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Production of Iron(III) Oxide
There are two different iron oxides that abound: Iron(II,III) oxide (Fe3O4)and the far more common Iron(III) oxide (Fe2O3). Iron (III) oxide is commonly known as rust. Due to iron’s paramagnetic properties iron it was used to coat old floppy disks. The particles were magnetized to either positive or negative representing 1 or 0 in the binary system. If the rust is a very fine powder it can be used by jewelers to polish metallic jewelry. However jewelers now opt for new polishes, because iron oxide cuts slowly and can stain the metals. The most exciting use for rust though is in production of pure iron through the highly exothermic thermite reaction.
Safety and Disclaimer
Safety and Disclaimer:
· Breathing chlorine gas is toxic and cause health complications. Please view the MSDS.
· Bleach can cause burns to the skin. Please view the MSDS.
· When using a car battery charge please be aware of the potential for electric shock.
· Always use gloves when handling hazardous chemicals.
· Always allow charges to dissipate or ground when working with electricity
Please be aware that there is a certain risk you absorb when following the procedures. You are responsible if your car charger breaks, plastic melts, or you incur some form of body harm. Also if you intend to use iron oxide for any malicious actions, please be aware that I am not responsible for your actions and any bodily harm you incur. You should always check local and national laws before you engaging in any legally questionable activities.
Choosing an Iron Source
To produce iron(III) oxide one must first choose a source for iron. Two common choices are pure iron bolts found at the local hardware store or steel wool found at most super marts. Each option has it strengths and weakness. Iron bolts react slower because of reduced surface area and must be scrapped occasionally to expose new iron to continue the reaction, but the product is pure Iron(III) oxide. Steel wool will react quickly as there is a much higher surface area, however steel wool is not pure iron. Steel (Fe3C) is an alloy of iron and carbon. The carbon is distributed in the iron’s crystal lattice at molecular level adding strength. When steel wool is oxidized this carbon will remain behind in the solution.
Chemical Reaction for the Production of Iron Oxide
To chemically produce iron oxide one needs bleach, often 6% sodium hypochlorite (NaOCl) by weight, either iron bolts or steal wool, and a paint scrapper. There are some who argue that vinegar which is often 5% acetic acid (CH3COOH), should be added to the mixture in a 1:1 ratio with bleach as a catalyst. I find this is unnecessary as the acetic acid reacts with the sodium hypochlorite realizing toxic chlorine gas by the reaction NaOCl (aq.) + CH3COOH (aq.) → Na+ (aq.) + H2O(l) + Cl2 (g) + CH3COO-(aq.). The sodium hypochlorite in bleach is sufficient to oxidize iron by the reaction: Fe3+(s) + NaOCl (aq.) → Fe2O3 (s) + Na+(aq.) + Cl-(aq.). Please understand this is the reaction that takes place if pure sodium hypochlorite is reacted with pure iron, because bleach contains more than sodium hypochlorite, secondary reactions will occur. Amounts of toxic chlorine gas will result from other reactions so this must be done in a well-ventilated area.
1. Place iron bolts or steel wool in plastic container.
2. Place container in a well ventilated area, preferably outside in direct sunlight. This will allow the sunlight to heat the reaction, increasing the reaction speed, and the wind will disperse any toxic fumes produced.
3. While wearing safety gloves, plastic dishwashing gloves work, pour enough bleach in to cover the iron or steel wool by more than an inch.
4. Leave the area and check every 30 minutes.
5. The solid iron may need to have the iron oxide scraped off to expose more iron to be oxidized. To do this pick up the iron with gloves and use a paint scraper to expose new iron.
6. When finished filter using multiple layers of coffee filters. If the filtered solution still contains a reddish-brown tint, let stand for 30 minutes and refilter with new coffee filters.
7. Wash your iron oxide copiously with water to remove any residues.
8. If you are concerned about the presence of carbon in your solid iron oxide, dump your iron oxide into a 2 liter container full of water and shake it up. Let stand for about a minute or until most of the iron oxide sinks to the bottom and a small black layer forms above it. Decant, carefully pour, this black layer off. This will remove most the carbon without taking a large amount of your product with it.
9. Let your iron oxide dry in the sun and then grind with mortar and pestle to desired mesh, also known as fineness.
Electrolytic Production of Iron Oxide
The electrolytic production of iron oxide requires a large power supple, a car battery charger works best, but a large 6V battery will suffice, iron bolts or steel wool, water, paint scraper, and table salt. This process works by sending an electrical current through water (H2O) causing the oxygen and hydrogen to split apart. This method of splitting water is known as electrolysis. Adding table salt (NaCl) to the solution allows the water to conduct electricity easier. The Sodium (Na+) and Chlorine (Cl-) disassociate, break apart, to form their respective ions, contributing electrons to the water. When the salt-water solution becomes part of a circuit, the negative end (cathode) looses electrons as they are sent into the solution to travel to the positive end (anode). As the electrons travel through the solution the will cause oxygen to form at the anode and hydrogen and trace amounts of chlorine form at the cathode. If the anode is composed of iron it readily oxidizes as the iron is reduced from Fe3+ to Fe2+ increasing its ability to interact with the oxygen gathering at the anode. While the iron has gained an extra electron the reaction still occurs by treating iron as 3+ charge, the extra electron helps to split the diatomic oxygen (O2). The reaction is 4Fe3+(s) +3O2 (aq.) → 2Fe2O3 (aq.). While most of the chlorine ions stays suspended in the solution some ions may bond together at the cathode and escape as chlorine gas (Cl2). With the possibility for trace amounts of toxic chlorine gas to be produced this should also be conducted in a well ventilated area.
1. Run an extension cord outside for the car battery charger. This will ensure ventilation.
2. Fill a plastic or glass container with water, 2 liters is preferable.
3. For every liter of water add about a tablespoon (14 grams) of salt.
4. Before plugging in the car battery charger, clip the positive end (anode) often red to the iron bolt or steel wool. If the negative end (cathode) often black is clipped to the iron nothing will happen, except the corrosion of whatever metal the anode is composed of. If you are unsure which side is positive just clip iron to both ends.
5. Submerge the iron in water and place the cathode and anode about 1-3 inches apart. Make sure they do not touch as this will complete the circuit and prevent the reaction.
6. Plug the car battery in and watch from a distance. You should notice rust rapidly forming on the anode.
7. About every 5 minutes or when you see the reaction slow, unplug the car battery charger. Wait about a minute for any charges to dissipate, before using the paint scrapper to scrap away the rust and expose new iron.
8. Plug the car battery charger back in and continue the reaction until sufficient iron oxide is produced.
9. When finished filter using multiple layers of coffee filters. If the filtered solution still contains a reddish-brown tint, let stand for 30 minutes and refilter with new coffee filters.
10. Wash your iron oxide copiously with water to remove any residues.
11. If you are concerned about the presence of carbon in your solid iron oxide, dump your iron oxide into a 2 liter container full of water and shake it up. Let stand for about a minute or until most of the iron oxide sinks to the bottom and a small black layer forms above it. Decant, carefully pour, this black layer off. This will remove most the carbon without taking a large amount of your product with it.
12. Let your iron oxide dry in the sun and then grind with mortar and pestle to desired mesh, also known as fineness.