Feldspar And Olivine Essay

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Feldspar and Olivine are two silicate minerals commonly found on the Earth’s surface, their chemical formulas are KAlSi3O8 – NaAlSi3O8 –CaAl2Si2O8 for feldspars and (Mg, Fe)2SiO4 for olivine. Olivine is a nesosilicate, whereas feldspars are a group of tectosilicates, both minerals are anhydrous, since they contain no water in their chemical structure. Feldspars hold differing quantities of different elements, such as potassium, calcium, and sodium; making them classifiable in terms of composition, for instance, NaAlSi3O8 is Albite, while CaAl2Si2O8 is referred to as Anorthite.

Here (Figure 1), we can see the crystalline structure of potassium feldspar (KAlSi3O8), which consists of corners that share AlO4 and SiO4 tetrahedrons. These tetrahedrons contain either an aluminum or a silicon atom, each connected to four oxygen atoms, and also there are relatively large potassium cations that reside on junctions within the framework.

Feldspar and olivine are both widely used as abrasive minerals. Abrasives must be hard, tough and sharp, they must also be abundant and in some cases unadulterated. However, olivine and feldspar share these properties in different degrees.
For instance, olivine (Mohs 6.5-7.0) is harder than feldspar (Mohs 6.0-6.5) [2]. For this reason, feldspar and olivine are not used together in abrasive applications, even though their properties are similar. This is mostly because olivine is harder, has a higher specific gravity and its sharper particles make it more suitable for rapid, powerful cleaning and cutting action. Feldspar on the other hand, is softer and lighter, making it perfect for polishing and more delicate cleaning work, such as personal ornaments and fragile artifacts.

These properties that make thes...

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...For olivine, a method of chemical and thermal extraction is commonly used. First, the ore is combined with concentrated sulfuric acid to a certain ratio that depends on the concentration of olivine. Secondly, the mixture obtained is heated up to 250 degrees Celsius for approximately 7.5 hours, these number can vary in large amount depending on the concentration of magnesium and iron in olivine. Finally, to finish the process, the mixture is dissolved in water and the olivine precipitates as a solid and is removed from the solution by filtration.

In conclusion, both feldspar and olivine are chemically separated in industrial scales. Feldspar by the method of flotation that takes advantage of the hydrophilic and hydrophobic properties of minerals, and olivine by the method of thermal separation that takes advantage of the melting point of olivine and other materials.

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