Products steament® Production In the Federal Republic of Germany, about 4 million tonnes of fly ash are produced each year by the burning of coal for energy production. For the burning process, the coal is ground to fine powder in coal mills and blown into the power plant boiler. However, mineral coal does not consist of 100% carbon. Depending on the type of coal used, 5 to 35% non-combustible mineral rock is blown into the boiler as well, which remains as ash. Depending on the boiler type, the ash is either removed from the boiler bottom as boiler slag or bottom ash, or extracted from the flue gas stream by means of multiple-stage electrostatic precipitators. In contrast to a slag tap boiler (wet bottom boiler), in a dry bottom boiler the ash does not melt because of the lower temperatures in the boiler of about 1200°C (2200°F). The non-combustible mineral particles are only partially melted on their surface and are carried along with the flue gas stream after being blown into the boiler. About 10 to 15% of the sintered ash particles stick to each other and fall to the boiler bottom because of their weight, and from there into a water quench. This ash is called bottom ash. The ash remaining in the flue gas stream is cooled down quickly and forms spherical, mainly amorphous particles – the steament fly ash. Properties steament fly ash is a powdery material with a light to dark gray color. In its chemical composition, steament is very similar to natural aluminate silicates. The main components are oxides of silicon, aluminum, and iron. SiO2 47 - 53 AL2O3 26 - 30 Fe2O3 5.0 - 15 CaO 2.4 - 3.9 MgO 1.9 - 2.5 SO3 0.2 - 2.0 K2O 3.0 - 4.6 Na2O 0.6 - 1.1 CL ≤ 0.01 Value range of some exemplary material analysis results Both physical effects and chemical reactions are responsible for the effects of steament fly ash in bound building materials. Both types of effects are closely connected however. The very fine-grained structure of fly ash and the mainly spherical shape of the individual particles, as well as the advantageous particle distribution, are responsible for the filler effect and the ball bearing effect in bound building materials. In concrete, the spherical steament particles act like many small ball bearings. This effect of fly ash, called the ball bearing effect, positively influences the workability, the water demand and the compressibility of the concrete. At the same time, the fine fly ash particles fill the remaining cavities between the coarser cement and aggregate particles, thus reducing the cavity portion of the concrete (filler effect). Another strength-increasing factor in concrete is the pozzolanic reactivity of fly ash. Pozzolans have the capability to create strength-increasing products (calcium silicate hydrates, CSH) in the presence of humidity and lime or cement. As an artificial pozzolan, steament produces hydration products (CSH) similar to those created in the hardening of cement. Loss on ignition 1.5 - 5.0 M.-% Fineness>0.045 mm < 40% Raw density 2.1 - 2.4 kg/dm³ Schüttdichte 0.7 - 1.1 kg/dm³ Water demandacc. to DIN 1164 22 - 32% Value range of some exemplary material properties Applications Due to its chemical and physical properties (filler effect, ball bearing effect, and pozzolanic properties) steament fly ash has become a much sought-after material for the construction and building material industry. Intensive research and development work has meanwhile opened up a wide range of applications for steament. The positive characteristics of steament can be utilized not only for cement-bound building materials, but also for lime-bound building materials such as sand-lime bricks, aerated concrete bricks, and all types of plasters and mortars. Application areas of steament: Concrete constructionReady-mix concreteSulphate-resistant concretePrestressed, quick-setting concrete Pre-frabricated concrete partsConcrete products Building material industryCement industryBrick industryMortar industryMining mortar industryFilling mortar industry Earthwork and road constructionAsphalt fillerBase layer materialDam building material For more than 25 years, steament fly ash has proved its positive effect on concrete characteristics. As a standardized building material according to DIN EN 450 "Fly Ash for Concrete", steament today has a firm market position as an additive in concrete production. steament® is a registered trademark of STEAG Entsorgungs-GmbH
In the Federal Republic of Germany, about 4 million tonnes of fly ash are produced each year by the burning of coal for energy production.
For the burning process, the coal is ground to fine powder in coal mills and blown into the power plant boiler. However, mineral coal does not consist of 100% carbon. Depending on the type of coal used, 5 to 35% non-combustible mineral rock is blown into the boiler as well, which remains as ash. Depending on the boiler type, the ash is either removed from the boiler bottom as boiler slag or bottom ash, or extracted from the flue gas stream by means of multiple-stage electrostatic precipitators.
In contrast to a slag tap boiler (wet bottom boiler), in a dry bottom boiler the ash does not melt because of the lower temperatures in the boiler of about 1200°C (2200°F). The non-combustible mineral particles are only partially melted on their surface and are carried along with the flue gas stream after being blown into the boiler. About 10 to 15% of the sintered ash particles stick to each other and fall to the boiler bottom because of their weight, and from there into a water quench. This ash is called bottom ash.
The ash remaining in the flue gas stream is cooled down quickly and forms spherical, mainly amorphous particles – the steament fly ash.
Properties
steament fly ash is a powdery material with a light to dark gray color. In its chemical composition, steament is very similar to natural aluminate silicates. The main components are oxides of silicon, aluminum, and iron.
Both physical effects and chemical reactions are responsible for the effects of steament fly ash in bound building materials. Both types of effects are closely connected however. The very fine-grained structure of fly ash and the mainly spherical shape of the individual particles, as well as the advantageous particle distribution, are responsible for the filler effect and the ball bearing effect in bound building materials.
In concrete, the spherical steament particles act like many small ball bearings. This effect of fly ash, called the ball bearing effect, positively influences the workability, the water demand and the compressibility of the concrete. At the same time, the fine fly ash particles fill the remaining cavities between the coarser cement and aggregate particles, thus reducing the cavity portion of the concrete (filler effect).
Another strength-increasing factor in concrete is the pozzolanic reactivity of fly ash. Pozzolans have the capability to create strength-increasing products (calcium silicate hydrates, CSH) in the presence of humidity and lime or cement. As an artificial pozzolan, steament produces hydration products (CSH) similar to those created in the hardening of cement.
Loss on ignition 1.5 - 5.0 M.-% Fineness>0.045 mm < 40% Raw density 2.1 - 2.4 kg/dm³ Schüttdichte 0.7 - 1.1 kg/dm³ Water demandacc. to DIN 1164 22 - 32% Value range of some exemplary material properties
Loss on ignition
1.5 - 5.0 M.-%
Fineness>0.045 mm
< 40%
Raw density
2.1 - 2.4 kg/dm³
Schüttdichte
0.7 - 1.1 kg/dm³
Water demandacc. to DIN 1164
22 - 32%
Applications
Due to its chemical and physical properties (filler effect, ball bearing effect, and pozzolanic properties) steament fly ash has become a much sought-after material for the construction and building material industry. Intensive research and development work has meanwhile opened up a wide range of applications for steament.
The positive characteristics of steament can be utilized not only for cement-bound building materials, but also for lime-bound building materials such as sand-lime bricks, aerated concrete bricks, and all types of plasters and mortars.
Application areas of steament:
Concrete constructionReady-mix concreteSulphate-resistant concretePrestressed, quick-setting concrete Pre-frabricated concrete partsConcrete products Building material industryCement industryBrick industryMortar industryMining mortar industryFilling mortar industry Earthwork and road constructionAsphalt fillerBase layer materialDam building material
For more than 25 years, steament fly ash has proved its positive effect on concrete characteristics. As a standardized building material according to DIN EN 450 "Fly Ash for Concrete", steament today has a firm market position as an additive in concrete production.
steament® is a registered trademark of STEAG Entsorgungs-GmbH