| 摘要 |
<p>The present invention is related to a process for concentrating highly impure titanium ore, such as anatase, with the main purpose of obtaining a final concentrate having a chemical composition similar to that of ilmenite. The proposed process is based on the utilization as best as possible of the iron contents of the raw ore, in such a way that the final concentrate obtained can be used as an intermediate raw material for the production of titanium slag. The main characteristic of the proposed process is that during the calcination step of the mechanically treated ore, in the presence of sodium and/or potassium carbonate, compounds such as Na2O.Al2O3, Na2O.SiO2 are obtained at elevated temperatures, wherein such compounds derive from reactions between the ore impurities and the sodium or potassium salt and are soluble in a slightly alkaline medium or dilute acid solutions. Thus, the main deleterious impurities present in the raw ore are removed by alkaline and/or acid leaching of the calcination product from the ore/carbonate blend, without any loss of titanium and iron contents of the ore. The final concentrate is the leaching residue that is obtained by filtering the pulp from the leaching, and the leaching liquor can be treated in order to either recover the rare earths from the ore or regenerate the alkaline agent used in the calcination step. The process is based on the use of the following sequence of operations for the beneficiation of titanium ores: disintegration, screening, crushing, classification, low intensity magnetic separation, attrition and slimes removal, calcination in the presence of sodium carbonate (Na2CO3) and/or potassium carbonate (K2CO3), comminution of the calcination to a partide size below 1 mm, leaching in alkaline medium (pH in excess of 10) followed by acid leaching. The final concentrate, which is rich in titanium and iron and has a low content of impurities, is the intermediate raw material for the process of producing titanium slag.</p> |
