Original Technology

Iodine and natural gas

What is iodine?

Characteristics -- what is it like?

Iodine is well known for the iodo-starch reaction under which a blue color develops and, as a nutrient, contained in various seaweeds. Since iodine is an element, it can not be obtained through a chemical synthesis and there being no other way to produce it than to extract from the natural resources containing it, we can say that iodine is valuable material. Iodine is, as a commercial product, solid and heavy like metal and has black-purple luster. It easily sublimates at the room temperature and has a peculiar odor.

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Use -- what is it used for?

Because of its high reactivity, various compounds are derived from iodine to be used in many fields, thus making it indispensable material to human life. Also, iodine is said to be an essential element to human growth, the necessary daily intake of it by man being 150μg.


Main uses
1.

Because of its excellent function to absorb Xray, iodine is used as a substituent when various contrast-media for diagnostic purposes are produced.
Some of the pharmaceuticals and crop protecting agents have iodine as the substituent

2.

Iodine, being the simple substance and having an anti-biotic function by nature, Is used as a raw material for the production of various bactericides or disinfectants.

3.

Iodine compounds are added to table salt and feed to treat and prevent "iodine deficiency symptom".

4.
Iodine has a wide range of uses, for example, in photo-sensitizers, catalysts, stabilizers and polarizing films on the liquid crystal display. Also, iodine compounds are widely used as intermediates for various reactions because of their high reactivity.

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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.

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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. 
We have our own mining lot and pump up brine there.

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What is natural gas ?

Characteristics -- what is it like?

It is well known that what is normally called 'natural gas' is naturally yielded flammable gas of which main components are hydrocarbons and which is produced in the oil field and imported into Japan in a huge quantity in the form of LNG (liquefied natural gas). This LNG is mostly oil soluble gas and a mixture containing methane, ethane, propane, butane, etc, yielded together with oil. The natural gas which we use is called 'water soluble natural gas' and pumped up with brine from the deposit of water soluble natural gas / brine, which is called Southern Kanto gas field, forming a sedimentary basin and stretching under Chiba, Ibaraki, Saitama, Tokyo and Kanagawa. We have our own mining area and pump up gas and brine there. The gas is almost pure methane without sulfur and is used as clean energy for the fuel purpose, for example, as town gas, while at the same time it is used as a chemical raw material as it is. Also, we use the yielded gas as a fuel within the company and as a raw material for synthesis of HCN, and supply it to a town gas company.

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Existence -- where does it exist?

In Japan the deposit of water soluble natural gas / brine is widely distributed over such regions as Hokkaido, Akita, Niigata, Chiba, Shizuoka, Miyazaki, Okinawa, but of these Southern Kanto (Chiba) gas field boasts of the biggest size in terms of production and deposits. Especially, the deposit which stretches over Chiba is rich in iodine and from the brine yielded together with natural gas, iodine is produced.

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Origin -- how did it come into existence?

The deposit of water soluble natural gas / brine, which stretches under Chiba, is a water layer containing lots of salt and existing along with natural gas in the stratum which was created some 2 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 seaweeds ashes) and other organic substances piled up together with earth and sand on the ancient sea bottom over Tertiary and Quaternary period of Cenozoic era of geographical age about the time when the glacial era started and mankind came into existence, where iodine had been concentrated through many years. Water soluble natural gas is methane gas yielded from the organic substances which had been buried in the ground and decomposed by bacteria. Lots of seaweeds rich in iodine are believed to have existed in the sediment and those organic substances had decomposed through many years and gradually melted into water under the ground and thus the underground water in the deposit of water soluble natural gas / brine is thought to have been created through accumulation and concentration. This underground water exists in the gap among the grains of sand and mud in the stratum called Joso layers which comprise sandstone and mudstone found 200-2,000m under the ground. Natural gas is found underground dissolved into the underground water (brine) by high pressure and when pumped up, the mixture separates into natural gas and brine. The salt concentration in brine is almost the same as in sea water but that of iodine 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 therefore iodine is especially important material for a country like Japan very poor in natural resources.

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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.


Recent Patents:Japanese Patents Nos.2732635, 2732636, 2732637, 2732642

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Recycling of Iodine

There are many cases where the simple substance iodine and iodine compounds are used for various chemical products but iodine itself does not remain in them after production.
Iodine compounds are used as reaction intermediates because of their high reactivity but often iodine itself is not introduced in the target products and therefore is discharged outside the system after reaction. It remains as a sort of industrial waste, which is brought about after the production of chemical products, is normally called "recycled iodine" and exists in the form of water solutions and solids. In such waste not only iodine but various other inorganic and organic substances are contained and if discharged outside as it is, much impact can be caused on the environment without saying that valuable material iodine is wasted, which means a big loss. We address ourselves to the task of collecting and recycling of iodine in view of the environment protection and conservation of natural resources. There are various types of waste and accordingly the iodine content and impurities in them are different. We undertake reproduction of iodine doing a proper treatment suited to each type of waste based on our own technology and experience accumulated so far.


Recent Patents:Japanese Patents Nos. 2539858, 2575152, 4674168, 4758766

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Synthetic process of HCN

We produce HCN using the natural gas (methane) yielded with brine as a raw material by the Andrussow process and utilize it for cyanation. Based on the technology accumulated in the past many years, we can easily handle liquified HCN.

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Characteristics of HCN
HCN
Chemical formula
HCN
Specific gravity
d20 0.688
Molecular weight
27.03
Melting point
-13.3℃
   
Boiling point
25.7℃

It is well known that HCN is yielded as a by-product during the production of acrylonitrile and then neutralized so that sodium cyanide can be produced. As you might know, sodium cyanide is an essential chemical substance for the general industry, as can be seen from the representative example of it being used for a plating purpose, and therefore is widely distributed. Cyanide compounds are widely used for the general industry as useful and essential chemical substances under the strict control by the law.  Making use of the geographical advantage, we synthesize HCN from natural gas (methane) and liquefy it to do various types of cyanation.

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Treatment of HCN waste

When the production of cyanides compounds takes place, occurrence of effluent containing HCN waste is inevitable. The effluent treatment regulations enforced in Chiba are exceptionally stringent and it is stipulated that no cyanide compounds are to be detected at all.
Though it is responsibility of a producer and user of cyanide compounds, we pay much attention so that no effluent containing them is discharged into the environment. The system to do this has been well established. Without fail, we treat effluent containing cyanides according to the procedure suited to each type of effluent and we also remove all other organic substances from it so that it conforms to the effluent discharge regulations. In the case of effluent containing organic cyanides, which is especially difficult to treat chemically, we incinerate it at the temperature of 1,000oC using natural gas yielded as a fuel. By doing so, not only cyanides but all the other organic compounds can be removed without yielding any type of dioxin.