EFFECTS OF APATITE AND IRON-OXIDES ON ACID LEACHING OF KANAWA URANIUMORES

Surphuric acid leaching experiments were conducted on iron- and phosph ate-rich ore samples from Kanawa uranium occurrence, Gubrunde horst, n ortheast, Nigeria. This ore is associated with rhyolitic dykes which w ere intruded into biotite-muscovite granite. The factorial variables c onsidered in this study are acid concentration, temperature of slurry, ana residence lime for leaching. Leach liquors at the end of leaching were assayed for U, PO43-, Ca, and Fe. The depressing effects of apat ile and iron oxides on the degree of leachibility of uranium at high t emperatures as well as low and very high acid concentration are outlin ed using the time-dissolution curves of these elements. A uranium reco very of 83 percent was readily obtained by leaching at ambient tempera ture for 4 hours although with relatively high acid loading (100 k2 H2 SO4 per tonne ore). This is the most optimal condition at which minimu m activity or interference of iron oxides and apatite affects uranium recovery from the ore.