Perlite insulation is used in high temperature applications in the steel and foundry industries such as ladle topping, hot topping and risering, in topping compounds, in exothermic and insulating shapes, as a cushioning agent, in moulding sand and in the manufacture of refractory blocks and bricks. High temperature performance of expandedhas been well documented.
Expanded or unexpanded granular ore forms ofare added to molten metal pouring ladles. Most often the ore form is used which reacts slag in the ladle to allow easy removal of the slag layer. In cases where it is desirable to maintain a metal temperature in a ladle, the expanded layer forms an efficient insulating blanket.
When introduced during ladle filling, a gentle rolling motion is produced which cleanses the metal by coagulating impurities. In addition, ladle-lining life is increased by virtue of a vitreous residual coating left on the refractory by the. An added advantage of is in this application is that no objectionable smoke or noxious fumes are produced.
Hot Topping and Risering
Perlite is often mixed with exothermic powders and used in hot tops and risers to prevent shrinkage cavities in ingots and castings. Perlite is the most used lightweight filler used for these applications because of its availability, competitive price, and superior properties. Normal additions ofto insulating and exothermic compounds are in the range of 3 to 20% by weight.
Used in the manufacture of refractories where the average temperature does not exceed 1100°c. Its excellent insulating properties ensure substantial usage ofin refractory castables, bricks and blocks. In higher duty applications, refractories are used as reserve insulating layers for higher duty refractories.
Foundry Core and Moulding Sand
Perlite is added to foundry core and moulding sand mixtures as a cushioning agent to compensate for the expansion of crystalline silica as it goes through the phase of changes of temperature in excess of 540°c. Casting defects such as buckles, veining, fissuring and penetration are minimized and cleaning room costs are reduced. In addition,improves permeability of core sands thus reducing defects attributable to poor venting.
Our Foundry gradeis distributed throughout New Zealand, North and South East Asia, Australia, and Southern Africa. We are adept at producing the required product, in the best packaging and supplying at the requested destination quickly and efficiently.
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