Binder composition for iron ore agglomeration

A binder composition for the manufacture of iron ore pellets, said binder composition containing:

• a) at least two organic binding agents LO in the form of solid particles, which are at least:
• a water-soluble anionic polymer P1 with a weight average molecular weight between 500 and 200,000 daltons, and
• a water-soluble anionic or amphoteric polymer P2 with a weight average molecular weight greater than 500,000 daltons;
• and
• b) at least one inorganic binding agent LI in the form of solid particles, the solid particles of the binders LO having a number median size greater than 500 micrometers, the particles of the binding agent LI have a number median size of less than one-third of the number median size of the solid particles of the binding agents LO,
• wherein polymer P1 is a polymer:
• of at least one anionic monomer containing (1) at least one carboxylate function —C(═O)—O−X+ where X is an alkali metal;
• and
• of at least one anionic monomer containing (2) at least one carboxylate function —C(═O)—O− X+ where X′ is an alkaline earth metal, and
• wherein said binder composition consists of P1+P2+LI, and contains:
• between 2 and 40% by weight of polymer P1,
• between 20 and 60% by weight of polymer P2, and
• between 30 and 70% by weight of binding agent LI,
• the sum of the percentages by weight of P1+P2+LI being equal to 100%.