The best composition of bentonites depends on the intended use. For high water absorption and swelling properties, sodium bentonite is the best option due to its high montmorillonite content. For applications that require lower swelling, like in certain industrial processes, calcium bentonite is more suitable. The exact composition also depends on factors like purity, particle size, and other mineral content.

You may refer to my recently published work on sodium bentonite

Article The Role of Calcium-Based Additives in Bentonite Stabilizati...