I am currently attempting to purify technical grade sodium tetraborate decahydrate by recrystallization for use as a titration standard. I don't have a requirement for a specific grade or purity. I'm just looking to improve my results a bit.
I understand that one of its qualities for use as a primary standard is the stable hydration number. However, if I'm drying wet crystals, what would be the best way to ensure that there is no extra water without affecting this? Could heating produce the pentahydrate or anhydrous form?
This is a separate question really, but would it be better to convert to boric acid, recrystallise and then neutralise with a sodium base?