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.