Abstract: A nanoclay purification process for removing impurities, includes the steps of separating the nanoclay from rocks and other large non-clay impurities; dispersing the nanoclay and smaller impurities in water to provide a slurry; passing the clay slurry through a series of hydrocyclones to remove the larger particle-size impurities while retaining clay particles having a size of about 100 microns or less, ion exchanging the nanoclay to remove interlayer multivalent (e.g., divalent and trivalent) cations, wherein the multivalent ions are replaced by monovalent cations, such as sodium, lithium and/or hydrogen; and then centrifuging the nanoclay to remove particles having a size in the range of about 0.5µm to about 100µm.