meal that is used as kiln feed.·calcination and burning (sintering). This conversion process takes place within the cement kiln and its associated equipment.·Finish milling, the grinding of clinker to produce cement. Cement manufacturing is an energy intensive process because raw materials must be dried and heated to temperatures of about 1400 °C to initiate the chemical reaction that produces cement clinker.
The core technology of a cement plant is the cement kiln (Fig. 2). This is the area where investment costs are high-est, fuel demands are largest, and pro-cess control is the most crucial. All kilns rely on the same basic process – raw feed passing through the kiln is heated to very high temperatures and trans-formed chemically and physically into clinker.Kiln technology has developed over years from vertical shaft to rotating kilns and from wet to dry processes. There are wet rotary kilns, rotary kilns with grid preheaters and rotary kiln with cyclone preheaters (with or without precalciners). Wet process kilns are generally older than dry kilns. Long wet and dry kilns have only one combustion zone, whereas kilns with a precalciner have a second combustion stage upstream the kiln inlet.
Preheaters and precalciner have been introduced to improve the energy efficiency of the process. Energy savings are estimated to reach 50 %.
The main raw material for the manufacture of clinker is lime-bearing material. Limestone consisting almost entirely of calcium carbonate (CaCO3) and shale containing a high proportion of silica (SiO2) and lesser amounts of alumina (Al2O3) and ferrous oxide (Fe2O3) provide the essential constituents for the manufacture of cement. Mined or dredged from the quarry and separately crushed, the materials are stored and then blended to the required mixture. The proportions are governed by the chemical properties of the mate-rials and the desired product. Moisture content of the raw materials is important because energy is required to dry them before the chemical conversion reaction can start.
Cave and Mines
CAVE CERRUTI S.p.A.
PERLITE DI ORISTANO
CALCESTRUZZI CAVA DI CARBONIA
VINCON FIGLI S.PA.
CONSORZIO SMALTIMENTO RIFIUTI DI S. GIORGIO DI N.
TEGOLA CANADESE VITTORIO VENETO
Plants Raw Materials for the management of the following machines and equipment for screening, selection and transport of aggregates:
• Vibrating feeders
• Power to the primary cart
• Power Plate
• Jaw Crushers
• Cone Crusher
• Crusher hammers
• Vertical Axis Windmills
Complete plants for Quarries and Mines
Equipment for recycling of rubble and waste