METHOD OF PRODUCTION OF METALLIC THALLIUM Russian patent published in 2005 - IPC

FIELD: separation and cleaning of metallic thallium, isotope-enriched thallium inclusive.

SUBSTANCE: contaminated metallic thallium is dissolved in diluted nitric acid for obtaining concentrated solution of thallium sulfate; then, solution is cleaned from admixtures and thallium halogenide is settled for subsequent dissolving in sulfuric acid and electroevolution of thallium from cleaned solution Tl₂SO₄ is performed. Solution obtained during dissolving of metal in diluted nitric acid is neutralized with ammonia to pH 11 and thallium iodide is settled from it. Concentrated solution of thallium sulfate is obtained through dissolving settled thallium iodide in sulfuric acid at heating. Solution thus obtained is cleaned from admixtures by settling of lead in form of its sulfide and iron and chromium in form of hydroxides. Thallium halogenide is settled in form of iodide from solution neutralized by ammonia to pH 10-11. Thallium iodide is settled from solutions at concentration of thallium of 1-4 g/l, lead is separated from solution at concentration of thallium of 60-80 g/l, iron and chromium are separated from solution at concentration of 20-40 g/l and electroevolution is performed from solution at concentration of 75-85 g/l.

EFFECT: possibility of obtaining degree of thallium purity of 99,9995% at minimum losses at all stages of chemical treatment.

2 cl, 5 ex