Refining of Hot Metal Containing Nb with Multi-staged Continuous Selective Oxydation Process

Abstract

The extraction of Nb from the pig iron containing Nb, which is produced in Baotou, Inner Mongolia, China has been jointly investigated by National Research Institute for Metals, Japan and Beijing University of Iron and Steel Technology, China. By the use of 2 stage tank type continuous selective oxidation furnaces in series, where the most of Si and a part of Mn were removed in the 1st stage and Nb was selectively oxidized in the 2nd stage, the optimum refining conditions to obtain high Nb content slag in the 2nd stage were found out. Through the operations of 11 times the slag holding Nb₂O₅ of as high as 7 to 10% was constantly produced at the recovery rate over 70%. This is due to the adoption of continuous refining process.