Industrial grade Food Grade 98% 99%Potassium iodide CAS 7681-11-0

What is Potassium iodide?

Potassium iodide, also known as potassium iodide, is the iodide of potassium. It is one of the most important carriers of iodine in the food and industrial fields. Food grade potassium iodide is usually made by reacting potassium hydroxide with iodine to make potassium iodate, which is then reduced and purified.  Its chemical formula is usually written as:

KI (CAS No.: 7681-11-0, EINECS No.: 231-659-4, molecular weight approximately 166.00, iodine content approximately 76.45%)

Potassium iodide is a colorless or white crystalline powder at room temperature, odorless, with a salty and bitter taste. It has a melting point of approximately 681℃, a boiling point of approximately 1330℃, and a relative density of approximately 3.12. It is extremely soluble in water (approximately 1280-1440 g/L), and its aqueous solution is neutral or slightly alkaline. It is slightly soluble in ethanol. Potassium iodide is hygroscopic and will precipitate free iodine and turn yellow upon prolonged exposure to light or oxidizing agents.

From a molecular structure perspective, potassium iodide is a typical ionic crystal, composed of potassium ions (K+) and iodide ions (I-) bonded together by ionic bonds. Iodine atoms have a large atomic radius and low electronegativity, and iodide ions are easily oxidized to elemental iodine (I-→I2). Therefore, potassium iodide is not only a stable and easily absorbed iodine source, but also has a certain reducing property and can dissolve elemental iodine to generate triiodide ions (I3-)—a property that makes it a core substance for iodized nutrition fortification and iodometric analysis.

It is hygroscopic and will readily absorb moisture from the air. Chemically potassium iodide is Under light, acidic and oxidizing conditions the iodide ions are easily oxidized (free iodine is released) and the product turns yellow. That means food grade potassium iodide has to be stored in containers that protect it from both light and moisture. Potassium iodide is safe when taken by mouth, but too little or too much iodine can affect the thyroid gland and must be used within the recommended limits.

Food-grade potassium iodide refers to products that comply with GB 29203-2012 "National Food Safety Standard for Potassium Iodide as a Food Additive," and is mainly used for iodizing table salt and for food fortification. Compared to industrial-grade products, food-grade products pay more attention to the following indicators:

Content (purity of potassium iodide)

The main content, calculated on a dry basis, is generally not less than 99.0%, which is the basic indicator determining the iodine fortification effect and product quality.

Moisture

Potassium iodide is hygroscopic and tends to form lumps. The moisture content must be carefully controlled to ensure the fluidity, stability and shelf-life of the product.

Iodate limits

A specific quality requirement for food-grade products is the control of the content of iodate, an oxidation product, for the product purity and food safety.

Heavy metal limits (lead, arsenic, etc.)

The strict limits for heavy metals, like lead and arsenic, are critical parameters to ensure the safety of food-grade products.

Solution transparency

The aqueous solution should be clear and transparent without obvious turbidity or insoluble matter, which is a reflection of the purity of the product and the degree of process control.

What are the uses of food-grade Potassium iodide?

Food-grade potassium iodide is mainly used as a nutritional fortifier, with its core mission being the scientific supplementation of iodine and the prevention of iodine deficiency disorders. Its applications are concentrated in the following areas:

1. Iodized salt (nutritional fortifier, core application)

Potassium iodide is one of the core iodine sources for iodized salt and is used in the production of iodized salt. China's "Iodine Content in Edible Salt" (GB 26878) stipulates that the average iodine content of iodized salt should be 20-30 mg/kg. Iodized salt is a public health strategy in China to prevent and eliminate iodine deficiency disorders and is also the most widespread application of potassium iodide.

2. Fortified food, e.g. modified milk powder

Potassium iodide can be used to fortify food categories such as milk powder with iodine, according to GB 14880 “Standard for the Use of Food Fortifiers”, which facilitates specific groups of people to supplement iodine nutrition through daily food and improve dietary iodine intake.

3. Iodine fortification in infant formula

Iodine is an essential nutrient for infant formula. Potassium iodide is used for iodine fortification in infant formula and complementary foods. Its use must comply with the infant formula food standards such as GB 10765 to ensure the iodine nutrition and growth and development of infants.

4. Health foods and iodine dietary supplements

Potassium iodide is used as a raw material for iodine-containing health foods and dietary supplements, providing a convenient way for people with insufficient iodine intake to supplement their iodine intake. Products must be registered or filed and labeled with the appropriate population and dosage.

5. Aquaculture and feed (indirect contact)

Potassium iodide is used as an iodine additive in aquaculture and livestock feed, serving the aquaculture industry chain. The farming of the fish, shrimp, meat, eggs and dairy products we consume may be indirectly involved in it.

6. International Salt Market and Exported Food Products

In international markets such as the United States and Europe, potassium iodide is the mainstream choice for iodizing salt (potassium iodide is commonly used in iodized salt in the United States). Food-grade potassium iodide is also used in the production of exported food and international condiments, and is the standard iodine source in the international salt market.

7. Testing and Laboratory (Indirect Contact)

Potassium iodide is a fundamental reagent in iodometric analysis, used to detect iodine content in food and water. It may also be used indirectly in laboratory testing processes.

8. Other Applications

The application scope of food-grade potassium iodide continues to expand, including in areas such as iodine fortification in sports nutrition and special dietary foods, and supporting reagents for iodine content detection (iodometric method) in food enterprise quality inspection.

It should be noted that iodine is a micronutrient that is "too much of a good thing": the recommended daily intake of iodine for Chinese residents is about 120 micrograms for adults, and iodized salt produced according to national standards can meet the daily needs; special groups such as pregnant women and breastfeeding women have higher iodine requirements, but they should also supplement their diet reasonably under the guidance of a doctor or nutritionist, and should not blindly consume excessive amounts.

Summarize

Potassium iodide (KI, CAS No. 7681-11-0) is a colorless or white crystalline powder that is highly soluble in water . It possesses both stable iodine supplementation and mild reducing properties. In daily life, we encounter it through iodized salt, fortified foods, infant formula, potassium iodide tablets, aquaculture and feed, and testing laboratories. In the food sector, food-grade potassium iodide conforming to GB 29203-2012 is widely used in iodized salt, fortified milk powder and other nutritionally fortified foods, infant formula, health foods and dietary supplements, and the international salt market. It is a core food fortifier for preventing iodine deficiency disorders and ensuring adequate iodine nutrition for the population.