This report describes the characterization of a sedimentary occurrence from the Parnaíba Basin, Brazil, containing the zeolite stilbite intertwined with smectitic clay mineral. The head samples from different sites present a wide content range of the zeolitic phase - 15% to 50%. The use of simple separation techniques - conventional gravitic treatments - yields concentrates containing about 67% of the zeolitic component. Assays with the amendments of these concentrates with plant nutrients yield release rates matching those reported for similar commercial products.
sedimentary zeolite; Parnaíba Basin; plant nutrients; nutrient attachment and release
