Method and apparatus for production of lightweight aggregates by thermal treatment in a fluidized bed

A method for producing lightweight aggregates, comprising the steps of:

• (a) providing:
• i. an elongate vessel having a delivery end and a downstream particulate matter discharge end;
• ii. a perforated distributor plate positioned in the vessel and defining above the plate a material zone having an upstream heating section and a downstream cooling section and defining below the plate a heating compartment and a cooling compartment;
• (b) delivering particulate matter feedstock to be processed into the delivery end of the vessel at a predetermined rate;
• (c) delivering combustion gases upward through the perforations in the distributor plate from the heating compartment into the heating section;
• (d) causing the feedstock to travel downstream in a suspended condition in a fluidizing air stream due to combustion gases delivered upward through the distributor plate;
• (e) exposing the feedstock to the combustion gases for converting the feedstock into processed particulate matter;
• (f) cooling the fluidized air stream of the processed particulate matter in the cooling section by delivering cooling air into the cooling compartment, through the perforations in the distributor plate and finally into the fluidized processed particulate matter in the cooling section;
• and
• (g) discharging the processed particulate matter from the vessel from the discharge end.

A method for producing lightweight aggregates, comprising the steps of:

• (a) providing:
• i. an elongate vessel having a delivery end and a downstream particulate matter discharge end;
• ii. a perforated distributor plate positioned in the vessel and defining above the plate a material zone having an upstream heating section and a downstream cooling section and defining below the plate a heating compartment and a cooling compartment;
• (b) delivering particulate matter feedstock to be processed into the delivery end of the vessel at a predetermined rate;
• (c) blowing ambient air through a heat exchanger to preheat the air;
• (d) inserting fuel into the air;
• (e) igniting the fuel and air to create combustion gases;
• (f) delivering combustion gases upward through the perforations in the distributor plate from the heating compartment into the heating section;
• (g) causing the feedstock to travel downstream in a suspended condition in a fluidizing air stream due to combustion gases delivered upward through the distributor plate;
• (h) exposing the feedstock to the combustion gases for converting the feedstock into processed particulate matter;
• (i) cooling the fluidized air stream of the processed particulate matter in the cooling section by delivering cooling air into the cooling compartment, through the perforations in the distributor plate and finally into the fluidized processed particulate matter in the cooling section;
• and discharging the processed particulate matter from the vessel from the discharge end.