What is silver nitrate?
It is not known exactly when, but it is known for certain who discovered this substance. Carried away by the search for the elixir of immortality, Jan Baptiste Van Helmont, the famous Belgian chemist discovered what he believed was one of the components capable of giving a person immortality. Alas, the elixir was probably multi-component, but the resulting salt received a very interesting name - lapis infernalis or “hell stone”.
But that was just the beginning of the story. As it turned out, after continuing his research, Van Helmont discovered that it was silver nitrate that had an antiseptic effect. In large quantities, if it comes into contact with the skin, it causes burns and tissue death. But in small doses or in the form of a solution, it can disinfect the skin and even stop bleeding. In the 16th century, such drugs were valued more than gold.
What does silver nitrate look like?
In fact, the Belgian managed to obtain whitish crystals related to salts of nitric acid containing silver. True, there was not even a hint of silver shine left in the crystals.
Silver in Rus'
In ancient Rus', the measure of the value of various items was bars of silver. In cases where an item of trade was worth less than the entire bar, a part corresponding to the indicated value of the item was cut off from it. These parts were called “rubles.” It was from them that the name of the currency adopted in Russia, the ruble, came.
As early as 2500 BC, Egyptian warriors used silver to treat battle wounds. They applied thin plates of silver to them, and the wounds healed quickly. In the Russian Orthodox Church, holy water for parishioners was kept only in silver vessels. Since the middle of the last century, such industries as photography, electrical engineering, and radio electronics have appeared, which led to a sharp increase in demand for silver and its withdrawal from monetary circulation.
The high electrical conductivity, good ductility, low melting point, and low chemical activity of silver also interested radio engineers.
Formula and properties
Since silver nitrate is a salt of nitric acid, its formula is expressed as follows:
AgNO3
Where Ag is silver, and NO3 is the remainder of nitric acid. Despite the fact that this is a salt, it has retained many of the properties of the acid itself - HNO3.
As a result of the chemical reaction of acid and silver, a crystalline substance is formed - the crystals are almost regular orthorhombic in shape. Salt has a high density of 4.3 grams per cubic centimeter. This figure is slightly higher than that of other minerals; most salts have a density of up to 3.6 grams per cubic meter. cm.
It is easy to obtain a solution of silver nitrate from salt - it simply dissolves phenomenally in water. At room temperature it dissolves completely. Moreover, just 100 ml can absorb 222 grams of crystals. But dissolution in alcohol is not so simple; only 2.2 grams can be dissolved in 100 grams.
When heated, salt begins to melt at 209 degrees Celsius. At 299 degrees, the decomposition of the substance begins.
Highest standard silver
In the final part of the refining, you need to build an electrolytic bath.
The bottom of a cut lemonade bottle can be used as a container. The height of the container must be such that it can hold at least 1 liter of solution. A block made from silver cement is placed in a tea filter. A ribbon of pure silver is welded to it in advance and clings to the middle of a brass stick. It is necessary to put insulation on it, since it will play the role of an anode. The stick is threaded through the edges of the tea filter and placed above the bathtub.
The fork handle is wrapped with electrical tape, and its end is bent so that the fork can be hung on the edge of the bath. The result was a miniature electrolytic container.
The solution with silver nitrate is diluted with distilled water in a 1:1 ratio and poured into the bath. The liquid should not touch the joint between the silver bar and the tape, otherwise the metal will dissolve.
The plug is placed in the bathroom, a “minus” cable goes from the power supply to it, and a “plus” cable goes to the brass stick. Make sure that the current voltage is no more than 4-8 W and the power is 5 A.
The reaction begins immediately: the walls of the bath are covered with silver crystals, and the bar gradually becomes smaller. The tea filter is used to collect suspended matter and debris. The crystals should not reach the tea bag, otherwise a short circuit will occur.
Place the electrolyte solution in a container. The resulting crystals need to be washed several times in water, dried and fused into one piece, as was previously done with silver cement.
The refining is complete, as a result you have received 999 silver, from which you can make original jewelry.
Source
Preparation of silver nitrate
The traditional method for producing silver nitrate is to dissolve metallic silver in high concentration nitric acid. This is the standard method that the great Belgian himself used. Today, this method is used infrequently, it is very dangerous; during the reaction, nitrogen oxides, a very toxic substance, are formed.
The industry uses a method of etching silver by heating acid. After completion of the reaction, the resulting solution is evaporated to a concentrate. And then the process of crystallization.
New methods eliminate the use of acid concentrate and avoid the evaporation process. For this, a 98% solution of nitric acid is used, and heating is used by releasing the energy of the chemical reaction itself. To do this, ozone O3 is introduced into the solution, and sometimes hydrogen peroxide is used. During the reaction, crystallization of silver nitrate begins immediately.
Silver cement
The task of the next stage will be to obtain metal from silver nitrate.
For this you will need copper. Since silver nitrate has a blue tint, it already contains copper. The lighter the solution, the better it is. You can use ordinary pipes as a source of copper. Old water pipes will do, they just need to be cleaned of dirt and deposits. Pieces of copper pipes are placed in a silver solution. Copper serves as a catalyst and speeds up the process. The pipes quickly become covered with a silver coating – cement. Periodically, they need to be removed and the cement shaken into a jar of solution. Copper pipes gradually dissolve, releasing copper to silver nitrate. If there are not enough of them, new ones should be added.
The pipes can be left in this position for 1-2 days, periodically checking them and making sure that no foreign objects get into the container. The process ends with the formation of a sediment of silver cement at the bottom of the container and the cessation of the reaction.
The solution must be filtered. To do this you will need a funnel and several coffee filters. The sediment must be washed at least 5 times with clean water. Moisture evaporates from the remaining cement (you can wait until it evaporates naturally).
Do not rush to throw away the solution after filtration: it still contains silver. Add some table salt to it and keep it aside. After some time, silver chloride will appear in the container.
Silver cement, consisting of crumbs and dust, must be collected into a single piece. This is done by heating it in a crucible. You need to heat it evenly and slowly, otherwise the silver dust will fly in different directions. The silver obtained at the second stage at home is not pure; it can be conventionally designated as 980 fineness. The bar will undergo further purification by electrolysis.
Scope of application of silver nitrate
First of all, silver nitrate is an excellent reagent and is often used in chemical laboratories for experiments.
In medicine, the substance is used as a local disinfectant. For example, in dentistry, caries is treated with microscopic doses of silver nitrate; salt simply burns out the area affected by bacteria.
By the way, it is known that about 650 types of bacteria and microorganisms are actively destroyed by silver nitrate. Among the diseases in the treatment of which silver nitrate is used are diseases of the internal organs, oral cavity, ulcers, diseases of bone tissue. Silver nitrate is often used to disinfect limb wounds in disaster areas.
Salt-based drugs are produced that ensure the binding of proteins, which in the body are responsible for covering nerve endings. The use of drugs provides an analgesic effect.
Some drugs contain silver nitrate in minute doses. For example, silver nitrate is found in drugs used to treat gastritis. In this case, the permitted age of use starts from 3 years.
In everyday life, people indirectly encounter silver nitrate almost every day. When buying a newspaper or opening a book, few people realize that in printing, silver nitrate is used for etching the original proofs - the plates from which newspaper issues are printed.
Silver nitrate is used in printing
Even when wearing a T-shirt with a bright print, it is difficult to guess that silver nitrate is also used to apply the design to the fabric or leather.
Silver nitrate is used in the production of higher capacity batteries. Ocean-going ships and submarines cannot do without such batteries.
The manufacture of lenses for binoculars, telescopes, optical instruments and even ordinary light-protective glasses cannot be done without treating the glass with silver nitrate. Even in a lady's handbag where cosmetics are stored there is glass treated with nitrate - a mirror. What can we say about scientific telescopes, which have simply fantastic mirror diameters.
However, a number of tasks for this substance are consigned to history. Today, with the massive transition from conventional film cameras to digital ones, the very concept of photography as an art is disappearing into oblivion. And along with this era, an important area of application of silver nitrate is disappearing - photoreagents.
But for jewelers, the damn stone will always be important - it is used to process costume jewelry and jewelry.
Silver nitrate price
When it comes to the price of this dangerous substance, you need to understand for what purpose and in what volume the reagent is purchased. For individual use, you can buy salt in small quantities. Many enterprises offer small volume packaging - 40-50 grams. But this is for individual buyers. For enterprises and organizations, the volume of supplies is specified in tons or even tens of tons.
Prices for the drug offered today for individual buyers:
- Packaged in 1 gram – from 40 rubles;
- Packaging up to 50 grams – from 43 rubles per gram;
- For industrial consumers the price is 41,900 rubles per kilogram.
In Moscow you can buy silver nitrate at a price of 32 rubles per 1 gram*.
Obtained in the laboratory
The working solution (electrolyte) can be spent fixer, which contains silver cations. The halides of this metal form a series of complex salts with thiosulfate. During electrolysis, silver, a metal, is released at the cathode. Obtaining it in this way is accompanied by the release of sulfur, which leads to the appearance of a thin black layer of silver sulfide on its surface.
Preparation of silver nitrate
The preparation of silver nitrate in the laboratory is usually carried out with the strictest precautions. The fact is that the work involves the use of acid and the release of a large number of toxic substances during the reaction. Therefore, it is necessary to prepare the workplace for the experiment:
- It is necessary to clean the work area from foreign substances, especially those containing alkalis;
- Turn on the hood;
- Wear safety glasses to protect your eyes;
- Wear a filtration mask or facepiece respirator;
- To protect your hands, you should use laboratory gloves and a gown.
- You cannot conduct the experiment in shorts, flip-flops or bare feet.
When creating silver nitrate, you must wear safety glasses and a respirator.
To work, you need a ventilated room and a wide laboratory table.
The influx of clean air and the removal of contaminated air is an important point in the preparation of silver nitrate - during the reaction, a large amount of toxic steam is released, which quickly reaches a lethal concentration in a closed room. It is imperative that people around you be warned about your intention to work with nitric acid. This will help to avoid injuries on the one hand, and if there is a threat to life, then someone will definitely help and call for help
How to make silver nitrate at home?
In order to make silver nitrate we need silver Ag and nitric acid HNO3. As silver, you can take various silver objects (spoons, coins, chains, silver contacts). Place the silver in a glass of nitric acid. As a result of the chemical reaction, the silver immediately begins to darken, and gas bubbles are released. The resulting gas is brown vapor of nitrogen dioxide (NO2). During the reaction, the color of the solution will change, which means that there are impurities in the silver. In order to speed up the chemical reaction, you can place a glass of nitric acid in hot water. After this, we take out the rest of the silver, and place the glass with dissolved silver and nitric acid in the refrigerator for 30 minutes to allow the silver nitrate crystals to precipitate. After half an hour, we take the crystals out of the refrigerator, filter and dry them. The resulting crystals are white and will be silver nitrate.
