Process for the preparation of high alumina cement

Abstract

High alumina cement is produced in a submerged combustion melter, cooled and ground.

1 . Process for the preparation of high alumina cement comprising:
 introducing a solid batch material for preparation of high alumina cement into a melter;   melting the solid batch material in the melter by submerged combustion to form a liquid melt;   withdrawing at least a portion of the liquid melt from the melter;   cooling said discharged liquid melt to obtain solidified melt; and   grinding the solidified melt to appropriate grain size.   
     
     
         2 . The process of  claim 1 , wherein the melting chamber walls are cooled comprising double steel walls separated by circulating cooling liquid, and are not covered by a refractory lining. 
     
     
         3 . The process of  claim 1 , wherein heat is recovered from the hot fumes and/or from the cooling liquid. 
     
     
         4 . The process of  claim 1  wherein heat is recovered from the hot fumes to preheat the raw materials. 
     
     
         5 . The process of  claim 1  wherein part at least of the melt is withdrawn continuously or batchwise from the melter. 
     
     
         6 . The process of  claim 1  wherein the submerged burners of the melter are controlled such that the melt volume is increased by at least 8% compared to the volume the melt would have with no burners firing. 
     
     
         7 . The process of  claim 1  wherein the submerged combustion is performed such that a substantially toroidal melt flow pattern is generated in the melt, having a substantially vertical central axis of revolution, comprising major centrally inwardly convergent flows at the melt surface; the melt moves downwardly at proximity of the vertical central axis of revolution and is recirculated in an ascending movement back to the melt surface, thus defining a substantially toroidal flow pattern. 
     
     
         8 . The process of  claim 1  wherein the melting step comprises melting the solid batch material, in a submerged combustion melter by subjecting the melt to a flow pattern which when simulated by computational fluid dynamic analysis shows a substantially toroidal melt flow pattern in the melt, comprising major centrally inwardly convergent flow vectors at the melt surface, with the central axis of revolution of the toroid being substantially vertical. 
     
     
         9 . The process of  claim 8  wherein towards the melter bottom, the flow vectors change orientation showing outward and then upward components. 
     
     
         10 . Production equipment for the preparation of high alumina cement comprising (i) a submerged combustion melter ( 1 ) comprising melting chamber ( 3 ) walls ( 19 ) and a melting chamber bottom, submerged burners ( 21 , 22 , 23 , 24 , 25 , 26 ), and equipped with a raw material discharge ( 10 ) or feeder and melt outlet ( 9 ), (ii) a melt cooling station and (iii) a grinding station. 
     
     
         11 . The production equipment of  claim 10  wherein the melting chamber walls ( 19 ) are cooled, comprising double steel walls separated by circulating cooling liquid, and are not covered by refractory lining. 
     
     
         12 . The production equipment of  claim 10  wherein submerged combustion burners ( 21 , 22 , 23 , 24 , 25 , 26 ) are arranged at the melter bottom in a substantially annular burner zone. 
     
     
         13 . The production equipment of  claim 10  wherein the burners ( 21 , 22 , 23 , 24 , 25 , 26 ) are arranged with a distance between adjacent burners of about 250-1250 mm. 
     
     
         14 . The production equipment of  claim 10  wherein each burner axis and/or a speed vector of the melt moving upwards over or adjacent to the submerged burners ( 21 , 22 , 23 , 24 , 25 , 26 ) is slightly inclined from the vertical, by an angle which is ≥1°, ≥2°, ≥3 or ≥5 and/or which is ≤30°, towards the center of the melter. 
     
     
         15 . The production equipment of  claim 1  wherein each central burner axis is inclined by a swirl angle with respect to a vertical plane passing through a central vertical axis of the melter and the burner center, the swirl angle being ≥1°, ≥2°, ≥3°, ≥5 and/or ≤30°, ≤20°, ≤15° or ≤10°.