A review: research progress of flux pellets and their application in China

Abstract

The flux pellets as the burden materials of blast furnace have been widely investigated and used. However, its research and practical applications keep slowly developing in China due to the historical status of the sinter and the limitation of raw material condition. The sinter output is constrained by the environmental department due to its great emission of air pollutants. Therefore, enhancing the development of pellets becomes an urgent task for China's steel enterprises. Flux pellets shows excellent adaptability in ironmaking compared with acid pellet, but the investigation on its preparation and utilisation in China is far from enough. This review provides a summary of the current research status and application of flux pellets in China, which mainly focuses on the metallurgical properties and their interfering factors, as well as BF production indexes after using, hoping to provide a comprehensive understanding for flux pellets and push its technical progress continuously.

Research on the ring formation mechanism of magnesian flux pellets in rotary kiln

“…Magnesian flux pellet has become a high-quality and efficiency blast furnace raw material with high grade, low energy consumption and environmental protection 2-4 . According to statistics, compared with sintering process, pollutants CO 2 , SO 2 and NO x produced by tons of products in pelletizing process were reduced respectively by 75%, 53% and 16%, and energy consumption in pelletizing process was reduced by 11.9% 5,6 . Therefore, pelletizing process was more environmental friendly than sintering process.Production processes of pellets mainly included shaft furnace, belt roaster and grate rotary kiln [7][8][9] .…”

Study on Properties of Cold‐Bonded Briquettes Prepared from Return Fines of Sinter

“…With the reduction from hematite to magnetite and wustite, the volume expansion change of the iron ores can be expressed as Fe 2 O 3 (100%)→Fe 3 O 4 (124%)→FeO (131%)→Fe (126%). [ 11 ] The required volume increase for oriented growth of magnetite (111) planes parallel to hematite (0001) planes and associated internal cracks developed normal to these planes, which causes the volume expansion of iron ores during the reduction process. [ 12 ] When the degree of low‐temperature reduction degradation is serious, the amount of the reducing gas passing through the burden column decreases, and then the pressure difference inside the blast furnace increases and the reduction efficiency decreases; even the smooth operation of blast furnace could be influenced negatively.…”

“…; moreover, the higher RI means a higher indirect reduction percentage, lower coke rate, and higher productivity in the blast furnace. [ 11 ]…”

“…; moreover, the higher RI means a higher indirect reduction percentage, lower coke rate, and higher productivity in the blast furnace. [11] The binders must be added during the preparation to increase the CBB strength. [14,15] Widely used binders include starch, bentonite, Portland cement, etc.…”

Physicochemical Aspects of Oxidative Consolidation Behavior of Manganese Ore Powders with Various Mn/Fe Mass Ratios for Pellet Preparation

“…Previous research has mainly concentrated on the characterization, as well as pelletizing and sintering behaviors, of pure iron ores and manganese ores with very high Mn/Fe mass ratios [ 15 , 16 , 17 , 18 , 19 ]. Faria et al investigated the high-temperature disintegration of a Brazilian rich manganese lump ore and roasted pellets and found that the pellets demonstrated better mechanical and metallurgical properties than the natural lump ore [ 17 , 18 ].…”