SU1244087A1 - Method of isolating iodine from solutions - Google Patents

Description

The invention relates to a process for the production of iodine and can be used to extract iodine from the oBj solution obtained when it is extracted from groundwater or petrochemical waste.

The purpose of the invention is to reduce the loss of iodine while maintaining high purity of the product.

Example 1 B prom1 1shanked crystallizer serves 6 m-solution (mass concentrate iodide 26 g / l) The solution is treated with sulfuric acid (total 1.2 tons / ton iodide) and. sodium bichromate (in the amount of 0.37 t / t of iodide), after which the precipitated crystals are separated from the solution, washed and dried in accordance with known methods;. During the work, the following solutions are implemented:

1- treatment of the solution by simultaneous feeding of acid and sodium dichromate solution (according to the prototype),

2- treatment of the solution with a part of acid (0.6 tons per 1 ton of iodide), then treatment with crystalline bichromate and subsequent dosage of the rest of the acid at a rate

15 g-eq / (m min),

3.- treatment of the solution with a part of the acid (0.6 tons per 1 ton of iodide), then sodium dichromate solution, then the dosage of the rest of the acid at a rate of 15 g-eq / (min) °,

4- simultaneous feeding of a part of the acid (0.6 tons per 1 ton of iodide) and potassium dichromate, then the dosage of the rest of the acid at a rate of 15 g-eq / / (min). Solution temperature before processing in all cases x 40 C.

The results of the experiments are summarized in table 1

As follows from the table. 1, iodine recovery in the prototype method leads to 6onbmiiM product loss.

The release of iodine in variants 2-4 allows to significantly reduce the loss of iodine while maintaining the quality of the product at the qualification level pure. Product loss when used to treat crystalline bichromate is less than when using a reagent solution.

Example 2. B mold serves 6 m solution (mass con

2440872

The iodide residue is 25 g / l) and is first treated with a part of the acid, then with crystalline sodium bichromate, after which the rest is metered

5 acid. Acid consumption (total) 1.0 tons per 1 ton of iodide, dichromate - 0.35 tons per 1 ton of iodide. The temperature of the solution is 40 C. The iodine crystals precipitated are separated from the solution, washed

To and dehydrate in accordance with known methods.

The results of the experiments are given in table. 2

 As follows from the analysis given

15 in the table. 2 data, low iodine losses are achieved under both process conditions, i.e. when the solution is treated first with a part of sulfuric acid (0.4-0.7 tons per 1 ton of iodide) and dichro20 and at a dosage rate of the rest of the acid in the range of 5-20 g-eq / (min).

Example 3. In the mold, serves the solution (temperature 40 ° C) with

25 mass concentration of iodide 85 g / l. The solution is treated with sulfuric acid in the amount of 0.7 tons per 1 ton of iodide, then crystalline sodium bichromate (0.38 tons of la 1 ton of iodide).

30 After that, the rest of the acid is metered at a rate of 20 g-eq / (). The precipitated crystals are separated from the solution, washed and dried.

The total amount of iodine supplied with a solution is 222.5 kg. Obp; its amount of the selected product is 221,5 kg. Iodine loss 1.0 kg or 0.45% (product yield 99.55%). The quality of iodine corresponds to the reactive qualification pure.

When the solution is treated with acid less than 0.4 tons per 1 ton of iodide, only technical product is obtained (Table 2). When treating the solution with an acid in an amount exceeding 0.7 tons per 1 ton of iodide (for example, examples at 0.8 tons in Table 2), the quality of the product also does not correspond to the qualification pure. The product does not satisfy the qualifications of the pure in the experiments, where the solution was treated with acid in the amount of 0.4-0.7 tons per 1 ton of iodide, but the acid dosage rate was different from that proposed.

Etc

IMECHANE According to the type of product yield of 92.5%

Table 1

table 2

Editor A.Lezhnina

Compiled by G. Mitropolska

Tehred O.Gortvay Proofreader V.Sinitska

Order 3765/23 Circulation 450 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-355, Raushsk nab., 4/5

Production and printing company, Uzhgorod, Proektna str., 4

Continuation of table 2

Claims (2)

1 . METHOD FOR ISODIUM ISOLATION FROM SOLUTIONS, comprising treating the solution with sulfuric acid in an amount I, 0-1.5 t per 1 ton of iodide in solution and alkali metal bichromate, followed by separation of the iodine precipitate from the reaction suspension, characterized in that, in order to reduce iodine losses while maintaining its high purity, the initial solution is treated with sulfuric acid and dichromate alkali metal with the introduction of acid in an amount of 0.4-0.7 tons per 1 ton of iodide, after which the remaining amount of sulfuric acid is additionally introduced into the resulting reaction solution before separation of the precipitate at a rate of 5-20 g-equiv / m ³ · min. 2. The method of pop. 1. distinguishing with .a in that, as a bichromate of alkali metal, they take sodium or potassium dichromate. • 1244087