Technology for obtaining iodine paste from technogenic iodine-containing solutions

Purpose. The technology was developed for the purpose of obtaining iodine “pure” (iodine paste), as the starting material for obtaining high-purity iodine, from the residues of the production of iodine-containing scintillation single crystals.

Specifications. The production capacity is 22.9 tons/year (328 kg/transaction) of iodine “h” (iodine paste). Product characteristics: mass fraction of the main substance (I2) no less than 99%, mass fraction of non-volatile residue no more than 0.8%, mass fraction of chlorine and bromine (in terms of Cl) no more than 0.3%, mass fraction of sulfates (SO4) no more than 0.4%.

Application area. Chemical industry (iodine production).

Advantages. The technology makes it possible to obtain iodine “pure grade” (iodine paste) with a reduced content of heavy metals from the residues of the production of iodine-containing scintillation single crystals dissolved in water.

Technical and economic effect. The developed technology makes it possible to convert the production residues of iodine-containing scintillation single crystals, which are accumulated in significant quantities and are environmentally hazardous, into raw iodine, which is subsequently used in the production of alkali metal iodides of special purity for growing optical (scintillation) single crystals. The introduction of technology allows us to create new jobs.

Description. The essence of the technology is the precipitation of iodine “pure” (iodine paste) from technogenic iodine-containing solutions, pre-treated to remove heavy metal impurities. Iodine precipitation is carried out by treating a technogenic solution acidified with sulfate acid with hydrogen peroxide. A technogenic iodine-containing solution is loaded into a pre-treatment reactor and magnesium metal is added to remove heavy metals. The solution thus purified is pumped into a precipitation reactor, where it is acidified with sulfate acid and crystalline iodine is precipitated by adding hydrogen peroxide. The resulting iodine suspension is poured onto a suction filter, where iodine crystals “h” are separated from the mother solution, washed and dried.

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