Preparation of BF burden from Titanomagnetite concentrate by Composite agglomeration process (CAP)

Abstract

Titanomagnetite concentrate with high-TiO 2 content, is endowed with poor sintering property due to the coarse granularity and poor hydrophilicity compared to the conventional TiO 2 -free iron concentrates. In this study, Composite agglomeration process (CAP), an innovative route for preparing blast furnace burden, was introduced to overcome the difficulties in titanomagnetite concentrate sintering. CAP results showed that the sinter yield of 75.52%, tumbler index of 62.87% and productivity of 1.633 t·(m 2 ·h) -1 were achieved in a laboratorial sinter pot. They are 17.38%, 13.08% and 17.82% higher than those of traditional sintering process (TSP) respectively. Moreover, CAP lowered solid fuel consumption by 3.52 kg coke /t product. In addition, the reduction disintegration index of the product (RDI +3.15) was improved by 20.61%, while reduction index (RI) was decreased by 4.34%. In the CAP process of preparing BF burdens from titanomagntite concentrate, very few perovskite was generated in the pelletized part of CAP product for low CaO content. In the matrix part of CAP product, a large number of SFCA generated after perovskite fully crystallized from sinter melting for ultra-high CaO containing, thus the negative effects of perovskite on sinter quality were offset by SFCA for its excellent bonding property. Some melting phases in matrix part permeated through the outer layer of pellets and formed an interweaving structure, which bonded the pelletized part and matrix part together. As a results of this kind of mineralization mechanism, the high strength and excellent RDI property of CAP product were obtained, which proves that CAP is an effective agglomeration measure treatment for titanomagnetite concentrate.