Sodium tetraborate (pentahydrate) multifunctional inorganic compound

chemical formula of Na ₂ B ₄ O ₇ · 5H ₂ O, a molecular weight of 291.29, and a CAS registration number of 12045-88-4. This compound is often referred to as "borax pentahydrate" in the Chinese context, while in English it is called "sodium tetraborate pentahydrate" and "borax pentahydrate". From a physical observation, it appears as a white crystalline powder with a relative density of 1.815, which gives it a medium to high specific gravity in solid matter. This compound is sensitive to heat and undergoes dehydration at 122 ℃, losing its crystalline water and transforming into an anhydrous substance. In a dry environment, its chemical properties remain stable; But under humid conditions, it will gradually transform into decahydrate borax (Na ₂ B ₄ O ₇ · 10H ₂ O) through the process of moisture absorption, and this phase transition process is closely related to the change in its hydration energy.

2、 Diversified industrial application fields

1. Basic chemical raw materials

As the basic raw material of boron compounds, sodium tetraborate (pentahydrate) is the starting material for the production of various borates, including boric acid, zinc borate, etc. These derivatives are widely used in flame retardants, wood preservatives, and other fields.

2. Agricultural applications

In the field of agriculture, this compound is a key intermediate for synthesizing herbicides and soil fungicides. Its boron element composition can effectively inhibit weed growth and also has a certain soil disinfection function.

3. Glass industry

In glass manufacturing, sodium tetraborate (pentahydrate) is an indispensable flux and network former. It can significantly reduce the melting temperature of glass, improve the chemical stability and mechanical strength of glass, and is particularly suitable for producing optical glass and heat-resistant glass products.

4. Enamel and Ceramic Industry

As an important component of enamel glaze, it can improve the glossiness and adhesion of the glaze surface. In the ceramic industry, as a glaze component, it can enhance the wear resistance and corrosion resistance of ceramic products.

5. Mining and Metallurgy

In the mining field, this compound is used as an antifreeze and anticoagulant to prevent the slurry from freezing at low temperatures. In non-ferrous metal processing, it can effectively lower the melting point of metals as a welding agent, and as an electrolyte additive, it can optimize the electrolysis process.

6. Other applications

In addition, it is widely used in cosmetics as a water softener, in metal surface treatment as a preservative, rust inhibitor, and in the electronics industry as a raw material for electronic grade boron compounds.

3、 Production process and quality control

The industrial production of sodium tetraborate (pentahydrate) mainly adopts the recrystallization process. The process first dissolves borax decahydrate in hot water, and by precisely controlling the solution temperature (usually maintained at 60-80 ℃), the pentahydrate crystallizes and precipitates from the solution. Subsequently, centrifugal separation technology was used to separate the crystals from the mother liquor, and surface moisture was removed through drying equipment to obtain finished products that meet industrial standards. The key to this process lies in controlling the crystallization temperature and cooling rate to achieve the desired crystal morphology and purity.

4、 Security information and protective measures

According to the International Chemical Safety Labeling System, the safety labels for this substance include S26 (rinse immediately with plenty of water and seek medical attention in case of accidental eye contact) and S36 (wear appropriate protective clothing). Its hazard declaration is R22 (harmful if swallowed) and R36/38 (irritating to eyes and skin). Therefore, protective goggles, gloves, and protective clothing should be equipped during operation to ensure good ventilation in the workplace. When storing, it should be placed in a dry and cool place, avoiding contact with strong acids and oxidants.

5、 Market Status and Development Trends

At present, the supply and demand of sodium tetraborate (pentahydrate) in the global market are basically balanced, and the main producers include the United States, Türkiye and China. With the development of clean energy, electronic materials, and environmentally friendly materials, the demand for high-purity borates continues to grow. In the future, this compound has broad application prospects in functional materials, new energy batteries, and other fields, especially in solid electrolytes and flame retardant materials where breakthrough applications may be made.