Olivine is a high-magnesia asbestos-free, quartz-free, refractory, hard, inert, hydration free mineral produced from intrusive or effusive volcanic rocks (e.g. Forsterite Mg2SiO4, Fayalite Fe2SiO4 (Mg, Fe2SiO4).
It has a low degree of thermal dilation. The density and solubility increase and the melting point decreases with increasing iron content.
Olivine requires no calcination prior to use. Willemite, tephroite, and crisoberite and similar.
Olivine has good insulating properties and high resistance to alkaline oxides, sulphates, carbonates and halides and is excellent for use in resin bonded brick, ramming, gunning and sprayable refractories. It is also a cost effective source of MgO in refractories.
The absence of free silica eliminates temperature inversion to produce creep resistance equal to or better than bauxite, corundum and andalusite-based refractories. Its zero-quartz status and hardness make it ideal for sand blasting.
Rock with high olivine and low iron content are used mainly in iron metallurgy as foundry sands. The olivine is added to the blast furnace with iron mineral and coke. It binds to the iron impurities to create slag and increases the fluidity of the molten material. Thanks to its basicity and good refractory qualities (better than those of the more commonly used silica sands), olivine sand is used for special smelting such as stainless and manganese steel. The refractory industry uses olivine in the manufacture of formed and non-formed basic products (sprayed masses and granules) used mainly in iron metallurgy.
Olivine is used for sandblasting because of its absence of free silica even in the finest fractions.
Olivine is available in a wide range of sizes from aggregate to granular to 325 mesh and finer. In bulk bags and regular paper bags. And suppliers can often ship large quantities by sea.
Olivine at Wikipedia
Iron silicate mineral.
|By Tony Hansen
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