Many exegetes interpret the Qur'ānic verses scientifically. You claim that the Holy Qur'an is not a book of science. This is a book of religious guidance and we should study specifically with this point of view. What I want to know is that why should not we explain the verses scientifically that discuss scientific matters.
Nobody can deny the fact that the Holy Qur'an is a prophetic book of admonition and its main subject is to provide knowledge of divine scheme and to teach the best manners to serve God. It does elaborate some aspects regarding the universe and the creation of mankind by God but its main target is to draw the attention of mankind towards their Lord and make them conceive His greatness. It has nothing to do with scientific discoveries.
There are two points of view regarding the scientific discoveries. The first one is that whatever the scientists discover should be examined in the light of the Holy Qur'an. This is because some people give their own interpretations totally brushing aside the context of the Holy Qur'an. This attitude cannot be considered right. There is great danger in this approach. If, for example, a scientific theory is modified following some new discoveries what would come of the claim that we ascribed to God. It will certainly be falsified. The second point of view is the one you have mentioned. The Holy Qur'an carries some information about the regarding the creation of man and the heaven and the earth. This information has been recorded in a language easily understandable to an Arab at the time of revelation. It is true that these predictions can never be wrong and the corroboration through the scientific discoveries makes the speech of God more prominent. But this is a bit risky as we might give some different meanings to the words of the Holy Qur'an and then the scientific discoveries prove it wrong and we are forced to eat our words.
The fact is that the Holy Qur'an is an ultimate truth that does not require any corroboration from science. We should prove its authenticity by only the evidences that never fade away. However, we can carefully derive benefits from scientific discoveries in favour of the Holy Qur'an.
(Translated into English by Abid Mahmood)