Functions and molecular structure of organic binders for iron ore pelletization

Organic binders of iron ore pellets were widely investigated in past decades because they do not contaminate the product. This paper mainly involves the functions and molecular structure of ideal organic binders for iron ore pelletization based on fundamental principles of molecular design, interface chemistry, polymer science as well as failure model of a binding system. Investigation shows that good wettability, great adhesive and cohesive forces as well as fine thermal stability are essential functions of binders for iron ore pelletization. The molecular structure mold [XPY]n of organic binders is proposed. Ionization potential, electron affinity, group electronegativity, bond ionicity and bond energy are calculated and/or applied in the selection and judgement of polar group (X) and hydrophilic group (Y). Organic chain skeleton (P) and polymerization degree (n) are investigated on the basis of the structure–property relationships of polymers. It is shown that COO− and OH are excellent polar group and hydrophilic group of organic binders of iron ore pellet, respectively, and organic skeletons with unsaturated hydrocarbon chain and ring aromatic structure are the best for organic binders of iron pellets. Two kinds of organic binders are synthesized and prepared on the basis of the investigations and they are found to be effective for pelletizing of iron ore concentrates. One of them has been used in commercial production of iron ore pellets in China.