Iodine plant

Iodine plant locations in the United States and Japan are dictated primarily by the availabiHty of natural brines or bitterns containing adequate amounts of iodine. In 1992, the United States had three iodine-producing companies Woodward Iodine Corp., North American Brine Resources, and loChem. In Japan there are five iodine-producing companies, with over 30 plants Ise, Godo, Nippo, Nitten, and Kanto. AH these companies deHver iodine as flaked material except Ise, which also produces pfiUed iodine. 

Plant investment and maintenance costs are relatively high for a new iodine plant in the United States or in Japan because of the deep weUs required for brine production and disposal as weU as the corrosive nature of the plant streams. The principal materials cost is for chlorine and for sulfur dioxide, although in the United States the additives used for the brines, such as scale inhibitors and bactericides, also have a considerable influence on costs. 

As a matter of fact, it is easily shown that, using an average cost of 15 per kg of Iodine [11], the production of 1 kg of H2 requires the handling of 20 000 of iodine. As a direct consequence. Iodine molar losses of, for instance, 10, would increase the hydrogen production cost of 0.2 per kg H2 clearly, the control of Iodine losses would be an important question in the operation of a Sulphur-Iodine plant. 

Parameter Nebitdag iodine plant Cheleken chemical plant ... 

During the evaporation of the brines, the toxic element strontium is accumulated in the liquid phase, to a maximum of 6.24 kg m Sr at the beginning of the calcium-magnesium chloride sedimentation with the strontium decreasing in the brine. During the evaporation process of the exhaust brine at the Nebitdag iodine plant the strontium ion is distributed as follows ... 

A mathematical model was established for the evaporation of high mineralized brines to permit management of the concentration processes in the effluents in the reservoir in relationship to the rate of the brine evaporation at the Nebitdag iodine plant. The elasticity of the water stream over the brines at different concentrations and at different temperatures (10, 15, 20, 25, and 30 °C) was identified. The data was processed using a computer by the method of the least squares and the deduction of an equation for the calculation of the elasticity of the vapor above the brines during different degrees of concentration in the temperature interval from 5 to 35 °C. 

Trichloroethanoic acid, CCI3COOH. A crystalline solid which rapidly absorbs water vapour m.p. 58°C, b.p. 196-5" C. Manufactured by the action of chlorine on ethanoic acid at 160°C in the presence of red phosphorus, sulphur or iodine. It is decomposed into chloroform and carbon dioxide by boiling water. It is a much stronger acid than either the mono- or the dichloro-acids and has been used to extract alkaloids and ascorbic acid from plant and animal tissues. It is a precipitant for proteins and may be used to test for the presence of albumin in urine. The sodium salt is used as a selective weedkiller. 

If the spent fuel is processed in a nuclear fuel reprocessing plant, the radioactive iodine species (elemental iodine and methyl iodide) trapped in the spent fuel elements ate ultimately released into dissolver off gases. The radioactive iodine may then be captured by chemisorption on molecular sieve 2eohtes containing silver (89). 

Although not abundant in quantity, iodine is distributed in rocks, soils, waters, plants, animal tissues, and foodstuffs (3,4). Excepting the possible occurrence of elemental iodine vapor in the air near certain iodine-rich springs, iodine never occurs free in nature. It is always found combined with other elements. 

First Alternative. Figure 1 illustrates the first of the two alternative production processes. Here the mother Hquor from the sodium nitrate crystallization plant, normally containing about 1.5 g/L iodine as iodate, is decanted for clarification and concentration homogenization. From there the solution is spHt into two fractions. The larger fraction is fed into an absorption tower where it is contacted with SO2 obtained by sulfur combustion. In the absorption tower iodate is reduced to iodide according to the following reaction ... 

After leaving the absorption tower, the resulting iodide solution, together with the iodide solution coming from the kerosene extraction plant as described below, is contacted with the smaller iodate fraction in the stoichometric proportion shown, producing iodine ... 

Second Jiltemative. The second alternative production process is shown in Figure 2. The treatment of a diluted iodate solution does not require a flotation step, because all the iodine stays in solution. Therefore only the kerosene extraction unit is used, and the final product of this plant is a concentrated iodide solution, which is used to react with the iodate mother Hquor stream of the plants using concentrated iodate solutions. 

Plants in the United States are basicaHy iodine producers and must extract the solutions from deep (between 2000- and 3000-m) weUs. The depleted solutions are reinjected for environmental reasons and maintain the pressure of the exploitation area. In Japan, on the other hand, iodine is mainly a by-product of natural gas production, and the weUs are less deep (about 1500 m). Depleted solutions are often discarded into the ocean. Costs associated with deep weUs are relatively high, reaching 1.7 to 2.0 x 10 in the United States and up to ca 0.7 x 10 in Japan. 

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. 

Iodine is extensively used in a variety of forms as both an antiseptic and a disinfectant. lodophors, usually nonionic surfactants (qv) complexed with iodine, were developed for more readily usable iodine-based antiseptics and disinfectants. These are used as disinfectants in dairies, laboratories, and food processing (qv) plants, and for sanitation of dishes in restaurants. The reaction product of lanolin and iodine shows utiHty as a germicide (149). 

D. W. HoWid.2cy, A Eiterature Survey Methodsfor the Removal of Iodine Spedafrom Off-Gas andEiquid Waste Streams of Nuclear Power and Nuclear Fuel Reprocessing Plants, with Emphasis on Solid Sorbents, ORNL/TM-6350, Oak Ridge National Laboratory, Oak Ridge, Term., 1979. 

Occurrence. Iodine [7553-56-2] is widely distributed in the Hthosphere at low concentrations (about 0.3 ppm) (32). It is present in seawater at a concentration of 0.05 ppm (33). Certain marine plants concentrate iodine to higher levels than occur in the sea brine these plants have been used for their iodine content. A significant source of iodine is caUche deposits of the Atacama Desert, Chile. About 40% of the free world s iodine was produced in Japan from natural gas wells (34), but production from Atacama Desert caUche deposits is relatively inexpensive and on the increase. By 1992, Chile was the primary world producer. In the United States, underground brine is the sole commercial source of iodine (35). Such brine can be found in the northern Oklahoma oil fields originating in the Mississippian geological system (see Iodine and iodine compounds). 

Povidone—iodine is a brown, water-soluble powder containing approximately 10% iodine. However, the amount of free iodine, which is responsible for the antimicrobial activity, is low in a concentrated solution, but is released as the solution is diluted (41). Concentrated solutions have actually been contaminated with bacteria (42). For use as an antiseptic, povidine—iodine is diluted with water or alcohol to a concentration of 1% iodine. Detergents are added if it is used as a surgical scmb. lodophors are important as broad-spectmm antiseptics for the skin, although they do not have the persistent action of some other antiseptics. They are also used as disinfectants for clinical thermometers that have been used by tuberculous patients, for surface disinfection of tables, etc, and for clean equipment in hospitals, food plants, and dairies, much as chlorine disinfectants are used. 

Answer Use the plant s PSA to determine the risk of accidents that include containment failure from overpressurization. Then make a preliminary design of a vented containment that has sufficiently low impedance to the gas at the pressure predicted for the most severe accident sequences such that the containment is not damaged. This containment bypass will include iodine and HEPA filters as well as scrubbers and a discharge through a stack. Estimate the dose that the population would get using this bypass for comparison with the PSA result for ruptured containment sequences. 

Zirconium, too, is produced commercially by the Kroll process, but the van Arkel-de Boer process is also useful when it is especially important to remove all oxygen and nitrogen. In this latter method the crude zirconium is heated in an evacuated vessel with a little iodine, to a temperature of about 200° C when Zrl4 volatilizes. A tungsten or zirconium filament is simultaneously electrically heated to about 1300°C. This decomposes the Zrl4 and pure zirconium is deposited on the filament. As the deposit grows the current is steadily increased so as to maintain the temperatures. The method is applicable to many metals by judicious adjustment of the temperatures. Zirconium has a high corrosion resistance and in certain chemical plants is preferred to alternatives such as stainless... 

Starches can be separated into two major components, amylose and amylopectin, which exist in different proportions in various plants. Amylose, which is a straight-chain compound and is abundant in potato starch, gives a blue colour with iodine and the chain assumes a spiral form. Amylopectin, which has a branched-chain structure, forms a red-purple product, probably by adsorption. 

Cucumber cotyledons were inoculated with purified tobacco mosaic virus (TMV) 20 to 24 hours before vacuum infiltration with different concentrations of crude water extracts of plant leaves (4). After 7 days, inoculated leaves were harvested and stored 24 hours in the dark in a moist chamber to remove excess starch. Starch lesions were counted after clearing with alcohol and staining with an iodine-potassium iodide-lactic acid mixture. The inhibitory effects of various extracts were demonstrated by comparing lesion counts of treated cotyledons to counts on control cotyledons. 

If an aqueous solution of a compound is shaken with another liquid that is immiscible (mutually insoluble) with water, some of the compound may dissolve in the other solvent. For example, molecular iodine, I>, is very slightly soluble in water but is highly soluble in tetrachloromethane, CC14, which is immiscible with water. When tetrachloromethane is added to water containing iodine, most of the iodine dissolves in the CC14. The solute is said to partition itself between the two solvents. Solvent extraction is used to obtain plant flavors and aromas from aqueous slurries of the plant that have been crushed in a blender. 

Half-lives span a very wide range (Table 17.5). Consider strontium-90, for which the half-life is 28 a. This nuclide is present in nuclear fallout, the fine dust that settles from clouds of airborne particles after the explosion of a nuclear bomb, and may also be present in the accidental release of radioactive materials into the air. Because it is chemically very similar to calcium, strontium may accompany that element through the environment and become incorporated into bones once there, it continues to emit radiation for many years. About 10 half-lives (for strontium-90, 280 a) must pass before the activity of a sample has fallen to 1/1000 of its initial value. Iodine-131, which was released in the accidental fire at the Chernobyl nuclear power plant, has a half-life of only 8.05 d, but it accumulates in the thyroid gland. Several cases of thyroid cancer have been linked to iodine-131 exposure from the accident. Plutonium-239 has a half-life of 24 ka (24000 years). Consequently, very long term storage facilities are required for plutonium waste, and land contaminated with plutonium cannot be inhabited again for thousands of years without expensive remediation efforts. 

Last but not least HMDS 2 is, in the laboratory and in pilot plants, quite stable when stored in a normal closed vessel whereas trimethylchlorosilane (TCS) 14 should be stored in a hood, because it reacts with humidity to hexamethyldisilox-ane 7 and HCl. Because HMDS 2 is a very non-polar compound, the silylation of very polar compounds, e.g. purines or pteridines, with HMDS 2 wiU often proceed only on addition of a polar solvent such as pyridine which is, however, readily removed after silylation, with excess HMDS 2, on codistillation with abs. xylene. Interestingly, it was recently reported that addition of catalytic amounts of iodine dramatically accelerates the silylation of alcohols, in particular tertiary alcohols, with HMDS 2 in CH2CI2 at room temperature [63]. 

The nuclear explosions that devastated Hiroshima and Nagasaki killed 100,000 to 200,000 people instantaneously. Probably an equal number died later, victims of the radiation released in those explosions. Millions of people were exposed to the radioactivity released by the accident at the Chernobyl nuclear power plant. The full health effects of that accident may never be known, but 31 people died of radiation sickness within a few weeks of the accident, and more than 2000 people have developed thyroid cancer through exposure to radioactive iodine released in the accident. Even low levels of radiation can cause health problems. For this reason, workers in facilities that use radioisotopes monitor their exposure to radiation continually, and they must be rotated to other duties if their total exposure exceeds prescribed levels. 

The major fatty acids present in plant-derived fatty substances are oleic acid (9-octadecenoic, C18 l), linoleic acid (9,12-octadecadienoic, C18 2) and the conjugated isomers thereof and linolenic acid (9,12,15-octadecatrienoic, C18 3) (Scheme 31.1). Their rates of oxygen absorption are 100 40 1, respectively, hence partial hydrogenation with consequent lowering of the iodine number would lead to a significant increase in oxidative stabihty, particularly when C18 3 is reduced. 

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