How to make lots of steel disappear in a pretty short time.

Superacids don't dissolve more metal than more ordinary acids. They simply react faster, and with a wider variety of substances. However, there are extraordinary problems with handling such materials, plus they are extremely expensive to make.

 

Ok, ok. Then sulfuric at 25% should work just fine with steel.

The thermite melting option isn't optimal either. It would be much better to cut the steel in small pieces with an appropiate tool and carry it away in simple carts.

However, I may suggest an additional option. Instead of sand, fill the hole under the statue with TNT. The statue won't disappear, but the chances of it landing anywhere near the original point and in any recongizable shape, are slim.

 

Omm, it was supposed to proceed with no one noticing...

 

Well, considering this, TNT would not be really the option that immediately comes to mind

My boyfriend also just came up with an idea, it sounds perfect: Antimatter!

 

Antimatter? Huge explosion ripping away much of the planet's atmosphere, lots of noise, light and gamma rays. Someone MIGHT notice.

In fact, if it were equal in mass to the steel (to convert all the metal to energy), you'd probably shatter the planet.

I don't think "Nobody noticed because no one is left alive" fits the parameters of the problem.

 

I'm no chemist so i can't comment on that. But as far as the OP's ideal of silent and quickish, acid seemed relatively plausible. Cumbersome definitely, but as far i can tell, it fits the bill more or less. I might have missed a better answer by now tho.

 

Kind of off topic, but I find it rather funny how there is an advertisement for magnets above this thread for me. Just pointing that out.

Also, nanobots.

 

Again, with acid or (other chemical reactions), you will still have the problem of removing reaction products. Iron does not have gaseous compounds at normal temperatures, so uy eaiter have to remove solids or liquids (solutions).

For ten tons of iron (conservative estimate), you will have to remove considerably more than ten tons of reaction products. It will undoubtedly require a great deal of time for the reaction to take place (overnight would be pushing it, but lets assume it is possible), but removing more than ten tons of reaction products with no one noticing and no obvious clues (like a giant drainage pipe) left behind would be - difficult.

 

Ah, you're right. Makes total sense.
Still think it would be a cool concept, but yeah, realistically and all.