Cleaning rust and restoring metal in a carbon environment. Rust remover How to restore rusty metal

Often you come across rusty iron products that fall apart in your hands. How to restore iron? How to restore a found rusty iron item?

I discovered an interesting preservation method, restoring rusty iron. I'll use it in the near future.

Even if the item found looks more like a large piece of solid rust, do not despair. There is a way to bring a found treasure back to life. This is the restoration of iron in carbon environment. This is a very simple method that is accessible to everyone.

For restoration you will need an iron box with a bolted lid, crushed charcoal (on which we grill kebabs) and a rustic stove.

So, in order. The find, first of all, must be preserved in the form in which it was discovered, with pieces of earth, if you dug it up, and rust. There is no need to try to “forcibly” clean it from the soil or from flaking rust mechanically or in any other way.

If you catch an object from a pond, wrap it in bandages, like a mummy. This will prevent the metal from delaminating when drying.

IN iron box, let’s call it “reactor”, crushed charcoal, so that our iron objects do not come into contact with the walls of the reactor. We completely fill the reactor with coal, close it with a lid and place it in a heated oven on a bed of orange coals and cover it with firewood on all sides. pay attention to temperature regime, the “reactor” must be red-hot.

After about 2 hours, you need to remove the “reactor” from the oven and allow it to cool completely. Please note that only completely dried items are loaded into the reactor.

After the reactor, items are cleaned in NaOH alkali (for example, “Mole” pipe cleaner) and washed in acidified water. If necessary, the restoration procedure in the reactor can be repeated several times.

The method is to reduce rust, that is, iron oxide Fe2O3, to free iron in a carbonaceous environment. Sergey Dmitriev spoke about this method.

Http://www.clubklad.ru/blog/article/2399/

In every home, among household utensils and interior items, there are materials, tools or parts made of metal. They are practical, wear-resistant, but sooner or later they corrode. How to prevent this process? How to treat metal so that it does not rust?

There are several methods that can extend the life of iron parts and objects. Most effective method– this is processing chemicals. These include inhibitor compounds that coat metal objects with a thin film. It is this that allows you to protect the product from destruction. Such drugs are often used for preventive purposes.

Let's look at the main methods to prevent corrosion:

• mechanical rust removal;
• chemical treatment;
• anti-corrosion substances;
• folk remedies for rust.

Mechanical cleaning

To perform mechanical anti-corrosion treatment manually, you need to purchase a metal brush or coarse abrasive sandpaper. Items can be processed dry or wet method. In the first option, the rust is usually scraped off, and in the second, the skin is wetted in a solution of white spirit or kerosene.

You can also mechanically clean rusting materials using hardware, such as:

• Bulgarian.

• Sander.

• Electric drill with a metal brush attachment.

• Sandblasting machine.

Undoubtedly, manually You can clean the surface more thoroughly. But it is applied to small areas. Hardware materials will speed up the workflow, but they can also harm the parts. During processing, a large layer of metal will be removed. Most best option, which will carefully remove corrosion – sandblasting machine. Such equipment has its own small drawback - high cost.

When processing objects with sandblasting equipment, the metal surface is not ground down, but retains its structure. A powerful jet of sand gently removes rust.

Treatment with chemicals

Chemicals are divided into two groups:

• Acids (the most popular is phosphoric acid);
• Rust converters.

Acids often mean ordinary solvents. Some of them have an orthophosphorus composition, which allows you to restore rusting material. The method of using acid is quite simple: wipe the iron or metal from dust with a damp cloth, then remove any remaining moisture, apply a thin layer of acid to the object with a silicone brush.

The substance will react with the damaged surface, leave it for 30 minutes. When the part is cleaned, wipe the treated area with a dry cloth. Before use chemicals wear protective clothing against rust. During the work, take care that the composition does not get on you. open areas skin.

Orthophosphoric acid has a number of advantages over other compounds. It is gentle on metal objects, removes rust and prevents the appearance of new areas of infection.

Rust converters are applied to the entire metal surface, thereby forming a protective layer that will subsequently prevent corrosion of the entire item. After the composition has dried, you can open it with paint or varnish. Today, a large number of converters are produced in the construction industry, the most popular of which are:

• Berner rust modifier. Designed for processing bolts and nuts that cannot be dismantled.

• Rust neutralizer VSN-1. Used on small areas. Neutralizes rusty areas, forming a gray film that can be easily wiped off with a dry cloth.

• Aerosol "Zinkor". The degreasing composition allows you to restore rusted objects and forms a protective film on the surface.

• This is a fast-acting gel, does not spread, and removes all types of corrosion.

• Converter SF-1. Used for cast iron, galvanized, aluminum surfaces. Removes rust, after treatment protects the material, extends its service life up to 10 years.

Most anti-corrosion substances consist of toxic chemical compounds. Make sure you have a respirator. This way you will protect the mucous membranes of the respiratory tract from irritation.

Application of anti-corrosion compounds

One of the leading chemical companies Rocket Chemical offers a wide range of anti-corrosion products. But the most effective is considered to be a line of five substances:

• Long acting inhibitor. Metal products treated with the substance may be all year round on the street. At the same time, they are protected from any weather influences that provoke a corrosion process.

• Protective lithium grease. The material is applied to the surface to protect and prevent rusting. It is recommended for application to door hinges, chains, cables, rack and pinion mechanisms. Forms a protective film that is not washed off by precipitation.

• Waterproof silicone grease. Thanks to its silicone composition, the lubricant is applied to metal surfaces with elements of plastic, vinyl and rubber. Dries quickly, forms a thin, transparent, non-sticky coating.

• Anti-rust spray. The drug is used to treat hard-to-reach places, is intended for deep penetration, and protects products from the reappearance of rust. Widely used for processing threaded connections and bolts from corrosion.

• A solution that removes corrosion stains. The solution contains non-toxic substances. It can be used for processing building materials, and various kitchen utensils. How to prevent a knife from rusting? Feel free to treat it with the solution, leave it for 5 hours, then wash it well with detergent. And the knife is ready for use again.

On video: WD-40 rust destroyer.

Folk remedies

What to do if you are allergic to chemicals and rust metal objects need to be cleaned? Don't despair, there are plenty folk remedies, which are in no way inferior to factory-made drugs:

• Cilit is a product for cleaning plaque and rust in the bathroom and kitchen. This gel is often used for taps, mixers, if the knife becomes rusty, or other metal appliances. Also used to remove corrosion from any iron and metal products. But remember that its chemical composition can corrode the paint.
• A solution of kerosene and paraffin. It must be prepared in a ratio of 10:1. Leave to brew for a day. Afterwards we treat the items damaged by rust and leave for 12 hours. Finally, you need to clean the treated area with a dry cloth. This method is suitable for building materials and tools.
• Coca Cola against rust. Its alkaline composition eats away corrosive stains. To do this, immerse the item in a container of drink or dampen a rag. Leave for a day, then rinse the item under running water.

As you can see, nothing is impossible. Therefore, choose a more acceptable option for yourself in order to return your metal products to their original appearance.

Top 5 ways to remove rust (1 video)

Due to the appearance of a certain gas that causes an instant burning cough. This article is the identification of this gas. The article is replete with formulas; the number of formulas is due to the non-trivial nature of both the electrolysis process itself and the rust itself. Chemists and chemical engineers, help bring the article to full compliance with reality; it is your duty: to take care of your “little brothers” in case of chemical danger.

Let there be iron Fe 0:
- if there was no water on Earth, then oxygen would arrive and make oxide: 2Fe + O 2 = 2FeO (black). The oxide oxidizes further: 4FeO + O 2 = 2Fe 2 O 3 (red-brown). FeO 2 does not exist, it is an invention of schoolchildren; but Fe 3 O 4 (black) is quite real, but artificial: supplying superheated steam to iron or reducing Fe 2 O 3 with hydrogen at a temperature of about 600 degrees;
- but there is water on Earth - as a result, both iron and iron oxides tend to turn into the base Fe(OH) 2 (white?!. It gets dark quickly in air - isn’t it the point below): 2Fe + 2H 2 O + O 2 = 2Fe(OH) 2, 2FeO + H 2 O = 2Fe(OH) 2;
- it’s even worse: there is electricity on Earth - all the named substances tend to turn into the base Fe(OH) 3 (brown) due to the presence of moisture and potential difference (galvanic couple). 8Fe(OH) 2 + 4H 2 O + 2O 2 = 8Fe(OH) 3, Fe 2 O 3 + 3H 2 O = 2Fe(OH) 3 (slow). That is, if iron is stored in a dry apartment, it rusts slowly, but holds on; increasing the humidity or getting it wet will make it worse, but sticking it into the ground will be really bad.

Preparing a solution for electrolysis is also an interesting process:
- first, an analysis of the available substances for preparing solutions is carried out. Why soda ash and water? Soda ash Na 2 CO 3 contains the metal Na, which is much to the left of hydrogen in the series electrical potentials- this means that during electrolysis the metal will not be reduced at the cathode (in solution, but not in the melt), and water will decompose into hydrogen and oxygen (in solution). There are only 3 variants of the solution reaction: metals strongly to the left of hydrogen are not reduced, metals weakly to the left of hydrogen are reduced with the release of H 2 and O 2, and metals to the right of hydrogen are simply reduced at the cathode. Here it is, the process of copper plating of the surface of parts in a CuSo 4 solution, galvanizing in ZnCl 2, nickel plating in NiSO 4 + NiCl 2, etc.;
- dilute soda ash in water in a calm place, slowly and without breathing. Do not tear the package with your hands, but cut it with scissors. After this, the scissors must be placed in water. Any of the four types of soda (baking soda, soda ash, washing soda, caustic soda) removes moisture from the air; its shelf life is essentially determined by the time of moisture accumulation and clumping. That is, in a glass jar the shelf life is forever. Also, any soda generates a solution of sodium hydroxide when mixed with water and electrolysis, differing only in the concentration of NaOH;
- soda ash is mixed with water, the solution becomes bluish. It would seem that a chemical reaction has taken place, but no: as in the case of table salt and water, the solution does not have a chemical reaction, but only a physical one: dissolution solid in a liquid solvent (water). You can drink this solution and get mild to moderate poisoning - nothing fatal. Or evaporate and get the soda ash back.

The choice of anode and cathode is a whole undertaking:
- it is advisable to choose the anode as a solid inert material (so that it does not collapse, including from oxygen, and does not participate in chemical reactions) - that is why stainless steel plays the role of it (I read a lot of heresy on the Internet and almost got poisoned);
- it is pure iron that is the cathode, otherwise rust will act as an excessively high resistance of the electrical circuit. To place the iron to be cleaned completely in the solution, you need to solder or screw it to some other iron. Otherwise, the metal of the iron holder itself will take part in the solution as a non-inert material and as a section of the circuit with the least resistance (parallel connection of metals);
- not yet specified, but there should be a dependence of the flowing current and the rate of electrolysis on the surface area of ​​the anode and cathode. That is, one M5x30 stainless steel bolt may not be enough to quickly remove rust from a car door (to realize the full potential of electrolysis).

Let us take an inert anode and cathode as an example: considering the electrolysis of only a blue solution. As soon as voltage is applied, the solution begins to transform to the final solution: Na 2 CO 3 + 4H 2 O = 2NaOH + H 2 CO 3 + 2H 2 + O 2 . NaOH - sodium hydroxide - crazy alkali, caustic soda, Freddy Krueger in a nightmare: the slightest contact of this dry substance with wet surfaces(skin, lungs, eyes, etc.) causes hellish pain and rapid irreversible (but recoverable in mild burns) damage. Fortunately, sodium hydroxide is dissolved in carbonic acid H 2 CO 3 and water; when the water is finally evaporated by hydrogen at the cathode and oxygen at the anode, the maximum concentration of NaOH is formed in carbonic acid. You should absolutely not drink or smell this solution, and you should also not stick your fingers in (the longer the electrolysis, the more it burns). You can clean pipes with it, while understanding its high chemical activity: if the pipes are plastic, you can hold them for 2 hours, but if they are metal (grounded, by the way), the pipes will begin to eat: Fe + 2NaOH + 2H 2 O = Na 2 + H 2 , Fe + H 2 CO 3 = FeCO 3 + H 2.

This is the first of possible reasons suffocating “gas”, physical and chemical process: saturation of air with a solution of concentrated caustic soda in carbonic acid (boiling bubbles of oxygen and hydrogen as carriers). In books of the 19th century, carbonic acid is described as a poisonous substance (in large quantities). This is why drivers who install a battery inside a car are damaged by sulfuric acid (essentially the same electrolysis): during the process of overcurrent on a heavily discharged battery (the car has no current limit), the electrolyte boils for a short time, the sulfuric acid comes out along with oxygen and hydrogen into the cabin. If the room is made completely sealed, due to the oxygen-hydrogen mixture (explosive gas), you can get a good bang with the destruction of the room. The video shows bang in miniature: water under the influence of molten copper decomposes into hydrogen and oxygen, and metal is more than 1100 degrees (I can imagine how a room completely filled with it stinks)... About the symptoms of inhaling NaOH: caustic, burning sensation, sore throat, cough, difficulty breathing, shortness of breath ; symptoms may be delayed. It feels quite suitable.
...at the same time, Vladimir Vernadsky writes that life on Earth is impossible without carbonic acid dissolved in water.

We replace the cathode with a rusty piece of iron. A whole series of funny chemical reactions begins (and here it is, borscht!):
- rust Fe(OH) 3 and Fe(OH) 2, as bases, begin to react with carbonic acid (released at the cathode), producing siderite (red-brown): 2Fe(OH) 3 + 3H 2 CO 3 = 6H 2 O + Fe 2 (CO3) 3, Fe(OH) 2 + H 2 CO 3 = FeCO 3 + 2 (H 2 O). Iron oxides do not participate in the reaction with carbonic acid, because there is no strong heat, and the acid is weak. Also, electrolysis does not reduce iron at the cathode, because these bases are not a solution, and the anode is not iron;
- caustic soda, as a base, does not react with bases. Necessary conditions for Fe(OH) 2 (amphoteric hydroxide): NaOH>50% + boiling in a nitrogen atmosphere (Fe(OH) 2 + 2NaOH = Na2). Necessary conditions for Fe(OH) 3 (amphoteric hydroxide): fusion (Fe(OH) 3 + NaOH = NaFeO 2 + 2H 2 O). Necessary conditions for FeO: 400-500 degrees (FeO+4NaOH=2H 2 O+Na 4 FeO 3). Or maybe there is a reaction with FeO? FeO + 4NaOH = Na 4 FeO 3 + 2H 2 O - but only at a temperature of 400-500 degrees. Okay, maybe sodium hydroxide removes some of the iron and the rust just falls off? But here’s a bummer: Fe + 2NaOH + 2H 2 O = Na 2 + H 2 - but when boiling in a nitrogen atmosphere. Why the hell does a caustic soda solution without electrolysis remove rust? But it doesn’t remove it in any way (I drained the clear solution of caustic soda from the Auchan). It removes grease, and in my case, with a piece of Matiz, it dissolved the paint and primer (the resistance of the primer to NaOH is in its performance characteristics) - which exposed a clean iron surface, the rust simply disappeared. Conclusion: soda ash is needed only to produce acid by electrolysis, which cleans the metal, taking on rust at an accelerated pace; Sodium hydroxide seems to be of no use (but will react with debris in the cathode, cleaning it).

About third-party substances after electrolysis:
- the solution changed its color and became “dirty”: with reacted bases Fe(OH) 3, Fe(OH) 2;
- black plaque on the iron. First thought: iron carbide Fe 3 C (triiron carbide, cementite), insoluble in acids and oxygen. But the conditions are not the same: to obtain it you need to apply a temperature of 2000 degrees; and in chemical reactions there is no free carbon to join the iron. Second thought: one of the iron hydrides (saturation of iron with hydrogen) - but this is also incorrect: the conditions for obtaining are not the same. And then it came: iron oxide FeO, the basic oxide does not react with either acid or sodium hydroxide; as well as Fe 2 O 3. And amphoteric hydroxides are located in layers above the main oxides, protecting the metal from further penetration of oxygen (they do not dissolve in water, preventing the access of water and air to FeO). You can put the cleaned parts in citric acid: Fe 2 O 3 + C 6 H 8 O 7 = 2FeO + 6CO + 2H 2 O + 2H 2 (special attention to the release of carbon monoxide and the fact that the acid and metal eat on contact) - and FeO is removed with a regular brush. And if you heat the higher oxide in carbon monoxide and at the same time not get burned - then it will reduce iron: Fe 2 O 3 + 3CO = 2Fe + 3CO 2;
- white flakes in solution: certain salts that are insoluble during electrolysis in either water or acid;
- other substances: iron is initially “dirty”, water is not initially distilled, dissolution of the anode.

The second of the possible causes of the suffocating “gas” is a physical and chemical process: iron, as a rule, is not pure - with galvanization, primer and other foreign substances; and water - with minerals, sulfates, etc. Their reaction during electrolysis is unpredictable; anything can be released into the air. However, my piece was so small (0.5x100x5), and tap water (poorly mineralized) - this reason is unlikely. Also, the idea of ​​the presence of foreign substances in the soda ash itself has disappeared: only this is indicated on the packaging.

The third possible cause of asphyxiating gas is a chemical process. If the cathode is restored, then the anode must be destroyed by oxidation, if not inert. Stainless steel contains about 18% chromium. And this chromium, when destroyed, enters the air in the form of hexavalent chromium or its oxide (CrO 3, chromic anhydride, reddish - we will talk about it later), a strong poison and carcinogen with delayed catalysis of lung cancer. Lethal dose 0.08g/kg. Ignites gasoline when room temperature. Released when welding stainless steel. The scary thing is that the symptoms are the same as sodium hydroxide when inhaled; and sodium hydroxide already seems like a harmless animal. Judging by the descriptions of cases of at least bronchial asthma, you need to work as a roofer for 9 years, breathing this poison; however, a clear delayed effect is described - that is, it can shoot both 5 and 15 years after a single poisoning.

How to check whether chromium has been released from stainless steel (where - the question remains). After the reaction, the bolt became shinier compared to the same bolt from the same batch - a bad sign. As it turned out, stainless steel is such as long as chromium oxide exists in the form protective coating. If chromium oxide was destroyed by oxidation during electrolysis, it means that such a bolt will rust more intensely (free iron will react, and then the chromium in the untouched stainless steel will oxidize to CrO). Therefore, I created all the conditions for the two bolts to rust: salt water and a solution temperature of 60-80 degrees. Stainless steel grade A2 12Х18Н9 (Х18Н9): it contains 17-19% chromium (and in stainless iron-nickel alloys there is even more chromium, up to ~35%). One of the bolts has rusted in several places, all places in the area of ​​contact between the stainless steel and the solution! The reddest one is along the line of contact with the solution.

And my happiness is that the current strength was then only 0.15A during electrolysis, the kitchen was closed and the window in it was open. It was clearly imprinted in my mind: exclude stainless steel from electrolysis or do it in an open area and at a distance (there is no stainless steel without chromium, this is its alloying element). Because stainless steel is NOT an inert anode during electrolysis: it dissolves and releases toxic chromium oxide; armchair chemists, hit the wall before someone dies from your advice! The question remains, in what form, how much and where; but taking into account the release of pure oxygen at the anode, CrO is already oxidized to the intermediate oxide Cr 3 O 2 (also toxic, MPC 0.01 mg/m 3), and then to the higher oxide CrO 3: 2Cr 2 O 3 + 3O 2 = 4CrO3. The latter remains a guess (the required alkaline environment is present, but is high heat required for this reaction), but it is better to be on the safe side. Even blood and urine tests for chromium are difficult to do (they are not in the price lists, not even in the advanced general analysis blood).

Inert electrode - graphite. You need to go to the trolleybus depot and remove the discarded brushes. Because even on Aliexpress it’s 250 rubles per pin. And this is the cheapest of the inert electrodes.

And here's 1 more real example when sofa electronics led to material losses. And to the right knowledge, really. As in this article. The benefits of sofa idle talk? - unlikely, they wreak havoc; and you have to wipe up after them.

I am inclined to the first reason for the suffocating “gas”: evaporation into the air of a solution of sodium hydroxide in carbonic acid. Because with chromium oxides they use hose gas masks with mechanical air supply - I would have suffocated in my pathetic RPG-67, but it was noticeably easier to breathe in it at the very epicenter.
How to check for chromium oxide in the air? Start the process of water decomposition in a clean solution soda ash on a graphite anode (pick it out of a pencil, but not every pencil contains a pure graphite rod) and an iron cathode. And risk breathing the air in the kitchen again in 2.5 hours. Logical? Almost: the symptoms of caustic soda and hexavalent chromium oxide are identical - the presence of caustic soda in the air will not prove the absence of hexavalent chromium vapor. However, the absence of odor without stainless steel will clearly indicate the presence of hexavalent chromium. I checked, there was a smell - a phrase with hope "hurray! I breathed caustic soda, not hexavalent chromium!" You can tell jokes.

What else did you forget:
- How do acid and alkali exist together in one vessel? In theory, salt and water should appear. There is a very subtle point here that can only be understood experimentally (I haven’t tested it). If you decompose all the water during electrolysis and isolate the solution from the salts in the sediment - option 2: what remains is either a solution of caustic soda or caustic soda with carbonic acid. If the latter is in the composition, the release of salt will begin under normal conditions and the precipitation of... soda ash: 2NaOH + H 2 CO 3 = Na 2 CO 3 + 2H 2 O. The problem is that it will dissolve in water right away - it’s a pity, you cannot taste it and compare it with the original solution: suddenly the caustic soda has not completely reacted;
- Does carbonic acid interact with iron itself? The question is serious, because... The formation of carbonic acid occurs precisely at the cathode. You can check by creating a more concentrated solution and doing electrolysis until a thin piece of metal is completely dissolved (haven’t checked). Electrolysis is a more gentle method of removing rust than acid etching;
- What are the symptoms of inhaling detonating gas? No + no smell, no color;
- Do caustic soda and carbonic acid react with plastic? Perform identical electrolysis in plastic and glass containers and compare the turbidity of the solution and the transparency of the surface of the container (I did not test it on glass). Plastic - has become less transparent in places of contact with the solution. However, these turned out to be salts that could be easily removed with a finger. Therefore, food grade plastic does not react with the solution. Glass is used to store concentrated alkalis and acids.

If you have inhaled a lot of scalding gas, regardless of whether it is NaOH or CrO 3, you need to take “unithiol” or similar drug. And the general rule applies: no matter what poisoning occurs, no matter what the strength and origin of it, drink a lot of water in the next 1-2 days, if your kidneys allow. Objective: remove the toxin from the body, and if vomiting or expectoration does not do this, give additional features do this to the liver and urinary system.

The most annoying thing is that this is all school program 9th grade. Damn, I'm 31 years old - and I won't pass the Unified State Exam...

Electrolysis is interesting because it turns back time:
- a solution of NaOH and H 2 CO 3 under normal conditions will lead to the formation of soda ash, but electrolysis inverts this reaction;
- iron is oxidized under natural conditions, but is reduced during electrolysis;
- hydrogen and oxygen tend to combine in any way: mix with air, burn and become water, be absorbed or react with something; electrolysis, on the contrary, generates gases various substances in its purest form.
A local time machine, no less: it returns the position of the molecules of substances to their original state.

According to the reaction formulas, a solution of powdered caustic soda is more dangerous during its creation and electrolysis, but more effective in certain situations:
- for inert electrodes: NaOH + 2H 2 O = NaOH + 2H 2 + O 2 (the solution is a source of pure hydrogen and oxygen without impurities);
- reacts more intensely with organic materials, there is no carbonic acid (a fast and cheap degreaser);
- if you take iron as an anode, it will begin to dissolve at the anode and be reduced at the cathode, thickening the layer of iron on the cathode in the absence of carbonic acid. This is a way to restore the cathode material or coat it with another metal when there is no solution with the desired metal at hand. Removal of rust, according to experimenters, also goes faster if the anode is made of iron in the case of soda ash;
- but the concentration of NaOH in the air during evaporation will be higher (you still need to decide what is more dangerous: carbonic acid with caustic soda or moisture with caustic soda).

Earlier I wrote about education that a lot of time is wasted in school and university. This article does not cancel this opinion, because the average person will not need matan in life, organic chemistry or quantum physics (only at work, and when I needed math 10 years later, I learned it again, I didn’t remember anything at all). But inorganic chemistry, electrical engineering, physical laws, Russian and foreign languages- this is what should be a priority (we would also like to introduce the psychology of interaction between the sexes and the foundations of scientific atheism). Now, I didn’t study at the Faculty of Electronics; and then bam, it happened - and I learned to use Visio, and I learned MultiSim and some of the element symbols, etc. Even if I had studied at the Faculty of Psychology, the result would have been the same: stuck in life - bit into it - figured it out. But if at school the emphasis on natural sciences and languages ​​was strengthened (and young people were explained why it was strengthened), life would be easier. Both at school and at the institute in chemistry: they talked about electrolysis (theory without practice), but not about the toxicity of the vapors.

Finally, an example of producing pure gases (using inert electrodes): 2LiCl + 2H 2 O = H 2 + Cl 2 + 2LiOH. That is, first we poison ourselves with pure chlorine, and then we explode with hydrogen (again to the issue of the safety of the released substances). If there was a solution of CuSO 4, and the cathode was iron, the metal would leave the base and leave an oxygen-containing acidic residue SO4 2-, it does not participate in the reactions. If the acidic residue did not contain oxygen, it would decompose into simple substances(as can be seen in the example of C 1 - released as Cl 2).

(added 05/24/2016) If you need to boil NaOH with rust for their mutual reaction - why not? Nitrogen in the air is 80%. The efficiency of rust removal will increase significantly, but then this process must be done outdoors.

About hydrogenation of metal (increased fragility): I did not find any formulas or adequate opinions on this topic. If possible, I will electrolyze the metal for several days, adding a reagent, and then knock with a hammer.

(added 05/27/2016) Graphite can be removed from a used salt battery. If it stubbornly resists disassembly, deform it in a vice.

(added 06/10/2016) Hydrogenation of metal: H + + e - = H adc. H ads + H ads = H 2, where ADS is adsorption. If the metal has necessary conditions dissolve hydrogen in itself (that's a number!) - then it dissolves it in itself. The conditions of occurrence for iron have not been discovered, but for steel they are described in the book by A.V. Schrader. "The influence of hydrogen on chemical and petroleum equipment." In Figure 58 p. 108 there is a graph of brand 12Х18Н10Т: at a pressure comparable to atmospheric pressure and a temperature of 300-900 degrees: 30-68 cm 3 /kg. Figure 59 shows the dependencies for other steel grades. The general formula for hydrogenation of steel: K s = K 0 e -∆H/2RT, where K 0 is the pre-exponential factor 1011 l/mol s, ∆H is the heat of dissolution of steel ~1793K), R is the universal gas constant 8.3144598 J/(mol ·K), T - medium temperature. As a result, at room temperature 300 K we have K s = 843 L/mol. The number is not correct, you need to double-check the parameters.

(added 06/12/2016) If caustic soda does not interact with metals without high temperature, it is a safe (for metal) degreaser for pallets, pots and other things (iron, copper, stainless steel - but not aluminum, Teflon, titanium, zinc).

With inspiration - clarifications. The pre-exponential factor K 0 lies in the range of 2.75-1011 l/mol s; this is not a constant value. Its calculation for stainless steel: 10 13 · C m 2/3, where C m is the atomic density of steel. Atomic density of stainless steel 8 · 10 22 at/cm 3 - K 0 = 37132710668902231139280610806.786 at/cm 3 = - and then everything is stuck.

If you look closely at Schrader’s graphs, you can make an approximate conclusion about the hydrogenation of steel in HC (a decrease in temperature by 2 times slows down the process by 1.5 times): approximately 5.93 cm 3 /kg at 18.75 degrees Celsius - but the time of penetration into the metal of such a volume is not indicated. In the book by Sukhotin A.M., Zotikov V.S. "Chemical resistance of materials. Handbook" on page 95 in table 8 indicates the effect of hydrogen on the long-term strength of steels. It makes it possible to understand that the hydrogenation of steels with hydrogen under a pressure of 150-460 atmospheres changes the long-term strength limit by a maximum of 1.5 times over a period of 1000-10000 hours. Therefore, one should not consider the hydrogenation of steels during electrolysis in HC as a destructive factor.

(added 06/17/2016) Good way disassembling the battery: do not flatten the case, but open it like a tulip bud. From the positive input, bend down parts of the cylinder piece by piece - the positive input is removed, the graphite rod is exposed - and smoothly unscrewed with pliers.

(added 06/22/2016) The easiest batteries to disassemble are Ashanov batteries. And then in some models there are 8 circles of plastic to fix the graphite rod - it becomes difficult to pull it out and begins to crumble.

(added 07/05/2016) Surprise: the graphite rod breaks down much faster than the metal anode: literally in a few hours. Using stainless steel as an anode is optimal solution, if you forget about toxicity. The conclusion from this whole story is simple: electrolysis should be carried out only in the open air. If in this role there will be open balcony- do not open the windows, but pass the wires through rubber compressor doors (just press the wires against the door). Taking into account the current during electrolysis up to 8A (Internet opinion) and up to 1.5A (my experience), as well as the maximum voltage of the PSU PC 24V, the wire should be rated at 24V/11A - this is any insulated wire with a cross-section of 0.5mm 2.

Now about iron oxide on an already processed part. There are parts that are difficult to reach into to wipe off black deposits (or an object under restoration, when you cannot rub the surface with an iron brush). While analyzing chemical processes, I came across a method for removing it with citric acid and tried it out. Indeed, it also works with FeO - the plaque disappeared/crumbled within 4 hours at room temperature, and the solution turned green. But this method is considered less gentle, because acid and metal eat away (cannot be overexposed, constant monitoring). Plus, a final rinse with a soda solution is required: otherwise the remaining acid will eat away at the metal in the air, and you will get an undesirable coating (an awl for soap). And you need to be careful: if as much as 6CO is released with Fe 2 O 3, then what is released with FeO is difficult to predict (an organic acid). It is assumed that FeO + C 6 H 8 O 7 = H 2 O + FeC 6 H 6 O 7 (formation of iron citrate) - but I also release gas (3Fe + 2C 6 H 8 O 7 → Fe 3 (C 6 H 5 O 7) 2 + 3H 2). They also write that citric acid decomposes in light and temperature - I can’t find a correct reaction.

(added 07/06/2016) I tried citric acid on a thick layer of rust on nails - it dissolved in 29 hours. As I expected: citric acid is suitable specifically for post-purification of metal. To clean thick rust: use high concentration citric acid, high temperature(up to a boil), frequent stirring - to speed up the process, which is inconvenient.

In practice, a soda ash solution after electrolysis is difficult to regenerate. It’s not clear: add water or add soda. Adding table salt as a catalyst completely killed the solution + the graphite anode collapsed in just an hour.

Total: coarse rust is removed by electrolysis, FeO is etched with citric acid, the part is washed with a soda solution - and almost pure iron is obtained. Gas when reacting with citric acid - CO 2 (decarboxylation of citric acid), darkish deposit on iron - iron citrate (cleaned off easily, does not perform any protective functions, soluble in warm water).

In theory, these methods of removing oxides are ideal for restoring coins. Unless weaker proportions of reagents are needed for lower solution concentrations and lower currents.

(added 07/09/2016) Conducted experiments with graphite. It is during the electrolysis of soda ash that it is destroyed extremely quickly. Graphite is carbon; when dissolved at the time of electrolysis, it can react with steel and precipitate iron carbide Fe 3 C. The condition of 2000 degrees is not met, but electrolysis is not NU.

(added 07/10/2016) When electrolyzing soda ash using graphite rods, the voltage should not be increased above 12V. A lower value may be needed - keep an eye on the graphite breakdown time at your voltage.

(added 07/17/2016) Discovered a method for local rust removal.

(added 07/25/2016) Instead of citric acid, you can use oxalic acid.

(added 07/29/2016) Steel grades A2, A4 and others are written in English letters: imported and from the word “austenitic”.

(added 10/11/2016) It turns out that there is 1 more type of rust: iron metahydroxide FeO(OH). Formed when iron is buried in the ground; in the Caucasus they used this method of rusting strip iron to saturate it with carbon. After 10-15 years, the resulting high-carbon steel became sabers.

Step 1: Preparation

Apple cider vinegar (white vinegar will also work, although I haven't tried it yet),
- salt (not sure if this is really necessary - but I know it works well for cleaning coins, along with vinegar),
- a plastic dish large enough to immerse rusty parts or tools that need to be restored,
- an old toothbrush.

Step 2: Immerse the tool to be restored in vinegar

Place recoverable tool, with subject to removing rust from metal, into the dish.
Pour in enough vinegar to submerge the rusty parts.

Step 3: Add Salt

Sprinkle salt liberally over the entire area of ​​the instrument being restored.

Step 4: Check it tomorrow

Leave the instrument in the mixture for 24 hours.

Step 5: Take the Brush

The next day, look at the restored instrument. You should see a lot of rust removed from the metal, flakes and debris in the solution.
Use an old toothbrush to scrub away any remaining deposits.

Step 6: Move the tool being restored

Try working with a recoverable tool. You can feel him move a little. Tug it a few times. Wet it and rub it a little with the brush. Let them sit in the solution again for a while. Move it a little more. Rub with a brush, repeat. And one day suddenly you will be able to pull them off. Stir, brush, and dip a few more times.
If that doesn't work, maybe leave it on for another 24 hours. But this treatment should be enough to restore the instrument - to get it back in working order. Give it a few drops of oil and work to disperse the oil and keep the tool from rusting later. Not sure which oil is appropriate here, I used a 3-in-1 oil that I had on hand. Some commenters will swear by using WD40.
And many will continue to mention that the best way to restore a tool and remove rust from metal is through the electrolytic process. If you have the means to do this, the flag is in your hands!

Salvaging old tools will require patience, durable abrasives, and good eyesight.

The Forgotten One has a strange power of attraction. He beckons, attracts. Pick it up and the next thing you'll do is scrape off the rust with your fingernail. thumb, trying to discern the name of the manufacturer of this instrument.

You vaguely remember how it came into your hands: either it was taken at a sale, or your father-in-law gave it to you, or maybe a compassionate neighbor left it as a souvenir during the move, just so as not to throw it away...

“Everyone has these little lost gems.”“, - my friend, an excellent carpenter who gravitates towards collecting various tools, once said, looking thoughtfully at the rusty hammer lying in the corner of my balcony. Planes, chisels, chisels, hammers, pliers and a whole bunch of rare and strange devices for working with materials of different hardness from different countries and eras decorated his workshop.

But here’s what’s interesting: all these production tools were in perfect condition, there wasn’t even any rust on them, and sharpening, if provided, was like a new tool. They waited their turn to work, their oiled sides shining, each in his place. It always surprised me. How does he keep such old instruments in such great order...? I decided to find out his secret.

“It’s quite easy to restore them,” said a friend, “but, unfortunately, I’m leaving early tomorrow morning on a business trip, so I won’t have time to tell you all the details. You better read about this somewhere on the Internet. You’ll find a lot of good ways there.”

And indeed, I found it. I will provide excerpts from one such article in this material. In my opinion, it will be a good instruction on the practical restoration of old instruments that have long been abandoned to the mercy of fate.

"We took a bunch of old instruments with us and went into the studio ( former church in North Salem, New York) to get them in order. We realized that all it takes is some basic chemistry and a little effort to salvage instruments that look like they've been sitting on the ocean floor for centuries.", - this is where the article on restoring old rusty junk began. But is it really trash?

The round head of this figured hammer (in the title photo) looked deader than dead. But it was worth removing the rust from the metal, polishing the rusty steel to a shine, applying a thin layer of machine oil and add a hammer new pen, how life returned completely to this delicate instrument for graceful work.

A method for cleaning a large area of ​​rust. Rusty, wobbly table saw

1980s Craftsman table cutter purchased at church auction for $80

Metal cutting machine, which will stand in unheated garage, store or barn, sooner or later it will rust. Condensation settles specifically on steel and cast iron parts, since they are colder than the surrounding air.

Rust makes it difficult for a piece of plywood or wood to slide on a table, which should be smooth and non-abrasive. This makes it more difficult to position the blade or adjust its angle. This 1980s Craftsman table, purchased at a church auction for $80, is about to get a second life. This is how he is revived.

First of all, the saw table top was removed from the bed. After which she was loaded into a Ford F-150 and taken to a warm workshop for further work.

INSTRUMENTS GET tarnished, and when they become dull, they are put aside, and when they are put aside, they begin to rust.

The good news was that the motor ended up with two capacitors: one to start the motor turning and the other to provide an extra kick to start the winding. It's more reliable. The electric motor itself, the motor shaft and pulley were in good shape. Before the rust work began, all dirt, sawdust and cobwebs were removed from the nooks and crannies of the saw.

The work for which everything was started has begun.

For this the rusty surface was first moistened with kerosene- it acted as a solvent and coolant (cutting fluid). After leaving him alone for an hour, they returned with a drill.

To remove rust, an abrasive material was clamped into the fists of the drill nylon brush with aluminum oxide 240 grit. At low speeds about 500 (the drill should be with variable speed rotation), moving back and forth, the brush easily cleaned off the rust without damaging the metal surface.

Be prepared for the fact that the removed parts may not fit back into place. This is exactly what happened with the wings that expanded the tabletop - it was impossible to align them with the plane of the tabletop. They had to be gently tapped until they fit into the grooves in the desired position. The main thing here is to take your time.

Remember to put all the parts back when reassembling. In the case of a saw, we are talking about an electric motor, a new saw blade and other small elements, which were put in their rightful places.

The method of getting rid of rust is not for everyone: hydrolysis in the fight against rust from video blogger Mizantrop

How to Clean Up Corroded Hand Tools

Any rust and oxides can be removed from metal tool. It doesn’t even matter how much rust has penetrated into the metal structure.

Here's an example:

To restore a pile of hammer heads and a couple of hatchets, first remove any excess from them. They will no longer need half-rotten parts of handles and old handles. Usually, in order to remove the handle, it is most convenient to hold a hammer or hatchet in a vice and knock out the remaining part of the handle with an object of suitable diameter. Or split something rotten with a sharp object.

Corrosion can be removed using white vinegar. Place the metal to be processed into Plastic container, pour in enough white vinegar to submerge the parts.

Depending on the degree of oxidation, leave the parts for several hours or a day.

For the second cleaning step, you will need steel wool. Please note that iron wool has eight abrasiveness classes: from the gentlest - 0000# to the most coarse - 4#. The thicker the layer of rust, the coarser you should use, ideally decreasing the abrasiveness as the rust is removed.

When there is no more rust left, rinse the workpieces thoroughly in clean water, to wash away traces of vinegar, finally wiping the parts dry.

A surface scratched during rust removal can be sanded using a 100-grit abrasive on a sanding disc.

Finally, the tools were wiped down with mineral spirits, primed with anti-corrosion metal primer and painted with gloss alkyd enamel.

The cutting edges of the axes were sharpened by hand on a series of water stones used for woodworking tools.

The assembly process was completed by installing the handles and then wedging them.

Restoring a not very rusty knife

Is it possible to restore rusted precision instruments?

Restoring any composite precision instrument must begin with careful disassembly.

For example, the plane in the photo above. Please note that not all parts are rusty. This means we separate the wheat from the chaff and work only with those parts where there is.

Most of the rust was removed using a hand wire brush. Then we sanded the metal with coarse 60 grit sandpaper and continued polishing with 1000 grit sandpaper.

To make finishing polishing less hassle, stick sandpaper onto a flat surface and, changing the ends of the part, begin to move it along the paper until the desired shine and evenness appears. You can add a couple of drops of mineral alcohol as a lubricant.

PRECISION INSTRUMENTS REQUIRE CAREFUL APPROACH TO RESTORATION AND ADJUSTMENT

Sharpening the plane blade and polishing the handles completes the restoration work.

Restoration of the highest class