Characterization of Colemanite and Its Effect on Cold Compressive Strength and Swelling Index of Iron Ore Pellets
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Characterization of Colemanite and Its Effect on Cold Compressive Strength and Swelling Index of Iron Ore Pellets Mahaboob Basha Shaik 1 & Chandra Sekhar 1 & Srinivas Dwarapudi 1 & Neha Gupta 1 & Indrajit Paul 2 & Arvind Kumar Patel 3 & Shakuntala Tudu 4 & Amit Kumar 3 Received: 1 April 2020 / Accepted: 5 October 2020 # Society for Mining, Metallurgy & Exploration Inc. 2020
Abstract In this study, the effect of colemanite and calcined colemanite (CC) addition on the properties of iron ore pellets is studied. The pellets are prepared in a lab without and with 0.2% colemanite and varying amounts of CC from 0 to 1.0 wt% in steps of 0.2%. A reference pellet is prepared under typical plant conditions, and the properties of the reference pellet are considered as the base value for improving the cold compressive strength (CCS) while maintaining the other parameters at an acceptable limit without altering the pellet. The study also aims to provide a detailed characterization of colemanite and calcined colemanite to better understand their behaviour during firing. The lab-scale results show that the CCS of pellets made with 0.2% colemanite was reduced by 222 points (60%) as compared to the reference pellets due to crack formation during firing. The results show an improvement in the CCS of the indurated pellets with CC dosage up to 0.4%, and decreasing strength is noted thereafter. It is observed that the swelling index increases with the increase in calcined colemanite dosage. To simulate plant conditions, reference pellets and pellets with optimized CC dosage were fired in a plant furnace. Keywords Cold compressive strength . Iron ore pellet . Colemanite . Swelling index . Calcined colemanite
1 Introduction The strength of iron ore pellets is an important property which represents their ability to withstand the load during storage and handling, and the load of the burden material in the reduction furnace. Strength has direct influence on lowering energy consumption and improving productivity in reduction furnaces [1, 2]. To increase the performance of pellets in a blast furnace, the strength of iron ore pellets must be increased.
The strength of iron ore pellets largely depends on slag bonds formed during induration. The type and amount of slag bonds formed depends mainly on the chemical composition and physical properties of the concentrates, fluxes and firing conditions [3–5]. The use of fluxes and some binders is necessary to provide sufficient strength to the pellets [6, 7]. In recent years, efforts have focused on increasing the fired pellet strength by adding low-melting temperature and slag-bonding constituents such as colemanite and calcined colemanite in combination with organic binders [8]. Colemanite has the
* Mahaboob Basha Shaik [email protected]
Shakuntala Tudu [email protected]
Chandra Sekhar [email protected] Srinivas Dwarapudi [email protected] Neha Gupta [email protected] Indrajit Paul [email protected] Arvind Kumar Patel arvindkr.patel@tataste
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