Production manner and spherical high purity iodide thallium null of high purity iodide

摘要

PROBLEM TO BE SOLVED: To obtain high-purity spherical thallium iodide useful as a glass additive having an extremely low lead concentration, consequently excellent infrared ray transmission, X-ray transmission, ion conductivity, etc., and high-purity spherical thallium iodide having excellent handleability. ;SOLUTION: A solution of crude thallium in nitric acid or sulfuric acid is adjusted to pH ≥0.5 and ≤50 ppm dissolved oxygen in the solution, metal thallium is added to the solution to replace and precipitate impurity metals, which are separated. An iodide is added to the solution and precipitated thallium iodide is recovered to give high-purity thallium iodide having ≤1.0 ppm lead content. Further, the high-purity thallium iodide is heated, melted and dripped in an inert atmosphere to give spherical high-purity thallium iodide.;COPYRIGHT: (C)2000,JPO