Discovery of radium 2005-9-13 NECPKU
Discovery of radium Flow Chart of the Major Steps in the Separation and Purification of Radium from Pitchblende Based on Procedure described in Marie Curie's Thesis) Pitchblende ore Crush and treat with sodium carbonate Wash with warm water and dissolve in dilute sulphuric acid Yield: 1 ton: Radioactivity 4 times that of uranium Supernatant contains uranium Residue: Sulphates of Pb, Ca, silica, alumina, iron oxide. small amounts of Cu, Bi, Zn, co, Mn, Ni, Va, Sb, Th, rare Processed for uranium earths, niobidium, Ta, As, Ba, etc. Radium present as sulphate Boil with sodium hydroxide solution to remove sulfuric acid reat with hydrochloric acid 2005-9-13 NECPKU
Discovery of radium Treat with hydrochloric acid Solution Insoluble part (Po. Ac) Wash with water and boil with sodium carbonate to For separation of convert Ra and Ba sulphates to carbonates Wash with water, then with dilute hydrochloric acid Precipitate with sulphuric acid(contains Ra, Ba, Ca, Pb, Fe, etc. Yield: 10-20 kg. times of uranium Boil with sodium carbonate, treat with hydrogen su oxidize with chlorine and precipitate with pure alumilyphide 2005-9-13 NECPKU
Discovery of radium Continued Yield: 8 kg: Activity: 60 times more active than uraniu Precipitate(Ac) Supematant: Precipitate with sodium carbonate (Carbonates of alkali earth, Ra, Ba, etc. Wash the precipitate convert carbonates to chloride solution Fractional crystallisation(FC)with pure water Crystals enriched in Ra by Supernatant(B) a factor of five(5). Repeat Crystals(A) FC with both a and B Evaporate to FC dryness, FC 2005-9-13 NECPKU
Discovery of radium Evaporate to dryness, FC Supernatant I Supernatant Crystals FC More active p of B is combined with less active part of A SupernatantCrystals Supernatant FC Supernatant rystals Supernatant Crystals FC continued for 6 stages: -Activity of the most soluble fraction decreases each time, when it becomes negligible, it is discarded; -At some stage the most active crystals are withdrawn from further FC and pooled: Final yield was nearly 100 mg of pure radium chloride; -Activity nearly 2 x 10 times that of equal weight of uranium 2005-9-13 NECPKU