Use of Perlite in Metallurgy
- As metallurgical flux in the foundry
- As an additive to foundry sand
-In protecting the molten metal in the crucible
-To prevent heat loss in forging or hot metal ingots going to rolling
-Slag control of molten metal in the iron and steel industry

Perlite is used in raw and expanded form in foundry. Expanded perlite is used as an additive to casting sand, to protect the molten metal, and to transport hot ingots, and crushed and sieved perlite is used to collect the slag.
Benefits of Akper Perlit in Foundry
· It prevents abnormal surface tensions as it ensures slow and even cooling of the metal.
· It does not burn, does not emit gas, and does not react with metal during casting.
· It allows the gases formed during casting to escape through the spaces and channels within it.
· Clean, solid, high-quality, and efficient casting is achieved.
· Since it minimizes casting errors, it reduces the cleaning time and labor of the product.

HIGH TEMPERATURE APPLICATIONS
Perlite insulation is used in high-temperature applications in the steel and foundry industries.
For example, it is used in ladle covering (breakout), hot covering and covering of alloys in feeders, in molding sand as a cushioning agent in exothermic and insulating forms, and as an insulating material in the production of refractory bricks and blocks.
POT COVERING APPLICATIONS
In crucible covering applications, expanded or unexpanded granulated perlite ores are thrown into liquid metal discharge crucibles. Mostly, unexpanded granulated perlite is used to interact with the slag layer in the crucible and ensure easy slag extraction. In addition, effective thermal insulation is provided by placing expanded perlite on the crucible to prevent the metal in the crucible from cooling. Thus, due to its insulation feature, it reduces the solidification rate of the molten metal and therefore casting errors are reduced. If granulated perlite is added during the crucible filling, a slight mixing movement occurs that cleans the slag (impurities) from the metal. In addition, the life of the liner is increased by coating the slag remaining on the refractory with perlite. Another advantage is that it ensures that unpleasant odors and harmful fumes do not occur during this process.
HOT-TOP AND FEEDERS (RISING)
Perlite is mostly used in hot tops and feeders by mixing with exothermic primer to prevent shrinkage gaps in ingots and casting parts. Perlite is frequently used as a lightweight filling material in these types of applications due to its suitability, cost, and superior properties. Perlite is generally added to insulation and exothermic compounds at a rate of 3 - 20%. These hollow cylindrical (arm assembly) shapes are used for feeder and hot-top panels. These shapes work the same as hot-top and nutritional powders and compounds.
Approximately 8-12% of foundry sand in iron and steel casting,
In the casting of non-ferrous metals, 20-30% perlite is used.
Perlite added to the casting sand shrinks in volume at high temperatures, making it suitable for casting.
It allows the sand to expand.
Applications in this field are as follows;
– As a metallurgical slag maker in foundry
– As an additive to foundry sand
– Slag control of molten metal in the Iron and Steel industry
– In the production of insulating refractories
· It is used to create slag by throwing it into the furnace during the melting of mines and to control the slag.

· In the casting industry, it is placed on the bottom of the crucible before the metal is taken from the furnace to the crucible. When perlite comes into contact with hot metal, it boils in a way and carries the impurities that may be in the metal to the crucible surface, allowing for a cleaner casting.
· It is also used in the casting industry to prevent the superficial cooling of the metal during transportation in the crucible.