Chemistry is a fascinating science. Those who are interested not only in theory, but also try their skills in practice, know exactly what we are talking about. Every schoolchild is familiar with most of the elements from the periodic table. But has everyone been able to try mixing reagents and conducting chemical tests first-hand? Even today, not all modern schools have the necessary equipment and reagents, so chemistry remains a science open to independent study. Many seek to understand it more deeply by conducting research at home.
Not a single homemaker can do without nitric acid - an extremely important thing in the household. It is difficult to obtain the substance: it can only be purchased in a specialized store, where purchases are made using documents confirming the peaceful use of the substance. Therefore, if you are a DIYer, you most likely will not be able to get this component. This is where the question arises of how to make nitric acid at home. The process does not seem to be complicated, however, the output should be a substance of a sufficient level of purity and the required concentration. There is no way to do this without the skills of an experimental chemist.
Where is the substance used?
It is reasonable to use nitric acid for safe purposes. The substance is used in the following areas of human activity:
- creation of coloring pigments;
- developing photographic films;
- preparation of medicines;
- recycling of plastic products;
- use in chemistry;
- fertilization of garden and vegetable crops;
- dynamite production.
Pure nitric acid in its unchanged form appears as a liquid substance, which upon contact with air begins to release white vapors. It freezes already at -42 o C, and boils at +80 o C. How to remove a substance such as nitric acid with your own hands at home?
Method 1
The fuming substance is obtained by exposing the concentrate to sodium (potassium) nitrate (sodium (potassium) nitrate). As a result of the reaction, the desired substance and sodium (potassium) hydrogen sulfate are obtained. The reaction scheme looks like this: NaNO 3 + H 2 SO 4 => HNO 3 + NaHSO 4. Remember that the concentration of the resulting substance depends on before entering into the reaction.
Method 2
Obtaining nitric acid at home with a lower concentration of the substance occurs in the same way, you only need to replace sodium nitrate with ammonium nitrate. The chemical equation looks like this: N.H. 4 NO 3 + H 2 SO 4 =>(N.H.4) 2 SO 4 + HNO 3 . Please note that ammonium nitrate is more accessible than potassium or sodium nitrate, which is why most researchers carry out the reaction based on it.
The higher the concentration of H 2 SO 4, the more concentrated the nitric acid will be. To obtain a balanced substance, it is necessary to increase the volume of electrolyte required for the reaction. To achieve the desired result, in practice they use the evaporation method, which consists of gradually reducing the volume of the electrolyte by about 4 times the original.
Features of the evaporation method
Sifted sand is poured into the bottom of the dish and a reservoir with electrolyte is placed. In this process, the gas stove is boiled by turning up or reducing the heat. The process takes a long time, so patience is important in this matter. Experts recommend using boilers - glass or ceramic tubes designed for chemical experiments, including evaporation. They neutralize the formation of bubbles and reduce the boiling force, preventing splashing of the substance. Under such conditions, it is permissible to obtain nitric acid at home with a concentration of about 93%.
Tools and reagents for practical preparation of the substance
To carry out the reaction you will need:
- concentrated H 2 SO 4 (>95%) - 50 ml;
- ammonium nitrate, potassium, sodium;
- 100 ml container;
- 1000 ml container;
- glass funnel;
- elastic bands;
- water bath;
- crushed ice (can be replaced with snow or cold water);
- thermometer.
Obtaining nitric acid at home, like carrying out any other chemical reaction, requires the following precautions:
- In the process of producing nitric acid at home, it is necessary to maintain the temperature within 60-70 o C. If these limits are exceeded, the acid will begin to disintegrate.
- During the reaction, vapors and gases may be released, so when working with acids, be sure to use a protective mask. Hands must be protected from sudden contact of the substance with the skin, so chemists work in rubber gloves. In large chemical plants, where people come into contact with substances hazardous to health, workers generally work in special protective suits.
Now you know how to get nitric acid in a simple reaction. Be careful when using such a substance and use it only for peaceful purposes.
Nitrate is the name given to nitrate salts (nitrates) of ammonium, sodium, calcium and potassium. They are mainly used in agriculture, as mineral fertilizers, and in the industrial production of pyrotechnic products and explosives.
Potassium nitrate is considered a very valuable fertilizer, as it simultaneously contains two substances important for plant life - nitrogen and potassium. But, at the same time, potassium nitrate is the basis of black gunpowder and is simply irreplaceable in the manufacture of various pyrotechnics. However, experiments by home-grown craftsmen to create rockets, smoke bombs and other “explosives” often end very disastrously. Therefore, the sale of potassium nitrate has recently been limited, and with the onset of spring, summer residents are increasingly forced to think about how to make nitrate themselves. Our advice is intended for amateur gardeners who use potassium nitrate exclusively for peaceful purposes.
How to make potassium nitrate
- Buy potassium carbonate, also known as potash, and ammonium nitrate at the hardware store.
- Dissolve them separately in warm water, preferably distilled. Use equal parts by weight of reagents. Mix both solutions in an unnecessary container, pouring the potash solution into the ammonium nitrate solution.
- Place the pan over low heat. The pan must be large enough, since during the reaction the mixture foams and increases in volume. Stir the mixture regularly. Soon ammonia gas with a sharp characteristic odor will begin to be released from it - this means that the reaction has begun. Due to the pungent odor of gas, it is better to carry out the process outdoors or indoors with good ventilation.
- After the gas evolution stops, remove the pan from the heat and leave in a cool place for a day. After this, large needle-shaped crystals of potassium nitrate form at the bottom, which can only be removed by draining the liquid and dried.
Ammonium nitrate is one of the most common fertilizers; it is applied when sowing almost all agricultural crops, both grains and vegetables, and is also used as a top dressing for adult plants. In mining, ammonium nitrate is widely used as the main component of high explosives - ammonal, ammonite or ammotol. Ammonium nitrate is sold in all hardware stores in the “Fertilizer” departments, where it can be easily purchased. Making ammonium nitrate in artisanal conditions is extremely dangerous and completely unprofitable! You can try to synthesize it yourself only in small doses, observing all safety rules, for educational purposes.
How to make ammonium nitrate
- At the hardware store you need to buy: ammonia, copper sulfate, calcium nitrate.
- Mix ammonia with copper sulfate until a blue solution is obtained. As a result of the substitution reaction, we get copper hydroxide precipitated and ammonium sulfate remaining in solution.
- Drain the ammonium sulfate solution from the sediment and mix it with calcium nitrate. As a result, we obtain calcium sulfate in the form of a precipitate and a solution containing our ammonium nitrate.
We have described the main methods for obtaining saltpeter, and it’s up to you to decide what can be done from saltpeter produced at home.
(A) Nitrites
Subject to compliance exceptions specified in the general provisions for this subgroup, this heading includes nitrites, metal salts of nitrous acid (HNO 2) (heading).
- Sodium nitrite(NaNO2). It is obtained by reducing sodium nitrate with lead and during the production of lead litharge. Colorless crystals, hygroscopic and highly soluble in water. Used as an oxidizing agent in vat dyeing; in organic synthesis; for meat processing; in photography; like rat poison, etc.
- Potassium nitrite(KNO 2). It is obtained by the same methods as sodium nitrite, or by the action of sulfur dioxide on a mixture of calcium oxide and potassium nitrate. White crystalline powder or yellowish sticks; often contains other salts as impurities. It dissolves in water and becomes very diffuse in air with deterioration in properties. Used for the same purposes as sodium nitrite.
- Barium nitrite(Ba(NO 2) 2). Crystals used in pyrotechnics.
- Others nitrites. These include ammonium nitrite, an unstable and explosive product; used as a solution to produce nitrogen in the laboratory.
(B) Nitrates
Subject to compliance exceptions, specified in the general provisions for this subgroup, this heading includes nitrates, salts of metals and nitric acid (heading), except ammonium nitrate and sodium nitrate, both pure and crude ( commodity item or ). (See below for other exceptions.)
Basic nitrates are also included here.
- Potassium nitrate(KNO 3) (also called "saltpeter"). Obtained from sodium nitrate and potassium chloride. It is colorless crystals or glassy mass, or white crystalline powder, soluble in water and hygroscopic in its crude form. It is used similarly to sodium nitrate, and also for the production of gunpowder, chemical detonators, in pyrotechnics, for the manufacture of matches and metallurgical fluxes.
- Bismuth nitrates:
(A) neutral bismuth nitrate(Bi(NO 3) 3 5H 2 O). It is obtained by the action of nitric acid on bismuth; large colorless diffuse crystals. Used to produce oxides or salts of bismuth and some varnishes;
(b) basic bismuth nitrate(BiNO 3 (OH) 2). Obtained from neutral bismuth nitrate; pearly white powder, insoluble in water. Used in medicine (for the treatment of gastrointestinal diseases); in the production of ceramics (rainbow paints), in cosmetics, in the production of fuses, etc.
- Magnesium nitrate(Mg(NO 3) 2 6H 2 O). Colorless crystals, soluble in water. Used in pyrotechnics, for the production of fire-resistant products (with magnesium oxide), glow grids, etc.
- Calcium nitrate(Ca(NO 3) 2). It is obtained by treating crushed limestone with nitric acid. White deliquescent mass, soluble in water, alcohol and acetone. Used in pyrotechnics, in the production of explosives, matches, fertilizers, etc.
- Ferrous nitrate(Fe(NO 3) 3 6H 2 O or 9H 2 O). Blue crystals. Used as a mordant for dyeing and printing (pure or mixed with acetate). Pure aqueous solution is used in medicine.
- Cobalt nitrate(Co(NO 3) 2 6H 2 O). Purple, reddish or brownish crystals, soluble in water and deliquescent. Used in the production of cobalt blue or cobalt yellow and sympathetic inks; for decorating ceramics; for electrodeposition of cobalt, etc.
- Nickel nitrate(Ni(NO 3) 2 6H 2 O). Water-soluble, deliquescent green crystals. Used in the production of ceramics (brown pigments); for dyeing (as a mordant); during electrodeposition of nickel; for the production of nickel oxide or pure nickel catalysts.
- Cupric nitrate(Cu(NO 3) 2). It is obtained by dissolving copper in nitric acid and subsequent crystallization (contains 3 or 6 water molecules depending on temperature). Blue or green crystals, soluble in water, hygroscopic; poisonous. Used in pyrotechnics; in the production of dyes; when dyeing or printing textile materials (mordant); for the production of cuprous oxide and the production of photographic paper; when applying galvanic coating, to give metals an artificial patina, etc.
- Strontium nitrate(Sg(NO 3) 2). It is obtained by the action of strontium oxide or strontium sulfide on nitric acid when heated in the form of an anhydrous salt or in the form of a hydrated salt (with 4 water molecules) at low temperatures. Colorless crystalline powder, deliquescent, soluble in water, decomposes when heated. Used in pyrotechnics (red light), in the manufacture of matches.
- Cadmium nitrate(Cd(NO 3) 2 4H 2 O). Obtained from oxide. Colorless needles, diffuse, soluble in water. Used as a coloring agent in the ceramic or glass industries.
- Barium nitrate(Ba(NO 3) 2). Obtained from natural carbonate (witherite) (commodity item). Colorless or white crystals or crystalline powder; soluble in water, poisonous. Used in pyrotechnics (green light); in the production of explosives, optical glass, ceramic glazes, barium salts or nitrates, etc.
- Lead nitrate(Pb(NO 3) 2). Lead nitrate is formed as a by-product in the production of lead dioxide by the action of nitric acid on red lead. Colorless crystals, soluble in water; poisonous. Used in pyrotechnics (yellow light), in the production of matches, explosives and some dyes; in tanning, photography and lithography; to obtain lead salts as an oxidizing agent in organic synthesis.
In addition to the above exceptions, Also don't turn on following products.
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Making nitrous oxide at home
There are several ways to obtain laughing gas. The most accessible at home is G. Davy’s method - the thermal decomposition of ammonium nitrate (ammonium nitrate) according to the reaction:
NH 4 NO 3 = N 2 O + 2H 2 O.
In laboratory conditions, it is more convenient to heat sulfamic acid with nitric acid:
NH 2 SO 2 OH + HNO 3 (73%) = N 2 O + H 2 SO 4 + H 2 O.
However, sulfamic and nitric acids are more difficult to obtain, so we will focus on the decomposition of ammonium nitrate. By the way, the decomposition of ammonium nitrate is used to synthesize nitrous oxide on an industrial scale.
When ammonium nitrate is heated, several reactions take place. Here are excerpts from the book L.I. Bagal Chemistry and Technology of Initiating Explosives (1975)
Ammonium nitrate, when heated slightly above its melting point (dry ammonium nitrate melts at 169.6°C), decomposes according to the reaction
NH 4 NO 3 NH 3 + HNO 3 (1)
<...>
The reaction of decomposition to nitrous oxide and water was studied by Berthelot, Thomsen and Velay. The first two researchers found that the reaction was exothermic
NH 4 NO 3 => N 2 O + 2H 2 O + 8.8 kcal (2)
The main reactions of ammonium nitrate decomposition at temperatures up to 270°C are (1) and (2). Molten ammonium nitrate, when heated above 250-260°C, can release nitrogen oxides, nitrogen and water:
NH 4 NO 3 => 0.5N 2 + NO + 2H 2 O
4NH 4 NO 3 => 3N 2 + N 2 O 4 + 8H 2 O
3NH 4 NO 3 => 2N 2 + N 2 O 3 + 6H 2 O
Saunders (1922), based on the results of gas analysis, came to the conclusion that the main decomposition reactions at temperatures up to 260°C are (1) and (2), as well as the reaction
5NH 3 + 3HNO 3 => 4N 2 + 9H 2 O
In his opinion, decomposition during an explosion proceeds according to the reaction
8NH 4 NO 3 => 16H 2 O + 2NO 2 + 4NO + 5N 2
<...>
For the normal process of formation of nitrous oxide by decomposition of ammonium nitrate, its temperature regime and degree of purity are of exceptional importance.
As can be seen from the above data, ammonium nitrate, when heated to 240-250°C, decomposes to form nitrous oxide and water, however, even at this temperature the resulting “raw” gas contains nitric acid vapor, nitrogen oxides NO and NO 2, ammonia, chlorine (due to chloride impurities), nitrogen and “fog” of sublimated ammonium nitrate. It is clear that such a mixture cannot be inhaled (if the idea arises of repeating Davy’s experiments), since it deadly! Moreover, if the flask is closed with a rubber stopper, then even after short-term use it gradually collapses (with the formation of completely harmless products).
Therefore, the method of producing laughing gas by heating ammonium nitrate in a frying pan (which is often recommended by “gurus” to laugh at “laymen”) looks at best like black humor.
Let's move on to the installation. Ammonium nitrate is decomposed in a Wurtz flask under gentle heating. It is better to use a thermometer, but you can do without it if necessary. As experience has shown, it is better to use heating to approximately 220°C, in which case a slight “boiling” of the melt is observed. The resulting “raw gas” for purification is first passed through an ice-cooled trap to collect distilled water mixed with nitric acid. Next, the gas passes through a Drexel flask with a solution of iron sulfate; it also serves as a kind of indicator of the rate of gas release. Then the gas is washed in an improvised washing machine (with a porous spray) with a solution of 5-7% alkali (sodium or potassium hydroxide), where it is cleared of NO 2, nitric acid, and chlorine. And finally, in the third wash with a porous spray, into which a solution of iron (II) sulfate is poured, nitrous oxide is cleared of NO and traces of remaining impurities. After this, the gas contains nitrous oxide with some water and nitrogen, as well as traces of NO 2 and NO.
It should be remembered that the purification of nitrous oxide, if it is used to repeat Davy's experiments, should be given Special attention, otherwise the gas will be toxic.
Ammonium nitrate fertilizer (ammonium nitrate) was used as a reaction load.
The invention relates to the production of nitric acid salts. The essence of the method is that nitrite-nitrate solutions obtained by absorption of nitrogen oxides with soda or caustic soda are evaporated to a total salt concentration of 750-900 g/l without isolating the solid phase and at a temperature of 70-90 o C are sent for inversion, inversion the gases are diluted with air and returned to the absorption stage, and the contact separation of ammonia to produce nitrous gases is turned on periodically as sodium nitrite is processed, and the product solutions of sodium nitrate are processed into a salt product in a known manner, including crystallization and drying of the product. The technical result is that the method makes it possible to obtain sodium nitrate without producing sodium nitrite, and also to use nitric acid as a donor of nitrogen oxides at the inversion stage instead of the catalytic oxidation of ammonia. 1 salary f-ly, 1 ill.
The invention relates to the chemical industry and can be used in enterprises producing nitric acid salts. There is a known method for producing sodium nitrate by neutralizing a solution of soda and (or) sodium hydroxide with nitric acid (V.A. Klevke, N.N. Polyakov, L.Z. Arsenyeva. Technology of nitrogen fertilizers. - M.: Goskhimizdat, 1956, p. 94; RF patent 2159738 dated December 3, 1999. Method for producing sodium nitrate). The disadvantage of the known methods is the low concentration of sodium nitrate in the product solution (320-360 g/l) and the associated high consumption of steam for its concentration before crystallization of the finished product. The closest in technical essence is the method of obtaining sodium nitrate from nitrite-nitrate solutions by inverting the latter with nitric acid (M.A. Miniovich, V.M. Miniovich. Salts of nitrous acid. - M.: Chemistry, 1997, pp. 100-101 ). The disadvantage of this method is the need for simultaneous production of sodium nitrite and the use of expensive platinum catalysts for the conversion of ammonia to nitrogen oxides. The objective of this proposed invention is to develop a method for producing sodium nitrate from nitrite-nitrate solutions without the production of sodium nitrite, the demand for which is highly seasonal, as well as the use of nitric acid to produce nitrogen oxides at the inversion stage instead of the catalytic oxidation of ammonia with atmospheric oxygen. This goal is achieved by the fact that after the stage of ammonia oxidation with atmospheric oxygen, cooling of nitrous gases, their absorption with a solution of soda or caustic soda, the nitrite-nitrate solution is evaporated without isolating the solid phase to a total salt content of 750-900 g/l and sent for inversion. When a solution is mixed with non-concentrated nitric acid, a well-known reaction occurs intensively: 3NaNO 2 + 2HNO 3 = 3NaNO 3 + 2NO + H 2 O. The ratio of the flows of nitric acid and a solution of nitrite-nitrate salts, in which the sum of salts is 750-900 g/l, is maintained in such a way that the acidity of the intermediate production solution is in the range of 30-80 g/l HNO 3 . The resulting nitrogen oxides are blown off with air in the inversion column. Since the inversion is carried out in the presence of an increased concentration of sodium nitrite, the inversion gases are diluted with additional air before entering the absorption stage. During absorption, they are absorbed by a circulating solution containing excess alkalinity in the form of soda or sodium hydroxide. In this case, sodium nitrite and nitrate are formed again. The drawing shows a diagram of the implementation of the method for producing sodium nitrate. The start-up of the technological scheme is carried out in the traditional way: the contact apparatus is ignited at the ammonia conversion stage, for which ammonia gas and air are used. Nitrous gases pass through a waste heat boiler, where they are cooled to 200-220 o C and enter an absorber irrigated with a circulating nitrite-nitrate solution containing an excess amount of soda or caustic soda. This solution (the sum of salts is 320-400 g/l) is periodically taken for evaporation, where by evaporation the sum of salts (NaNO 2 + NaNO 3 + Na 2 CO 3) increases to 750-900 g/l. The temperature of the evaporated solution is maintained within 70-90 o C to prevent precipitation of the solid phase. This solution is sent to a continuous inversion reactor column, into which non-concentrated nitric acid containing 56-58 wt.% HNO 3 is simultaneously dosed. The ratio of the flows of nitric acid and a solution of nitrite-nitrate salts is selected in such a way that an acidic environment is maintained in the column and the intermediate product solution has an acidity of 30-80 g/l HNO 3 . Air is continuously supplied to the reactor, which, in addition to improving the mixing of the reagents, ensures the removal of nitrous gases from the reaction zone. The intermediate acidic solution of sodium nitrate is sent to a neutralizer, where it is neutralized to a pH of 8-10 by mixing with a solution of soda or caustic soda. The inverted nitrous gases are diluted with additional air and sent to an absorption column. After the accumulation of a certain amount of nitrite-nitrate solutions, the contact department is stopped, and the production of sodium nitrate continues due to inversion nitrous gases. In this case, as can be seen from the above reaction, the donor of nitric oxide is nitric acid, and the process continues as long as the reducing agent sodium nitrite is present in the system. As sodium nitrite is used up and the concentration of nitrous gases decreases, it becomes necessary to connect contact oxidation of ammonia. The resulting product solution of sodium nitrate is processed into a salt product according to a known method by evaporation, crystallization and separation of sodium nitrate, followed by drying. Recycled mother liquors, after the accumulation of impurities (Cl-ions) in them, are used in the process of conversion of potassium nitrate from potassium chloride.
Claim
1. A method for producing sodium nitrate, including the oxidation of ammonia with atmospheric oxygen, cooling of nitrous gases, their absorption with a solution of soda or caustic soda, evaporation of the resulting nitrite-nitrate solutions, inversion of sodium nitrite with nitric acid at a temperature of 70-90 o C with the return of inversion gases to the stage absorption, neutralization of the intermediate solution of sodium nitrate, evaporation, crystallization and drying of the finished product, characterized in that nitrite-nitrate solutions evaporated to a total salt concentration of 750-900 g/l without isolating the solid phase are sent for inversion and the acidity of the intermediate solution is maintained at 30-80 g/l HNO 3, and the inversion gases are diluted with air before returning to the absorption stage. 2. The method according to claim 1, characterized in that the ammonia oxidation stage is switched on periodically as sodium nitrite is processed in inversion and the concentration of inversion nitrous gases decreases.
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The invention relates to a method for producing alkali metal nitrate and alkali metal phosphate in the same technological process from phosphate raw materials and nitrate raw materials, including the following steps: a) interaction of phosphate raw materials with nitrate raw materials to form an aqueous nitrophosphate reaction mixture, followed by optional separation of solid material, b) introducing an aqueous nitrophosphate reaction mixture into the first ion exchange stage, carried out in the presence of a cation exchange resin saturated with alkali metal ions, to exchange cations present in the reaction mixture for alkali metal ions present in this resin, obtaining a stream enriched with ions alkali metal, c) carrying out the first crystallization of the stream obtained in step (b), under conditions ensuring crystallization of the alkali metal nitrate, and separating the crystallized alkali metal nitrate from the mother liquor, d) introducing the mother liquor formed in step (c) into a second ion exchange step carried out in the presence of an alkali metal ion-rich cation exchange resin to exchange cations present in the mother liquor for alkali metal ions present in the resin to produce an alkali metal ion-rich phosphate containing stream, and e) performing second crystallization of the stream obtained in step (d), under conditions ensuring crystallization of the alkali metal phosphate, and separation of the crystallized alkali metal phosphate from the mother liquor
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