CASTING PERLITE
It is extensively used as an additive to foundry sand in the foundry industry. It is added to the casting sand at the rate of 10-12% by volume in iron-steel castings, and 25-30% in the casting of other materials. Unexpanded, sorted Raw Perlite ore is used in the Foundry Industry.
It prevents abnormal surface tensions as it provides slow and balanced cooling of the metal.
It does not burn, does not emit gas and does not react with the metal during casting.
It allows the gases formed during casting to escape through the gaps and channels within it.
Clean, robust, high quality and efficient casting is obtained.
As 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 as an insulating material in molding sand and in the production of refractory bricks and blocks, as a means of ladle covering (breaking off), hot covering, covering alloys in feeders, cushioning in exothermic and insulating forms.
COVERING APPLICATIONS
In ladle cover applications, expanded or unexpanded granulated perlite ores are thrown into liquid metal discharge crucibles. Often, unexpanded granulated perlite is used to interact with the slag layer in the ladle and allow easy slag removal. In addition, to prevent the cooling of the metal in the crucible, expanded perlite is thrown on the crucible to provide an effective thermal insulation. Thus, thanks to its insulation feature, the solidification rate of the molten metal is reduced, and thus casting errors are also reduced. If granulated perlite is thrown during crucible filling, a gentle mixing action occurs, which cleans the slag (impurities) from the metal. Another advantage is that it prevents the formation of unpleasant odors and harmful fumes during this process.
HOT- TOP AND FEEDERS ( RISERING )
Perlite is mostly used in hot-tops and feeders by mixing with exothermic lining to prevent shrinkage gaps in ingots and castings. Perlite is frequently used as a light filled material in such 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 the feeder and hot-top panels. These shapes work the same as hot-ball and nutrient powders and compounds.