Improving Granulating and Sintering Performance by Pretreating Specularite Concentrates Through Mechanical Activation

Abstract

In this paper, the pretreatment of specularite concentrates through roller press was present to improve the granulation of blends comprising some 10-30% specularite concentrates and enhance the sintering performance. It was shown that the content of +3 mm fractions of granulation mixture is elevated by 10% and the sinter mixture permeability is elevated by 35%. In the meantime, a sinter tumble index increasing from 62.00 to 64.13% was attainted with similar sinter productivity and at lower fuel rate. The mechanism of the pretreating concentrates process to improve sintering performance was demonstrated from mineralogy analysis that better permeability and improved reactivity which help to form more calcium ferrite and good microstructure of sinter, further proven by the better metallurgical performance of sinter.

Granulation Behavior of an Iron Ore Sintering Mixture Containing High Grade Pellet Feed with Different Specific Surface

“…Other authors investigated the use of concentrates and pellet feed, which were previously pre-treated in roller press aiming to increase its specific surface, in sintering process showing that the pre-treatment allows to use these materials without losing process permeability. [14][15][16] Those findings were recently reinforced by Yang et al 2) who investigated different size distribution of specular hematite ore types and Oliveira et al 17) whom reported that it was also possible to replace coarse sinter feeds without losing productivity.…”

“…It can be observed that the fraction below 0.045 mm of the pressed pellet feed presents the highest specific surface area through both techniques, similar results were reported in literature. 17,23) Concerning the ballability index (K), it increases as the specific surface of the pellet feed increases, reaching values over 0.6, which is considered a good level of K factor for a good agglomeration behavior according to Jian et al 15)…”

“…method), using Quantachrome equipment (NOVA 1000e model). Additionally, the ballability index (K) of the pellet feeds was determined using an apparatus specially manufactured for such analysis and based on the method mainly used and developed in China 15) which is based on water retention capacity and the maximum capillarity forces of the iron ore sample. The ballability index (K) is used to evaluate how easy iron ores can be pelletized, based in the interaction with water, which can be calculated from the following Eq.…”

“…The micropellet particles became more important recently due to the increase of fine particles below 0.15 mm as a result of the incorporation of pellet feed or concentrates into the iron ore mixtures as reported by different authors. [14][15][16][17]20,21) The samples were analyzed by optical microscopy, using a Carl Zeiss ® microscope, AxioImager Z2m model. An image analyzer software was used and the agglomerated particles (quasi-particles, micropellets, non-agglomerated particles) were quantified in different types by dot counting.…”

A study of pre-briquetting granulation sintering of the mixtures with high ratio of Brazilian specularite concentrate

“…As a result, the proportion of specularite concentrate in the blends for sintering is very low, such as less than 12% in Baosteel and commonly 3-5% in other China steel mills, and when further increasing the proportion of specularite concentrate, the obtained sinter productivity would be unaccepted. [1][2][3][4] Therefore, the extensive application of this concentrate has been restricted seriously.…”