Regular Article

The bonding mechanism and effects of sodium ligninsulfonate (SL) in iron ore pelletization

¹ State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, 430081 Wuhan, Hubei, China
² Collaborative Innovation Center for Advanced Steels, Wuhan University of Science and Technology, 430081 Wuhan, China

^* e-mail: wangbao1983@wust.edu.cn

Received: 22 February 2022
Accepted: 14 March 2022

Abstract

Bentonite is the most commonly used binder for iron ore pellets. However, due to its high alumina and silica content, the slag volume and energy consumption are increased. The aim of the present work is to identify the CSL (sodium ligninsulfonate added CaCO₃) as an alternative binder in iron ore pelletization. FTIR and zeta potential tests verified that sodium ligninsulfonate (SL) reacted with magnetite mainly through ligand exchange, hydrogen bond and electrostatic interaction. Compared with SL, CSL has more active sites and stronger adsorbability. The strength of CSL preheated and roasted pellets was determined by TG and SEM. CaCO₃ as a fluxing agent develops oxide bridging and bonding between the magnetite grains, forming more slag, reducing porosity and improving the compressive strength of roasted pellets. The experimental results show that it is feasible to add CaCO₃ in SL as binder in pellet production.