For the conditions of Example 16.8, determine the effect on leaching time of particle sizes from 0.5 mm to 50 mm.

Example 16.8

A copper ore containing 2 wt% CuO is to be leached with 0.5-M  H₂SO₄. The reaction is

The leaching process is controlled by diffusion of hydrogen ions through the leached layer. The effective diffusivity, De, of the hydrogen ion by laboratory tests is 0.6 x 10^-6 cm²/s. The SG of the ore is 2.7. For ore particles of 10-mm diameter, estimate the time required to leach 98% of the copper, assuming that CuO is uniformly distributed throughout the particles. Also, check the validity of the pseudosteady- state assumption by comparing the amount of hydrogen ions held up in the liquid in the pores with the amount reacted with CuO.

Transcribed Image Text:

1 CuO(s) + Haq) → Cu ¹(aq) 2+ Cuq) + H₂O (aq) (aq) 2 (1)