Iodine from brines

Brines. About 65% of the iodine consumed in the world comes from brines processed in Japan, the United States, and the former Soviet Union (see Chemicals frombrine). The predorninant production process for iodine from brines is the blow-out process, which was first used in Japan. Iodine is present in brines as iodide, and its concentration varies from about 10 to 150 ppm. As shown in Figure 3, the recovery process can be divided into brine clean-up, iodide oxidation to iodine followed by air blowing out and recovery, and iodine finishing. 

Manufacture of Iodine and Iodine Compounds I.7.6.2.1 Iodine From Brines... 

In Turkmenistan the extraction of bromine and iodine from brines produce effluents which caused considerable environmental damage. 

Historically, six different processes have been used to produce iodine from brines, and three processes are currently in use (Lyday 2002). 

Control Method—Commercial Experience There is no effective method to chemically remove iodine from brine. However, ion-exchange methods are being developed to remove I2 generated by treating the brine with chlorine (see Chapter 5 for details). 

As do other swing processes, this one requires two beds (or sets of beds), which cycle between service and regeneration. It offers an estimated cost reduction of 13% compared to the original NDS process [146]. It can also be adapted to the removal of silica and iodine from brine (Section 7.5.8.9). 

Typical process applications include (1) the collection of valuable solutes from dilute solutions e.g., the adsorption onto carbon of iodine from brines after liberation of the element from its salts by oxidation and the collection of insulin from dilute solutions and (2) the removal of undesirable contaminants from a solution. 

Not considering the former USSR, world production of iodine was ca 13,500 metric tons in 1992. Japan provided about 45% of the world total, compared to 44% from Chile and 11% from the United States. An annual output of 2300 t from 1976 to 1979 was estimated by the U.S. Bureau of Mines (66) but was revised to 2000 tons in 1981. No official data are available for the former USSR where iodine production is reported to be produced from iodine—bromine brines. Two areas have been mentioned the Neftechalinki field in the Slavianski-Triotskoe area near the Black Sea, and a plant in the Baku area in Azerbaidzhan on the Caspian Sea where ca 1400 metric tons was estimated for 1990 production. 

The main metals in brines throughout the world are sodium, magnesium, calcium, and potassium. Other metals, such as lithium and boron, are found in lesser amounts. The main nonmetals ate chloride, sulfate, and carbonate, with nitrate occurring in a few isolated areas. A significant fraction of sodium nitrate and potassium nitrate comes from these isolated deposits. Other nonmetals produced from brine ate bromine and iodine. 

The newest process to be developed oxidizes the brine with CI2 and then treats the solution with an ion-exchange resin the iodine is adsorbed in the form of polyiodide which can be eluted with alkali followed by NaCl to regenerate the column. About 65% of the iodine consumed in the world comes from brines. 

Recovery of iodine from Chilean saltpetre differs entirely from its recovery from brine since it is present as iodate. NalOs is extracted from the caliche and is allowed to accumulate in the mother liquors from the crystallization of NaNOs... 

The remaining halogens, bromine and iodine, are isolated from brines by treatment with CI2, which oxidizes the... 

Chemicals from brine, 5 784-803 calcium chloride, 5 793-795 iodine, 5 795—796 lithium, 5 796-797 magnesium compounds, 5 797-798 minerals from brine, 5 790-793 potassium compounds, 5 798-799 recovery process, 5 786-790 sodium carbonate, 5 799-800 sodium chloride, 5 800-801 sodium sulfate, 5 801-802 Chemicals Guideline, integrated,... 

Substructure—likeness search, 6 8 Subsurface aspirating aerators, 26 168 Subsurface brines, iodine from, 74 362-365... 

Similar elements also occur in the same natural environment. For instance, the halogens are markedly concentrated in seawater. (The major salt in ocean brines is sodium chloride.) The other halogens are extracted from seawater that has been further concentrated—bromine from salt beds formed by evaporation and iodine from kelp, which grows in oceans. 

In the United States and most parts of the world, iodine is obtained com-merciaUy from brine wells. Many subsurface brines have iodine concentrations in the range of 10 to 100 mg/L. Various extraction processes are known including (i) precipitation with silver nitrate, (ii) oxidation with chlorine, and (hi) ion exchange. In the chlorine oxidation process, natural subsurface brine first is acidified with sulfuric acid and then treated with chlorine. Chlorine hberates iodine from the brine solution. Iodine is blown out into a counter-current stream of air. It is dissolved in a solution of hydriodic acid and sulfu-... 

The recovery of important metals or their salts is possible by electrolysis in cells provided with ion-selective membranes, e.g. of uranium (71, 72, 73, 75), of magnesium from sea water (130), of iodine from iodide containing brines (158), of manganese (74). 

Iodine can also be produced from brine. This process (Fig. 2) consists of cleaning the solution (of clays and other materials), adding sulfuric acid to a pH <2.5 followed by treatment with gaseous chlorine ... 

Iodine is produced by similar methods, namely, oxidation of the iodide anion from brines by chlorine. However, iodine is also produced in a reductive process by reacting NalOs, extracted from the natural source of Chilean saltpeter, with sodium hydrogen snffite. The pentavalent iodine is reduced to iodide (equations), which is then treated and oxidized with a sufficient amonnt of the mother liquor to liberate elemental iodine (equation 5). In contrast to chlorine and bromine, which have large industrial uses, iodine has no predominant commercial use. 

It occurs as 1 in seawater and as an impurity in Chile saltpeter, KNO3. The best source is the brine from oil wells. Elemental iodine is produced from brine wells by the oxidation of I by CB. Elemental iodine is slightly soluble in water, but it dissolves well in iodide solutions because it reacts with aqueous I to form the triodide ion, 13 . 

Shortly after 1920, a project was undertaken to recover iodine from petroleum brines this required a carbon that has not only a good M-RE but also adequate adsorptive power for iodine. To aid in developing a suitable carbon, the iodine test (I-RE) was included in the study of activation conditions. 

Indirect effects of carbon are sometimes confused with direct catalytic activity, e.g., some reactions are accelerated by activated carbon as a result of the adsorption of inhibitors. An example is found in the recovery of iodine from iodides present in petroleum salt brines. Nitrous acid is employed to oxidize the iodides to iodine —a reaction that may be retarded by the presence of inhibitors in the brine. Treatment of the brine with an activated carbon removes the inhibitors and enables the oxidation reaction to proceed. 

This was used fw the analysis of the solid phases and the diagrams for the solubility of the multi-component waters-salt system resulting from salt crystallization from the exhaust and raw iodine-bromine brines. 

Most of the world s production of iodine comes from the saltpeter deposits in Chile and natural brines in Japan. In Chile, calcium iodate is found in caliche deposits extracted from open pit mines in the Atacama Desert. Applying an alkaline solution to the caliche yields sodium iodate and iodine is obtained from the sodium iodate by reduction with sulfur dioxide. In Japan, iodine is a by-product of the production of natural gas, which is extracted from brine deposits a mile or two below ground. Iodine is recovered from the brines by one of the following two methods. In the blowout process elemental iodine is liberated as a result of the reaction of chlorine with sodium iodide in the brines. Elemental iodine is blown out of the brine with air and then purified in subsequent reaction steps. The second method, ion exchange, involves recovery of dissolved iodine from oxidized brines using anion-exchange resins packed in columns. In 2010, Chile produced 18 000 metric tons of iodine, compared to Japan s output of 9800 metric tons. Chile has reserves of 9 million metric tons, some 60% of the world s total reserves of iodine [10],... 

Chlorine is produced mainly by electrolysis of either molten or aqueous sodium chloride. Both bromine and iodine are obtained commercially from brines containing the halide ions the reaction used is oxidation with CI2. 

Wakai S, Ito K, lino T, Tomoe Y, Mori K, Harayama S (2014) Corrosion of iron by iodide-oxidizing bacteria isolated from brine in an iodine production facility. Microb Ecol 68 519-527... 

Iodine is difficult to remove from brine. Techniques suggested for its removal include treatment with chlorine to oxidize the 1 ion ... 

Recently, a novel ion-exchange material based on ZtO(OH)2 has been developed by Chlorine Engineers [195]. This has been shown to remove sulfate, iodide, and silicate from brines. The advantage of this material is that one does not have to liberate iodine and capture it on a conventional ion-exchange material. Instead, the iodine liberated by the chlorination of brine can be allowed to oxidize to iodate or periodate, which is then taken up by the Zr-based oxide at pH 2 and later desorbed with caustic at pH 12 (Figs 7.92 and 7.93). Iodate is completely desorbed at 50°C but not at 25 C. Figure 7.94... 

The element iodine (from Greek iodes, violet) occurs as iodide ion, 1, in very small quantities in seawater, and, as sodium iodate, NalOa, in deposits of Chile saltpeter. It is made commercially from sodium iodate obtained from saltpeter, from kelp, which concentrates it from the seawater, and from oil-well brines. 

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