A process for the separation of a multiple domain solid feedstock such as
that derived from ASR, WSR, and/or ESR is disclosed which comprises
granulating the feedstock to produce particles each of substantially a
single domain, with each type of particle having a different density. The
particles are introduced into a suitable aqueous salt solution. Aqueous
salt solutions containing cations comprising sodium, calcium and
ammonium, and anions comprising nitrate, bromide, and chloride are
useful. A dispersion mixer having a high shear and/or turbulent zone is
utilized to disperse agglomerated particles and a quiescent hydrogravity
tank is utilized to effect binary separation of the mixture of particles
into a stream with a higher average specific gravity, and a stream with a
lower average specific gravity. A higher degree of product purity can be
obtained by subjecting either of the product streams from the first
hydrogravity stage to additional stages of hydrogravity separation. Froth
flotation may be used to further separate particles of similar specific
gravity but different chemical composition.