So, secession was intended as a way to get rid of slavery?
"Intended"? No. But many if not most knew that secession would cause its collapse before very long. But they also knew it was doomed anyway. They could see what had been slowly happening in the Northern states, what had happened in the British Empire a generation earlier, what was happening in the other European colonial empires, etc.
"Secession, southerners argued, would 'liberate' the South and produce the kind of balanced economy that was proving so successful in the North and so unachievable in the South." (John A. Garraty and Robert McCaughey, The American Nation: A History of the United States to 1877, Volume One, Sixth Edition, New York: Harper & Row, Publishers, 1987, pp. 418-419, emphasis in original)
Secession would make the Southern states richer by freeing them of the burdens imposed on them by the Northern states. This extra money would speed up their own economic development/industrialization.