The ruling on burning old Qurans and Islamic books that contain the Quran, Hadith, or the mention of Allah is that it is permissible to dispose of them by burning or shredding them so that no trace remains. The evidence for this is the action of Uthman (may Allah be pleased with him) in burning the manuscripts containing Quran and papers of the companions after he had compiled the Quran in copies.
Ibn Hajar said in Al-Fath: ” Musaab bin Sa’d said: I witnessed people present when Uthman burned the manuscripts containing Quran, and they were amazed by it. Or he said: None of them objected to it.”
This action is considered almost a consensus because only Ibn Mas’ud objected to it, not because of the burning itself but for another reason.
Therefore, what happened in the incident mentioned is permissible in order to preserve the sanctity of the Quran and books.
Fatwa by Dr. Khālid Naṣr