US 4,168,951 AGranted

Method of sintering and apparatus for carrying out the method

AssigneeLuossavaara-Kiirunavaara Aktiebolag

InventorRoland Drugge

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Abstract

Agglomerates are fired in a sintering apparatus of the type, in which the agglomerates during transport on a travelling grate in zones along said grate are pre-dried with substantially pure warm air passing upwardly through the grate and finally dried and heated with hot process gas passing downwardly through the grate, and in which the hot process gas is generated by combusting fuel while using, as secondary air of combustion, air previously used to cool fired agglomerates. In order to reduce the quantity of gas contaminated during the firing process there is maintained in a sealing zone located between the pre-drying and final-drying zones and mechanically shielded thereagainst, by supplying air above the grate and removing air by suction from beneath the grate, pressures which are substantially equal to the pressure above the grate and the pressure beneath the grate respectively in the adjacent final-drying zone.

Claims22

Dependent claims

A method of continuously firing agglomerated material and agglomerates, particularly pellet sintering, the method using an apparatus having a housing which is shielded from the surrounding atmosphere, at least one movable grate for transporting agglomerated material through the housing, means within the housing for defining a plurality of drying zones and for defining a cooling section, and means for sealing the plurality of drying zones from each other, said method comprising:

transporting agglomerated material through said apparatus on the movable grate;
pre-drying the agglomerated material in a first of said plurality of drying zones with substantially pure air passing upwardly through the grate;
combustion fuel, using secondary air of combustion, to generate a hot process gas;
finally drying the agglomerated material in a last of the plurality of drying zones by passing the hot process gas downwardly through the grate;
establishing a sealing zone between the first and the last of the plurality of drying zones by supplying air above the grate and by removing, by suction, air from beneath the grate, the pressures within the sealing zone being substantially equal to the pressures in the last drying zone;
and
passing cooling air through the agglomerated material in the cooling section to cool the finally dried agglomerated material, the cooling air, after passing through the cooling section being used as secondary air of combustion while combusting fuel.

4 more elements

An apparatus for continuously firing agglomerates and agglomerated material, particularly pellet sintering, said apparatus comprising a housing;

means for shielding the housing from the surrounding atmosphere;
at least one movable grate for receiving agglomerated material and for transporting material through the housing;
a plurality of sequentially arranged zones disposed within the housing for drying the material, a first of the drying zones being adapted to use substantially pure air passing upwardly through the grate to pre-dry the material, a last of the drying zones being adapted to use a hot process gas passing downwardly through the grate to finally dry and heat the material;
a cooling section using cooling air for cooling the fired agglomerates;
at least one burner for generating hot process gas required for a firing process;
means for conducting air used as cooling air to the burner for use as secondary air;
and means for forming a sealing zone between the pre-drying and final-drying zones that is mechanically shielded thereagainst, said sealing zone having means connected thereto for controlled supply of air above the grate and controlled removal of air by suction from beneath the grate in such a manner that there is maintained in said sealing zone, pressures which are substantially equal to the pressure above the grate and the pressure beneath the grate, respectively, in the adjacent final-drying zone.

4 more elements

Dependencies are inferred from the claim text.