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Study of Organic and Inorganic Binders on Strength of Iron Oxide Pellets
URVASHI SRIVASTAVA, S. KOMAR KAWATRA, and TIMOTHY C. EISELE
Bentonite is a predominant binder used in iron ore pelletization. However, the presence of a high content of silica and alumina in bentonite is considered undesirable for ironmaking operations. The objective of this study was to identify the alternatives of bentonite for iron ore pelletization. To achieve this goal, dierent types of organic and inorganic binders were utilized to produce iron oxide pellets. The quality of these iron oxide pellets was compared with pellets made using bentonite. All pellets were tested for physical strength at dierent stages of pelletization to determine their ability to survive during shipping and handling. The results show that organic binders such as lactose monohydrate, hemicellulose, and sodium lignosulfonate can provide sucient strength to indurated pellets.
DOI: 10.1007/s11663-013-9838-4 The Minerals, Metals & Materials Society and ASM International 2013
I. INTRODUCTION
RUN-OF-MINE iron ore contains approximately 25 pct iron. This is too low to be directly used in blast furnace and direct reduced iron (DRI) operations. Therefore, it must be upgraded to a ne particle concentrate. Fine iron ore concentrates are converted into suitable pellet feed through pelletization with the aid of a binder. The pellets are typically balled in a rotating drum or disk and are red in a furnace to increase their compression strength. The process of ring is called induration or sintering, and these red pellets are called indurated or sintered pellets. It is important that nished (indurated) pellets achieve compressive strength of the pellets 1780 N (400 pound force) or above to be able to survive during shipping, handling and ironmaking operation.[1] During pelletization, as a part of quality control, pellets are tested for their mechanical strength at dierent stages in the process. Common measurements include drop test of green pellets (wet pellets), compressive strength of dry pellets, and compressive strength of indurated pellets. Generally, pellets are 9 to 12 mm in diameter and must meet a minimum of 400 lbf (1780N) of compressive strength.[1,2]
A binder is required to combine the iron oxide particles and hold them together during the green pellet production. Bentonite is a standard and most common binder used for iron ore pelletization....