RAW MATERIAL GRIDING.
CLINKER PRODUCTION.STORAGE AND GRIDING. SILO AND DISPATCHING.
Extraction of the raw material (limestone, shale, silica, and pyrite) is done by blasting or by scraping with the use of shearer loaders. The material is delivered to the crusher where it is reduced to chunks by crushing or pounding. Crushed limestone and the other raw materials are often stored under cover to protect them from the elements and to minimize dust. In most cases the quarry is distant from the cement plant, therefore separate or standalone electrical supply equipment will be required.
In the raw mill, the material chunks are ground finer to allow high-quality blending. In this phase vertical mills are used which grind the material through pressure exerted by rollers and horizontal mills which pulverize the material by means of steel balls. By far the greatest part of the electrical energy demanded for grinding is not exploited for comminution but rather converted into lost heat. It is therefore an economical demand to adjust the grinding plant so that energy losses are kept as low as possible. A process automation system which optimizes mill process and electrical equipment with low energy consumption is essential. The raw meal is finally transported to the homogenization silo for storage and further material blending.
Calcination is the core portion of this process. The raw meal is continuously weighed and fed into the top most cyclone of the preheater. The material is heated by hot air rising from the kiln. Inside of huge rotary kilns the raw material is transformed into clinker at 1,450 degrees Celsius. From the kiln, the clinker goes to the clinker cooler for heat recuperation and cooling. The cooled clinker is then transported by a pan conveyor to the clinker silo for storage. Because of the high energy consumption of the calcination process, automation and optimization play an essential role in this production stage. The main requirement for low emission and low energy consumption is a highly uniform kiln operation. Therefore, the burning process must be monitored continuously using modern process control technology.
Clinker is extracted from the clinker storage and sent to feed bins for further proportioning with gypsum and additives before passing the finishing mill. Clinker enters the finishing mill to be ground into a fine gray powder: cement! This highly energy consuming process needs automation and optimization to ensure today's quality demands.
Finished cement is stored in large concrete silos. It can be loaded directly into trucks or railroad cars in bulk for distribution to customers, or packaged in bags for delivery on standard pallets. Among the functions required to run a cement plant, the processing of the deliveries represents one of the main tasks. As the dispatching facilities are usually also employed for the weighing and loading/unloading procedures of materials received from external supplies, these systems must also support the processing of feedstock deliveries. Modern dispatching systems offer all-out logistical support and make the dispatching process transparent to the operators