Q. Show Chemical properties of Thorium metal?
You know that actinium and all the actinides are radioactive. Of these only uranium and thorium are extracted from ores, all others are prepared artificially by nuclear reactions. The chief ores of uranium and thorium are monazite and pitchblende, respectively. For extraction of thorium monazite is dissolved in concentrated sulphuric acid. By suitably adjusting the pH of this solution a precipitate of Tho2 is obtained. The impure Tho2 is purified by dissolving it in hydrochloric acid and then extracting ThCl4 by tributyl phosphate. From this solution Tho2 is reprecipitated by adjusting the pH. Purified Tho2 is converted into anhydrous ThF4 or Thcl4 by the action of HF or CC4 at 900K. Thorium metal is then prepared by reduction of ThF4 or ThCl4 with calcium:
ThX4 + 2Ca-----------------> Th + 2CaX2