Absorbents based on chemically modified lime are highly reactive. Due to their high reactivity, absorbents are used in a multitude of industrial processes - mainly for flue gas treatment in power plants, but also for water treatment.
AFESIKOS is an iron-free, synthetic, mineral-based, environment-friendly blasting agent; it is especially suitable for gentle blast cleaning of sensitive surfaces, e.g. stainless steel surfaces.
The alkali-silica reaction (ASR in short) is a chemical reaction occurring in concrete between the soluble silica present in rock-based aggregates and the alkali and hydroxide ions present in the concrete's pore solution. This reaction produces an alkali-silica gel which due to its water-absorbing tendency can cause expansion and cracks as the concrete hardens. The detrimental alkali-silica reaction can be avoided by purposefully using hard coal fly ash as the main cement component.
Abbreviation for alkali-silica reaction (see Alkali-silica reaction)
"Betonkopp" is the name of a comic-strip character developed specifically for STEAG Power Minerals' customer magazine SEGMENT which is published twice per year. "Betonkopp" translates literally as "concrete head" and, in the German dialect spoken in the Ruhr district, means a somewhat stubborn man. In each of his articles in the magazine, Betonkopp addresses a current topic. And last not least: He is also keen to learn what readers think about SEGMENT in general and about his own articles in particular.
Bottom ash is a mineral-based by-product arising from the combustion in coal in power plants. In the combustion process, coal particles are blown into a dry furnace at a temperature of around 1,200°C. Depending on its origin, the coal used contains between 64 and 95 percent of carbon and 5 to 35 percent of non-combustible mineral constituents. In den combustion process, the carbon is burned while 10 to 15 percent of the non-combustible mineral constituents agglomerate and fall to the furnace bottom. This ash is rapidly cooled down and removed from the boiler; the dark-gray, porous material thereby produced is called "bottom ash".
Calcium sulfate is the chemical name for gypsum. (see Gypsum)
Calcium sulfate dihydrate
Calcium sulfate dihydrate is the chemical name for the gypsum arising in flue gas desulfurization plants ("FGD gypsum") (see FGD-gypsum)
Concrete is a mixture of a binder (normally cement produced from limestone and clay as raw materials), aggregate (sand, gravel), water and, as the case may be, additives (e.g. fly ash). STEAG produces and supplies high-quality concrete additives designed to improve strength, workability, compressibility and water demand of the concrete.
FGD gypsum is gypsum obtained from flue gas desulfurization (FGD) systems in power plants (see Opens internal link in current windowflue gas desulfurization). In the FGD system, sulfur is removed from the flue gas by "scrubbing". steagips® is produced only in wet scrubbing processes, where an aqueous suspension of limestone or calcium oxide is sprayed into the flue gas flow. In a first step, the sulfur dioxide contained in the flue gas is converted to calcium sulfite; reacting with the oxygen in air, the calcium sulfite then oxidizes to form calcium sulfate. The calcium sulfate dihydrate, occurring in suspension in water, is referred to as "FGD gypsum", and is separated in a mechanical process from the aqueous phase and dewatered to a residual moisture content of about 10 percent. Steagips® is available in moist, fine-grained form.
Hard coal fly ash is a fine dust arising in the coal combustion process; it consists mainly of spherical, vitreous particles. Fly ash has puzzolanic properties and mainly consists of SiO2 and Al2O3. STEAG produces hard coal fly ash in its own modern hard coal fired power plants and also recycles fly ash arising in third-party power plants in Europe.
General building inspectorate approval
On application, the Deutsches Institut für Bautechnik (DIBt) can grant a general building inspectorate approval for building materials and building techniques for which no generally accepted rules of sound engineering practice exist. Once granted, the general building inspectorate approval is proof of the usability of such materials and techniques and thus approval for their use in the building industry.
Glass granulate is an iron-free reusable blasting abrasive. Similarly to glass beads, it is also used for finish blasting and cleaning of sensitive surfaces, but with its angular form it is slightly more aggressive and has a greater abrasive effect. Furthermore, it is optimally usable for the production of visual effects such as matting of metallic surfaces, and for treatment of non-ferrous metals.
Glass bead blasting abrasives from STEAG Power Minerals are made from fused sodium glass, and are therefore especially environmentally friendly. The iron-free beads are suitable for a wide range of applications, and are used, for example, for finish blasting and burnishing, shot peening, cleaning of sensitive surfaces and blasting of non-ferrous metals.
Coal consists of organic matter, minerals and water. The organic matter mainly consists of carbon, hydrogen, nitrogen, sulfur and oxygen, with the percentages of the different constituent elements varying depending on the origin and type of the coal. If the percentage of sulfur in the coal is 2 % or more, then the coal is considered to be a high-sulfur coal.
The chemical-physical reaction of cement with water is called hydration. The heat released in this reaction is referred to as hydration heat. Adding "steament®" hard coal fly ash to the concrete not only contributes to achieving a higher ultimate strength of the concrete, but also to reducing hydration heat. This effect is of particular benefit when massive concrete parts have to be produced in very hot regions (e.g. in the Arab countries or in Africa), because less hydration heat means a lower risk of crack formation.
Loss on ignition
"Loss on ignition" is the percentage of unburned carbon in fly ash. In the electricity production process, hard coal is burned in a steam boiler furnace, and this combustion process gives rise to hard coal fly ash. The percentage of unburned carbon contained in fly ash is what we generally refer to as "loss on ignition". For fly ash to DIN EN 450-1, the loss on ignition must not exceed 5 %.
Photoment® is an innovative, photocatalytically active concrete additive. It consists of fine-grained, mainly glassy particles of silicon, aluminum and iron oxides and titanium dioxide (TiO2); titanium dioxide is known for its use as a white pigment in paints and plastic materials. Photoment® has been designed to improve the air quality and the quality of life.
In terms of chemical composition, steament® hard coal fly ash is similar to volcanic tuffs, and it is therefore also referred to as "artificial pozzolan". Pozzolanicity is the ability of pozzolans to form, in the presence of moisture and lime or cement, cementitious products in concrete, so-called calcium silicate hydrates (C-S-H phases). C-S-H phases present in concrete not only increase the strength of the concrete, but also result in a denser pore structure which is less penetrable by gases and liquids. The citizens of the Italian town of Pozzuoli could never have imagined that the name of their town one day would be associated with an important material property of the hard coal fly ash steament®. They noticed, however, that they were able to produce hardening construction materials by using the volcanic tuffs occurring in their region. Named after their town, finely ground tuff is also called "natural pozzolan".
A power plant is a technical facility designed for electricity production. The core competencies of STEAG are engineering, implementation and operation of highly efficient power plants based on fossil fuels (hard coal, natural gas, refinery by-products) and renewable sources of energy (biomass, biogas, mine gas, geothermal energy and wind).
Power plant byproducts
Fly ash, slag-tap granulate, bottom ash, and FGD gypsum from flue gas desulfurization plants are power plant by-products arising from the hard coal combustion process. Each year, STEAG recycles about 5 million metric tons of power plant byproducts, by marketing them to customers around the world.
Refuse derived fuels
Refuse derived fuels (RDF) excel in their high heating value and are an environmentally friendly alternative to other fuels, as they are produced from waste. Most of the RDFs supplied by STEAG come from wastewater treatment in sewage plants; by using such RDFs in their power plants our clients can considerably improve their CO2 balance, as RDF of biological origin can be a substitute for fossil fuels burned in power plants.
SEGMENT is the customer magazine published by STEAG Power Minerals. Two bilingual (German/English) issues published every year inform our customers and partners about current topics around fly ash, concrete, cement, FGD gypsum, blasting abrasives and many other topics.
Single-use blasting abrasive
Single-use blasting abrasives are mineral based abrasives whose abrasive particles disintegrate on impact on the surface to be cleaned or which are heavily contaminated in the blast cleaning process; their useful life is therefore limited to a single use. AFESIKOS and ASILIKOS are single-use blasting abrasives supplied by STEAG Power Minerals.
steagips is the trade name of the FGD gypsum supplied by STEAG Power Minerals (see FGD gypsum)
steament is the trade name of the fly ash supplied by STEAG Power Minerals (see Ofly ash)
steasint is the trade name of the bottom ash supplied by STEAG Power Minerals (see bottom ash)