Products for the manufacture of molds and cores used in metal casting and a method for their manufacture and recycle from crushed rock

Abstract

A system and method for producing foundry quality sand from non-conventional starting materials through the combination of oolitization and classification. Incoming particulate matter is first directed into a controlled energy attrition unit where the particles are made to collide with one another. Such collisions clean and round the particles by chipping away surface projections and coatings without crushing the particles. The particle stream is then directed through a multi-fraction classifier where it is separated into two or more useable grades of foundry sand. An air classifier is preferred for the classification stage.

1 - 18  are cancelled.  
     
     
         19  A method of preparing foundry sand from particles of a base material with no thermal treatment of said sand, comprising the steps as ordered of: 
 shaping the particles through treatment in a controlled energy impactor, said treatment causing the particles to collide with one another such that surface irregularities are chipped away to produce smoothed particles;  
 directing the smoothed particles to an air classifying system coupled to said controlled energy impactor, said air classifying system separating said smoothed particles to produce at least one grade of finished sand.  
 
     
     
         20  A method of preparing foundry sand from particles of a base material with no thermal treatment of said sand, comprising the steps as ordered of: 
 shaping the particles through treatment in a controlled energy impactor, said treatment causing the particles to collide with one another such that surface irregularities are chipped away to produce smoothed particles;  
 directing the smoothed particles to an air classifying system coupled to said controlled energy impactor, said air classifying system separating said smoothed particles to produce at least one grade of finished sand and at least one oversize fraction; and  
 returning the oversize fraction to the controlled energy impactor in a sand recycle loop for repeat attrition by said impactor and subsequent classification by said air classifying system.  
 
     
     
         21  The method as set forth in  claim 20 , wherein the controlled energy impactor is operated at a throughput rate higher than a throughput rate of said air classifying system, excess output from said impactor being returned to an input of said impactor for repeat attrition.