What is organic limestone


Cement is made up of the raw materials limestone, clay, gypsum stone, iron oxide, sand and silt. The material is crushed in powder form and dried. When heated to 1,450 ° C, cement is created as a very reactive material. Due to the immensely energy-intensive manufacturing process, cement is not considered a sustainable product, even though the raw materials are of purely mineral origin. Since heavy metals are contained in the minerals used, fly ash containing heavy metals is produced during cement production, which poses a disposal problem.

The lime or limestone, which consists of the mineral calcium carbonate, is free of harmful substances. To turn the raw material into a suitable binding agent, it has to be heated to 898 ° C. First of all, the burnt lime (calcium oxide) is created, then by adding water one gets the "slaked lime". The setting reaction in turn produces the starting product calcium carbonate. In addition to its very good reusability, lime offers many other useful properties as a binding agent: Since it is highly alkaline, it protects steel reinforcing parts from rust, has a moisture-regulating and pollutant-absorbing effect.

The chemical name of gypsum is calcium sulfate. The previously mainly used natural gypsum, which came from gypsum quarries, is now increasingly being replaced by REA gypsum. This is created in flue gas desulphurization systems (FGD) through the reaction of sulfur compounds with calcium carbonate. Chemically, it does not differ from natural gypsum, but it can be contaminated with heavy metals. Therefore, one should find out about the purity from the manufacturer before using it. In order for plaster of paris to be used as a binding agent, it is heated to 120-180 °. Plaster of paris is susceptible to moisture, but also has very positive properties such as low shrinkage, controlled setting times and also uses relatively little energy in its manufacture.

The mineral magnesite consists of magnesium carbonate. For use as a binding agent, it is burned to form magnesium oxide (magnesia) at 600-800 ° C. Magnesium chloride is often added to accelerate the setting process. Magnesia binder is mainly used in lightweight wood wool panels or for magnesia screeds. Its moisture-regulating properties have a particularly positive effect, so that there are hardly any dimensional changes in either the lightweight panels or the screeds.

Synthetic resin
Synthetic resins are used as binders in many paints and also in plasters. Synthetic resins are produced synthetically through polymerization, polyaddition or polycondensation. Their raw materials are often of natural origin, e.g. alkyd resins, but are heavily modified in the end product. Synthetic resins include a large number of compounds, including acrylic and epoxy resins, silicones and polyester resins. These binders usually consist of a resin component and a hardener. The manufacturing process is very energy-intensive. Harmful emissions can be emitted from the end products.

Natural resin
Natural resins are mainly used as binders for vegetable paints. They come as insoluble secretions from plants (e.g. tree resins) or animals (lacquer scale insect). The best known natural resin is rosin (pine resin). Manufacturers of natural paints change the natural resins only slightly chemically, so that energy consumption is reduced to a minimum and no toxic waste is produced. Since most natural resins tend to self-ignite due to their drying oils (e.g. linseed oil), the rags used must be spread out smoothly and dried individually.

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