Potassium nitrate: properties, preparation and application. E252: you have nitrate in your food

Potassium (potassium) nitrate or potassium nitrate is a potassium-nitrogen fertilizer that is used for all types of crops on all types of soil. Most often, potassium nitrate is used as an additional fertilizer in summer period for plants that do not tolerate chlorine.

IN agriculture Potassium nitrate is used for strawberries, raspberries, blueberries, beets, carrots, grapes and many other plants.

Potassium nitrate is highly soluble in water and is non-toxic. This fertilizer is an anhydrous crystalline salt white(sometimes with a yellowish tint). Potassium nitrate is used for both root and foliar feeding throughout the growing season.

In some sources, potassium nitrate is called Indian.

Article outline

Properties of potassium nitrate

The properties of any substance are usually divided into physical and chemical. Under natural conditions, the substance is colorless crystals; when crushed, it produces a white crystalline powder. At long-term storage the powder tends to cake (to prevent this from happening, it is necessary to seal the fertilizer bags hermetically), but it Chemical properties this doesn't make it worse.

When using potassium nitrate as a fertilizer, it is dissolved in water. It also dissolves in glycerin, hydrazine, and liquid ammonia. Potassium nitrate formula: KNO 3.

What is potassium nitrate used for?

It is the chemical properties of a substance that determine the scope of its use and application. Potassium nitrate contains two main components: nitrogen (13%) and potassium (44%). This ratio of elements allows the successful use of potassium nitrate even after the plant has flowered and formed ovaries.

Thanks to potassium nitrate in plants:

growth accelerates;
the suction power of the root system increases;
the respiration of plant cells improves;
the plant’s immunity is activated, which protects it from many diseases, which entails an increase in productivity;
the size of the fruit increases and their taste improves;
the shelf life of the crop increases;
berry and perennial fruit crops increase their winter hardiness and frost resistance.

Potassium nitrate is used for both root and foliar feeding. This fertilizer contains almost no chlorine and is therefore ideal for chlorophobic crops such as potatoes, tobacco, grapes and others. The following crops also respond well to potassium nitrate:

carrots and beets;
most berry crops;
tomatoes, raspberries, blackberries, blueberries;
currants, all flowers and ornamental plants, as well as fruit trees.

Experienced farmers do not recommend fertilizing radishes, cabbage or greens with potassium nitrate. Also, many villagers talk about the low effectiveness of this fertilizer for potatoes - this crop responds better to phosphorus fertilizers.

During the fruiting period, potassium nitrate is fertilized for cucumbers. The peculiarity of this fertilizer is that it promotes their productivity, while there is no active growth of greenery, which takes away all the nutrients from the plant. The plant directs most of the feeding to the formation and ripening of green plants.

Fertilizing with potassium nitrate can be carried out throughout the season. The fertilizer itself is sold in packaged sizes from 1 to 5 kg for homestead farms, as well as in packages of 25-50 kilograms within industrial agronomy and for vegetable farms.

Potassium nitrate can be applied as a fertilizer in either liquid or dry form. Since liquid fertilizer acts much faster, it is used much more often. According to the experience of farmers and gardeners, the following proportions of potassium nitrate are the most effective:

Flowers and ornamental plants - 15g of fertilizer per 10l of water;
Currants, raspberries, blackberries, blueberries - 20g of dry fertilizer per 10l of water;
For fruit trees– 25g per 10l of water.

Such proportions are only suitable if you apply a liquid solution of nitrate under the root - in trunk circle or a hole. And if you want to produce foliar feeding, then it is better to make a more concentrated solution, since in any case, part of the fertilizer will be lost by evaporation from the leaves or washed away during watering. Therefore, you should make a higher concentration - about 25 g of fertilizer per 10 liters of water. The prepared solution is used to spray plants. It is recommended to use it in the following quantities:

For flowers, ornamental plants and strawberries - 0.7 l per 1 sq.m.
For berry bushes– 1l per 1 sq.m.
For fruit trees - from 1.5 liters to 6 liters per 1 square meter, depending on the density of the tree crown and its age.

10 days before harvesting, it is necessary to water the berry rows and tree crowns with water (it is best to use a hose with a sprayer);
watering should be repeated every other day (three times) and stopped 2-3 days before harvesting;
This procedure must be performed very carefully so as not to knock the fruits and berries off the stalks.

Potassium nitrate for cucumbers and tomatoes is rightfully considered one of the best fertilizers. It accelerates photosynthesis processes, helps strengthen the root system and increases productivity. Most often, liquid potassium nitrate is used in agricultural technology for growing these vegetables. It can be purchased as ready solution or make your own from the powder.

The question of how to make potassium nitrate is not difficult, the main thing is to maintain the proportions. So, To feed cucumbers, you need to take 25 grams of saltpeter per 15 liters of water.. This solution is enough to make a one-time fertilizing at the beginning of the growing season of one large greenhouse with cucumbers.

For tomatoes, you can use the same proportions of potassium nitrate, but apply root feeding. Under each bush you need to pour about 0.7-1 liters of solution. Thus, 15 liters of solution will be enough for 15-20 tomato bushes. Root feeding with potassium nitrate is carried out during the period of active flowering.

Potassium nitrate is also used to fertilize tomato seedlings. You can water tomato seedlings with a liquid solution already at the stage of appearance of 3-4 leaves, as well as before planting in the ground, about a week. It is also advisable to use this fertilizer during the picking period of seedlings.

Rules of application

In addition, you should not get carried away with watering with the addition of potassium nitrate. In fact, over the summer it is enough to feed the plants with saltpeter no more than 3-4 times (in most cases, 2 feedings are enough). Otherwise in the fruits vegetable crops Nitrates will accumulate. To prevent this from happening, after using saltpeter, the plants need to be provided with abundant watering. You can also feed the plants during the rainy season. This is especially true for tomatoes and cucumbers - in the future it will be easier for them to resist diseases.

In rainy summers, tomatoes are prone to late blight, and scab appears on cucumbers. Potassium makes the plant less susceptible to these diseases.

Features of using saltpeter for root vegetables

When growing root crops, potassium nitrate is used in dry form. Crystals of the substance are added directly to the soil before planting in a proportion of up to 50 grams per square meter plot. This should be done when digging the soil. Root crops should be planted after applying fertilizer within a couple of days.

For potato and cabbage beds, saltpeter is recommended to be used in combination with other fertilizers. For cabbage, saltpeter should be mixed with calcium, and for potatoes with phosphorus. Carrots and beets love potassium nitrate in pure form, but you can add calcium.

Flower crops also need potassium fertilizers. Potassium nitrate for flowers has the same meaning as for vegetables and root crops. Before planting flowers, during the preparation of flower beds, saltpeter crystals can be added directly to the soil by digging. This promotes soil mineralization. In addition, harmful insects leave the soil.

In its pure form, rhododendrons love saltpeter. Small-bulbed flower crops also have a positive attitude towards potassium nitrate. To fertilize them, it should be mixed with ash. In early spring You can fertilize lilies with potassium nitrate, or use its crystals when planting dahlias, gladioli, and tulips. During budding, liquid saltpeter is used. Clematis are fed with saltpeter no more than twice during the entire season. Potassium nitrate has found application in floriculture and growing indoor plants. It has a good effect on the growth of begonias and violets.

Safety rules when using potassium nitrate as a fertilizer

Potassium nitrate is an oxidizing agent that quickly reacts with flammable substances, so it is often used in pyrotechnics. When storing and using potassium nitrate as a fertilizer, the following rules must be observed:

2.7 out of 5

Potassium nitrate, otherwise called potassium nitrate, potassium nitrate, potassium nitrate, Indian saltpeter (other names are possible), is an inorganic binary compound, a potassium salt of nitric acid. Chemical formula – KNO 3.

Previously, it was extracted from wood ash or limestone, but today it is extracted from plants. Potassium nitrate is also found in nature as a mineral. Since one of its largest deposits is located in the East Indies, this is where the name “Indian saltpeter” comes from.

IN Food Industry Potassium nitrate is known as food preservative E252. It is used to ensure the safety of products, since it is an obstacle to the reproduction and growth of fungi and bacteria.

In the territory Russian Federation its use is prohibited, however, in other countries manufacturers are officially allowed to add it to products, albeit in limited quantities.

Properties of potassium nitrate

Externally, it is a crystalline powder that is odorless or colorless. Decomposes only when high temperatures ah (more than 400 degrees), with the release of oxygen. May react with flammable materials.

One of the properties of potassium nitrate is its good solubility in water In addition, the substance has some hygroscopicity, but is odorless and non-volatile. It also dissolves in glycerin, liquid ammonia, hydrazine, but does not dissolve in pure ethanol and ether. Amenable to purification by recrystallization.

Applications of potassium nitrate

The main application today is the use of potassium nitrate as a fertilizer in agriculture. This fertilizer combines two elements that somewhat block the absorption of each other by plants.

In addition, the substance is indispensable in pyrotechnics, the production of black powder, and caramel rocket fuel. It is used in such areas as the electric vacuum industry, optical glass melting (with its help, technical crystal glasses are decolorized and brightened, and strength is imparted to glass products).

Potassium nitrate is also used in metallurgy as an oxidizing agent, for example, in the process of processing nickel ores.

In the food industry, preservative E252 is used in the production of meat products such as sausages, sausages and canned meat, as well as for the production of cheeses. Due to the high content of potassium nitrate, the product may change color, which is why it is used in the processing of anchovies. It should be noted that the preservative has some antimicrobial effect.

In addition, this food preservative is contained in prophylactic toothpastes.

Harm of potassium nitrate

Preservative E252 may be harmful to human health. This is due to the fact that when it is used for preparing food, a fairly large part of it enters the body. There it can be transformed into nitrites, which have negative effects on internal systems human body.

If potassium nitrate enters the body for a long time and in large doses, it can affect the kidneys, cause anemia, pulse irregularities. The main symptom of its excess in the body is abdominal pain; in addition, vomiting, weakness, and loss of coordination may occur. In asthma sufferers, it may cause suffocation due to its ability to affect the oxygen balance in the blood. It aggravates some diseases and is considered a provocateur of tumor development. Children are strictly contraindicated from consuming foods that contain this food additive.

Composition and properties of potassium nitrate

The substance is based on nitric acid and sodium. The salt obtained by combining these elements is a white or yellowish powder, endowed with neither smell nor taste. In its natural form, the substance consists of colorless, elongated, needle-shaped crystals.

Potassium nitrate owes its particular popularity and wide range of applications to its properties:

has no volatility;
has weak hygroscopicity;
non-toxic;
absolutely harmless to humans;
soluble in water, liquid ammonia, glycerin and hydrazine.

In addition, potassium nitrate is a strong oxidizing agent, and when exposed to high temperatures it becomes explosive. It is capable of explosive contact with flammable materials. This property of the substance allows it to be successfully used in the production of fireworks.

If organic substances are involved in the reaction, saltpeter can easily ignite them, so the use of potassium nitrate requires caution and special safety measures.

Who needs potassium nitrate

Potassium nitrate surrounds a person on all sides. This substance is actively used in many economic fields. Modern man daily uses items made with potassium nitrate. He even eats it along with food.

Agriculture. It is used as a universal fertilizer that can increase the yield of vegetables and fruits many times over.
Food industry. Included in products as preservative E252. Responsible for protecting them from the development of putrefactive bacteria, maintaining color and attractive appearance. In addition, potassium nitrate is used in the production of certain types of cheeses, sausages, and canned fish.
Glass production. Used to brighten crystal.
Space industry. Potassium nitrate is the basis for making solid fuel for rockets. Its mass in this product reaches 65%.
Metallurgy. Due to its pronounced oxidizing properties, it is used in the process of nickel-containing ores.
Pyrotechnic products. It is the basis for the production of gunpowder, which is used in the military industry, and is also used to make fireworks.
Pharmacology. When added to toothpaste, it can significantly reduce the sensitivity of tooth enamel. Included in some types of eye drops.

Rules for the use of potassium nitrate

Regardless of which sector of the national economy uses potassium nitrate, its properties force users to strictly follow the rules of use.

Considering the ability of nitrate to spontaneously ignite, as well as to enter into chemical reactions, the substance was assigned hazard class 3, which must necessarily be reflected in the conditions of its transportation and storage:

Transportation. Transportation of potassium nitrate is carried out only in wagons specially designed for this purpose or on other specialized types of transport. closed type.
Storage. To prevent the powder from compacting over time, saltpeter should be stored only in hermetically sealed packaging. It should be located away from flammable substances and hot objects. The warehouse should be a closed premises equipped with a fire safety system.

Safety rules for use as fertilizer

Potassium nitrate is very actively used in agricultural production as a fertilizer. It contains elements necessary for the growth and enhancement of vegetative functions of plants, but in this area of application, safety rules must be followed.

Plants can be fertilized only with a dry substance or a solution of nitrate with water. Under no circumstances should it be mixed with organic fertilizers, such as peat, straw, sawdust or manure.
When using fertilizer, you must strictly observe the measure. During the summer, experts recommend no more than 3-4 feedings. In case of excessive use of nitrate, plants can accumulate large amounts of nitrates, which can affect bad influence on the human body.
Workers who come into direct contact with the fertilizer must follow the proper technique personal safety using respirators to protect the respiratory tract, rubber gloves and utensils not intended for food consumption.

Potassium nitrate belongs to the category of “useful” chemistry, which can greatly facilitate and even decorate a person’s life. Don’t be alarmed when you see the designation E252 on the label of your favorite sausage. It has been proven that potassium nitrate is not dangerous to humans.

However, it should be remembered that its excessive consumption with products containing high level nitrates may have Negative influence on health, which is why it is so important to observe safety measures when using this substance in agriculture.

Potassium nitrate is an inorganic binary compound represented by the formula KNO 3, also known as potassium nitrate, potassium nitrate, potassium nitrate. The KNO 3 compound is a colorless crystalline powder, non-volatile, odorless, and has hygroscopic properties. The substance is highly soluble in water. Not toxic to animals. In nature, the substance KNO 3 is found in the form of the mineral nitrocalite, the largest deposits of which are found in the East Indies and Chile. It is found in small quantities in plants and animal organisms.

Chemical properties and methods of obtaining potassium nitrate

Potassium nitrate KNO 3 decomposes at a temperature of 400°C to form potassium nitrite KNO 2 and oxygen O 2 . This substance acts as a strong oxidizer and reacts with flammable materials and reducing agents. The substance KNO 3 is reduced by hydrogen at the time of release.

In laboratory conditions, KNO 3 is obtained by the reaction of potash Ca(NO 3) 2 and calcium nitrate K 2 CO 3, which is the oldest method of producing this substance. Currently, potassium sulfate K 2 SO 4 is used instead of potash. A solution of potassium nitrate is obtained by the same reaction. Among modern methods To obtain potassium nitrate KNO 3, the reaction of potassium chloride KCl and sodium nitrate NaNO 3 is more accessible and cheaper.

Areas of application of potassium nitrate

Potassium nitrate KNO 3, as well as a solution of potassium nitrate, is used as a fertilizer (one of nitrogen fertilizers, rich in potassium, which is an essential component for plant growth). The substance is also used in the electric vacuum industry, metallurgy, optical glass melting, and in the production of gunpowder.

Nutritional properties of potassium nitrate

Potassium nitrate is widely used in the food industry as a food additive E252, classified as a preservative.

Preservatives – chemical substances, food additives E200 - E299, suppressing the growth of microorganisms in the product, as well as preventing the appearance unpleasant odor and taste of the product, the development of molding processes, the formation of toxins of microbial origin.

Potassium nitrate is used in the production of:

cheeses (hard, semi-hard, soft);
milk-based cheese analogues;
sausages and meat products (salted, boiled, smoked), canned meat;
fish products (herring, salted and marinated sprat);
goose liver products.

The food additive is also a color fixative. The substance is added to food products to preserve attractiveness for a longer period of time. appearance product. Has a weak antibacterial effect.

Effects of potassium nitrate on the body

Potassium nitrate produces a carcinogenic effect - the development of malignant tumors under the influence of external factors. However, in recommended doses, E252 does not have any effect harmful effects on the adult body. The negative impact of nitrates is explained by their transformation in the human body into nitrites (uncontrolled conversion of potassium nitrate into nitrites occurs in food products) and carcinogenic nitrosamines. The amount of nitrates entering the body with food additives, in particular with E252, is negligible compared to the content of these substances in drinking water, and also in vegetables (as a result of overfertilization).

Long-term exposure to E252 in small doses on the body can lead to the development of the following symptoms and diseases:

Severe abdominal pain
Weakness
Dizziness
Mental disorders
Spatial orientation disorder
Arrhythmia
Kidney inflammation
Anemia

legal information

Potassium nitrate as a food additive is approved for use in food production in the Russian Federation and Ukraine, as well as the countries of the European Union.

Structural formula

True, empirical, or gross formula: KNO 3

Chemical composition of potassium nitrate

Molecular weight: 101.106

Potassium nitrate, potassium nitrate(potassium nitrate, potassium nitrate, Indian nitrate, etc.) - an inorganic compound, potassium salt of nitric acid with the formula KNO 3. In the crystalline state it is a colorless substance, non-volatile, slightly hygroscopic, odorless. Potassium nitrate is highly soluble in water. Virtually non-toxic to living organisms.
It is found in nature in the form of the mineral nitrocalite; one of the largest deposits is located in the East Indies, hence the second name - Indian saltpeter. It is found in very small quantities in plants and animals.
The shape of the crystals is needle-like, the crystals themselves are very long. Easily purified by recrystallization with minimal losses.
Its main application is in pyrotechnics (until the 20th century, especially widely, as a component of the main at that time explosive- black powder) and as a potassium-nitrogen fertilizer (a very convenient combination of two elements that are usually poorly combined when absorbed by plants).

Physical properties

Potassium nitrate in normal conditions are colorless crystals (white powder when crushed) with an ionic structure and rhombic or hexagonal crystal lattice. Slightly hygroscopic, tends to slightly cake over time. Odorless, non-volatile. Well soluble in water, moderately soluble in glycerin, liquid ammonia, hydrazine, insoluble in pure ethanol and ether (poorly soluble in diluted water). Solubility table in some solvents, in grams of KNO 3 per 100 g of H 2 O:

Solvent/Temperature	0 °C	10 °C	20 °C	25 °C	30 °C	40 °C	60 °C	80 °C	100 °C
Water	13,9	21,2	31,6	37,9	46,0	61,3	106,2	166,6	245,0
Liquid ammonia	10,52			10,4
Hydrazine			14
Diethyl ether
Ethanol
Methanol
Glycerol

With slow crystallization, very long needle-shaped crystals grow. Potassium nitrate lends itself well to purification by recrystallization, and with small losses, due to the strong increase in solubility with increasing temperature.

Chemical properties

Decomposes at 400-520 °C with the formation of potassium nitrite KNO 2 and oxygen O 2 (the release of the latter increases the fire hazard of potassium nitrate):
2KNO 3 → 2KNO 2 + O 2
It is a strong oxidizing agent, reacts with flammable materials and reducing agents, and when crushed, actively and often explosively. Mixtures of potassium nitrate with some organic materials prone to spontaneous combustion.
It is reduced by hydrogen at the moment of separation (in the reaction dilute hydrochloric acid):
Zn + 2HCl → ZnCl 2 + 2H 0
KNO 3 + 2H 0 → KNO 2 + H 2 O
Potassium nitrate melt can be used to produce potassium by electrolysis, however, due to the high oxidizing properties of potassium nitrate, potassium hydroxide is preferred in this state.

Receipt

In the Middle Ages and the New Age (when gunpowder was actively used), saltpeter pits were used to produce potassium nitrate - heaps of a mixture of manure (and other rotting components) with limestone, construction waste and other limestone material with layers of straw or brushwood, covered with turf to retain the resulting gases When manure rotted, ammonia was formed, which, accumulating in layers of straw, underwent nitrification and was converted first into nitrous and then into nitric acid. The latter, interacting with limestone, gave Ca (NO 3) 2, which was leached with water. The addition of wood ash (consisting mainly of potash) led to the precipitation of CaCO 3 and the production of a solution of potassium nitrate; often ash was added directly to the heap instead of limestone, then potassium nitrate was obtained immediately. Reaction of potash with calcium nitrate (calcium nitrate).
Ca(NO 3) 2 + K 2 CO 3 → 2KNO 3 + CaCO 3
is the oldest used by humans to obtain potassium nitrate and is still popular today. Instead of potash, however, now in laboratories they most often use potassium sulfate, the reaction is very similar:
Ca(NO 3) 2 + K 2 SO 4 → KNO 3 + CaSO 4
The first method was used until 1854, when the German chemist K. Nöllner invented the production of potassium nitrate, based on the reaction of more accessible and cheaper potassium chloride and sodium nitrate:
KCl + NaNO 3 → KNO 3 + NaCl
There are several other ways to obtain potassium nitrate. This is the reaction of ammonium nitrate and potassium chloride to form potassium nitrate and ammonium chloride, the latter is easily separated:
KCl + NH 4 NO 3 → KNO 3 + NH 4 Cl
KOH + HNO 3 → KNO 3 + ammonia by nitrobacteria, which is facilitated by moisture and heat, so the largest deposits are located in countries with hot climates.
It is found in very small quantities in plants and animals and is an intermediate product during their processing of soil sulfate and potassium carbonate.

Application

Potassium nitrate is mainly used today as valuable fertilizer, since it combines two elements that partially block the absorption of each other by plants when they are part of separate compounds.
It is indispensable in the production of black powder and some other compounds (for example, caramel rocket fuel), which are now almost entirely used in the production of pyrotechnics.
It is also used in the electric vacuum industry and optical glass melting for decolorization and brightening of technical crystal glasses and imparting strength to glass products.
The melt is often used in laboratories and hobbyists to produce elemental potassium by electrolysis, along with potassium hydroxide.
It is used as a strong oxidizing agent in metallurgy, in particular in the processing of nickel ores.
In the food industry, potassium nitrate is used as a preservative E252. By itself, it does not have a pronounced antibacterial effect, but it is produced by potassium nitrite formed in meat products (where potassium nitrate is most widely used).