A Majority of raw material to produce traditional Brick is clay. In some cases; however, the soils, which their main mixture is silicon sands, are used as a subsidiary material along with clay material. Clay soils are produced either Direct decomposition of igneous rocks or Shale dissociation.
In the first case, this material shows itself in 2 shapes: primary and residual. One group of clays is primary which are containing amounts of high alumina clays, silicon sands, mica, and feldspars. These soils are generally in li
ght colors and somewhat gray. This kind of soil is not used in construction field and is used to produce fire brick, having a medium Plastysty. Second group is residual, or named sedimentary rocks. These types include colors from gray to black or from dark Beige color to red ones. The mineral inside, mainly is full Alumina clays (such as Kaolinite-pirofilite , and pyrite Silica are in the shape of Quartz. In addition to their color, the characteristics of these soils is a high amount of plastysty . These soils difference with clay soils produced, in the result of Shale weather ability, is in a lack of or limitation of existence materials like plaster, salt, and other soluble salts. Some examples of these soils are the soils from southern parts of Tehran province. The color of this kind of soil after cooked is usually red .However, since shales of surface ground Adjacent to limestone beds in parts of having Protrusions, then are washed in exposure to weather ability plus acid rains ,and next flow on plains, so they consist a noticeable amount of Calcium carbonate, Magnesium and soluble salts of Calcium and sodium. The major clay mineral of these clays are Montmorillonite , Colorite, and illite. The percentage of a high quality amount in clays such as kaolin is less within this type of soil. A frequent study for XRD analysis proves that this kind of clays have passed further frequently erosion steps than the clays produced from Direct decomposition of igneous rocks.
Sedimentary Soils from Eastern and Central areas of Isfahan is in the result of decomposition in addition to shale weather ability spread out north to eastern north, and western north and even southern region.
XRD analysis of these shale represents that the minerals in these shales are the same as mentioned soils. The earth goes an elliptical orbit around the sun, and according to the scientific theories, it turns to circular shape each 150000 year. In this situation, when the earth turning a complete elliptical way, the cold duration will be more in just one circulation around the sun. Consequently, the earth passes the cold period. Furthermore, when situated in more circular route, then passes warm period.
On the other hand, fumes like Carbon dioxide (CO2) and Sulfur dioxide (SO2) is more soluble in cold weather which it means that in cold times, a less Sedimentation, in the shape of Calcium carbonates (CaCO3) and sulfate carbonate (CaSO4) are produced, plus more sedimentation of Calcium carbonate or chalk in warm weather. Due to this matter, it is obvious that while sedimentation in different seasons, clay is having different amount of clay salts especially calcium carbonate. This is why clay sedimentary layers in each category, which is not even likely to reach to a few millimeters, will be various to each other as chemical analysis. Therefore, if you want to produce uniformity on material into a mine, it is essential it do Depo-out and Homogenization in chemical composition.
In a general point of view, it is necessary to point out that to foresee the clay existence in one area it should be mentioned in areas with Plutonic, silicon rocks, and shale in heights, there is also clay soil in its lowland and alluvium.
This matter is clearly visible with Satellite pictures observation.
Raw material of clay is typically consisting clay and non-clay minerals.
- Uniformity and Homogenisation : If there is no difference between the average quality index in each part of cairn or soil . Mineral general properties in natural clayThe necessary noticeable topics to mention:
- The clay mineralogy combination: each one available types and proportional amount
- Physical combination: particles size, distribution, and each mineral shape .
- Chemical combination.
- The phenomenon of ion absorbtion.
- Compression and clay texture.
- Dry strength.
- Drying constriction.
- Plastysyty.
- Clay motion behavior in washy flow.
- Stability of suspension in water.
- Operation in drying task flow.
- Penetration capability.
- Curing, Sintering and, fusion temperature.
- The color in oxidants Atmosphere.
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Curing contraction.
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Clay amineral: the The word clay is generally the generic name for Sedimentary rocks with a Diagonal of less than 0.004mm which find a feature of plastysyty when wet absorption. Clay mineral are all considered components of Phyllosilicate or sheet silicates. All these minerals conclude basis Si2O5. Due to existence of different elements in clay minerals crystal lattice, these minerals represent various physical and chemical properties, and their environmental differs.