Sodium Nitrate - China

Brief Overview

Sodium nitrate exist naturally in Chile and Peru. It is a white solid with the formula of NaNO₃. It is very soluble in water and is also a good source of nitrate anion, which is greatly used by many industries. Being available as a natural resource, sodium nitrate is mined extensively to meet its huge demand till the 20th century.

Nitrate salts are bounded within the mineral caliche ore and serves as the main source of sodium nitrate till the 20th century. German chemist Fritz Haber and Carl Bosch developed a process to synthesize nitrate on an industrial scale.

Manufacturing Process

Method 1: Mining: Sodium nitrate and its nitrate salts can be mined from the caliche ore in Chile and Peru. For more than a century, supply of nitrate salts was purely mined from Chile and Peru. Mined nitrate salts are processed, purified and standardized for industrial consumption. However, with the increase in demand for sodium nitrate, alternative methods are required before natural supplies are depleted.

Method 2: Haber Process: Sodium nitrate is manufactured on an industrial scale using hydrogen and nitrogen gas, with the presence of CaO catalyst. As the reaction is exothermic, it is thermodynamically favorable under low-pressure conditions of 200-atmospheric pressure. Using this process, ammonia is manufactured and can be converted to nitrate easily through the process of nitrification.

Method 3: Neutralization: Sodium nitrate can also be manufactured by neutralizing nitric acid with soda ash. Alternatively, mixing ammonium nitrate with either sodium hydroxide, sodium bicarbonate or sodium carbonate can also yield sodium nitrate.

Textile Industry

Sodium nitrate is used in dyeing and printing of textiles. It is used in the manufacture of azo dyes and for oxidizing dyeings and prints with leuco vat dyes. It is a versatile bleaching agent for cellulosics, synthetics and blends, especially poly-cotton blends. It is also safe for those synthetic fibers which are sensitive to alkali. Sodium Nitrate is non-sensitive metal ions and hard water under acidic conditions.

Food Industry

Sodium nitrate is also a food additive used as a preservative and color fixative in cured meats and poultry. It is listed under its INS number 251 or E number E251. It is approved for use in the EU, USA and Australia and New Zealand.

Other Applications

Sodium nitrate is also used in antiseptic dental mouthwash, wastewater industry for facultative microorganism respiration and color fixation, fertilizer, manufacture of high-strength glass and manufacture of gunpowder.