| 摘要 |
<p>A metal is selectively removed from a metal-bearing material by leaching with aqueous HCl, separating the solution, selectively crystallizing and separating the chloride, reducing the chloride to metal by heating in H2 below its melting point, and hydrolysing the liquor to give HCl gas, which is absorbed in water and recycled. The metal may be Fe, Co, Ni, Sn, Zn, or Cu. In the example, FeCl2 is reduced at 575-675 DEG C., e.g. in H2 given off in the leaching process, thus generating a mixture of H2+HCl which may be used to dehydrate the crystals prior to reduction, or the HCl may be absorbed and the H2 recycled. Product Fe is cooled in H2 or inert gas, scrubbed with water to remove soluble chlorides and dried. In Fig. 7 (not shown), metal chloride is fed from inert atmosphere hopper 66 via vibrating feeder 70 into tube 60, along which it is carried by rotating paddles. H2 is passed along in counter-current.ALSO:A metal chloride is obtained by leaching a metal-bearing material with aqueous HCl, separating the solution, selectively crystallizing and separating the chloride, and hydrolysing the resulting liquor to give HCl gas which is absorbed in water and recycled. The metal may be Fe, Co, Ni, Sn, Zn, or Cu. The crystals may be washed, filtered, and at least partially dehydrated (wash liquor and water removed being recycled) and are then heated in H2 below their melting point to give the metal. The metal-bearing material may first be crushed and partially reduced below 1000 DEG C. to render it acid soluble. In the example, Fe3+ is reduced with coal at 750-875 DEG C. to Fe2+ and then leached at 110 DEG C. with 30-38% HCl. The temperature and pressure of crystallization are controlled to permit selective crystallization of FeCl2 (see Fig. 3, not shown), which may be recrystallized. The liquor containing the other chlorides may then be crystallized under different conditions to give e.g. AlCl3 crystals. The FeCl2 crystals are dehydrated in a counter-current of H2 + HCl at 300-450 DEG C. and reduced (see Fig. 7, not shown) at 575-675 DEG C., e.g. in H2 given off in the leaching process, thus generating a mixture of H29HCl, which may be used in the dehydration, or the HCl may be absorbed in water and recycled, and the H2 used in the reduction. The product iron is cooled in H2 or inert gas, scrubbed with water to remove soluble chlorides, and dried. The process may be operated continuously. The mother liquor from both FeCl2 and AlCl3 crystallizations may be hydrolysed in a fluidized bed, with air and natural gas (see Fig. 4, not shown), to give oxides of the other metal chlorides present. These oxides, e.g. Al, Ca, Mg, may be used as pigments, or reduced to metallic form.</p> |
