Process Routes. There are four main process routes for manufacturing cement: the dry process, the semi-dry process, the semi-wet process and the wet process. As a matter of fact, the choice of the type is largely determined by the state of the available raw materials (dry or wet). The trend converges on dry processes. A large part of world clinker production is still based on wet processes. However, in Europe, around 90% of production is based on dry processes thanks to the availability of dry raw materials. Wet processes are more energy-consuming and, thus, more expensive. It can thus be argued that plants using semi-dry processes are likely to switch to dry technologies whenever expansion or major improvement is required, while plants using wet or semi-wet processes normally have access to only moist raw materials. All these process routes include the same three main activities that can be summarised as: (1) quarrying,
Process Routes. Steel can be produced using different raw materials and methods. It is possible to distinguish three alternative steel production routes, as it is shown in Figure 29 • If a Blast Furnace (BF)with a Basic-Oxygen Furnace (BOF) are used for steelmaking it is called an integrated route; • The second way for steelmaking is via Direct Reduction (DR) and Electric-Arc Furnace (EAF). • The third route is based on the direct use of recycled steel (scrap). (The technologies are detailed in the paragraph 5.3.3.4). Following this division, it is possible to analyse step by step the supply chain of the three different routes identified:
Process Routes. The ceramic processing can be divided into three main steps: powder processing, shaping, and firing. Brick manufacturing typically includes raw-materials shipping and storing before use. As logistics can of course impact on costs, clustering is a good practice, and brick manufacturers are generally located near clay deposits. For a brick formulation, one or more clays are needed. The raw materials are ground and/or mixed in pug or roll xxxxx. Bricks are then shaped by extrusion from pastes, whereas for roof tile forming, uniaxial pressing is applied to a plastic body using different die designs for several shapes and sizes. After shaping, excess moisture is evaporated by natural or forced drying. Finally, firing is performed in intermittent kilns (mostly) or tunnel kilns (in modern brick plants). After firing, the products are inspected, packed, and stored for later shipping. Gases originating from raw material decomposition or burning out of organic matter and additives are released during the firing schedule before the bodies are densified by sintering93. Electric power is needed by almost all process. It is required by mechanical equipment, such as xxxxx, presses, extruders, and glazing machines, as well as for heating as dryers and kilns need electric power. Particularly in firing processes, heat is usually generated from fossil fuels. These can be solid (such as coal or biomass), liquid (such as liquefied petroleum gas (LPG)), or gaseous (such as natural gas (NG)). Excess heat from hot gas emissions, may be eventually recovered for drying or preheating purposes, increasing energy efficiency. Figure 49. Ceramic brick process 93 92 xxxxx://xx.xxxxxx.xx/growth/sectors/raw-materials/industries/non-metals/cement-lime_en 93 xxxxx://xxx.xxxxxxxxxxxxx.xxx/topics/materials-science/ceramics-processing Pigment processing: Inorganic pigments for the colouring of ceramics are produced through a reaction to the solid state at high temperatures (700°-1400°). Below, all types of inorganic, organic and special pigments are reported and associated to the field of application.
