Corrosion – main enemy everything that is metal - from a fence to a car body. The fact is that the corrosion process is irreversible, irreversibly destroying metal products. Therefore, it is so important to “intervene” in this process and stop it, which can be done with the help of a rust remover, or, as it is also called, a “rust converter.”
What is rust remover
Rust remover is a concentrate of chemically active substances that stop metal rusting and protect its surface from corrosion.
The basis of this product is orthophosphoric (phosphoric) acid (up to 48% depending on the manufacturer’s brand). Additionally, inhibitors are introduced into the product to make working with the drug more comfortable, because, as is known, this acid can burn the skin and destroy teeth.
Rust converter functions:
- “Eating” corrosion products and stopping subsequent rusting of the metal.
- Removes acid stains from products and coatings made of copper, brass, aluminum and other types of metal.
- Restores the porous surface of metal damaged by corrosion.
- Wets the metal surface well.
- Improves adhesion of primer and other coatings after treatment.
The concentrate is highly soluble in water, so it can be diluted to the required state. For example, if the rusting on the surface is minor, you should not use the product in a concentrated state.
How to use rust remover
Depending on the degree of rust and the type of metal that needs to be cleaned, rust remover is used in different concentrations. The exposure time of the drug applied to the scale also differs.
- Cleaning ferrous metals heavily damaged by corrosion.
To remove a thick layer of rust, you need to take part of the concentrate and dilute it in three parts of water. Mix thoroughly and apply with a stiff brush to the damaged metal or dip metal products with scale into the resulting solution. The exposure time in both cases is from 25 minutes to an hour.
After time has passed, cleaned surfaces and products must be thoroughly rinsed with water and dried completely. For a better effect, you can coat the treated surfaces with a moisture-displacing compound.
- Cleaning non-ferrous metals that are heavily damaged by corrosion.
To remove rust from non-ferrous metals, it is necessary to prepare a solution of rust remover and water in a ratio of 1/7 or 1/10, depending on the degree of scale damage to the metal.
Thoroughly treat products and surfaces with the prepared solution, leaving the product to act for 20-60 minutes. Then rinse thoroughly clean water treated surfaces and allow to dry completely.
- Cleaning ferrous metals slightly damaged by corrosion.
IN in this case the solution is prepared in the following proportion: one part of concentrate to 15-20 parts of water. Thoroughly mix and treat rusty products and metal surfaces. Leave to act for up to 40 minutes.
To speed up the process of cleaning metal from rust, the solution can be heated to 60 degrees, then use it for its intended purpose and wait half the standard exposure time.
At the end of the procedure, wash the products and surfaces with water, dry thoroughly and treat with a water-repellent composition.
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 a number of 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 glass jar 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 it has not: as in the case of table salt and water, the solution does not have a chemical reaction, but only a physical one: the dissolution of a solid substance 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 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 quick irreversible (but recoverable in case of 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 used 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 briefly, sulfuric acid exits 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 for the release of carbon monoxide and the fact that acid and metal eat on contact) - and FeO is removed with a regular brush. And if you heat the higher oxide in carbon monoxide without getting burned, 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 at 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 on 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; couch 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 an assumption (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 (not included in price lists, not even included in an extended general blood test).
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 pure solution of 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 present in the composition, salt will begin to be released into the 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 can’t taste it and compare it with the original solution: suddenly it’s caustic the sodium has not all 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 a similar drug. And it works general rule: no matter what poisoning occurs, no matter 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 the 9th grade school curriculum. 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, no carbonic acid (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, organic chemistry or the quantum physics(only at work, and when I needed matan 10 years later, I learned it again, I didn’t remember anything at all). And here 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 there is an open balcony in this role, 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 boiling), 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. Addition table salt, as a catalyst, killed the solution completely + the graphite anode collapsed literally in 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), a darkish coating on iron - iron citrate (it is easy to clean off, 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.
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 method of saving, 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 a 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 an iron box, let's call it a “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 the temperature regime; the “reactor” should 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/
The find must be protected from impacts and other loads. After removal from the ground, irreversible changes begin in the find. The method should be started within a few days. If this is not possible, then you can store it by creating the same conditions as in the ground. It is harmful to store in water, kerosene, or a dry place.
Immediately before using the method, you must remove the soil using alkali (“Mole”). To do this, fill the find with an alkali solution for 1 hour, then rinse with water. There is no need to use any brushes. Here and further we take care of our hands and eyes. Alkali is not compatible with Aluminum, Magnesium, Zinc.
Furnace and reactor
The reactor must be welded on all sides with a strong, reliable sealed seam. The plug should be secured with bolts that can be easily replaced. The plug does not need to be sealed. Optimal thickness reactor walls 2 mm for ordinary steel or 1 mm for stainless steel. The shape of the reactor should be such that the finds are located inside at the same, minimum possible, distance from the walls on all sides.
The carbon used is charcoal, crushed to granules the size of peas. Such coal produces a lot of dust, which is very harmful. Therefore, for large-scale work, it is better to use activated coconut carbon to filter water.
Boiling container
The boiling tank is a welded trough rectangular shape made of ordinary sheet steel with a lid and a drain tap.
Algorithm
1. First warm-up
2. After heating, all rust is reduced to pure powdered iron. The color of the find should change from red to light gray. If the color is light gray, then you can proceed to step 3. If the color is black, this means that the rust has not been reduced to iron, but to iron II oxide. In this case, you need to take measures to increase the temperature and/or holding time and repeat step 1
3. The finds are placed in a boiling container and filled with alkali (Mole). Cooking time 30 minutes – 1 hour of active boiling. After cooling, drain the alkali and rinse the finds with running water without removing them from the container.
4. Wear rubber gloves. Prepare sandpaper, files, needle files, hacksaw blade, knife. Prepare running water. Under the influence of alkali, powdered iron turns into a gel. Using any of the listed tools, we smooth the gel on the surface of the find, like butter on bread. We carefully cut off the growths, open the holes, and clean the bushings. Rinse periodically with running water. This point allows you to save time and make plumbing work easier later, but it can only be done before the gel hardens. Usually, within an hour +/- after cooking, the gel hardens and in this case you need to immediately proceed to step 5. If the find has complex shape and/or requires disassembly, proceed immediately to step 5.
5. Place the finds in a boiling container and fill with vinegar. Concentration: 3 bottles of 0.2 liters of vinegar essence per 5 liters of water. Acid is poured into water and not vice versa. Soak in vinegar for at least 1 hour. The color of the finds should change from gray to black with a purple tint.
6. Drain the vinegar, rinse the finds with water and refill with alkali. Leave for less than 1 hour, rinse with water, spread out the finds and dry. There is no need to rinse with water too thoroughly, as the remaining alkali on the finds will only protect them until the next heating in the oven. This point is needed only to ensure that the finds do not rust again.
7. Second warm-up
8. Locksmith work. After the second heating, areas of powdered iron high density turn into metallic iron, areas of low density iron powder do not turn into metallic iron. Plumbing work comes down to removing powdered iron and leveling the restored metallic iron. Often, soldering marks form at the site of the growths, which also need to be cut off. Most often, a large solder is formed next to the sink; in addition, the entire surface of the find can be covered with many small solders that need to be removed. In general, at this stage the item needs to be given its final appearance. Complex mechanisms need to be disassembled and each part processed separately. You need to work carefully, as the restored fragments at this stage have low hardness, and thin places, edges and edges can be broken under the pressure of a file. To normalize the restored metal and transition to “ringing,” another heating is required, but the surfaces must be clean, white with a metallic sheen. If at this stage it is not possible to bring the find to its final final appearance, then step 7 is repeated, and then the plumbing work continues. As steps 7-8 are repeated, the restored fragments harden, become “ringing” and firmly adhere to the surrounding metal. In the case of using electric welding, it is also necessary to repeat steps 7 – 8 to homogenize the welded metal with the historical one.
9. Final warm-up. After final heating, the find should acquire a bright white, dazzling color over its entire surface. To clean dust and obtain a uniform optical reflection, use a stainless steel nozzle with firm pressure or polish if necessary. If the find has a dark or uneven color over the entire surface, then step 9 must be repeated, taking measures to eliminate the lack of temperature and/or time.
10. Conservation. For preservation, I use a hot solution of paraffin in turpentine. I personally don’t like this preservative, because under it the finds take on a leaden color. Its big advantage is that it allows you to quickly pass quarantine.
11. Quarantine. The find is placed in a dry room such as a city apartment. If salts remain in the depths, then after 2 weeks a local spot of rich red color will appear on the surface of the find around a small crack or shell. Most often, this is observed in massive objects and is a consequence of a lack of temperature and/or time in step 9. If, at the stage between steps 9 and 10, water, splashes, drops of sweat come into contact with the find or it is affected high humidity air, then after 2 weeks a thin, not bright coating of red flowers will appear on the surface. In either of these two cases, steps 9 and 10 must be repeated.
12. Hardening, bluing, darkening, debugging of mechanisms, installation on wood
13. Repeat points 9 and 10 if necessary.
Offline granddad
Granddad
- Moscow city
Manufacturing a furnace for the restoration of iron in a carbon environment
Small artifacts can be restored in an ordinary village brick oven which includes a small reactor, but for the restoration of blades and gun barrels, a home oven is a bit short. Sergei made a special furnace for a large reactor and showed the technology for its manufacture.
The design of the stove is exactly how I imagine it based on experience, without claims to be the only possible option.
The oven must provide long-term heating of the item up to 1000C. The optimal temperature range is 900-1000C. In the case of processing objects decorated with non-ferrous metals or having parts made of non-ferrous metals, the temperature must be lower than the melting point of the non-ferrous metal.
To make the furnace, a large diameter pipe was taken. You can buy used. The length of the pipe is such that any gun or saber placed in the reactor can fit into it with supplies.
To improve draft and uniform heating of the long oven, three air ducts are installed.
I installed dampers on the pipes that make it possible to reduce draft and thereby increase effective time operation of the stove without opening the damper to add firewood.
The main thing in any stove is good draft, which is ensured by a high straight pipe. The higher the pipe, the better the traction. The diameter of the pipe should not be less than 180 mm.
The grate and ash pan are an integral part of any furnace.
Suspensions for fastening the reactor.
Insulation of the furnace. Our furnace is not for heating, but for creating an optimally high temperature inside the furnace of 900-1000 degrees and heating the reactor placed in it. For achievement high temperatures We “insulate” the stove with mineral wool.
We also insulate the oven door and seal it.
The stove is ready, you can begin restoration.
The found gun of the 1812 model of a French soldier rather resembled a piece of pipe, and shapeless parts for it, which would very quickly begin to crumble in the air. We carefully removed from the ground everything that rings under the metal detector coil, and without cleaning it, we put it into the reactor along with the ground. We hang it on hangers. We load the stove with wood and set it on fire.
The gun after restoration.
Gun lock before restoration and after restoration.
How does the metal behave some time after such treatment? Won't it corrode intensely?
Rust spots may appear if you place wet artifacts in the reactor. After two weeks, spots appear. Also, if the item gets caught in the rain. Every drop of rain will leave a red coating. In any case, you need to use paraffin for preservation, since in some apartments the humidity is no less than in a barn. Local corrosion also appears due to insufficient heating temperature, especially if the object is massive and this applies to finds preserved with paraffin. I use this fact as a quality test. If you place a finished object preserved with paraffin in a damp shed, then pockets of corrosion will not appear at all if the transformations took place safely in the deep layers. In general, metal behaves a little more resistant than non-galvanized nails. Surprisingly, there are objects that do not rust at all even in a damp shed for six months.
For conservation, you can use bluing, which was described earlier on this site.
P.S. This method has been tested on many artifacts and has shown excellent results. Many things, even such miniature ones as needles and carnations from the time of Ivan the Terrible, were perfectly restored and restored their properties. You can still sew with needles. I want to thank Sergei for the story and good advice about the much-needed method of restoration.
Offline granddad
Granddad
- Moscow city
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.
Crushed charcoal is poured into an iron box, let's call it a “reactor,” 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 the temperature regime; the “reactor” should 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.
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. The most effective way is chemical treatment. These include inhibitor compounds that cover 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 execute machining from corrosion manually, you need to purchase a metal brush or coarse abrasive sandpaper. Items can be processed dry or wet. 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.
Also hold mechanical cleaning rusting materials can be done 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 - a 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 orthophosphorus composition, which allows you to restore rusting material. The method of using acid is quite simple: wipe off dust from iron or metal damp cloth, then remove any remaining moisture, thin layer Apply the acid to the item using 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 in 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 objects that are rusting, forms protective film on a 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 can be outdoors all year round. 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 for processing hard to reach places, created for deep penetration, protects products from reappearance 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 chemicals allergies, and rust with 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 it should be remembered that it chemical composition may 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 to return metal products pristine appearance.
Top 5 ways to remove rust (1 video)
