| 摘要 |
<p>A process for treating an ore containing a constituent capable of acquiring magnetic susceptibility as a result of reduction or oxidation comprises subjecting the ore to the action of a reducing gas for 10 to 30 minutes at 300-500 DEG C. and, subsequently and optionally, or alternatively, according to the known chemical properties of the constituent, to the action of an oxidizing gas for 5 to 20 minutes at 200-400 DEG C., whereby at least a part of said constituent is converted into a magnetically susceptible oxide, treating the material obtained with NaOH solution at about 130 DEG C. and submitting the resultant mixture to the action of a magnetic field to separate the magnetically susceptible oxide contained therein. The ore may contain Fe and/or Al, Mn, Ni, Co, Cu, Mg or Zn or it may consist of metallic residues e.g. blast furnace dusts, roast pyrites, slurries or muds derived from the Bayer process, or metallurgical coke. The reducing gas may be H2, CO, natural gas, or gases from gas generators or from blast furnaces. Air may be used for oxidation. Reduction and/or oxidation, which may only be partial, may be carried out in an inclined tunnel or rotary furnace. In an example, a -Fe2O3 in red muds was reduced by means of coke oven gas and oxidized by air to g -Fe2O3. The treated red muds were agitated in NaOH solution and subjected to a magnetic field of 1000 gauss generated by an electro-magnet under the container. The oxides were removed after decantation of the sodium aluminate liquors, washed, and dried. In another example, ferrous oxide in tungsten ore is oxidized to g -Fe2O3. The magnetic separation may be carried out using an endless belt, of a material resistant to hot conc. NaOH solution, having a plurality of electromagnets located on the upper strand of the belt, or, alternatively, by permanent magnets arranged outside or embedded in the belt. a -Fe2O3 in ores may also be converted into magnetite.</p> |
