Although the dates cannot be known with certainty, the following is an excellent quote about the stages in which Babylon sacked Jerusalem:
"Bible scholars recognize two great deportations. The first took place in the year 596 B.C., four years after the departure of Lehi from Jerusalem. Lehi was then about half way through the desert journey, which lasted eight years in all, and Jacob must have been a baby, since he was born in the desert. Lehi may have had a vision of this deportation. If so, he would certainly have related that vision to his family many times.
"On this occasion Nebuchadnezzar carried away King Jehoiachin and family, the Prophet Ezekiel and thousands of nobles and craftsmen. He destroyed the sacred vessels in the temple and looted the treasuries. And, finally, he appointed an uncle of Jehoiachin, Zedekiah, king in Jerusalem. (2 Kings 24:10–14)
"The second deportation took place in the year 586 B.C., ten years after the first. On that occasion all monumental and otherwise valuable buildings in Jerusalem were destroyed by fire. Everything of value was carried to Babylon. Some of the children of Zedekiah were cruelly butchered before his eyes, and that was the last thing he saw, before his eyes were put out. Gedaliah was made ruler in Jerusalem.
“As near as can be judged from Book of Mormon chronology, Lehi had passed away at that time. The Nephites had established themselves as an independent colony, and Jacob and Joseph had been appointed priests and teachers. (See 2 Ne. 5:28) It is more than probable that the Lord gave Jacob a vision of this second deportation shortly after it had taken place in the year 586 B.C., as he gave Lehi a vision of the first deportation. The Prophet Ezekiel and the captives in Babylon were notified by a special messenger of the epochal event. (Ex. 33:21)” (Reynolds and Sjodahl, Commentary on the Book of Mormon, vol. 1, p. 282)