Is salt made from urine halal or najis (ritually impure)?

If the impurity of urine transforms into salt, and thus acquires a different, non-impure reality, then this salt is pure, permissible, and lawful to use. This is the view of some scholars who maintain the purity of an impure substance if it undergoes a complete transformation from its original state. Sheikh al-Islam Ibn Taymiyyah preferred this opinion.