Iron-carbon nuggets coalescence: Influence of slag's liquidus temperatures

The self-reduction is an alternative and promising process for production of pig iron because offers decisive benefits such as enhancing the reaction kinetic with decrease in fuel consumption and CO₂ emissions. The self-reduction mixture of iron ore fines, carbonaceous reducer and additives for slag forming components, without agglomeration, was tested in a laboratory rotary kiln. The additives for slag were defined for presenting two different estimated liquidus temperatures (1623 K and 1773 K) to verify the effect of these temperatures on the iron-carbon nuggets coalescence process. These mixtures were tested at 1673 and 1773 K in an experimental rotary kiln. After reduction-melting and coalescence processes the samples were disaggregated and the iron nuggets were classified by size. It was considered that nuggets larger than 7,93mm would be a good reference for coalescence index. Low liquidus temperature slag presented 37% of this larger fraction against only 13.5% for high liquidus temperature one. The low liquidus temperature slag would facilitate contact between the particles of iron-carbon in a rotary kiln, enhancing the coalescence.