Abstract: Both porosity (φ) and permeability ( k ) of the weathered elutiondeposited rare earth ores are basic hydrodynamic parameters for RE leaching. The relationship between k and φ of two typical rare earth ores of South China in the packed bed was investigated by measuring the flow ( Q ) under various leaching pressure difference (Δp ). The experimental results show that the relationship between k and φ is unique, moreover the relationship between Q andΔp is in accord with the Darcy's law. The effects of the type of ores, the leaching reagents and its concentration, the granule ore size on the leaching permeability have also been investigated. It is demonstrated that k_H (for heavy RE ore, k_H=35.98?mm²)>k_M-H(for middle-heavy RE ore,k_M-H=28.50 mm²), whereas k(NH₄NO₃)>k(NH₄Cl)>k［(NH₄)₂SO₄］, and the k value increases with increasing leaching reagents concentration and granule ore size(k_{0.60～0.75 mm}=99.96 mm²， k_0.125～0.60 mm=11.83 mm², k_{0.074～0.125 mm}=0.84 mm²).

Key words:  hydrodynamics； rare earth ore； leach； porosity； permeability