硼酸

PHYSICAL AND CHEMICAL PROPERTIES

PHYSICAL STATE

white crystals

MELTING POINT

170 C

BOILING POINT

300 C

SPECIFIC GRAVITY

1.43 - 1.44

SOLUBILITY IN WATER

4 - 5 g/100 ml at 20 C

pH

5.2 (1% sol.) 

VAPOR DENSITY

AUTOIGNITION

NFPA RATINGS

Health: 2; Flammability: 0; Reactivity: 0

REFRACTIVE INDEX

FLASH POINT

STABILITY

Stable under ordinary conditions. Hygroscopic.

GENERAL DESCRIPTION AND APPLICATIONS

Boric acid refers to 3 compounds; orthoboric acid (also called boracic acid, H3BO3 or B2O3·3H2O), metaboric acid (HBO2 or B2O3·H2O), and tetraboric acid (also called pyroboric, H4B4O7 or B2O3·H2O). Orthoboric acid dehydrates to form metaboric acid and tetraboric acid above 170 C and 300C respectively. Orthoboric acid is derived from boric oxide in the form of white, triclinic crystals. It is poorly soluble in cold water but  dissolves readily in hot water, in alcohol and glycerine. Metaboric acid is a white, cubic crystalls. It is soluble in water slightly. Tetraboric acid is a white solid soluble in water. When tetraboric and metaboric acid are dissolved, it reverts to orthoboric acid. The main uses of boric acid is to make borate salts such as borax and other boron compounds. Boric acid is also used in heat resistant glass, in fireproofing fabrics, in electroplating baths, in leather manufacturing, porcelain enamels and in hardening steels. Boric acid has antiseptic and antiviral activity. Aqueous solutions have been used as mouth-washes, eye-drops, skin lotions and cosmetics. Boric acid and its salts are components of many commercial insecticides and wood preservatives.

SALES SPECIFICATION

APPEARANCE

white crystals

H3BO3

99.6% min

SULFATES (as SO4)

0.1% max

WATER INSOLUBLE MATTERS

0.01% max

Cl

0.01% max

HEAVY METALS (as Pb)

0.001% max