A clumping animal litter is disclosed that includes a non-swelling particle and a swelling agent coated on the surface of the non-swelling particle. In one embodiment, agglomerated non-swelling clay fines are coated....http://www.google.es/patents/US7429421?utm_source=gb-gplus-sharePatente US7429421 - Coated clumping litter comprising non-swelling particles
