Method and strand sintering equipment for continuous sintering of pelletized mineral material

1. A method for continuous sintering of pelletized mineral material, in which method

pellets are provided on a sintering underlay ( 1 ) to form an essentially even pellet bed ( 2 ) with a predetermined thickness;

the pellet bed ( 2 ) is conveyed on the sintering underlay ( 1 ) through process zones (I-VII) having different temperatures, including at least one drying/heating/sintering zone (I, II, III) and thereafter at least two cooling zones (V, VI, VII), and

during the conveying process, gas is conducted through the pellet bed ( 2 ) as the pellet bed proceeds through the process zones, characterized in that gas is allowed to circulate on top of the pellet bed ( 2 ) between two adjacent cooling zones (V, VI; VI, VII) in order to equalize the pressure therebetween.

2. A strand sintering equipment for continuous sintering of pelletized mineral material, said equipment comprising

a strand sintering furnace ( 3 ), which is divided into a number of sequential process zones having different temperature conditions, said zones including at least one drying/heating/sintering zone (I, II, III), where pellets are sintered, and thereafter at least two successive cooling zones (V, VI, VI), where the sintered pellets are cooled, and where the cooling zones are formed of cooling chambers ( 4 , 5 , 6 ), each of said two adjacent cooling chambers being separated by a partition wall ( 7 , 8 ),

a conveyor belt ( 1 ), which is arranged as an endless loop around a deflector roll ( 9 ) and a driven roll ( 10 ) for conveying the pellet bed, having a predetermined thickness, through the process zones of the strand sintering furnace, said conveyor belt being made permeable to gas,

an overhead circulation gas duct ( 11 , 12 , 13 ), which is placed above the conveyor belt ( 1 ) for conducting gas from the cooling zones (V, VI, VII) to the drying/heating/sintering zones (I, II, III) on top of the pellet bed,

a lower exhaust gas duct ( 14 , 15 , 16 , 17 ), which is located below the conveyor belt ( 1 ), for conducting the gas that was conducted through the pellet bed and the conveyor belt, and is exhausted from the drying/heating/sintering zone (I, II, III),

a lower inlet gas duct ( 18 , 19 , 20 , 21 ) which is located below the conveyor belt ( 1 ) for conducting gas to a cooling zone (V, VI, VII), and

a blower ( 22 ), which is arranged to set the gas in motion in the inlet gas duct ( 18 , 19 , 20 , 21 ), characterized in that the partition wall ( 7 , 8 ) is in the height direction placed at a distance from the pellet bed, so that in between the partition wall and the pellet bed, there is left a gap (s) for allowing a gas flow between two adjacent cooling chambers ( 4 , 5 ; 5 ; 6 ) through the gap (s) in order to equalize the pressure between the cooling chambers.