Each of us is a specialist in agriculture, and therefore we know everything that is connected with it. Everyone knows about nitrates, about their benefits and harms. But in fact, what is sodium nitrate?
The formula of this substance is NaNO3, its other name is sodium nitrate. In appearance, it is a white crystalline substance, sometimes having a grayish or yellowish tint. It dissolves well in water. It tastes bitter and salty. It is found in nature as a mineral - Chilean nitrate. Nitrate is hygroscopic, melting point 308 ° C, decomposition (boiling) - 380 °. Strong oxidizing agent, during boiling it releases oxygen.
Sodium nitrate is produced by synthesis from ammonia or nitrogen in the air. There are other technologies for the production of nitrate based on various reactions of interaction and decomposition. Types:
- A - for use in the composition of fluxes when soldering and welding metals;
- B - for etching metals and lightening alloys.
Store sodium nitrate in packaged form in multilayer paper bags. It can be transported by any means other than air; during transportation and unloading it must not be mixed with organic substances in order to avoid fire.
As it is also called, sodium nitrate is widely used in various fields of industry and agriculture. In agriculture, it is used as nitrogen fertilizer on all types of soils, for vegetable crops (potatoes, beets), fruit and berry plantings. Since nitrate is an alkaline type of fertilizer, it is better to use it on acidic soils. As fertilizer, they are applied to the soil in spring, and can be used as top dressing. A positive effect on plants has not only nitrogen, but also sodium.
In industry, sodium nitrate is used as:
- a component of the solution for pickling stainless pipes;
- a component of the lubricant on rolling mills of stainless pipes;
- clarifier when cooking glass;
- oxidizer in rocket fuel;
- component of salt refrigerants.
In the food industry, saltpeter is used as a preservative - E251. There are references that already in 1397 saltpeter was used to preserve fish. This is due to the effect of nitrites formed from nitrates on bacteria. Nitrate is used:
- in the manufacture of cheeses;
- when harvesting meat products. Nitrates under the influence of microorganisms turn into nitrites, which have a protective effect on products, at the same time giving them a corresponding bright color.
Nitrates can also be used as a solution. The meat is rubbed with a mixture of salt, saltpeter, sugar and placed under oppression. The resulting solution covers the meat.
As an oxidizing agent, nitrate is used in pyrotechnic compositions. In such formulations, its purpose is to provide oxygen to the combustion process.
Nitrate is also used in medicine as a vasodilator. In addition, it relieves intestinal cramps, serves as an antidote for cyanide poisoning and as a laxative.
At the same time, nitrate for mammals is considered a toxic substance. At a dosage of 180 mg / kg, half of the tested rats die. When doing research on E251, it was found that heating to temperatures above 120 ° C leads to the formation of carcinogens.
Studies conducted by the World Health Organization, allowed to determine the daily dose acceptable for nitrates at 3.7 milligrams per kilogram of body weight. The following happens - when nitrates are in the large intestine, under the influence of microorganisms, they turn into nitrites, and the latter, getting into the blood, turn hemoglobin into methemoglobin, which cannot carry oxygen.
In the presented material sodium nitrate is considered. What is it, where is it common in nature, how is it obtained and where is it used in industry; its effect on the human body is described.