Sodium antimonate is also called sodium pyroantimonate, and its molecular formula is NaSbO3. Sodium antimonate was mainly used in the glass industry and cast iron enamel. In recent years, with the development of science and technology, sodium antimony has partially replaced antimony trioxide in certain flame retardants and electronic products.
Uses of sodium antimonate
1. Used as opaque filler, milky agent for enamel, and acid-resistant paint for iron sheet and steel plate;
2. Used as high-end glass clarifiers and toners for picture tubes and optical glass. Resistant to sun exposure and good lighting performance;
3. Used in textile, plastic, rubber and other industrial flame retardants;
4. It is used for engineering plastics with low tinting strength and saves pigments; it is used for enamel, acid-resistant ceramics, and high-grade ceramics.
5. Used to identify sodium ion in chemical analysis.
Preparation method of sodium antimonate
After being crushed from the antimony block, it is mixed with sodium nitrate and heated, reacted with air, and obtained by leaching with nitric acid. It can also be obtained by mixing crude antimony trioxide with hydrochloric acid, then chlorinating with chlorine gas, hydrolyzing, and neutralizing with excess alkali. details as follows:
(1) The sodium nitrate method crushes the antimony block, mixes it with sodium nitrate, and heats the air in the reaction furnace to carry out the reaction. The obtained crude sodium antimonate is cooled, pulverized, leached with nitric acid for further reaction, and then filtered, dried, and pulverized to obtain a finished sodium antimonate product.
4NaNO3 + 4Sb + 3O2 ---> 4NaSbO3 + 2NO + 2NO2
(2) Chlorination method: Mix crude antimony trioxide powder with acid, react 3 to 4 at 70 to 75 ° C to generate antimony trichloride, filter and remove impurities, pass chlorine gas to chlorinate at 65 ° C to generate pentachloride antimony. Water is added to perform hydrolysis to precipitate antimony, wash and remove impurities, filter and neutralize with excess alkali to generate sodium antimonate, and then vacuum filter, wash, centrifuge, dry, pulverize, and sieve to obtain the final product of sodium antimonate. The reaction equation is:
Sb2O3 + 6HCI ---> 2SbCl3 + 3H2O
SbCl3 + Cl2 ---> SbCl5
SbCl5 + 2H2O ---> SbO2Cl ↓ + 4HCl
SbCl5 + 3H2O ---> HSbO3 ↓ + 5HCl
SbO2Cl + 2NaOH + 2H2O ---> NaSbO3 * 3H2O ↓ + NaCl
HSbO3 + NaOH + 2H2O ---> NaSbO3 * 3H2O ↓
The above is a summary of the use and manufacturing method of sodium antimonate by Haihang industry.