Process and apparatus for forming lightweight inorganic aggregate

An apparatus for expanding particles of an expandable lightweight inorganic aggregate material comprising:

• a housing comprising:
• an upper chamber having an inlet end and an outlet end;
• a lower chamber below the upper chamber;
• a partition separating the upper chamber from the lower chamber, said partition having a plurality of openings through which air introduced into the lower chamber can pass into the upper chamber;
• means for introducing the particles into the inlet end of the upper chamber;
• means for removing particles from the outlet end of the upper chamber;
• means for generating a stream of hot air;
• means for introducing the stream of hot air into the lower chamber;
• and
• means for adjusting the velocity of air passing through at least the openings of the partition adjacent the outlet end of the upper chamber so that the velocity of air passing through openings adjacent the outlet end of the upper chamber is sufficiently less than the velocity of the air passing through openings adjacent the inlet end of the upper chamber to assure generally uniform fluidization of particles within the upper chamber.

An apparatus for expanding particles of an expandable lightweight inorganic aggregate material comprising:

• a housing comprising:
• an upper chamber having an inlet end and an outlet end;
• a lower chamber below the upper chamber;
• a partition separating the upper chamber from the lower chamber, said partition having a plurality of openings through which air introduced into the lower chamber can pass into the upper chamber;
• at least one divider for subdividing the lower chamber into two or more compartments;
• means for introducing particles into the inlet end of the upper chamber at a select rate;
• means for removing particles from the outlet end of the upper chamber at a select rate;
• a blower for generating a stream of air;
• a burner for heating the generated stream of of air;
• and
• an air inlet duct associated with each compartment of the lower chamber for delivering a portion of the heated air stream to that compartment, each air inlet duct comprising means for regulating the flow of air therethrough.