System and method for cooling and removing iron from a hearth

Abstract

A system and method for cooling and removing metallic iron and other aggregate from a moving hearth is provided. Cooling may be provided by a secondary cooling system and a spray cooling system in a cooling zone. The secondary cooling system may include an arrangement of coolant tubes for absorbing heat. A flow of nitrogen may be provided through the cooling zone. The spray cooling system may provide evaporative cooling. Aggregate removal may be provided by a magnetic removal system, a plow system, and a sweeper system. The magnetic removal system uses a magnetic device and a moving belt to remove iron materials. The plow system uses a plow to separate and remove aggregate from the moving hearth. The sweeper system may use a vacuum device to pull materials from the moving hearth.

1 . A method of removing metallic iron and associated materials from a moving hearth comprising the steps of:
 a. providing a moving hearth supporting aggregate comprising metallic iron material, slag, and carbon-bearing material;   b. cooling the aggregate on the moving hearth in a cooling zone by secondary cooling;   c. spraying water over the aggregate on the moving hearth so as to evaporate and cool the aggregate on the moving hearth without substantial water run off to a temperature in the adjacent atmosphere at or below about 800° F.;   d. causing the moving hearth supporting aggregate to move beneath a moving belt positioned between the moving hearth and a magnetic device; and   e. removing magnetic material from the moving hearth by using the magnetic device to remove magnetic material from the aggregate.   
     
     
         2 . The method according to  claim 1 , where the step of cooling the aggregate by secondary cooling comprises the step of:
 providing coolant tubes in a serpentine configuration adjacent the moving hearth, the coolant tubes being capable of circulating coolant therethrough to remove heat from the aggregate on the moving hearth.   
     
     
         3 . The method according to  claim 1 , where the step of cooling the aggregate by secondary cooling comprises the step of:
 providing a plurality of coolant tubes capable of cooling the aggregate on the moving hearth to a temperature of the adjacent atmosphere at or below about 1200° F.   
     
     
         4 . The method according to  claim 1 , where the step of removing magnetic material from the moving hearth comprises the step of:
 moving such removed magnetic material traverse or along the direction of travel of the moving hearth.   
     
     
         5 . The method according to  claim 4 , the step of moving such removed magnetic material traverse or along the direction of travel of the moving hearth being performed at a velocity in a range of about 100 to about 400 feet per minute (about 30 to about 120 meters per minute). 
     
     
         6 . The method according to  claim 5 , further comprising the step of:
 causing the removed magnetic removed material to be impacted against a surface to separate metallic iron material from slag and other associated material.   
     
     
         7 . A method of removing metallic iron and associated materials from a moving hearth comprising the steps of:
 a. providing a moving hearth supporting aggregate comprising metallic iron material, slag, and carbon-bearing material;   b. cooling the aggregate on the moving hearth in a cooling zone by secondary cooling;   c. causing the moving hearth supporting aggregate to move beneath a moving belt positioned between the moving hearth and a magnetic device;   d. removing magnetic material from the moving hearth by using the magnetic device to remove magnetic material from the aggregate; and   e. then moving the moving hearth with aggregate thereon beneath a plow capable of selectively removing from the hearth a regulated amount of aggregate while leaving other aggregate on the moving hearth if desired   
     
     
         8 . The method according to  claim 7 , further comprising the step of:
 spraying water over the aggregate on the moving hearth to cool the aggregate by evaporation without substantial water run off to a temperature of the adjacent atmosphere at or below about 800° F.;   
     
     
         9 . The method according to  claim 7 , where the step of cooling the aggregate by secondary cooling comprises the step of:
 providing coolant tubes in a serpentine configuration adjacent the moving hearth, the coolant tubes being capable of circulating coolant therethrough and removing heat from the aggregate on the moving hearth.   
     
     
         10 . The method according to  claim 7 , where the step of cooling the aggregate by secondary cooling comprises the step of:
 providing a plurality of coolant tubes capable of circulating coolant to cast the aggregate on the moving hearth to a temperature in the adjacent atmosphere at or below about 1200° F.   
     
     
         11 . The method according to  claim 7 , where the step of removing magnetic material from the moving hearth comprises the step of:
 moving such removed magnetic material traverse or along the direction of travel of the moving hearth.   
     
     
         12 . The method according to  claim 11 , where the step of moving such removed magnetic material traverse or along the direction of travel of the moving hearth is performed at a velocity in a range of about 100 to about 400 feet per minute (about 30 to about 120 meters per minute). 
     
     
         13 . The method according to  claim 11 , further comprising the step of:
 causing the removed magnetic removed material to be impacted against a surface to separate metallic iron material from slag and other associated material.   
     
     
         14 . The method according to  claim 7 , where the step of moving the moving hearth beneath a plow comprises the steps of:
 removing aggregate from the moving hearth over a plow edge and adjacent inclined surface as the hearth moves beneath the plow;   positioning a brush adjacent to the inclined surface capable of moving aggregate along the surface of the plow; and   brushing the removed aggregate to a conveying device to remove the removed aggregate.   
     
     
         15 . The method according to  claim 14 , further comprising the steps of:
 positioning at an edge of the inclined surface a classifier for segregating the removed aggregate according to size; and   returning classified particles smaller than a selected size to the moving hearth.   
     
     
         16 . A method of removing metallic iron and associated materials from a moving hearth comprising the steps of:
 a. providing a moving hearth supporting aggregate comprising metallic iron material, slag, and carbon-bearing material;   b. cooling the aggregate on the moving hearth in a cooling zone by secondary cooling;   c. spraying water over the aggregate on the moving hearth so as to evaporate and cool the aggregate on the moving hearth by evaporation without substantial water run off to a temperature at or below about 800° F.;   d. causing the moving hearth supporting aggregate to move beneath a moving belt positioned between the moving hearth and a magnetic device;   e. removing magnetic material from the moving hearth by using the magnetic device to remove magnetic material from the aggregate;   f. then moving the moving hearth with aggregate thereon beneath a plow capable of selectively removing from the hearth a regulated amount of aggregate while leaving other aggregate on the moving hearth if desired; and   g. moving the hearth beneath a sweeper capable of selective removal of a regulated amount of aggregate from the moving hearth, and causing the sweeper to remove at least selected aggregate from the hearth.   
     
     
         17 . The method according to  claim 16 , where the step of cooling the aggregate by secondary cooling comprises the step of:
 providing coolant tubes in a serpentine configuration adjacent the aggregate on the moving hearth, the coolant tubes being capable of circulating coolant therethrough to remove heat from the aggregate on the moving hearth.   
     
     
         18 . The method according to  claim 16 , where the step of cooling the aggregate by secondary cooling comprises the step of:
 providing a plurality of coolant tubes capable of cooling the aggregate on the moving hearth to a temperature in the adjacent atmosphere at or below about 1200° F.   
     
     
         19 . The method according to  claim 16 , where the step of removing magnetic material from the moving hearth comprises the step of:
 moving such removed magnetic material traverse or along the direction of travel of the moving hearth.   
     
     
         20 . The method according to  claim 19 , where the step of moving such removed magnetic material traverse or along the direction of travel of the moving hearth is performed at a velocity in a range of about 100 to about 400 feet per minute (about 30 to about 120 meters per minute). 
     
     
         21 . The method according to  claim 20 , further comprising the step of:
 causing the removed magnetic material to be impacted against a surface to separate metallic iron material from slag and other associated material.   
     
     
         22 . The method according to  claim 16 , where the step of moving the moving hearth beneath a plow comprises the steps of:
 removing aggregate from the moving hearth over a plow edge and adjacent inclined surface as the hearth moves beneath the plow;   positioning a brush adjacent to the inclined surface capable of moving aggregate along the surface of the plow; and   brushing the removed aggregate to a conveying device to remove the removed aggregate.   
     
     
         23 . The method according to  claim 22 , further comprising the steps of:
 positioning at an edge of the inclined surface a classifier for segregating the removed aggregate according to size; and   returning classified particles smaller than a selected size to the moving hearth.   
     
     
         24 . The method according to  claim 16 , where the step of causing the sweeper to remove at least selected aggregate comprises the step of:
 removing aggregate from the moving hearth using a vacuum device.   
     
     
         25 . The method according to  claim 16 , where the step of causing the sweeper to remove at least selected aggregate comprises the step of:
 intermittently removing material from the hearth.   
     
     
         26 . A method of removing metallic iron and associated materials from a moving hearth comprising the steps of:
 a. providing a moving hearth supporting aggregate comprising metallic iron material, slag, and carbon-bearing material;   b. causing the moving hearth supporting aggregate to move beneath a moving belt positioned between the moving hearth and a magnetic device;   c. removing magnetic material from the moving hearth by using the magnetic device to remove magnetic material from the aggregate;   d. then moving the moving hearth with aggregate thereon beneath a plow capable of selectively removing from the hearth a regulated amount of aggregate while leaving other aggregate on the moving hearth if desired; and   e. moving the hearth beneath a sweeper capable of selective removal of a regulated amount of aggregate from the moving hearth, and causing the sweeper to remove at least selected aggregate from the hearth.   
     
     
         27 . The method according to  claim 26 , further comprising the steps of:
 prior to the step of moving the aggregate beneath the moving belt, cooling the aggregate on the moving hearth in a cooling zone by secondary cooling.   
     
     
         28 . The method according to  claim 27 , where the step of cooling the aggregate by secondary cooling comprises the step of:
 providing coolant tubes in a serpentine configuration adjacent the aggregate on the moving hearth, the coolant tubes being capable of removing heat from the aggregate on the moving hearth.   
     
     
         29 . The method according to  claim 27 , where the step of cooling the aggregate by secondary cooling comprises the step of:
 providing a plurality of coolant tubes capable of circulating coolant therethrough to cool the aggregate on the moving hearth to a temperature of an adjacent atmosphere at or below about 1200° F.   
     
     
         30 . The method according to  claim 26 , further comprising the step of:
 spraying water over the aggregate on the moving hearth to cool the aggregate on the moving hearth by evaporation without substantial water run off to a temperature in the adjacent atmosphere at or below about 800° F.   
     
     
         31 . The method according to  claim 26 , where the step of removing magnetic material from the moving hearth comprises:
 moving such removed magnetic material traverse or along the direction of travel of the moving hearth.   
     
     
         32 . The method according to  claim 31 , where the step of moving such removed magnetic material traverse or along the direction of travel of the moving hearth is performed at a velocity in a range of about 100 to about 400 feet per minute (about 30 to about 120 meters per minute). 
     
     
         33 . The method according to  claim 32 , further comprising the step of:
 causing the removed magnetic removed material to be impacted against a surface to separate metallic iron material from slag and other associated material.   
     
     
         34 . The method according to  claim 26 , where the step of moving the moving hearth beneath a plow comprises the steps of:
 removing aggregate from the moving hearth over a plow edge and adjacent inclined surface as the hearth moves beneath the plow;   positioning a brush adjacent to the inclined surface and capable of moving aggregate along the surface of the plow; and   brushing the removed aggregate to a conveying device to remove the removed aggregate.   
     
     
         35 . The method according to  claim 34 , further comprising the steps of:
 positioning at an edge of the inclined surface a classifier for segregating the removed aggregate according to size; and   returning classified particles smaller than a selected size to the moving hearth.   
     
     
         36 . The method according to  claim 26 , where the step of causing the sweeper to remove at least selected aggregate comprises the step of:
 removing aggregate from the moving hearth using a vacuum device.   
     
     
         37 . The method according to  claim 26 , where the sweeper is capable of intermittently removing material from the hearth. 
     
     
         38 . A method of removing metallic iron and associated materials from a moving hearth comprising the steps of:
 a. providing a moving hearth supporting aggregate comprising metallic iron material, slag, and carbon-bearing material;   b. causing the moving hearth to move beneath a drum positioned transverse to the aggregate on the moving hearth and supporting a belt moving in a continuous loop capable of moving magnetic material counter to the direction of travel of the moving hearth, with a magnetic device being positioned within the drum; and   c. removing magnetic material from the aggregate, and moving the removed magnetic material for separate processing.   
     
     
         39 . The method according to  claim 38 , further comprising:
 causing a coolant flow through a cooling jacket within the drum.   
     
     
         40 . A system for removing metallic iron and associated materials from a moving hearth comprising:
 a. a moving hearth capable of supporting aggregate comprising metallic iron material, slag, and carbon-bearing material;   b. a cooling zone capable of cooling the aggregate on the moving hearth by secondary cooling;   c. a spray of water capable of cooling the aggregate on the moving hearth to a temperature in the adjacent atmosphere at or below about 800° F. by evaporation without substantial water run off; and   d. a moving belt positioned between a magnetic device and the moving hearth, the magnetic device being capable of removing magnetic material from the aggregate, and the moving belt being capable of moving the removed magnetic material transverse or along the direction of travel of the moving hearth for separate processing.   
     
     
         41 . The system according to  claim 40 , the secondary cooling comprising:
 coolant tubes in a serpentine configuration adjacent the moving hearth, the coolant tubes being capable of circulating coolant therethrough to remove heat from the aggregate on the moving hearth.   
     
     
         42 . The system according to  claim 40 , the secondary cooling comprising:
 a plurality of coolant tubes capable of circulating coolant therethrough to cool the aggregate on the moving hearth to a temperature in the adjacent atmosphere at or below about 1200° F.   
     
     
         43 . The system according to  claim 40 , where the velocity of the moving belt is in a range of about 100 to about 400 feet per minute (about 30 to about 120 meters per minute). 
     
     
         44 . The system according to  claim 43 , where the moving belt is capable of impacting the removed magnetic material against a surface to separate metallic iron material from slag and other associated material in a direction transverse to the travel of the moving hearth. 
     
     
         45 . A system for removing iron from a moving hearth comprising:
 a. a moving hearth comprising a plurality of sections capable of supporting aggregate comprising metallic iron material, slag, and carbon-bearing material;   b. a moving belt positioned between a magnetic device and the moving hearth, the magnetic device being capable of removing magnetic material from the aggregate, and the moving belt being capable of moving the removed magnetic material traverse or along the direction of travel of the moving hearth for separate processing; and   c. a plow capable of selective removal from the moving hearth a regulated amount of aggregate while leaving other aggregate on the moving hearth if desired.   
     
     
         46 . The system according to  claim 45 , further comprising:
 a sweeper capable of selective removal of a regulated amount of aggregate from the moving hearth when the hearth moves beneath the sweeper.   
     
     
         47 . The system according to  claim 45 , further comprising:
 a cooling zone capable of cooling the aggregate by secondary cooling.   
     
     
         48 . The system according to  claim 47 , the secondary cooling comprising:
 coolant tubes in a serpentine configuration adjacent the moving hearth, the coolant tubes being capable of circulating coolant therethrough to remove heat from the aggregate on the moving hearth   
     
     
         49 . The system according to  claim 47 , the secondary cooling comprising:
 a plurality of coolant tubes capable of circulating coolant therethrough to cool the aggregate on the moving hearth to a temperature of the adjacent atmosphere at or below about 1200° F.   
     
     
         50 . The system according to  claim 45 , further comprising:
 a spray of water capable of cooling the aggregate on the moving hearth to a temperature in the adjacent atmosphere at or below about 800° F. by evaporation without substantial water run off.   
     
     
         51 . The system according to  claim 45 , where the velocity of the moving belt is in a range of about 100 to about 400 feet per minute (about 30 to about 120 meters per minute). 
     
     
         52 . The system according to  claim 51 , where the moving belt is capable of impacting the removed magnetic material against a surface to separate metallic iron material from slag and other associated material in a direction transverse to the travel of the moving hearth. 
     
     
         53 . The system according to  claim 45 , where the plow comprises:
 a plow edge and an adjacent inclined surface positioned to remove aggregate from the moving hearth when the hearth moves beneath the plow; and   a brush adjacent to the surface capable of moving aggregate along the surface of the plow to a conveying device to remove the removed aggregate.   
     
     
         54 . A system according to  claim 53 , further comprising:
 a classifier capable of segregating the removed aggregate according to size positioned at an edge of the inclined surface and positioned such that classified particles smaller than a selected size return to the moving hearth.   
     
     
         55 . A system according to  claim 46 , where the sweeper comprises a vacuum device capable of removing aggregate from the moving hearth. 
     
     
         56 . A system according to  claim 46 , where the sweeper is capable of removing material from front and rear portions of the moving hearth sections. 
     
     
         57 . A system for removing metallic iron and associated materials from a moving hearth comprising:
 a. a moving hearth capable of supporting aggregate comprising metallic iron material, slag, and carbon-bearing material; and   b. a moving belt positioned between a magnetic device and the moving hearth, with the magnetic device being capable of removing magnetic material from the aggregate; and   c. a drum being positioned transverse to the aggregate on the moving hearth and supporting the belt moving in a continuous loop capable of moving magnetic material counter to the direction of travel of the moving hearth, the magnetic device being positioned within the drum.   
     
     
         58 . The system according to  claim 57 , where the drum further comprises a cooling jacket capable of receiving a flow of coolant. 
     
     
         59 . A system for removing metallic iron and associated materials from a moving hearth comprising:
 a. a moving hearth supporting aggregate comprising metallic iron material, slag, and carbon-bearing material;   b. a moving belt positioned between a magnetic device and the moving hearth, the moving belt being positioned transverse or along the direction of travel of the hearth, the magnetic device being capable of removing magnetic material from the aggregate and the moving belt being capable of moving the removed magnetic material transverse or along the direction of travel of the moving hearth; and   c. a collector positioned to receive removed magnetic material from the moving belt.   
     
     
         60 . The system according to  claim 59 , where the velocity of the moving belt is in a range of about 100 to about 400 feet per minute (about 30 to about 120 meters per minute). 
     
     
         61 . The system according to  claim 59 , further comprising:
 an impact plate adjacent to the moving belt, where the moving belt is capable of impacting the metallic iron material against the impact plate to separate metallic iron material from slag and other associated material.   
     
     
         62 . A system of removing metallic iron and associated materials from a moving hearth comprising:
 a moving hearth supporting aggregate comprising metallic iron material, slag, and carbon-bearing material; and   a plow capable of selective removal from the moving hearth of a regulated amount of aggregate while leaving other aggregate on the moving hearth if desired when the hearth moves beneath the plow.   
     
     
         63 . The system according to  claim 62 , where the plow comprises:
 a plow edge and an adjacent inclined surface positioned to remove aggregate from the moving hearth when the hearth moves beneath the plow; and   a brush adjacent to the surface capable of moving aggregate along the surface of the plow to a conveying device to remove the removed aggregate.   
     
     
         64 . The system according to  claim 63 , comprising a classifier capable of segregating the removed aggregate according to size positioned at an edge of the inclined surface and positioned such that classified particles smaller than a selected size return to the moving hearth. 
     
     
         65 . The system according to  claim 63 , where the distance between the plow edge and the moving hearth is adjustable. 
     
     
         66 . The system according to  claim 63 , where the brush is a rotary brush positioned above the surface. 
     
     
         67 . A system of removing aggregate from a moving hearth comprising:
 a moving hearth comprising a plurality of sections capable of supporting aggregate comprising metallic iron material, slag, and carbon-bearing material; and   a sweeper capable of selective removal of a regulated amount of aggregate from the moving hearth when the hearth moves beneath the sweeper.   
     
     
         68 . A system according to  claim 67 , where the sweeper comprises a vacuum device capable of pulling aggregate from the moving hearth. 
     
     
         69 . A system according to  claim 67 , where the sweeper removes at least selected aggregate from the moving hearth. 
     
     
         70 . A system according to  claim 67 , where the sweeper removes at least selected aggregate from the front and rear portions of the moving hearth sections.