閃亜鉛精鉱の浸出について

抄録

The leaching of zinc blende concentrate by aqueous solution without the roasting process has become major interest as one method of zinc hydrometallurgy.
The study on the leaching mechanism of zinc blende has been carried on by means of varying the experimental factors i.e the leaching agent, the leaching time, the leaching temperature, the oxygen partial pressure and the agitation speed.
The summary of the experimental results is shown below;
(1) On the leaching by sulphuric acid solution, the leaching rate of zinc is under 85%(175°C, 1 hr., O₂pressure 30kg/cm², 50g/lH₂SO₄), but that of iron is over 90%.
(2) The blowing of oxygen into the H₂SO₄leaching solution under atmospheric pressure, produces elemental sulphur from H₂S generated by the leaching reaction.
(3) When the concentrate is leached by ammonia solution under high pressure, the main reaction is represented by the equation ZnS+4NH₃+20₂→Zn(NH₃)₄SO₄and the following subreaction occurs. ZnS+(NH₄)₂SO₄+20₂→Z
nSO₄·(NH₄)₂SO₄
(4) This leaching reaction is controlled by chemical reaction on the surface of the ore at low temperature range (55-100°C), and at high temperature (100-120°C), it is slightly shifted from chemical-control to diffusion-control. The activation energy of leaching is respectively 12.6kcal/mol. and 5.26kcal/mol.
(5) The leaching rate of zinc is about 95% under the following conditions; O₂pressure 10kg/cm², 3mol/l NH 3.1mol/l (NH₄) ₂SO₄. 175°C. 2 hours.