Abstract: A porous sintered material of good permeability and effective sound absorbability, being formed by combining between particles of aluminum or aluminum alloy powder into a body by means of sintering and having connecting pores among the particles of said aluminum or aluminum alloy powder. Said porous sintered material is obtained by mixing aluminum or an aluminum alloy with a low melting point aluminum alloy, forming the mixture into the predetermined shape and sintering it at a temperature which is at least 10.degree. C. lower than the melting point of the base material and higher than that of the low melting point material.

Abstract: Disclosed is a method for the recovery of useful metallic components such as lead, tin, copper, etc. from a closely layered member having its surface layer of copper or a copper or aluminum alloy closely layered on a back metal of steel or the like. The closely layered member is immersed in molten aluminum to dissolve therein the surface layer to separate it from the back metal, by which lead and/or tin is gathered under a molten aluminum or aluminum-copper layer and separated therefrom.