How to attract liquid metal with magnets?

_{G.F.Maxwell, CCASA 3}

Ferrofluid

Also, Liquid sodium can be made magnetic. I'm not sure if it is the kind of magnetism you had in mind.

Looks like there is a lot of research on mercury-based ferrofluids. See, e.g., http://orbit.dtu.dk/files/3475980/Linderoth2.pdf (Journal of Applied Physics, 69(8), 5124-5126 (1991))

You could run a current through the liquid mercury and make it into an electromagnet. The practicalities of this escape me though.

Magnetic fluids are rare in nature. One example is liquid oxygen, for which one needs very low operating temperature. There are some paramagnetic solutions. People tried mixing iron filings with liquids to force them have magnetic properties. This is also less optimal solution because such suspensions settle down under gravity. People turned little clever around 1960s (or 70s not sure) and made use of the Brownian motion! They prepared iron particles with size of few nano meters. These particles were Brownian, that is, the random kicks by the surrounding fluid's molecules were energetic enough to fight against the gravity. But there was a problem that these nano-particles made aggregates, and these aggregates would again settle down. People are clever, they came up with ways to coat these particles with some surfactant, and remedied this aggregation problem. The suspension could remain stable. These stable suspensions are called ferrofluids. So answering your question, you may look for magnetic nano-particles which can be suspended in mercury in a stable fashion.

If you are looking for cheaper alternatives (rather expensive) you can create amalgams.An amalgam is an alloy of mercury with another metal. It may be a liquid, a soft paste or a solid., depending upon the proportion of mercury. These alloys are formed through metallic bonding, with the electrostatic attractive force of the conduction electrons working to bind all the positively charged metal ions together into a crystal lattice structure. Sadly - Iron doesn't form an amalgam with mercury So you can try nickel, chromium or any other magnetic metal.

1. Amalgam is a mixture because it is an alloy.
2. This means the nickel wont separate from the liquid mercury giving the effect of magnetic fluid
3. As a mixture retains the properties of its constituent metals the liquid will be attracted towards a/an magnet/electromagnet

Note:- I haven't tried it but hope it helps ;)

Inspiration- Wikipedia