Element Collection

Element Collection

Friday, September 14, 2012

Titanium Thermite & Calcium Sulfate

Titanium metal from a thermite reaction has been one of my goals for a long time. I needed it for my element collection, and this thermite is particularly interesting because of the surprising chemicals it uses. The formulation I am using was developed by a fellow blogger and colleague on the Science Madness forum, Gert Meyers. His blog post on the subject can be found here. The following will talk about my efforts to obtain good quality titanium metal from the thermite reaction he lays out. This is a re-post of the info I shared on Science Madness, including many pictures and 3 unlisted Youtube videos never before seen by the general public!

My source for calcium sulfate was DAP brand plaster of paris, which is the hemihydrate (CaSO4 * 1/2H2O). The ingredients listed on the back are calcium sulfate, calcium carbonate, and silicon dioxide. Assuming the latter two were only there in small amounts, I set off using this plaster straight out of the box. After heating some of it in my oven for 2 hours at 425 F to dehydrate it, I mixed up a batch of thermite according to blogfast’s specs:

TiO2 – 30g
CaSO4 – 25.5g
Al – 27g
CaF2 – 17.5g

Here’s how it went: http://www.youtube.com/watch?v=KfqKOaZyllQ
That video is actually my second try, which used the extra booster formula (see the video’s description for specifics). As you can see, the burn was very “sputtery.” While it did produce titanium metal, the pieces were small spheres that didn’t coalesce together like they should if the whole thing were molten. The slag was also very sparkly throughout, likely from tiny pieces of Ti that were trapped before they could flow together. You can see in the picture at the end spheres of white titanium embedded throughout the slag. Apparently the impurities, likely added as fire retardants or to improve its setting properties, were more detrimental than I thought. Here’s the Ti I recovered from this batch:

 I looked up the MSDS for this particular brand of plaster: http://www.dap.com/docs/msds/00071008_english.pdf
Turns out, the impurities are pretty significant – CaCO3 at 15% – 25%, and SiO2 at 0% - 1%.

So, to remedy this I tried removing some of the additives. The silica isn’t worth the effort needed to remove it, but the CaCO3 is easy enough to destroy with a treatment in acid. As a bonus, by using sulfuric acid I make more of my desired reagent!

CaCO3 + H2SO4 == CaSO4 + H2O + CO2

I took some of the raw plaster, submerged it in a good amount of water (so it wouldn’t harden up on me), and added roughly 9M sulfuric acid slowly until the bubbling stopped. I filtered off the CaSO4, let it air dry, and then dehydrated the powder in a fused silica crucible over my small butane burner for about 45 minutes. Using this in the same thermite composition listed above, the reaction ran much smoother: http://www.youtube.com/watch?v=DSY4biEB88Y
When recovering the metal afterward, the pieces were much larger and I found 4 or 5 individual pieces about ½” in diameter. This is indicative of a much better reaction temperature, but there were still some problems with this batch. There were a number of large voids in the slag, the Ti metal was incredibly hard to separate from the adhering slag, and the metal pieces were much more tarnished.

My hypothesis is that all of these are due to water of crystallization still in the CaSO4, i.e. I didn’t heat it up enough. The water boiling off would cause the voids, and I suspect it would react with the hot Ti metal to tarnish its surface. The tarnish can be easily polished off, of course, but I feel that I can do better.



My next attempt was to make my own CaSO4, so I know it’s pure (or at least, I know for certain what’s in it!) I tried two methods to do this.

Method 1: CaCl2 + H2SO4 == CaSO4 + 2HCl
This uses calcium chloride and sulfuric acid, both of which are fairly OTC for me – CaCl2 is used in Damp Rid brand moisture absorbers, and my sulfuric acid is from Liquid Fire brand drain opener. It also produces hydrochloric acid as a byproduct, so this might be a handy way to get much higher purity acid than hardware store brand muriatic acid (which is highly contaminated with, mostly, iron).

Method 2: MgSO4 + CaCl2 == CaSO4 + MgCl2
I like this method a lot because it uses nothing hazardous at all, and both reactants are very easy to source: magnesium sulfate is Epsom salt and calcium chloride is used in Damp Rid.

I tried both methods, and they both work exceedingly well. As long as you use dilute solutions of everything (mine were < 5M), the precipitation doesn’t happen immediately. That means it is much less likely to form occlusions of impurities and you end up with a beautifully snow white product. I then heated both samples to 480F for two hours to dehydrate – here they are fresh out of the oven:

The Method 2 sulfate is on top, and Method 1 on bottom. The latter was quite a bit more powdery and a little purer white, which is interesting considering it was made from acid that has a dark red color to it.
I was able to use all the sulfate from Method 2 for a single 100g Ti thermite charge. The result can be seen here: http://www.youtube.com/watch?v=6TFty76NyHw
This one was a little slow to start, but burned fairly well once it got going. The slag was especially nice, conforming to the bottom of the flower pot very nicely with only one small void – meaning it was completely molten and (mostly) free of water. The pieces I recovered were about halfway between the first two reactions – larger spheres than the first run with their somewhat shiny cast, but smaller than the lumps of the second.


So that’s where I’m at now. Ideally, I want to produce large, shiny lumps of Ti for my element collection, but I think these will do nicely for now. If anyone else is trying this reaction, I hope my posting my efforts here was helpful!


  1. I found your blog trying to figure out why my Damp Rid Crystallized http://the-alice-of-wonderland.blogspot.com/2012/10/crystalized.html

    Do you think you could answer that?

    1. I tried commenting on your article but for some reason the comment window never showed up, hopefully it notifies you of this one!

      I read your page and that was very interesting! I think I know what happened. Damp-Rid contains anhydrous calcium chloride, in the form of white flakes. When you open this up to the air, it absorbs moisture, and does this so readily that the chemical dissolves in the water it takes up. That's when it liquifies and drips down into the bottom. What I believe happened is that your Damp-Rid came into equilibrium with its environment in the closet, meaning it would absorb no more water and also would not evaporate away. When you moved it to another environment, it must have been a bit drier than your closet. This caused the water to evaporate back into the air, and you were left with (fully hydrated) calcium chloride crystals! If you put them back in the closet, they may not liquify again because in their current form they already have a lot of water trapped in the crystal structure, and so are not nearly as powerful of a moisture absorber. Hope that helps!

  2. Hello Dan, I'm Dragonetti1976, listen i'm trying to currently develop a great idea for a invention, you are a very interesting fellow who know's his elements, thus i would like to ask you for some help, some questions that i need answering to, to accomplish my modern day invention so that people can benefit from it, and i need a partner with this kind of expertise in this field, to be-friend and possibly make tons of money with the right person, i'm not a science geek, but an idealist with drive,I'm a hard working person who's just trying to talk to the right people, i'm currently working a 40hr. job, 9yrs, with a good company,trying to support my family and start something new with my life. can you please e-mail me back at "Dragonetti_76@yahoo.com" for your interest, no pressure here, i don't normally do this, this is kind of a long shot I'm doing here writing to you. Thank you for hearing me out, Joe S. Milwaukee, WI

  3. Dan,
    I'm enjoying reading your posts as well as watching your videos. Nice work.
    I found you while looking for information on how to deal with old chemicals. I'm a new teacher (alternate route... I'm 57!) and part of my job is to inventory the chem lab store room. Our school just took over an old Catholic high school and there are loads of chemicals, some dating back almost 40 years. I think I'm going to neutralize the majority myself to save us money.

    But what really caught my interest was your element collection. I'm going to talk my science department into putting one together. So, do you have any posts or videos I missed that show your current status? I'd love to see the collection.

    Jim Shaw
    Elmwood Park, NJ

    1. Thanks James! If you don't want to go through the trouble of disposal, I'd be happy to take some chemicals off your hands :)

      Funny that you asked about my element collection, because when you wrote that comment I was just putting the finishing touches on five posts and a video featuring it! I built a fancy display unit for the collection, which I go into a lot of detail explaining. Check out the intro post here: http://thehomescientist.blogspot.com/2013/02/the-element-display-introduction.html . I'll be posting a few videos going through all the individual elements in the near future.

  4. Hi, mrhomescientist! I'm an aspiring home chemist myself, and am also in the process of building an element collection. I wanted to ask you how you went about extracting the Titanium pellets from the slag after your thermite cooled. I'm looking for a way to do this without producing a lot of Hydrogen Sulfide gas, as I live in a pretty cramped neighborhood and that would not be good for the neighbors. Thanks for making your videos for us, I've got you subscribed on YouTube and I can't wait to see what you do next!

    1. Extracting the pure metals from any thermite is very easy, and once you've done it once or twice you'll be able to spot things very quickly. If you watch the first video I linked in the article, the very end shows the product "cake" after I cracked it in half with a hammer. You can clearly see the Ti metal as shiny spheres. Further tapping with a hammer shatters the brittle aluminum oxide slag and these nodules fall right out. It's much the same for any type of thermite - the product metal will be shiny (usually), in spherical nodules or one large lump at the bottom of the cake, and will be much harder than the surrounding slag. A few raps with a hammer breaks up the oxide and frees the metal. This particular thermite didn't really have the sulfur smell at all. It's locked up in the sulfate anion and not much is liberated as elemental sulfur. My silicon thermite, on the other hand, seriously reeked of rotten eggs!

  5. I actually just prepared some silicon thermite today, but instead of using sulfur, I figured I'd add some sodium nitrate to keep the reaction going and sodium chloride as a flux. I highly recommend this method, I imagine potassium chlorate would be even better. The thermite worked great, but I'm pretty sure I'll have to scale it up for any considerable nodules to fall out. Anyway, thanks for your quick response!

  6. Hi. I did a couple of the titanium thermites and I really got very tiny bulbs of titanium although some the titanium pieces looked bronze and some were like orange chunks with holes. Do you have any recommendations of how to get clean big pieces of titanium? Also what did you do with the slag? Can you purify the slag to make more titanium?