| 摘要 |
A process for obtaining synthetic rutile with low contents of rare earth and radioactive elements from anatase mechanical concentrates, comprising the following sequential operations: calcination (1) of the anatase concentrate in a fluidized bed or rotary kiln wherein hydrated iron oxides are converted into hematite after hydration water is removed, providing a reduction in the time required for next step; reduction (2) of the calcined product, in a fluidized bed or rotary kiln, using hydrogen, natural gas or any carbon based reducing agent such as metallurgical coke, charcoal, petroleum coke, graphite, among others, the result of which is the transformation of 15 allurgical coke, charcoal, petroleum coke, graphite, among others, the result of which is the transformation of hematite into magnetite; dry or wet low-intensity magnetic separation (3) of the reduced product, high-intensity, high-gradient magnetic separation (4) of the low-intensity non-magnetic fraction, extracting silicates, secondary phosphates, monazite, calzirtite, zircolinite and uranium and thorium-containing minerals; leaching (5) of the magnetic fraction of the high-intensity, high-gradient separation in agitated tanks or fluidized bed columns, with a solution providing solubilization of impurities rich in iron, aluminium, phosphates, magnesium, barium, calcium, strontium, rare earths, uranium and thorium; filtering of the leached product drying of the filtered product oxidation (6) of the dried product in the presence of a mixture of the following substances, alkali, metal sulphates (mainly lithium, sodium and potassium), alkali metal carbonates (mainly lithium, sodium and potassium), phosphoric acid (HPO) and, eventually, sodium chroride; quenching of the oxidized product in water or compressed air; leaching (7) of the queched product in agitated tanks or colums, filtering of the product from the second leaching (7) in a belt filter; and drying of the filtered product in a rotary or fluidized bed drier, dry, high-intensity, high-gradient magnetic separation (8) of the product of the second leaching, in rare-earth permanent magnet, discarding of the magnetic fraction and recovering the non-magnetic fraction as final product (P), that is, the synthetic rutile of interest. |
