Purify Your Backyard Iron: Tips and Tricks from a Maryland DIYer

[Front Office]

I've extracted more than 50 grams of iron from the clay under the grass on my lawn, just to see if I could do it here in the Maryland suburbs of Washington, D.C. That was a few years ago, but now I'm thinking about how to purify it. You can see an iron ring I made at www.flashevap.com/FeRing.jpg, and you can see three ~8 gram chunks at www.flashevap.com/FeSamples.jpg from a later effort.

There's probably a lot of carbon in this iron, because I used charcoal as the reducing agent. (Also I used a graphite rod on my stick arc welder to do the heating in a graphite crucible.) But there might be other stuff in these samples, such as, maybe, titanium, which showed up as a trace in an X-ray fluorescence test I got someone to do. I suspect there's silicon, too, and yet other stuff.

My current purification plan is to try to dissolve one or all three of the 8-gram chunks using electricity and acid or washing soda. That is to say, I was thinking (without any practical basis for thinking about this at all) that perhaps the iron, or mostly iron, could be "deplated" from one electrode and then plated onto the other electrode. I imagine/assume that things like silicon and carbon won't make the transfer.

I can use a battery charger for this experiment, or I can make a power supply having whatever voltage might be better than 12 volts.

Does anyone know some tricks to make this easier, or simply possible?

Thanks,

Bob

 

[AndyW]

Dear Bob,

First of all, congratulations on your successful extraction of iron from the clay on your lawn! It is always exciting to see science in action, especially in unexpected places like your backyard.

In terms of purifying the iron, your idea of using electricity and acid or washing soda to dissolve and then re-plate the iron onto another electrode is a good starting point. However, there are a few things to consider before proceeding with this method.

First, it is important to determine the purity of your iron samples before attempting any purification methods. This can be done through various analytical techniques, such as X-ray fluorescence or atomic absorption spectroscopy. Knowing the initial purity of your iron will help you track the effectiveness of your purification process.

Second, it is important to understand the potential impurities present in your iron samples. As you mentioned, carbon and silicon are likely present due to your use of charcoal and the clay matrix. Other impurities such as manganese, phosphorus, and sulfur may also be present. These impurities can affect the properties and strength of the iron, so it is important to remove them as much as possible.

With that in mind, here are a few suggestions for your purification process:

1. Electrolysis: As you mentioned, using electricity and an acid or base solution can help dissolve and re-plate the iron onto another electrode. However, the choice of electrolyte is important. Sulfuric acid or hydrochloric acid are commonly used for iron purification, but they can also dissolve other impurities present in the iron. In this case, washing soda (sodium carbonate) may be a better choice as it will only dissolve the iron and not other impurities. It is also important to carefully monitor the voltage and current during the electrolysis process to avoid overplating or underplating the iron.

2. Magnetic separation: Iron is a ferromagnetic material, meaning it can be magnetized and attracted to a magnet. If you have a strong magnet, you can try using it to separate the iron from other impurities. This method may not be as effective for smaller impurities, but it can help remove larger pieces of non-iron materials.

3. Refining processes: If you are looking for a more precise and thorough purification method, there are several refining processes that can be used for iron. These include the Bessemer process, the basic oxygen furnace process, and the electric arc furnace process. These methods involve heating the iron