Sciencemadness Discussion Board

Sea salt as catalyst for derusting danger?

Darth-Vang - 2-7-2022 at 15:58

Hey all, I’m using sea salt as a electrolyte to acquire rust from a railroad spike, the cathode is carbon graphite rod. Is it dangerous to use sea salt as an electrolyte? I’m currently running it now and I can see that the water is turning green! Running at 6 volts with 2.5ish amps with variable power supply.

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[Edited on 3-7-2022 by Darth-Vang]

clearly_not_atara - 2-7-2022 at 19:05

Iron (II) chloride is green.

Darth-Vang - 3-7-2022 at 12:23

Quote: Originally posted by clearly_not_atara  
Iron (II) chloride is green.
I guess it looked green at first, but now it’s all blackish color, I see some white stuff, definitely see rust at the bottom of the jar. What’s the electrochemical equation for this? The water is tap water if I didn’t mention that.

unionised - 3-7-2022 at 13:18

It's not exactly dangerous.
You will probably find you get chloride in the rust (whether it's sea salt or any other sort of sodium chloride)
You are probably getting ferrous hydroxide which is not only green, but also insoluble.

If you blow air through it you will get ferric hydroxide which is orange/ brown.

What are you seeking to achieve?

Darth-Vang - 4-7-2022 at 02:04

Quote: Originally posted by unionised  
It's not exactly dangerous.
You will probably find you get chloride in the rust (whether it's sea salt or any other sort of sodium chloride)
You are probably getting ferrous hydroxide which is not only green, but also insoluble.

If you blow air through it you will get ferric hydroxide which is orange/ brown.

What are you seeking to achieve?
My compound of interests is iron oxide. I’m planning to run a small scale experiment for thermite or other experiments that may include rust in it.

Darth-Vang - 16-8-2022 at 16:15

Update: Finally got around to filtering the stuff and dry them on the mantle and got iron oxide!