Production method of medical sodium iodide

Abstract

A process for preparing medicinal sodium iodide from iodine, Fe powder and dicarbonate includes such steps as preparing ferrous iodide, reaction between ferrous iodide and dicarbonate to obtain ferrous carbonate, sodium iodide and water, separating sodium iodide, removing SO4 radicals, filtering, concentrating and crystallizing.

Description

technical field [0001] The invention relates to a method for producing sodium iodide, in particular to a method for producing pharmaceutical grade sodium iodide by using iodine, iron powder and sodium bicarbonate as raw materials. Background technique [0002] Sodium iodide, molecular formula: NaI, molecular weight: 149.9, white deliquescent crystals or granules, will slowly absorb water up to 5% in humid air, and slowly release free iodine, turning yellow, relative density 3.6777, melting point 660 ℃, heat of solution 23.60Kj / mol, boiling point 1304 ℃, soluble in water, ethanol, acetone, glycerin, and aqueous solution are acidic, mainly used as pharmaceutical raw materials. [0003] At present, the production method of sodium iodide mainly contains following two kinds: [0004] Method 1: Use iodine as a raw material, react with iron powder to generate ferrous iodide, and then react with sodium carbonate to obtain sodium iodide [0005] <chemistry...

AI Technical Summary

Problems solved by technology

[0019] Its shortcoming of this method is: one, the Fe of generation 3 o 4 Difficult to filter: Fe 3 o 4 In neutral or alkaline, it is easy to become Fe(OH) 3 Colloidal precipitation, the Fe(OH) 3 The colloid has a large adsorption capacity, and it is easy to form flocculent substances in the solution. A certain amount of sodium iodide is adsorbed on the surface of these flocculent substances. In addition, this flocculent substance settles slowly and is difficult to filter; 2. Difficulty in central control : Remove impurity SO in the solution after reaction 4 2- The process is more complicated, and the root cause is that Fe 3 o 4 The essence is a trivalent iron salt, which is unstable. In different acid and alkaline solutions, it will be Fe(FeO 4 ) 2- , FeO, Fe(OH) 3 , Fe 2 o 3 and other forms exist and transform each other, so that the central control indicator IO 3 - , SO 4 2- , PH, and free iodine are not accurately measured, and the timeliness is poor, which often makes the IO qualified in the central control 3 - , SO 4 2- , PH, and free iodine change during concentrated discharge, resulting in some unqualified indicators; three, due to colloidal Fe(OH) 3 After NaI, it is difficult to wash out repeatedly (NaI≤1%) in the discharge precipitation, thereby reducing the sodium iodide yield, prolonging the production time, and increasing the cost