I'm Brazilian so I think I might help, though I'm a lawyer, not a historian. This is a topic that is really common knowledge in Brazil so I hope it's alright by the mods.

One of the reasons Brazil took very long to abolish slavery was because its economy was heavily reliant on the production of sugar, coffee, tobacco and cotton, which exclusively used slave labor up until the mid 19th century.

Also, since Brazil had such vast lands, the monetary value of slaves was actually higher than the lands themselves, making them a very expensive and important asset. This would also create a resistance to change the elite's stance on slavery.

Finally, Portugal made a lot of money on taxes charged from slave merchants. This means that there probably was no institutional interest in changing the situation.

It all started to change with England's pressures, especially the Aberdeen Act in 1845. In 1850, the Eusébio de Queiroz Law finally prohibited the transatlantic trafficking of slaves. This intensified the internal slave market and actually made their prices go up, which kept slavery going.

Intellectuals started to voice their opinion against slavery and by the 1870s, a growing part of society was against slavery. In 1871 the Ventre Livre Law was created (Free Womb Law) which made it so that any child born from a slave would be free. By then, slaves were allowed to have private property and could eventually buy their freedom (alforria).

In 1885, the Sexagenários Law (Sexagenarian Law) was approved, which granted freedom to anyone over the age of 65. In 1889, princess Isabel, acting as a regent for Emperor Dom Pedro II, approved the Áurea Law (Golden Law), which unequivocally ended slavery in Brazil.

By then, though, most of the workforce was already composed by immigrants (most notably, Italians), who were cheaper to maintain, representing a better cost-effectiveness.