Gold has unique properties that are widely used in technology. Previously, in order to achieve high signal quality in equipment, quite a lot of it was used. Therefore, now many are trying to extract gold from radio components at home and are very successful. The main thing is to know which radio components contain gold in the greatest quantities, and what methods exist to obtain it.
Very often gold is used in radio electronics to coat tracks and contacts. A considerable percentage of this metal was contained, for example, in Soviet microcircuits - about 1/20 of the part. As is known, gold-containing capacitors are particularly rich in precious metals; You can also try your luck to detect gold in some transistors.
Gold in radio components
There are capacitors the size of a 3-liter jar, the gold content of which is 8 grams. However, it is now almost impossible to obtain such capacitors - they were used only for military needs and classified as “secret”, and they are expensive.
This metal is also contained, although in small quantities, in radio tubes. Next to the cathode there is a grid on which it is applied. Gold plating is placed on such a grid in order to prevent it from overheating, which can lead to lamp failure. Gold plating can also be found on some lighting fixture legs. Naturally, we are talking only about old-style devices.
Now, to save money, parts that were previously gold-plated are replaced with cheap tungsten and contain gold in very small quantities. Previously, precious metals could be found all over the place. Which, by the way, is a problem for people who work in government agencies, since when decommissioning a failed device, it is necessary to hand over all radio components containing precious metals. In many Soviet devices, their number was indicated even in passports.
Also, the precious metal in radio components can be found in devices that were manufactured for military needs. It may also contain the following details:
- gold, silver and platinum may be contained in small quantities in some semiconductors, for example, zener diodes, diodes, optocouplers and others;
- Many connectors were coated with gold several microns thick;
- capacitors used for military equipment also contain it in large quantities;
- radio tubes and transistor substrates.
Which radio components contain the largest amount of gold:
- some diodes from the D226 series;
- microcircuits 133 and 155 series;
- contacts and relays;
- some transistors from the KT series, for example, 603, 630, 117, 3102, 844A, 911 and others.
Gold refining
The main method, which is also called chemical, is essentially etching. All metals that can react with nitric acid dissolve in it. Nitric acid affects gold to a lesser extent, so at the end of this process all that remains is to separate the gold foil.
After the container with the acid is opened, you will notice that the nitric acid has released steam - this indicates that its properties have not been completely lost. The etching process is best carried out in an aluminum pan, since aluminum does not react with nitric acid. If you heat the acid to 60-70 degrees, the process can be accelerated, but this temperature must not be exceeded. All this must be done extremely carefully.
Gold refining They influence the speed at which the reaction occurs and parameters such as capacity and amount of acid. In order for the process to proceed quickly, it is desirable that the acid exceeds the parts by 3 times in volume. It is better to use a pan with high borates for another reason that bubbles will form during etching. In addition, when heated, the acid breaks down into nitrates, which can cause a temporary increase in its volume, and in a small saucepan you run the risk of not following the process.
Before you start etching, you need to remove all excess. Remove cases, contacts that do not contain precious metals, plastics, etc. The frequency of the solution will depend on this, and third-party elements will only pollute it. Then the reaction will slow down, and the solution will have to be changed periodically.
The extraction of gold from radio components can be carried out using another etching method - in aqua regia. Aqua regia is a strong solvent that dissolves almost all substances. It works well for gold. To obtain it, you need to mix nitric and hydrochloric acid. After finishing etching the parts in aqua regia, it will be necessary to add a hydrazine solution. The fact is that the smallest particles of gold have already settled on the bottom, but without this solution it is impossible to notice.
After adding hydrazine, a brown mass is formed. In fact, this metal is gold, only it has a low standard, i.e. the concentration of pure gold itself. Next, such low-grade gold is again etched in aqua regia, and the entire cycle is repeated 3-4 times.
Another way to extract gold
A solution of hydrochloric acid and hydrogen peroxide is prepared from 2 parts acid and 1 part peroxide. Cut sections of boards and microcircuits containing precious metal are placed in a container and filled with this solution for a week; it must be mixed daily. If the process occurs correctly, the solution should darken within a week. There should be pieces of exfoliated gold at the bottom. They will need to be filtered and washed. Methanol or distilled water is suitable for this.
It is not recommended to touch such gold with your hands, as there is a possibility of turning it into dust. For storage, it can be melted in a muffle furnace or using a torch. Before melting the precious metal, the crucible is treated with sodium tetrocarbonate. The crucible must be fireproof; it is best to make it from fireclay clay, but you can also buy it in a store.
You can also use a stove you made yourself. Gold melts at a temperature of about 1060 degrees, so the furnace must be such that it can be reached. It is also desirable that the inertia be small - this will make it possible to regulate the temperature and not exceed the required numbers.
Mining gold this way has some disadvantages. 10% of the metal is lost as a result. In addition, the gold remains with impurities and, accordingly, is not of the highest standard. Further cleaning cycles to achieve greater purity of the metal also lead to the loss of some of it.
And the last method is electrolysis. Gold is extracted in this way if it is deposited on copper or its alloys, such as brass. The metal will need to be placed in sulfuric or hydrochloric acid. During etching, it is worth keeping the temperature at about 20 degrees, and the current density should be 0.1-1 A/dm2. When the current drops, this will indicate that the etching process is complete.
Sometimes the gold obtained from radio components may not be yellow, but, for example, white or green. This may be due to the presence of a large number of impurities. The presence of 5% palladium will make the metal white, and 30% silver will make it green.
How to make money from this?
One of the most profitable ways to make money from precious metals is by buying or selling equipment that contains them. However, here you can have adverse consequences due to violation of the law - do not forget about this when you decide to sell the mined gold.
It is very important to find a source for radio components. In fact, the question is not so simple, because many people are doing this and a sufficient amount of equipment has been melted down. You may need to be smart here and come up with some more original method.
How profitable can refining gold from radio components be at home? Gold is a hard currency that rarely fluctuates. If we estimate the costs of gold mining, we get the following:
- reagents are inexpensive, 10% of the cost of gold;
- the cost of radio components, for which they are most often bought, will be 18% of the cost of gold;
- about another 10% will need to be added for labor;
- everything else is a profit of more than 60%.
Thus, mining gold from radio components is a profitable business. If you establish reception of radio components and acquire a good distribution channel, you can make quite good money. Of course, we are not talking about millions, but you can make this business your main job, as many do. It must be remembered that due to the high chemical inertness, the gold mining process is always associated with risks and harm to health, so you need to be careful and use protective equipment.
Gold is not only a means of payment. Due to its special properties, this precious metal is actively used in various electronics.
Today it is possible to extract gold from chips, circuit boards and other components. And this is quite easy to do. How to mine gold at home depends on your capabilities.
Do-it-yourself gold mining at home is a painstaking process. It requires significant time investment and diligence. A list of what gold can be mined from is given in the following table.
To extract gold from radio components at home, you can use Soviet-made products.
To get gold from old electronics, it is better to give preference to radios. Almost all of their internal elements are coated with this metal to one degree or another. In addition, you will get a lot of precious material if you can find connectors from Soviet electronics.
Particular attention should be paid to radio tubes. If we manage to get models 12P17L, 6ZH1P-EV, 6V1P, then we can start extracting platinum, tantalum and silver “ingots”. Moreover, it is recommended to give preference to radio tubes of the GMI series. From them you can get gold “ingots” weighing up to 16 grams.
Mining gold from radio components is the easiest way to extract precious metals at home.
The high frequency of its distribution in modern electronics is due to the fact that this material has good electrical conductivity. Moreover, it has increased resistance to oxidation.
There are several approaches to how to extract gold from radio components. Some of these technologies have been used for centuries. In particular, they made it possible to obtain gold from sand.
You can get precious metals at home from almost any radio components. This material is actively used today in electrical microcircuits: computers, tape recorders, televisions and much more.
Etching
For a long time, people used mercury to obtain the precious metal. She connects well with this material. However, mercury is highly toxic, so it is not recommended for use at home.
If you intend to mine gold from microcircuits, you should pay attention to the etching method. To obtain precious metals, you must first prepare the following components:
- any plastic container;
- container made of heat-resistant glass;
- scales (preferably laboratory scales);
- cotton fabric that will act as a filter;
- fireproof structure through which molten metal can be taken (crucible);
- electric stove;
- rubber gloves.
Most often, gold is extracted from microcircuits by etching it. This technology involves the use of an oxidizing agent consisting of hydrochloric nitric acid. Both components must be mixed in a 3:1 ratio. This oxidizing agent has been used for several centuries. Among chemists, this mixture is called “Royal Vodka”.
This acid actively corrodes organic and inorganic materials, so your hand should be covered with a rubber glove when handling microcircuits.
The oxidizer must be poured into a glass container, into which the radio components are then placed. The latter should first be cleaned of various impurities: plastic, dirt, etc. Next, the container is placed on an electric stove and heated. As a result, the liquid should acquire a bright green tint.
The next stage involves the extraction of the precious metal. This will require a 0.5% hydroquinone solution. For every 100 ml of water you need to take no more than 5 grams of the substance. The resulting composition should be carefully and slowly mixed with hydrochloric nitric acid at the rate of 1 ml of hydroquinone solution per 100 ml of “Royal Vodka”. After completing the described procedure, the composition is left for no more than four hours.
During this time, a gold deposit forms at the bottom of the container. Now, through evaporation and drying, we extract the material. To obtain a gold bar, you will need a crucible and drills, which can be borrowed from gas welders. The latter must be added to the resulting precipitate.
Electrolysis
Electrolysis is used when gold is extracted from electrical components. This method is considered more complex compared to the evaporation method.
However, electrolysis makes it possible to obtain gold with fewer different impurities.
The extraction process proceeds as follows:
- We fill the glass container with sulfuric or hydrochloric acid in an amount sufficient to accommodate the prepared microcircuits.
- We place two iron or lead plates in the container. During the electrolysis process they will play the role of a cathode. This method uses microcircuits as an anode, from which the precious metal is extracted.
- Both plates are connected using copper wire.
- After connecting the copper wire, we lower the prepared microcircuits into the container. Next, we pass an electric current through it - no more than 0.8 amperes for every 1 sq. dm of area.
- During the electrolysis process, the precious metal gradually settles on the plates. After they have acquired a yellow tint, the current is turned off.
Finally, you need to remove the gold from the metal plates. To do this you need to use the etching method. If the process is slow or the amount of deposited gold is not enough, it is necessary to increase the current value.
Both technologies do not require significant time and money. If you have a sufficient number of microcircuits, they can make good money. The result of all work will be gold, which contains many impurities. To remove them, you can use a method known as refining. It involves the use of various acids, through which foreign elements are removed from the precious metal.
If Soviet radio components were used in the electrolysis process, then refining allows us to ultimately obtain 999 purity material.
Electrolysis and etching are two of the most effective and relatively simple ways to obtain precious metal at home. Both technologies do not require serious training. At the same time, during metal etching, it is necessary to follow safety rules and avoid skin contact with acids.
Safety precautions
It is important to understand that when working with acids, they can cause serious burns. In particular, the etching process takes about 6 hours, during which a large amount of nitrogen oxide is released into the atmosphere. Therefore, it is highly not recommended to mine gold in an unventilated area.
Nitric oxide that enters the respiratory system can be fatal.
When working with acids and electricity, precautions must be taken. Before you start mining gold, you should wear rubber gloves, if possible safety glasses, an apron and a respirator. The latter can be gauze soaked in water.
Metal processing
It was said above that at the end of the etching process, it is necessary to add borax and soda to the resulting metal. The use of these substances makes it possible to eliminate material loss at the next stage of processing and achieve a beautiful shine that the finished ingot will emit.
When processing the resulting gold, it is necessary to use steel or cast iron products.
In addition, during the casting process it is necessary to ensure that the metal flows in a thin and continuous stream. At the end, the gold should cool to room temperature. Only after this can the casting mold be disassembled.
The result is a material with a rough surface. Now it needs to be processed and given the desired look. Polishing of the material is carried out using special pastes and soft rags. For this, for example, felt and toothpaste are suitable.
Is it worth mining gold at home?
Mining gold from radio parts has certain benefits, despite the fact that the whole process seems lengthy and labor-intensive.
However, you need to understand that to obtain the precious metal in sufficient quantities you will need a lot of microcircuits and other electrical parts. In addition, you should stock up on a large amount of acids.
You should also note that only licensed companies buy gold. Similar rules apply to the refining process. Moreover, purifying gold from impurities with acids on your own is prohibited by law. There is a corresponding article in the Criminal Code.
The gold obtained using the described methods can be used not for sale, but as solder in the reconstruction of jewelry. Restoration of such products is carried out using tinol or a special paste, which increases the strength of the solder.
Modern microcircuits are made using gold, which, with the appropriate materials and acids, can be mined at home. The resulting precious metal cannot be resold in the future, however, it is suitable as solder when restoring jewelry.
know that gold (chemical symbol Au) is also used in the production of electronics (including computer components) due to its excellent thermal and electrical conductivity, resistance to oxidation (that is, rust) and stability. The computer industry consumes several hundred tons of this metal annually.
The precious metal can be found in almost all computer components - processors, motherboards, expansion cards, memory DIMMs, and so on. Of course, every component uses a tiny fraction of gold. But gold prices have skyrocketed in recent years, making it increasingly more cost-effective to extract gold from old components than to mine it the traditional way. That is why specialized companies have appeared on the market doing just this. Now you will learn how you can get gold from old motherboards with your own hands. Please note: the chemicals we used in this demonstration are very dangerous, especially in the concentrations we used. Therefore, we do not recommend repeating this experiment at home. The article is educational in nature.
Gold is present in many elements of the motherboard: IDE connectors, PCI Express, PCI, AGP, ISA and other ports, jumpers, processor socket and DIMM slots (SIMM on older motherboards).
All these connectors are often coated with a thin layer of gold several microns thick.
The first stage of our experiment is to remove all these contacts and connectors. We will need wire cutters, pliers and a cutter, a flathead and Phillips screwdriver, as well as some time.
To carry out experiments, you need a large number of contacts - our “donor” motherboards provided them.
Chemical reagents and tools are also needed.
Electrolysis
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To get a few micrograms of gold deposited on the contacts, we need an electrolytic cell. 95% concentrated sulfuric acid is poured into the bath. The cathode is made of lead, the anode is made of copper. The contacts (raw materials) are connected to the anode, which we made in the shape of a basket.
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When we run electric current through the cell (we used a regular battery charger), the copper on the anode (and on the contacts) dissolves and deposits on the lead cathode. The gold, no longer bound to the copper, forms a sediment at the bottom of the cell. It should also be noted that during this process the temperature in the bath increases significantly.
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After the gold has been separated from the contacts, the bath must be allowed to settle. You should then remove as much of the sulfuric acid as possible, after which you can begin to dissolve the residue at the bottom of the electrolytic cell.
Dilution
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Be careful and always pour the acid into the water, and not the other way around! If you make a mistake, the first drops of water that come into contact with the sulfuric acid will instantly evaporate, and the acid may splash out.
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We have a solution of sulfuric acid, various metals (including gold) and waste that needs to be filtered. Why not filter the acid directly, without diluting it? Simply because paper filters cannot withstand concentrated sulfuric acid.
Dissolution
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A mixture of different metals and waste will remain in the filter. Now we will dissolve all this in a mixture of 35% hydrochloric acid and 5% chlorine bleach (sodium hypochlorite), in a 2:1 ratio.
2 HCl + NaClO -> Cl 2 + NaCl + H 2 O
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Be careful! This reaction is exothermic and releases chlorine, a very dangerous gas. Chlorine was used as a chemical weapon in the First World War.
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In fact, we will use the chlorine released as a result of mixing hydrochloric acid and chlorine bleach to dissolve gold in the form of gold chloride III.
2 Au + 3 Cl 2 -> 2 AuCl 3
Filtering again
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Now we need to filter again. The filter will retain all waste, leaving only the gold chloride solution III.
Precipitation
To obtain metallic gold, we need to precipitate it in solution. For this purpose we will use powdered m sodium etabisulfite. If there is water sodium metabisulfite gives sodium bisulfite.
Na 2 S 2 O 2 + H 2 O -> 2 NaHSO 3
It is sodium bisulfite that will allow us to precipitate gold.
3 NaHSO 3 + 2 AuCl 3 + 3 H 2 O -> 3 NaHSO 4 + 6 HCl + 2 Au
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We need to let the solution settle, after which we will get a gray powder at the bottom of the beaker. Don't lose a single grain - it's metallic gold!
Properties of metals
Silver- malleable ductile metal, density 10.49 g/cm 3 ; °t pl. = 960.5 °C. The polished surface has a reflectivity of up to 98%. Atomic mass 107.88.
Gold- malleable ductile metal, has low hardness. Density 19.3 g/cm3; °t pl. = 1063.4 °C. Atomic mass 197.2.
Gold is contained in a large number of radio components, some on the surface, others hidden under the housing (usually copper), or in both combinations.
Contained mainly in domestic radio components (especially in parts of the Soviet period), if imported, it is in very small quantities.
More information about radio components containing gold can be found in data sheets for radio equipment, in specialized literature on radio engineering, as well as on amateur radio sites on the Internet.
For example, some radio components containing gold:
Transistors - KT117; 2T203; KT630; KT312; KT602; KT603; KT605; KT608; KT3102; KT3844A.
Microcircuits - 133 series, 155 series, etc.
Diodes D226 of some series.
Methods for extracting gold from radio components
To extract gold, it is important to know its quantity in a particular part; the price of the radio component upon purchase, the amount of reagents for its extraction, the required time and, of course, profitability depend on this.
Electrolysis method.
Gold coating can be removed from brass and copper by anodic dissolution of gold in hydrochloric or sulfuric acid at a temperature of 15-25 ° C and a current density of 0.1-1 A/dm 2. Cathode – lead or iron. The end of dissolution is determined by the drop in current strength.
Another way:
Mix 1 l. sulfuric acid (density 1.8 g/cm3) and 250 ml of hydrochloric acid (density 1.19 g/cm3). Before immersing radio components, the mixture is heated to 60-70 °C. Having lowered the parts into the mixture, add a small amount of nitric acid to form aqua regia.
Methods for extracting silver from radio components
Two ways to use silver in radio components:
1.
Silver is applied to the contacts or housing (outside or inside) of the part, in a thin – “micron” layer.
2.
Silver contained in relay contacts in its pure form.
Silver can be removed from radio components in the following way:
You can remove silver from brass and copper parts using a mixture of solutions of sulfuric and nitric acids, taken in a ratio of 19: 1.2, heated to 80 °C. Silver can be recovered from this solution by reducing it with an equivalent amount of zinc dust or turnings. Silver can also be extracted by carefully acidifying the electrolyte with small doses of hydrochloric acid. The operation is extremely dangerous and must be performed in a fume hood. Silver is precipitated in the form of a white curd sediment of silver chloride, which is allowed to stand for at least a day, then a test is made to ensure the completeness of silver precipitation by adding hydrochloric acid to a filtered sample of the solution. The silver chloride precipitate is filtered through a thick cloth, washed and dried at a temperature of 105-120 °C.
Here is some data on the silver content in radio components:
Fuse link VP1-1 for 1000 pcs. – 15.611 gr.
Capacitors - K15-5 per 1000 pcs. – 29.901 gr. K10-7V for 1000 pcs. – 13.652 gr.
Silver is contained in such large quantities in radio components produced during the Soviet era.
Silver from contacts.
Several types of relays: RES6 for 1000 pcs. – 157 gr. RSCH52 for 1000 pcs. – 688 gr. RKMP1 for 1000 pcs. – 132 gr. RVM for 1000 pcs. – 897.4 g.
The fineness of the silver contained in these parts is sr999
To extract silver from these parts, it is necessary to remove the case and separate the contact part, then the silver contacts are removed using scissors or wire cutters, depending on the density of the material on which the contact is attached. If desired, the contacts can be melted into an ingot at home directly on a gas stove (you can make a porcelain crucible for this) because °t of silver melting = 960.5 °C.
When purchasing relays, be sure to make sure that they contain silver, because... different batches contain different amounts of it, or none at all.
Reagents for the extraction of precious metals are freely sold in specialized stores.
Gold-plated PCB contacts; photo from Wikipedia
Briefly about profitability
Let's take the KT605 transistor as an example - three legs and the body are gold-plated. One transistor contains 27.5537 mg of gold.
From 100 transistors you will get 2.75537 g. 999 gold.
When melted, approximately 10% copper can be mixed into gold (you will get 585 gold).
1. Place a piece of zinc in a glass or enamel vessel (a glass from a regular battery is zinc), the precious metal items to be cleaned and pour an aqueous solution of soda ash (baking) soda on top - 1 tablespoon of soda per 0.5 liters of water.
2. It is good to clean silver items with chalk and ammonia, then rinse with water and wipe dry.
Traditional methods for extracting precious metals from radio components
Getting silver
Any relays and microswitches of the MP type contain the largest amount of silver... So from one relay you can get from 0.5 to 3 g of almost pure silver, and from a microswitch 0.31 g. In these products, silver is used for contacts. You can remove the silver using regular pliers.
For reference: Radio silver in purity corresponds to approximately 817 purity.
Getting gold
Gold can be obtained from radio components using its property of not dissolving in acids.
The prepared raw materials (for example, contacts and terminals from radio components) are thrown into a glass container with nitric acid (sulfuric acid is possible, but the result is worse), the acid dissolves all foreign substances, and the gold remains as a sediment. It must be carefully separated from the acid by pouring it into another container, and then neutralize the resulting precipitate with a solution of baking soda until the reaction stops (the reaction is accompanied by hissing). The resulting precipitate, consisting of gold dust and a small amount of impurity, must be dried and smelted into a small ingot.
Extraction of silver from alloys, mirror glass, ash of photographic materials, etc.
Many people do not even suspect that the objects around them, which we unhesitatingly send to the landfill, can become a source, sometimes even of good profit. Here are a few such examples with descriptions of methods for extracting precious metals from them:
1. The emulsion layer is removed from glass photographic plates in a hot soda solution, and other photographic materials are burned in porcelain dishes. True, when burned, some of the silver will evaporate with smoke. To reduce losses, it is best to burn photographic materials with a smoldering fire or extract silver with sodium hyposulfite.
2. Mirror fights and Christmas tree decorations also contain a large amount of silver: mirrors - from 3 to 7 g/m2, toys - from 0.2 to 0.5% of the mass of the fragments. To remove the silver-containing layer from a mirror glass, it is placed in an acid-resistant container, filled with a hot solution of hydrochloric acid and subjected to mechanical treatment: in other words, it is turned until the silver-containing layer is completely separated from the glass. In industry, a rotating drum is used for this purpose.
3. To recover silver from the ashes of photographic materials, you will need a muffle furnace and heat-resistant crucibles that can withstand temperatures of thousands of degrees. The ash is thoroughly mixed with soda and broken glass in the following proportions: 30% ash, 65% sodium bicarbonate and 5% broken glass. The charge composed in this way is sintered at a temperature of 1200°C. The melt is poured into a cast iron mold coated with iron oxide powder. You can cool the melt in a crucible, but then you will have to break it, and at the bottom you will end up with an ingot of pure silver.
4. And this is a method for separating silver from a silver-copper alloy, described in the 20th volume of the “Technical Encyclopedia”, published in 1935: the product is dissolved in nitric acid, hydrochloric acid is added, the precipitated silver chloride is washed with water and metallic silver is recovered from it through interaction with zinc and dilute sulfuric or hydrochloric acid.
5. Another method was described in great detail in Do-It-Yourself magazine (No. 4, 1990). It consists of the following: The silver-containing product is thoroughly cleaned of oxides and washed first with a warm alkaline solution, and then with ordinary water. After this, the product is poured with 10% nitric acid until it is completely dissolved. The solution thus contains a mixture of silver and copper salts. The solution is evaporated, and the resulting powder is calcined in a porcelain cup, as a result of which copper nitrate turns into insoluble copper oxide. The completion of this process is determined by the cessation of the release of bubbles of a very caustic gas from the surface of the melt. Now the melt is cooled and dissolved in 2 parts of distilled water; a transparent solution containing pure silver nitrate is removed from the sediment - well, we have already discussed how to recover metallic silver from salts. In the described process there are some difficulties, such as: manipulations with nitric acid, toxic volatile compounds and evaporation of large volumes of solutions. However, such problems can be easily resolved in laboratory conditions.
6. Silver coatings (including those applied chemically) and silver alloys on bases of copper, nickel silver, brass, tombac, cupronickel and steel are removed in a mixture of concentrated sulfuric and nitric acids with a volume ratio of 19:1 at a temperature of 40 - 60 ° C. The solution is protected from dilution and regularly adjusted with nitric acid, which is used in the process of dissolving the coating.
Silver is removed from the surface of copper and its alloys by anodic treatment in a solution of the composition, %:
Sulfuric acid H 2 SO 4 (density 1.84 g/cm 3) – 91
Sodium nitrate (sodium nitrate) NaNO 2 – 3
at a temperature of 20-50°C and a DC source voltage of 2-3 V. Lead is used as cathodes.
Removing silver from parts with a thin coating thickness is usually carried out at a temperature of 40-50°C in a solution of the composition, g/l:
Potassium iodide KI – 250
Metallic iodine I 2 - 7
The alloy of silver and antimony is removed from the same parts in a solution of the composition, g/l:
Potassium iodide KI – 250
Metallic iodine I 2 - 7.5
Nitric acid HNO 2 (density 1.41 g/cm 3) - 150 ml/l
Publication source: lifeinfo.co.cc
The so-called “gold mining” from radio components is also possible at home. To do this, it is necessary to collect a certain amount of gold-containing radio components, clean them mechanically and carry out refining, that is, separation of gold from other noble and non-precious metals. However, before you begin to perform these manipulations yourself, you should be reminded of several unpleasant points.
- You should not immediately count on great success, since in most radio components the gold content is very negligible, and in order to get a gram of this precious metal, you will need to collect a kilogram, or even more, of transistors and microcircuits. Therefore, you should immediately be prepared for such a result and not have any great illusions.
- Working with chemical reagents without practical experience is fraught with poisoning from acid fumes.
- Legal factor. Activities in the processing of precious metals without the appropriate license are regarded as a criminal offense, therefore, it is necessary to have confidence that the actions taken will not entail liability.
So, elements such as microcircuits, transistors and connectors are suitable as experimental materials for home refining of gold from radio components. First, you should make sure which brands contain a protective layer of gold, so as not to simultaneously refining silver.
For home gold mining from radio components, the etching method is most suitable due to its simplicity and accessibility. The reagent used is a mixture of concentrated nitric and hydrochloric acid, called aqua regia. Their ratio should be equal to 1:3. It is better to prepare this mixture immediately before the etching procedure, since during long-term storage this mixture loses its oxidizing properties.
The separated gold, unlike silver, does not precipitate, but floats in the form of foil on the surface of the acids. In order to filter the foil, you should use a cloth; gauze in this case is too impractical.
The resulting foil must be smelted into an ingot, for which a fireproof melting container is used - a crucible. At home, a crucible can replace ordinary bricks. During the melting process, borax, a white sodium tetraborate powder, is added to the gold foil. The ingot obtained during the melting process has a purity of 99.99%.