These are difficult questions. I think that hell as many choose to understand it is more of a reflection of hellenistic understanding in the time of the New Testament or a chaotic void in the time of the Old Testament. When Jesus described those who will be cut off from the Kingdom of God he always mentioned that they would be on the outside, using descriptive metaphors like “weeping” “gnashing” etc. Many take the flames of the NT literally, while others understand it as the only way that the audience in the Roman world could understand eternal punishment, i.e.: hades. Revelation is the most unliteral book of the Bible and it uses horrid descriptions which many Evangelicals have taken literally:) but most of the Church understands that authors of apocalyptic literature are using a medium common to revelations of the end of the world and judgment day -apocalyptic metaphors. But, who knows, it may be quite a surprise that such metaphors were intended to be taken literally.
The question was not about hell though! But, a lot of thoughts on purification through purgatory is boggled in together with medieval notions of purification through punishment; physical anguish, which can easily be confused with eternal punishment though they are not the same. I like weather’s response that such punishment is likely seperation from God. But to be seperated from God may not allow receiving God’s grace possible.
You might want to read C.S. Lewis’ “The Great Divorce”, it’s a simple and quick read but provides an interesting answer and question on what happens to those who have not repented and why they have not repented and may never do so, while others will.
Bernardine, when you speak about “as through fire” are talking about 1 Cor 3:15? If so, F. F. Bruce (NT scholar) has something interesting to say about the fire. The buildings of their time could either easily withstand the fire (being of stones, which Paul turns to gold, silver, precious stones) or like wood, hay, and stubble burn up in a matter of minutes. Paul had taught the converts the basic truths of the Gospel. What kind of teachings had other teachers given them? Can these teachings withstand the fire? The foundation cannot be disputed, Paul provided sound basic truths, however, what was erected on top of this foundation?
However, you spoke of being “saved ‘as through fire'” so maybe this is not the passage you are talking about (?)