Manufacture of iodine form i. sea weeds (principle only) ii. caliche (Principle only)

Existence -- where does it exist?
Iodine exists in the form of iodine-compound ions in the sea, seaweeds, brine, minerals (niter), etc, but its contents normally being very low, the areas in the world where iodine can be economically collected are extremely limited. The world-wide total production of iodine per year is roughly 18,000 t, 50% of which is produced in Chile, 40% in Japan and 10% in the other areas including U.S. Most of Japanese iodine is made in Chiba prefecture from brine which is pumped up from the deposit of water soluble natural gas / brine, which stretches under the wide range of the prefecture. For a country like Japan very poor in natural resources, is iodine especially important material.

What is the deposit of water soluble natural gas / brine? -- Does iodine exist there?
The deposit of water soluble natural gas / brine, which stretches under Chiba prefecture, is a water layer containing lots of salt and existing along with natural gas in the stratum which was created some 2-12 million years ago. This underground water is called brine. The formation of this underground water layer is said to be the accumulation of seaweeds (seaweeds contain lots of iodine and it used to be obtained from seaweeds ashes) and other organic substances piled up together with earth and sand on the ancient sea bottom, where iodine had been concentrated through many years and thus the present day origin of iodine is thought to be traced back there. The salt concentration in brine is almost the same as in sea water but that of iodine in brine is more or less 100ppm, nearly 2,000 times higher than in sea water. That much natural concentration of iodine can not be found in any other area on the earth, and thus as much as 40% of the total world production of iodine has come to be produced in the above mentioned area.

Production process of Iodine
We produce iodine through a "blow-out" process. This is the process where one of the characteristics of iodine, that is, to easily evaporate is made use of. Iodine contained in brine in the form of iodine compound ions (I-) is limited, more or less 100ppm and the process is suited for the extraction of iodine from such low content solution. Sand and other impurities are first removed from brine by sedimentation and an oxidant is added to it to extricate iodine (I2) and then air is introduced to"blow it out".
After that, iodine is extracted, crystallized and purified. This process is widely employed by many companies in Japan and U.S. but we produce iodine from brine at a much higher yield through our own technology and experience accumulated for more than 50 years.

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