Metso Outotec has supplied more than 210 lime calcining systems, over 115 of them as preheater/rotary kiln systems. The worldwide total annual production capacity from Metso Outotec supplied systems exceeds 30 million metric tons per year.
The Metso Outotec experience encompasses complete plant design including limestone crushing and screening, calcining (of both high calcium and dolomitic limestones), kiln firing, emissions, product handling and storage, and lime hydration.
Chemical and industrial purposes such as cement
Steel and alumina production
As an alkali for many mineral and chemical processes
Metso Outotec’s worldwide experience and expertise allows for local sourcing of major system components, near the installation site, to minimize total project costs. In addition, with a local presence in more than 50 countries, Metso Outotec remains close to its customers throughout the service life of the calcining equipment and systems it provides.
Lime calcining is the conversion of limestone (CaCO3) to lime (CaO).
Limestone is a sedimentary rock, the third most abundant mineral. Limestone is mostly quarried above ground; however, some underground limestone mining is done. Limestone is found with many different characteristics and different impurities.
The limestone characteristics change from different parts of the world and even different depths of mining. These characteristic differences are largely due to how it was formed. Limestone can be formed by chemically, organically, or clastic formation. Common impurities that can become a problem depending on the use or application are: SiO2 (Silica), Al2O3 (Aluminum Oxide), Fe2O3 (Iron Oxide).
The limestone must be tested to determine the appropriate technology for calcining. Each lime kiln type and design is able to accommodate a given set of limestone characteristics. Testing to determine the suitability of a limestone for feed to a lime kiln is performed at Metso Outotec's Process Research & Test Center in Danville, Pennsylvania, USA using proprietary test procedures, referred to as a Limestone Evaluation (or LSE). Metso Outotec has established a reliable baseline against which to measure the suitability of a limestone for feed to a preheater-kiln system by evaluating nearly 1500 samples of limestone from around the world.