Foundry-grade bentonite powder is primarily used as a binding agent in molding sand for metal casting, creating strong, durable molds known as “green sand.” It ensures good flowability, compactability, and thermal stability, which are crucial for producing high-quality castings of iron, steel, and non-ferrous metals. Additionally, it can be used in core sand formulations for intricate parts and to clean impurities from melted metals before pouring.