1. n. [Drilling Fluids]
A product that enhances dispersion of a substance (such as clay) into colloidal form. Peptizing agents for drilling-mud clays are sodium carbonate, sodium metaphosphates, sodium polyacrylates, sodium hydroxide and other water-soluble sodium compounds, even common table salt, NaCl, if added at low concentration. The divalent cations on a clay are replaced by the sodium cations, aiding clay hydration and dispersion. Greater benefit is attained by an agent that contributes an anion (for example, carbonate, phosphate or polyacrylate) that precipitates divalent cations and removes them from solution. This process is successful only when the water first contacted is free of hardness ions, otherwise the anion in the peptizing salt (or polymer) will be precipitated by the hard water and make the peptizing agent much less effective.