Raw Materials

As natural gas in the Southern Kanto gas field is water-soluble, it is produced with water in the stratum. This water is brine containing natural gas and salt which was formed more than 2 million years ago. The salt concentration in brine is almost the same as that in sea water, while the iodine concentration in brine is almost 2,000 times that in the sea water, and sulfuric acid concentration is extremely low. It is rare to have such resources in any part of the world and therefore, almost half of iodine in the world is produced in this area.

Shirako, Yoro, and Kanaya are well known hot-spring resorts in Chiba Prefecture and such hot-spring water is brine containing iodine. Taking a hot bath in water containing rich salt prevents evaporation of sweat and helps keeping the body warm.

Generally, the production of brine is proportional to that of natural gas. We are the leading company in production of natural gas in Chiba Prefecture, while we are also a leader of brine production. This brine is not only used for our own iodine production, a certain amount is also used by other iodine manufacturers, as well as being distributed to hot-spring business. We probably have the largest iodine reseves in Japan, which is the sum of real and potential production.

Item	Brine（mg/l）	Sea Water（mg/l）
I-	110-130	0.05
CI-	18,000-19,500	18,230
Br-	120	56.2
Na+	10,000	9,350
K+	300	356
Ca2+	190	372
Mg2+	500	1,160
SO42-	0	2,450
HCO3-	1,000	105
CO32-	-	5.9
CO2（Free）	10-30	-
NH4+	120	1.5
HBO32-	10	21.9
Fe（Total）	2-5	0.2
pH	7.9	8.2

Characteristics

Iodine is known as a chemical material which turns purple by reacting with starch and also for being contained in various types of seaweed.

Iodine as a product is usually solid, with purplish black metallic luster and is heavy material like metals. It is liquefied even at a comparatively low temperature, and can also easily vaporize by sublimation of solid iodine like dry ice. It has a distinctive smell. It is rare for material to easily take the form of vapor, liquid, and solid. It is widely used in the production of various kinds of iodine compounds and is used in many areas due to its strong reactivity (for example oxidization).

Symbol of element	I	Specific Gravity	4.93
Atomic Number	53 (halogen family)	Melting Point	113.7℃
Atomic Weight	126.9	Boiling Point	184.5℃