Aerated concrete, also described as gas concrete, is a high-quality, versatile construction material which is manufactured as stone, layout element or sheet and is used almost throughout the entire construction industry. Due to its low weight and comfortable processing options, aerated concrete is often the best choice when renovating or reconstructing older buildings, also for half-timbered houses.
The construction material is manufactured from burnt lime, water, cement, and siliceous sand as well as a small quantity of aluminum. The mortar mix is poured in tubs where the metallic aluminum develops hydrogen gas. Several small gas bubbles are formed and foam up the material. The blocks are cut to the desired stone or construction component sizes using wires. By hardening it in the steam autoclaves, the aerated concrete is provided with its final properties.
Due to these excellent properties, aerated concrete is establishing growing acceptance as a preferred material for buildings worldwide. Wehrhahn is the global market leader for production plants to manufacture aerated concrete. In addition to standardized systems, the company develops and manufactures individual system concepts which are formed taking special consideration of respective requirements and on-site conditions.
The production conditions for construction materials vary widely. Wehrhahn takes all relevant factors such as the production quantity, location, available space and much more into account. The challenge is to guarantee a perfect manufacturing process under the respective conditions, whilst taking the raw materials available into consideration. For example, burnt lime is a raw material which is not available in sufficient quantities in all regions. Wehrhahn therefore supplies production systems with lime kilns and grinding systems for own burnt lime production. This avoids bottlenecks.
In the meantime, four NEUMAN & ESSER PM05 pendulum mills and one PM08 have been integrated into Wehrhahn's production systems and support the trouble-free manufacturing of quality products. Heino Drewes, Project Engineer at Wehrhahn, says: "Our customers expect first-class technology "Made in Germany" from us and that is precisely what they have received from us for more than 120 years. The NEUMAN & ESSER mills fit perfectly into our concept. They are low-maintenance, stable, and supply the quantity desired with a narrow particle size distribution." At the most, eight percent of the ground material exceeds the grain size of 90 µm.
However, not only our pendulum mills' fineness convinces. We guarantee a minimum throughput of 4,000 kg/h for the PM05, for the larger PM08 even 9,000 kg/h. The exceptionally short stop periods for servicing and repairs are important for users.
Burnt lime is manufactured on an industrial scale, whereby carbon dioxide is extracted from limestone at a temperature of more than 1,000°C, so-called lime burning. Caustic lime, calcareous earth and slack lime are further names used for burnt lime. With water, it reacts when heated strongly and becomes slaked lime. For Frank Verreck, NEUMAN & ESSER Area Sales Manager, burnt lime is an all-rounder: “After burnt lime is ground, it has a wide variety of industrial applications. Moreover, the better it is ground, the more precisely its properties can be fixed.”
Indeed, the area of application for the raw material is multifaceted: in the construction industry burnt lime serves as an admixture for mortar, plaster, and paint, for the industrial manufacturing of lime sand bricks and for cement clinker. In the chemicals sector, the substance is used as a drying agent and for the absorption of carbon dioxide. The further areas of use for dehydrated lime include fertilizer lime, the desulfurization of crude iron and flue gas desulfurization. One important area of use is for manufacturing soda.
