PERLITE FOR THE FOUNDRY INDUSTRY
Perlite in the ore form is used in high temperature application in the steel, ferrous and non-ferrous industries, as a slag coagulation agent, in ladle topping compounds, as an ingredient in exothermic and insulating sleeves and as a cushioning agent in moulding and core sand
AS SLAG COAGULANT:
Perlite ore is used in the granular form in size –8 + 40 # as a slag coagulant in continuous induction furnaces and in ladles. The ore will expand when it comes into contact with the melt, forming a light weight, viscous cellular mass. This mass attracts all individual slag particles in the metal and prevent retention or re-entry of the impurities into the metal bath, virtually eliminating the problem of slag inclusion.
The alkaline compounds present in the perlite ore also helps in reducing sulphur and phosphorous compounds in the melt.
CONSUMPTION NORM :
The quality of perlite ore will depend on the viscosity and coagulative nature of the melt. However, 1 to 2 kgs per ton of melt in ladle / furnace is recommended. Larger quantity can be used to get additional benefit of sulphur and phosphorous reduction.
ADVANTAGES:
•Produces cleaner metal.
•Coagulates slag and traps all impurities.
•Simplifies ladle skimming and removal of slag without raking.
•Reaction with melt produces no smoke or fume of health hazards.
•Additional benefit of sulphur and phosphorous reduction.
AS LADLE COVER:
Perlite ore in size –8 + 40 # can be added to molten metal pouring ladles to act as an insulating cover. The ore on expansion will prevent heatless maintaining the pouring temperature of the melt longer, especially in continous casting requiring longer hold time.
CONSUMPTION NORM :
10 to 15 kgs per ton of metal, depending on the size of the ladle.
ADVANTAGES:
•Facilities holding of melt for longer time permitting deoxidation and decarburisation Process.
•Energy saving as heat loss during transfer of melt from furnace to ladle can be eliminated.
•Eliminates shrinkage defects in cast materials.
REFRACTORY LINING PROTECTION:
Perlite ore can be used to protect the refractory lining of ladles thereby avoiding frequent relining. Addition of perlite forms a glassy coating on the ladle wall, which increases the life of the lining.
CONSUMPTION NORM :
10 to 15 kgs per ton of melt.
ADVANTAGES:
•Prolongs refractory ladle lining life.