Doug+Cavlert's+Ferro-Fluid+Chemistry+ISU+2

Materials
=Procedure= The magnetic particles in this ferrofluid consist of magnetite. If you aren't starting with magnetite, then the first step is to prepare it. This is done by reducing the ferric chloride (FeCl3) in PCB etchant to ferrous chloride (FeCl2). Ferric chloride is then reacted to produce magnetite. Commercial PCB etchant is usually 1.5M ferric chloride, to yield 5 grams of magnetite. If you are using a stock solution of ferric chloride, follow the procedure using a 1.5M solution. The next step is to take the magnetite and [|suspend it] in the carrier solution. The magnetic particles need to be coated with a surfactant so that they won't stick together when magnetized. Finally, the coated particles will be suspended in a carrier so the magnetic solution will flow like a liquid. Since you are going to be working with ammonia and kerosense, prepare the carrier in a well-ventilated area, outdoors or under a fume hood.
 * 1) household ammonia
 * 2) oleic acid (may be found in some pharmacies, craft, and health food stores)
 * 3) PCB etchant (ferric chloride solution) - from an electronics store or you can make your ferric chloride or ferrous chloride solution or you can use magnetite or magnetic hematite powder if you have either of those minerals handy (magnetic hematite is an inexpensive mineral used in jewelry)
 * 4) steel wool
 * 5) distilled water
 * 6) a magnet
 * 7) kerosene
 * 8) heat source
 * 9) 2 beakers or measuring cups
 * 10) a plastic syringe or medicine cup (something to measure 10 ml)
 * 11) filter papers or coffee filters
 * 1) Pour 10 ml of PCB etchant and 10 ml of distilled water in a glass cup.
 * 2) Add a piece of steel wool to the solution. Mix the liquid until you get a color change. The solution should become bright green (green is the FeCl2).
 * 3) Filter the liquid through filter paper or a coffee filter. Keep the liquid; discard the filter.
 * 4) Precipitate the magnetite out of the solution. Add 20 ml of PCB etchant (FeCl3) to the green solution (FeCl2). If you are using stock solutions of ferric and ferrous chloride, keep in mind FeCl3 and FeCl2 react in a 2:1 ratio.
 * 5) Stir in 150 ml of ammonia. The magnetite, Fe3O4, will fall out of solution. This is the product you want to collect.
 * 6) Heat the magnetite solution to just below boiling.
 * 7) Stir in 5 ml oleic acid. Maintain the heat until the ammonia evaporates (approximately an hour).
 * 8) Remove the mixture from heat and allow it to cool. The oleic acid reacts with ammonia to form ammonium oleate. Heat allows the oleate ion to enter solution, while the ammonia escapes as a gas (which is why you need ventilation). When the oleate ion binds to a magnetite particle it is reconverted to oleic acid.
 * 9) Add 100 ml kerosene to the coated magnetite suspension. Stir the suspension until most of the black color has been transferred into the kerosene. Magnetite and oleic acid are insoluble in water, while oleic acid is soluble in kerosene. The coated particles will leave the aqueous solution in favor of the kerosene. If you make a substitution for the kerosene, you want a solvent with the same property: the ability to dissolve the oleic acid but not uncoated magnetite.
 * 10) Decant and save the kerosene layer. Discard the water. The magnetite plus oleic acid plus kerosene is the ferrofluid.
 * 11) Create a aperatus to use electromagnetic feilds to influance the ferrofluds shape and structure.

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