The cement industry and welding world are interrelated to each other as mentioned in article 29 of the knowledge center, but let’s find out where welding is required particularly according to the processes. Cement manufacturing is divided into six phases which are as follows:
Raw materials extraction/Quarry: While extracting the raw material from the mines which are limestone, clay and sand. Calcium is generated from limestone, it further gets mixed with very fewer proportions of sand and clay. Clay and sand fulfill the needs of silicon, iron and aluminum. While extracting the raw materials machine’s part (Hammer) faces Impact or Abrasion which can stop the whole process in the start only, to avoid this D&H Secheron’s Lotherme 457 and Lotherme 611 can help to prevent any unnecessary losses.
Grinding- Proportioning- Blending: In the second phase, the raw materials from the quarry are now forwarded to the plant laboratory where they get analyzed and proportioning of limestone and clay are made possible before the grinding process. Generally, the percentage of limestone is 80% and the rest 20% is clay. The cement plan grinds the raw mixtures with the help of heavy wheel-type rollers and a rotating table. The rotating tables work continuously under the roller and bring the raw mixture in contact with the roller, then the roller crushes the material till it gets fine powder. While grinding the raw material the crusher plat or eccentric shaft can face friction issues or idelers, guides and track rollers can face the impact and friction. Lotherme range’s 610,605,616, OA611 and OA612 are used to bypass the issues faced by the above-mentioned reasons.
Pre-heater Phase: preheating chamber consists of a series of vertical cyclones from where the raw material passes before facing the kiln. Preheating chamber emits hot gasses from the kiln. In this step burner nozzle, clinker inlet and cooler plates work and due to heat and abrasion these parts can face issues, but by fabricating these parts with Lotherme 646 one can dodge the problems.
Kiln Phase: Kiln is a huge rotating furnace also called the heart of the cement making process. Here, the raw material is heated up to 1450 ⁰C. This temperature begins a chemical reaction so-called decarbonization. In this reaction material (like limestone) releases carbon dioxide. The high temperature of the kiln makes a slurry of the material. The series of chemical reactions between calcium and silicon dioxide compounds form the primary constituents of cement, that are, calcium silicate. The kiln is heated up from the exit side by the use of natural gas and coal. When the material reaches the lower part of the kiln, it forms the shape of a clinker. The bearing, mill gear drive pinion, mill head/journal, kiln tyre, and girth-gear tooth faces problems like friction, impact, and fatigue and a product like Lother 352 and 510N can help to resolve the issue.
Cooling and Final Grinding: After passing out from the kiln, clinkers are cooled by means of forced air. Clinker releases the absorbed heat and cools down to lower temperature. Released heat by the clinker is reused by recirculating it back to the kiln. This too saves energy. The final process of the 5th phase is the final grinding. There is a horizontal wall filled with steel balls. Clinker reaches into this rotating drum after cooling. Here, steel balls tumble and crush the clinker into a very fine powder. This fine powder is considered cement. During grinding gypsum is also added to the mix in a small percentage that controls the setting of cement. In this part, the risk of corrosion and friction rises in the slurry pump shaft and with Lotherme-468 the issue can be fixed.
Packing & Shipping: last but an important part, here material is directly conveyed to the silos (silos are the large storage tanks of cement) from the grinding mills. Further, it is packed to about 20-40 kg bags. Only a small percent of cement is packed in the bags only for those customers who need it very small. The remaining cement is shipped in bulk quantities by means of trucks, rails, or ships.