Sciencemadness Discussion Board - Bismuth Crystals, etc.

Bismuth Crystals, etc.

neutrino - 17-3-2005 at 20:03

I thought I might share my tinkerings with this beautiful element.

Bi forms hopper crystals, which I’m sure we’ve all seen at museum gift shops at one time or another without realizing what they are. Here is my (improvised) procedure on growing these things. I hope that someone here finds it useful.

First, get some bismuth. Get the highest purity you can. 99.99% is a good, cheap grade available on ebay, here, here, and many other places.

Next, get a small crucible to melt your bismuth. I have used a 10 mL beaker and the snuffer cap of my alcohol burner successfully for this. A word about metals: if you use a metal crucible, make sure that you melt your bismuth in the presence of air. This creates an oxide coating which separates the bismuth from the crucible and thus prevents alloying.

Melt enough bismuth in your crucible to produce a roughly cylindrical melt and remove the heat source shortly after the charge finishes melting. Do the heating with a small heat source; I’ve found that a simple alcohol burner works perfectly for both the cap and the beaker. The trick is to get all of the bismuth molten, but at as low a temperature as possible. If there is any solid bismuth around the sides, crystals will grow inward instead of outward. If the temperature is too high, proper nucleation will be difficult, but not impossible.

At this point you have a melt of liquid bismuth that is ready to crystallize around any cool object it touches. Place the points of a pair of pointed tweezers 1-2 mm into the surface of the charge and bring the tips together. This will give you two or more seed crystals firmly attached to the tweezers.

At this point, you should quickly skim the layer of gray bismuth oxide off the top of the melt. A new layer will immediately start forming, but it will be highly colored and give the top of your crystals a very nice coloration.

While waiting for the crystal to grow (this usually takes around 20 seconds), make sure to slowly and gently shake the tweezers around to get a feel for the size of the crystal. When it has reached the edges of the crucible, pull out the tweezers with the crystal mass on them and shake the whole thing violently until no more liquid bismuth flies off. Do this over a sheet of aluminum foil so the bulk of the bismuth gobs can be recovered. Make sure to insulate your hand, as molten bismuth will give second-degree burns easily. You can wear a glove, but I’ve found that most of the molten gobs land on the middle segment of my middle finger.

Wait for the crystal to cool down and remove it from the tweezers. You now have a colorful crystal mass comprised of several crystals with very sharp hopper formations (exposed by the shaking) and two small holes where the tweezer tips were. I will upload some pictures as soon as I can figure out how to take decent pictures of the crystals with my camera.

A word about the pesky oxide: you will get a lot of useless oxide mixed with metallic bismuth from the skimming. To recover the metal, simply heat the stuff in a test tube to about red heat. The oxide will melt and separate from the metallic bismuth, which can now simply be poured out and remelted.

Another form of bismuth that is a sight to behold is plates. If grown correctly, they can be very beautiful and sometimes even include patches of brilliant color. Plates are best grown under an inert liquid—cheap cooking oil works, but be careful not to overheat it or it will smoke and release a mild lachrymator.

The first thing to do when growing a plate is to remove all of the oxide on the bismuth. This can easily be done by placing bismuth in oil and stirring it rapidly. The oxide will come off as a black precipitate and leave clean, shiny bismuth at the bottom.

Melt your clean bismuth under clean oil in a beaker. Remove the beaker from your heat source and put it on a thin sheet of metal. What sheet to use varies, but I’ve found that my aluminum sheet kitchen sink works. If you get the correct rate of cooling, you will get a very nice plate with clearly visible crystal structures. If it cools too quickly, you will get a plate with a scaly top. Too slow and you get a plate composed of a few large crystals with few boundaries.

A variation on this method is to melt the bismuth in the cover plate of a glass Petri dish, covered by the bottom plate (under oil, of course). When the bismuth melts, turn off the heat source and put some weight on the dish. If all goes well, you will get a large, thin plate of bismuth. The rate of cooling is not as important with this method, but be careful not to overheat, as the low heat capacity of the whole system makes this all too easy. Also make sure to add the proper amount of oil, a very tricky feat with little room for error.

Occasionally, you will get a patch of intense color on one of the crystal faces. I can’t fully explain this, but my best guess is that this happens when a crystal grows at just the right angle with the glass surface and creates something like a diffraction grating.

Finally, here is a cropped image of a part of the bottom of a plate grown in a beaker.

plate.jpg - 109kB

neutrino - 17-3-2005 at 20:10

Here is a picture of one of these spots. Oddly, this batch of bismuth is the only one I got these colors with. The new, purer batch I melted down produced far fewer patches and all much less colored. I can’t tell you what was in this batch, as I’d remelted the stuff so many times I don’t know what could be in it.

patch.jpg - 40kB

chemoleo - 17-3-2005 at 20:40

Great stuff, thanks for sharing.

I wonder what factors influence crystal shape. For instance I have seen Bi crystals (not with my own eyes though) that were very regular, still somewhat jagged.

I wonder what factors could be applied to achieve smooth crystal growth - i.e. crystals that grow several cm in diameter, and yet show only a handful of different crystal faces (if that's the term). Obvioulsy, the more jaggy it is, the more it implies either impurities or hesitant/disrupted irregular crystal growth. Optimal crystal growth normally requires constant and unwavering conditions ( I know that from protein crystallography, so I reckon this applies here too), hence I suspect that 1) temperature control, 2) a spacially fixed crystallisation nucleus 3) selection of optimum temperature are of utmost importance.

Further, as an idea, rather than using a tweezer and hoping for random crystals, it might be a good idea to allow the first batch to grow, then to break off crystals of the desired shape, and use *that* as a nucleus for a second round of crystallisation (A process called seeding).
This should produce nicer crystals.

Saerynide - 18-3-2005 at 02:38

Thanks for sharing that. I can't wait to see the pics of your hopper crystals

If only I had some Bi...

neutrino - 18-3-2005 at 18:53

I’m still playing around with my camera, hopefully I’ll get some good pics soon.

Most of the crystals I have grown have 2-3 big crystals and a small one here and there. The big ones are always nicely formed—a pyramid with stepped sides. There was one exception, though, which grew much more ‘hoppered’ than usual. How jagged a crystal is doesn’t affect the number of faces you will see, they are always parallel.

I have considered seeding, but this would introduce problems of its own. The crystals are always hoppered/stepped, so getting them into the melt past the somewhat sticky oxide layer would be a real challenge. Another problem is temperature control. If you put the seed in when the melt’s temperature is too low, the crystal will not grow properly (as I already explained). Too high and the seed melts, as the crystals are rather thin (~1mm). If the seed is too cool, it will create a nucleation point where it touches the melt. If its too hot, it will simply melt.

Now that you have me thinking about this, I do have one idea that might prove feasible. If you slowly cooled a molten ingot, it would give you large internal crystals. Take a hammer to this and you will easily get a number of pyramids. If you melt the very outside of a big one and put it into a hot melt, it should incorporate itself into the melt properly. If you cool the melt quickly enough, some part of the crystal will remain solid and start to grow when the temperature gets low enough. If only I hadn’t contaminated my ingots with copper… Oh, well I will get some more Bi sooner or later.

neutrino - 19-3-2005 at 10:56

Here are some pictures, sorry about the lighting. The abnormal one is on top, the most average one I could find is on the bottom. The crystals don’t usually grow at this angle to each other, this one was also somewhat unique. That’s the problem with only making only two or three dozen of something: they’re all unique and you can’t get a very average sample.

P.S. Sorry about the double post, it's the only way to upload the pics.

crystals.JPG - 64kB

Saerynide - 19-3-2005 at 14:11

AWesome

I like the neat pyramid one. Im envious

tantan - 19-3-2005 at 15:23

Look very much like professionally-prepared Bi crystals, very beautiful indeed!

FWIW, here's a link to an article about growing bismuth crystals:

http://www.popsci.com/popsci/how2/article/0,20967,714559,00....

Mr. Wizard - 19-3-2005 at 17:48

The crystals are very pretty indeed. You can buy a few ounces of Bismuth from the sporting goods store:
http://www.cabelas.com
Do a search inside the site for Bismuth. The fishing weights are $3 for 3 of the 3/4 oz weights which is over 60 grams for $3. Don't buy the bismuth shot like I did. I paid too much.
Bismuth can also be used in levitation with strong magnets.

neutrino - 19-3-2005 at 19:00

$3 for 3/4 oz of no-purity Bi? There's a guy on ebay selling the 99.99% stuff for $8/lb. Don't you love shopping around?

I found a plate lying around and decided to grow some crystals. Annoyingly, I kept getting nucleations at the edge of the melt instead of the center. It seems that my glass crucible (10 mL beaker) likes to stick to the Bi for some reason. It sticks a little higher than the meniscus, cools down there, starts growing crystals… I don’t remember having this problem before.

Mr. Wizard - 19-3-2005 at 19:26

$8 a pound sounds better than $3 for 2 1/4 oz. I should get out more ;-) The shipping calculator adds another $11 to the cost, ouch.

neutrino - 21-3-2005 at 17:54

I’ve been working on the sticking problem and finally found a solution. Add a small amount of oil and the Bi won’t stick. Don’t add enough to see, just add enough to encircle the ring where the meniscus joins the crucible.

neutrino - 24-3-2005 at 13:07

It seems that working with my Bi steadily contaminates it. It must be dissolving my tweezers and steadily becoming contaminated that way. Does anyone know where I’d find some sort of a chart of what metals Bi forms alloys with?

chemoleo - 24-3-2005 at 13:10

Are you sure it's not low levels of oxidation, similar to what you get when melting tin and lead?

neutrino - 24-3-2005 at 15:01

I tell the approximate purity by the color of the crystals. Nice pure ones will be bright purple and green in some places, contaminated ones will be dark yellow.

Part of the reason I ask is that I’m trying to make a substitute for my tweezers: a rod of some metal with a slightly mushroomed end. The problem is that I’m not sure what metal to use. Glass doesn’t seem to have the thermal conductivity necessary and Bi pieces are too hard to make in a shape that can be firmly held with tweezers of tongs.

12AX7 - 24-3-2005 at 19:04

Heck, Bi alloys with lots of stuff. Especially in the 0.01% range.

Heck, "insoluble" magnesium carbonate is about that soluble in water as I recall.

I don't know of anything you could add to clean it, you'll have to electroplate it out or something.

Tim

neutrino - 24-3-2005 at 19:33

Hg also alloys with many metals, but iron is a notable exception. There has to be some equivalent here.

Would Al work for this? The surface oxide layer should hold well enough, shouldn’t it?

HNO3 - 24-3-2005 at 20:39

If you have access to pliers, glass rod or tubing, and a propane torch, you can make a spatula. All you have to do is heat teh end of the rod/tubing to a red /orange color, and then use gravity to get the glass blob 2-3mm away from the main portion of the rod/ tubing, and sqeeze it with the pliers.

12AX7 - 24-3-2005 at 21:07

I would think any oxide will be more than suitable. Aluminum, titanium and stainless are passivated by oxide layers.

Glass wouldn't be optimum because bismuth tends to oxidize and that makes it sticky (same reason gallium sticks to glass).

Tim

neutrino - 25-3-2005 at 07:34

Sorry, HNO3, glass doesn’t work. If I use glass, the crystals come out malformed. Immediately around the tip is a crust of solid, but not very crystalline, Bi. Immediately below this are nice, big crystals. The problem is that almost nothing connects the crystals to the crust and they always separate when you pull them out of the melt.

My best guess is that the Bi around the glass (which is cold when I put it into the supercooled melt) immediately crystallizes, raising the temperature of the surrounding melt above the mp of Bi. The melt cools a little and crystals then start growing off of the very bottom of the crust (by convection, cooler Bi would be farther down) and continue because the lower parts of the melt is cool enough to hold the heat released by crystallization without going above the mp.

I never had this problem with my tweezers because, I guess, they conducted that initial burst of heat away and allowed crystals to grow correctly.

Tim: The oxides aren’t so much of a problem at these low temperatures. Are you sure about SS being passivated by an oxide layer. It doesn’t seem right to me that something made of Fe (non-passivating), Cr and Ni (also non-passivating, IIRC) would passivate in this way.

BromicAcid - 25-3-2005 at 08:13

Try looking online at jewlers supplies, you can get fused silica rods which may work better and high purity carbon rods for working with molten gold. You could probably use these rods for nucleation quite well. You can also buy little disposeable crucibles ment to be heated with a torch ment for holding molten gold and such, these should be great for working with molten bismuth.

12AX7 - 25-3-2005 at 12:54

Ah, chromium is actually passivated. Most metals around that reactivity passivate; zinc does reasonably well. Stainless has 10-20% Cr which comes to the surface and oxidizes (or sometimes does not, allowing it to rust; in which case citric or hydrofluoric acids must be used to passivate it).

Tim

neutrino - 28-3-2005 at 20:26

I’ve recently been playing with nucleation using small pieces of Bi and found them to work decently well. To make the rods, I pour liquid Bi into cold water, giving me something like this:

I pick out the big pieces and cut small notches near their ends (this is where I hold them with my tweezers). To nucleate the melt, I melt the other end of the piece in a small flame and put it into the melt. Keeping the end of the piece right at the surface and resisting the urge to keep pushing it in because it’s slowly melting (until the melt cools enough to start crystallizing) is important at this step. The rest of this procedure follows what I wrote above.

I recently got a pound of 99.99% Bi and have been playing with that. It makes around 50mL when molten, but I’m still trying to work out how to get a good crystal mass from this. I keep getting random nucleations in the melt and around the edges. I’m still playing with the edges, but I’m lost on what to do with the ones on the inside. I had this same problem with the smaller crystal masses, but the crystals were too small to be much of a nuisance. Here, though, they are. I won't know how well picking them out works until I can get the edge problem fixed... this could take a while.

sparkgap - 29-3-2005 at 02:23

If I didn't know better, I would've thought that last picture was a pile of fish!

sparky (^_^)

Update

neutrino - 22-4-2005 at 18:28

Well I'm still playing with the Bi. Looking back on my old ‘snuffer cap’ experiments, I don’t remember too many nucleations around the edges. IIRC, they only occurred rarely and when you did something wrong.

In fear that the copper might be contaminating the Bi, I’ve been playing with glass lately. I kept getting nucleations because the oxide made the metal stick to the glass. Basically, small vibrations made the melt creep a bit above the meniscus, stick there, and cool disproportionately quickly, nucleating the melt when it wasn’t supposed to.

I then started coating the inside of the beaker with a thin layer of plaster, but this made things worse. The melt doesn’t stick to the plaster, but the entire plaster-bismuth boundary nucleates at once. The only major difference between the plaster and glass/copper is that the plaster is somewhat porous due to loosing its water of hydration at these temperatures. Maybe someone here with more crystallographic knowledge than me can explain this? I’m stuck up a wall on this one.

Another Update

neutrino - 20-5-2005 at 18:07

I haven’t done too much with the Bi lately, but I am playing with an idea. Basically, Bi is melted under a liquid of some sort. The liquid keeps air from the Bi and thus prevents sticking due to oxide formation. The problem is, what do I use? It has to be something inert at ~280*C (no phosphoric acid), does not evaporate considerably at this temperature (glycerin, vegetable oil), and can be cleaned from the crystals (no silicone oil, unfortunately). Any thoughts?

BromicAcid - 20-5-2005 at 21:00

Many brands of mineral oil (rock oil) have very high boiling points, anywhere in the range of 260 - 360 C depending on the manufacturer, I consistently use it for oil baths near 200 C and I've tried to use it higher (for a blanket in NaOH electrolysis). Cheap and widely avalible and you can use it as a laxitive

sparkgap - 20-5-2005 at 22:36

"...you can use it as a laxative..."

Yeah, but lipid pneumonia isn't nice to have, so don't.

A question for neutrino: do you have a picture of the biggest Bi crystal you ever grew?

sparky (~_~)

neutrino - 21-5-2005 at 05:32

Really, mineral oil? I would have thought it would smoke far below these temperatures (paraffin does). Well, it’s worth a try. I just wish my hotplate hadn’t died again yesterday.

The biggest crystal I’ve grown so far is 1.5 x 2.5 x 1 cm. It grew as a result of uneven cooling (too much on the top). A picture will follow.

edit: I just remembered that someone borrowed my camera for a trip, so those pictures will be delayed a few days. I finally fixed my plate, time to play with that.

edit2: I fixed the plate (again) and tried some mineral oil. It smoked excessively by the time the Bi was molten. I guess I need a new brand...

[Edited on 22-5-2005 by neutrino]

neutrino - 11-6-2005 at 08:09

Well, my search has not found anything feasible yet. A summary of all the materials tried:

Glass beaker: sticking, nucleation.

Coatings on glass:
Plaster: Best nonstick properties, nucleation over entire bismuth-plaster boundary.
Charred gelatin-based glue: weak, nucleation.
Charred oil: Not as weak as glue-based coating, nucleation.
Charred sugar: excessive foaming during charring leads to weak, unreliable coating.
Charred plaster + glue: Similar but inferior to pure plaster.
Teflon: Sticking, possible decomposition.
Salt (NaCl): Sticking, nucleation, impossible to get an even coating.

Liquids added to melt (to prevent Bi sticking to glass):
Mineral oil: Boils, chars.
Butter: Boils, chars.
Vegetable oils: Smoke somewhat, char slowly where contact with air is present, no unwanted nucleation, no sticking.
HDPE: Smokes excessively with decomposition.
Soap (synthetic): Smokes excessively, chars and decomposes.
Sodium Acetate: Chars, decomposes.

Other crucibles:
Nickel crucible (with heavy surface oxidation to prevent alloying): sticking, nucleation (probably over entire Bi-NiO boundary).
Aluminum crucible: same as nickel.

So far, the best material is vegetable oil, meaning that I’m right back where I started. I’m running low on ideas, having tried just about everything within my reach. Does anyone have any other ideas that could possibly work? What I don’t understand is why nothing can even come close to matching that simple copper crucible.

Before I forget, here's that picture:

12AX7 - 11-6-2005 at 08:33

Ooo, nice

If you want a cover flux, you might try a low-melting chloride - bismuth should be low enough potential to support just about anything, let's see, hey it's about the same voltage as copper in fact. Lead chloride comes to mind, *cough* if with poisonous fumes. An eutectic could be mixed with other common chlorides to get melting point down to bismuth range.

Tim

neutrino - 11-6-2005 at 09:03

I’ve looked into salts and the most feasible thing I found was indeed bismuth chloride. Unfortunately, it would require burning Bi in a stream of dry Cl2 to make. Eutectics might work. Where could I find a chart of these?

12AX7 - 11-6-2005 at 09:38

You can find a list of SGTE phase diagrams on Fact-web, the tree sort page is here:
http://www.crct.polymtl.ca/fact/xmltree/pdTree.php

And one I found on here in an old thread:
http://ras.material.tohoku.ac.jp/~molten/molten_eut_query1.p...

Making copper chloride doesn't seem too hard, you should be able to do the same with bismuth by piling chunks on top of pool chlorine in a narrow glass column and dripping HCl over it. Lead chloride of course can be made by refluxing lead with HCl.

Hm, BiCl3 decomposes to oxychloride, though apparently that is soluble in HCl. Probably a good idea to use more stable chlorides then. Maybe something using FeCl2?

Tim

neutrino - 11-6-2005 at 11:10

Thanks for the links. I looked through everything and didn’t find anything suitable that I could make.

There’s one big problem with BiCl3. Bi doesn’t dissolve in HCl, so it has to be made by some other way.

12AX7 - 11-6-2005 at 13:13

You sure? How about KCl-ZnCl2? (While you're making the ZnCl2, save some for tinning as well.

)

Tim

neutrino - 11-6-2005 at 14:10

I'd forgotten that Zn was readily available. Time to start dissolving pennies.

IrC - 23-6-2005 at 19:06

I think you are making things hard on yourself. I bought 50 pounds of very pure bismuth, do not know the number but it appears from reading this thread it must be 99.9 % or close. Anyway, I took a neat little aluminum pan that had a handle on it and cooked it hard in my kiln, keeping it well below actually melting metal of course. This just to be sure it was positively coated with oxide, but still a shiny aluminum pan in appearance. I have a little metal melting pot I bought on ebay which the pan fits into. Filling it up with 10 gram Bi pellots, and melting them, there is zero sticking. Every time. I think you should be raiding your kitchen for bismuth melting implements!

I built a pyramid using the golden rectangle math thing and cast a couple pounds into it. The only problem I had was a crystal an inch long grew out of the bottom of the pyramid (it is cast upside down so that pyramid bottom is liquid surface) as it very slowly cooled, which I had to cut off so as to make the bottom smooth.

In a conversation with Patrick Flanagan (the famous neurophone inventor) years ago about pyramid power, I remarked that I believed the term most people miss in pyramid power is the MASS, not just the shape. He made the comment that he would take discharged nicads and put them in homebuilt pyramids and see no change in measured voltage. But on a trip to Khufu he went inside and did the same tests, measuring over a one volt rise and so he agreed that the mass was a factor here. Anyway, this is not the subject of the thread but I thought I would throw that in.

In light of the facts I mentioned here, I have been casting really large quantities into correctly shaped pyramids in the hope of calling ET or in general doing something or other mad science related. The point being if the aluminum dish has been heated in the past, I have zero tendency for bismuth to stick, or alloy, with aluminum. Try that instead of glass, oils, or whatever else you have been playing with. It also casts nicely into wood, kiln fired clay, and plaster. I would like to know though in anyone has any cool ideas how to stop these really big crystals from coming up. What I am describing here is say I fill 5 pounds of molten bismuth into a form shape, which is upside down, so that you are looking at the bottom as a layer of molten liquid, perfectly flat due to gravity. If I cool it very slowly without any trace of vibration to the form, suddenly I will notice large shapes start to grow up out of the surface as it cools, sometimes several inches tall. When I cut these off to smooth the surface (the bottom of the pyramid), I notice very large crystalline structures, very shiny and no trace of color (inside the cut crystal, the outside of the cast pyramid looks beautiful!). Probably something you are trying for but to me a big pain.

The more I play with this stuff the more I am starting to believe Bismuth has just got to be one of the strangest elements on the chart. Certainly an element no true mad scientist should overlook playing around with!

12AX7 - 23-6-2005 at 20:44

Quote:

Originally posted by IrC
If I cool it very slowly without any trace of vibration to the form, suddenly I will notice large shapes start to grow up out of the surface as it cools, sometimes several inches tall. When I cut these off to smooth the surface (the bottom of the pyramid), I notice very large crystalline structures, very shiny and no trace of color (inside the cut crystal, the outside of the cast pyramid looks beautiful!).

Neato

Wish I could get growth like that with any metal I have on hand... my 99.9% lead and aluminum only make at most 1/4" difference in height from peaks to valleys in the cubic crystals formed.

Quote:

Probably something you are trying for but to me a big pain.

Try alloying with up to 20% or so of lead, tin, zinc (Zn doesn't mix well with Bi or Pb, no more than 1.5%), uh indium, cadmium, whatever white metals you have on hand.

Quote:

The more I play with this stuff the more I am starting to believe Bismuth has just got to be one of the strangest elements on the chart. Certainly an element no true mad scientist should overlook playing around with!

Being a nitrogen column metal it certainly combines a number of properties.

Tim

IrC - 23-6-2005 at 21:10

I have several ounces of Gallium, thought about putting some of that in the mix. I was reading MSDS's and realize how useless those things really are. A dozen different ones say a dozen different things! One tells not to put Bi with aluminum, reactivity problem and so on, but I haven't blown anything up yet. I imagine heating my Al container beforehand is the reason, I doubt bismuth has much use for sapphire. I notice the MSDS will give all the poison warnings, a 1 for health and mentions liver and kidneys, but the ones for lead are worse a 2 with no mention of target organs. I have been soldering for 30 years and the only thing I notice is bouts of kidney problems from time to time. One thing I did wonder about was the mention for Bi of kidney and liver toxicity, and the explosiveness of the fine powder. Of course not being K3VVL I did not light a pile of filings.

I notice to get the tall crystals coming up out of the metal I need two things. One is a lot melted, and the second is to have it in an insulating form which holds the heat in for a limited time, to allow for very slow cooling.

What about the aluminum reactivity? Should I not be using my pan? I have not noticed anything going on, and like I said in the last post the liquid does not stick, and letting a panfull cool just for the sake of checking it out, the whole mass falls out without any trace of bonding to the sides or bottom of the aluminum. I am wondering about the safety from a toxicity standpoint as to melting/casting/filing and so on. Anyone know? I sure cannot find anything from the MSDS's those things would say don't let water touch your skin, and five different ones would disagree with each other. Is there a better online source to look up metals and chemicals as to safety concerns, actually written by people with some experience in the field?

12AX7 - 23-6-2005 at 22:01

Dunno about references but just don't forget a reality check... NOTHING on EARTH gets a rating lower than 1, because EVERYTHING is hazardous, poisonous or reactive (no shit it'll explode when you put chromyl chloride on it! WTF!). Even table salt earns a 1 because you have to eat "only" a half pound to kill yourself.

I personally have been soldering since age 9 (mind you I don't have the best ventilation or hygene, especially when it comes to handling solder!) and I'm perfectly healthy. I hate everyone who BS's about lead. Hell, I wonder how many kids who got brain damage from eating paint chips weren't already going south from the get-go... I mean... mmm, paint?

(Yeah yeah toddlers, different story..)

Aluminum and bismuth form no intermetallics so I see no possibility of (whatever the term is) them combining exothermically. In fact they are largely insoluble, indeed immiscible in each other below orange heat. Bismuth isn't nearly reactive enough to reduce Al2O3, although exposed aluminum metal (say a scratch) can technically reduce Bi2O3. Would it ignite, let alone strong enough given the amount of available Bi2O3? Hell no!

So yeah... I really hate MSDS's... in fact I recently saw an online article taddling on "them" for essentially crying wolf about everything...

Tim

neutrino - 24-6-2005 at 09:50

To be fair, water is not listed as hazardous. As far as I know, though, that’s the only thing that isn’t.

Quote:

Originally posted by IrC
One thing I did wonder about was the mention for Bi of kidney and liver toxicity

I really doubt that is a problem. After all, bismuth subnitrate is an FDA-approved stomach remedy (Pepto-Bismol…)

Bismuth has one peculiarity that is probably causing those peaks: it expands on cooling. In my experience, the following string of events usually happens when casting bismuth: Liquid bismuth is poured into a mold. It instantly solidifies where it touches the cold mold, possibly remelting later. The top, which is exposed to the air, eventually (and permanently) solidifies. At this point, you have a crust of bismuth with a good deal of liquid inside. When this liquid solidifies, it expands. The extra liquid gets out however it can.

If you cool from the bottom and/or insulate the top, you don’t get this problem. Instead, you get a surface that tends to have visible bumps caused by crystal formations. Remember that Bi expands as it cools, so the loose crystals that tend to form float to the top and effectively destroy any flat surface.

I’ve tried using an aluminum crucible, but it kept sticking. Moreover, this started happening where Bi and Al met:

(sorry about the color here)

I didn’t think that heating would make the oxide film that much thicker, so I didn’t do it. If I ever come across another aluminum crucible of these dimensions, I will try it.

Anyway, back to those crystals. I’ve decided against using zinc. Although it shouldn’t react with the Bi to a very large extent, it should still be enough to contaminate the melt. I get the feeling that boric oxide might form eutectics of some sort (the pure material melts at ~450C), but I can’t find any information on this at all.

P.S. IrC, where did you get your bismuth?

IrC - 24-6-2005 at 11:14

I have bought a little over 15 pounds on ebay from Emovendo over the last year. He is a good source and a very good ebay seller. Right now he has very pure Bi at $60 US for 5 pounds, plus $10 S/H. I cannot give the information of an overseas supplier as it took way too long to find and all I would accomplish is either causing the supply to dry up in the worst case, and without a doubt I would be throwing away my money for nothing as the price would start going up the minute the world started buying there. It is just an economic thing, greater demand means I pay more for what I was getting cheaper before I gave up the source.

The picture needs more light so I can see what you are trying to show. I do not use a crucible, it is just a neat aluminum pan with a handle which fits the melting pot. Possibly you are applying way too much heat, I keep it as low as possible and wait for it all to liquify, no chemical reactivity at all that I can see other than oxide which I skim off. Can you show a picture with more light of your Al crucible?

Also, I never thought about it but could the crystals be lighter than the liquid? That seems correct, as logically atoms would space out in a structure as opposed to a liquid with no structure. The expansion statement also makes sense, except that what I see coming up is localized and of a clear structure underneath the smooth metal which covers it. This is why it seemed like large crystals were just growing up. Possibly the expansion is driving a crystal structure slowly up in a similar way to growing crystals by slowly pulling a seed up from a molten mixture as in the making of laser rods?

"I really doubt that is a problem. After all, bismuth subnitrate is an FDA-approved stomach remedy (Pepto-Bismol…)"

Now I am scared. Everytime the FDA approves of something a year or so later there are 50 ads a day on TV by lawyers going after money to sue someone or other over the latest rash of deaths caused by FDA approved medicines. I do not want 12 arms growing out of the side of my head. Or do I? I take PB all the time to deal with ulcer problems over 20 years, which believe it or not I have directly related to the amount of handling of lead solder when I am doing big runs of one thing or another. Don't know if that is backed up by the AMA but they are all a bunch of quacks anyway. No doubt they also write MSDS's.

I looked at your cool water crystals, and that sure looks like the big glob of Samarium metal I have. Does Bi alloy with the lanthanides? I have a lot of them all. I did try experimenting with Indium/Gallium/Bismuth/Tin and some other metals in alloys. One batch melts below the Gallium alone, you cannot even hold it in your hand without it running out. Some of them form very interesting crystals. I did buy a quarter pound bar of pure Cadmium with the thought in mind of alloying that. But so many studies of toxicity I have read for Cd convinced me to leave it sealed up. Maybe someday I can find someone who wants to trade it for something I will use. Just do not want to take the risk of it burning. This I found out with Germanium. I had a cheap helium source for ballons which I thought was an easy way to have an inert gas to melt things in. So when I tried melting several pure elements with pure Ge, the Ge caught on fire forming the not so bad and the very poisonous oxides, all over the place, quite a big cloud in the room. After that I started being much safer, reading all I could find about the dangers. Good thing this was before I ever decided to melt that bar of Cadmium. Oh yeah, what I found was never use ballon helium, it contains a large amount of oxygen, in case some kid might inhale it, to keep them from suffocating. The Ge started burning in it and of course got much worse when I opened the vessel in an attempt to stop the reaction.

Possibly if I ever found something to contribute to the book project it would be a chapter on the things to look out for, as like I have mentioned here chemistry books never seem to quite cover these aspects of chemistry no matter which book I locate and read. This is exactly what led me to SCM in the first place. I am not into drugs but I noticed that at least the sites related to the subject talked much more about what could go wrong and what to watch out for than what I saw in any "mainstream" chemistry sites. Looking for a site which was more into real science and chemistry overall, I came upon Science Madness. Here I have learned more about the pitfalls, dangers, what to do and what not to do, of so many experiments covering such a vast realm of just plain chemistry than anywhere else I have found.

In just a few months I have learned more real world chemical experience right here on this site than I did in the last decade at any other site, book, university, or you name it source on the science of chemistry.

12AX7 - 24-6-2005 at 11:50

Quote:

Originally posted by IrC
Also, I never thought about it but could the crystals be lighter than the liquid?

Since bismuth expands on cooling, like ice, that would seem to be true.

Quote:

That seems correct, as logically atoms would space out in a structure as opposed to a liquid with no structure.

Well, not really, a solid is ordered crystalline whereas a liquid is chaotic motion.

A solid block of legos takes up a lot less space than the bucket they came in.

With the exception of course for Bi, H2O and whatever other materials have that quirk.

Quote:

Possibly the expansion is driving a crystal structure slowly up in a similar way to growing crystals by slowly pulling a seed up from a molten mixture as in the making of laser rods?

It sounds to me like the liquid is solidifying, causing an internal pressure which ruptures the solid surface (remember that bismuth is horribly low in conductivity), forcing out any crystals in the path.

Quote:

"I really doubt that is a problem. After all, bismuth subnitrate is an FDA-approved stomach remedy (Pepto-Bismol…)"

Now I am scared.

Now I am scared. First he mentions pyramids...which is bad enough, I mean geez...pyramids? But scared of the FDA? I can understand anyone disliking a government agency, but seriously, their standards are too high...
(Heck- ever notice how medications always get approved in other countries before the USA?)

Quote:

Everytime the FDA approves of something a year or so later there are 50 ads a day on TV

Ayop...my added emphasis explains this quite nicely.

Quote:

Don't know if that is backed up by the AMA but they are all a bunch of quacks anyway.

Now you're either drunk posting, or you are a new-age quack yourself...tell me, has homeopathy healed anything for you particular well? Those pyramids sharpen a razor blade for 'ya?

Quote:

I looked at your cool water crystals, and that sure looks like the big glob of Samarium metal I have. Does Bi alloy with the lanthanides?

Probably, but forming intermetallics, all with high melting points, which generally describes those metals' behavior.

Quote:

I did buy a quarter pound bar of pure Cadmium with the thought in mind of alloying that.

Good...

Quote:

But so many studies of toxicity I have read for Cd convinced me to leave it sealed up.

...Bad.

Quote:

snip

Tim

IrC - 24-6-2005 at 15:59

"Good, Bad, snip"

Tells nothing and says nothing useful, just a waste of space. As to my correct statements about how dangerous Cadmium is I refer you to this link:

http://www.inchem.org/documents/pims/chemical/cadmium.htm

"Well, not really, a solid is ordered crystalline whereas a liquid is chaotic motion."

No kidding, to state the obvious.

"A solid block of legos takes up a lot less space than the bucket they came in."

Also obvious, the point I was making. Therefore less atoms per cubic centimeter therefore lighter. What did you think I meant.

"Those pyramids sharpen a razor blade for 'ya?"

No, but I never tried either, seeing as how I do not believe in the stupid. However, the very wise among us pick out the grains of truth in a subject and study those. Much knowledge has been lost to history. What do you think the scrolls from the library of Alexandria had written on them, that is until people like you burned them heating bath water for the elite.

"Now I am scared. First he mentions pyramids...which is bad enough, I mean geez...pyramids?"

What have you done? I don't recall seeing your name in lights, no magic inventions, no wonder drugs. People who are famous, such as Patrick Flanagan and Thomas Bearden, who have strings of degrees, patents, and such, have spent time studying them and talking about it. So why try to deride me here. People way better than you would not do so. I also do not see how you suddenly jump to homeopathy concerning me from anything I said on this board. If you think the medical profession is filled with gods it's not my fault you do not know any better. A clue, they only care about your money. I could say many things and back it up with many proofs but this is the incorrect place to discuss the subject.

As to pyramids, some of what I said was in jest but I see you are not able to discern such depths. I brought them up as that was what I was actually doing with the bismuth so I felt it was in context. I find them easy and fun to make and people like buying them so why not. It makes me honest and legal money so why are you complaining about it. Never mind I don't want to know.

"Now you're either drunk posting, or you are a new-age quack yourself"

How did this thread degenerate into personal attack and libelous slander against me? By the way I do not drink or do drugs. As to being a quack I doubt you are qualified to judge, especially on the basis of no information. In fact only a fool makes such judgement.

"tell me, has homeopathy healed anything for you particular well?"

To answer your question shifts the thread into something else which I do not want to do, but I will answer here since you asked it here.

Yes. I have not had the flu or a cold in 7 years, since I started making colloidal silver. I use the term colloidal but I rather believe oxides are also involved in it's properties. After August 20th 1988 when Bio Labs burned down in a suburb of Phoenix, I had constant cronic bouts of lung infections. 1.5 million pounds of 111 cyanuric acid trichloride went up after the fire department ignored the placards plastered all over the place and poured 3/4 million gallons of water all over it. Also a 75,000 gallon tank of muriatic acid exploded, the entire thing being an orange fireball a quarter mile high into the sky, 4 blocks from my house.

There was HCN, greenish yellow chlorine gas rolling along the ground, and only God knows what else. I will not waste too much space here telling about it, it was global news, go look it up. The sludge in the streets was loaded into boxcars that kept exploding weeks after, the California govenor stopped the waste from being shipped into his state.

For years after that every cold or flu that came by nearly killed me every time, and I always caught them from everyone. Then one day there was a flu in NM so bad it was killing many older people, and a friend of mine who was always in better health than me was out from work for 14 days with it, quite ill. He said it took 6 weeks for all the symptoms to be gone, just a neverending low grade infection in his lungs. I was studying about CS at the time and had ordered the wire, built a power supply and so forth, and the last step was building the cell itself.

With that in mind I was at Kmart in line to pay for my bottle, when I noticed I was soaking in sweat and feeling quite ill. I went home, finished my generator, drank a glassfull, went to bed. The next morning I woke up and noticed that not only was my temperature gone, but I felt not the slightest trace of pains, aftereffects, or any symptoms of being ill whatsoever. Around 7 years later, every time I notice people sick around me, and notice slight symptoms coming on, I make a batch and drink it. The same thing, zero symptoms of illness the following day, every single time in nearly a decade now.

Not one cold or flu since in all these years. The royals made it through the black death in the 12th century by eating and drinking from silver goblets and plates. The only reason they became known as "blue bloods" is because they also stupidly ingested compounds of Ag. I do not want to turn this thread away from the Bi origin but I thought your direct question deserved a direct answer. I could give you much more proof but you wouldn't believe it anyway and I don't care whether or not you do. Homeopathy served mankind for millenia, and most modern drugs were based upon the study of the healing power of natural substances. I would have thought you already knew that.

I have said it before, a man with experience is never at the mercy of a man with an argument.

I never voted in your poll, and was not going to so don't make me go vote no. I can see why so many did so if that helps in any way. I do hope you are done with your assault on my intelligence so the thread can get back to the original subject, bismuth.

neutrino - 24-6-2005 at 17:35

Agreed. If you two must duke it out, please do so in the appropriate thread.

I will try to get a decent picture of the crucible again tomorrow. Today has been far too long already.

IrC, that Bi is ~$15/lb. Another seller usually sells chunks of the same purity for half that.

IrC - 24-6-2005 at 18:17

I not going to get into duking anything, I have said to 12AX7 all I am going to about the subject. I do not go out dragging others into stupid flame wars and I try not to let others suck me into them either. I do feel it is right to respond to personal attacks to a point. I know about the other guy, I have bought Bi there also, Emo is the first one that came to mind when I was thinking about an answer to the question as to where I find Bismuth.

Fleaker - 22-7-2005 at 11:12

Emovendo is a good seller. I ordered 5 pounds of 4N bismuth for general experimentation (yes, crystal growing mainly, but also fusible alloys) and overpaid. He promptly sent the money back when he could've just kept it. He's honest.

But in regards to bismuth melting, if you have access to a muffle furnace and argon (or nitrogen) melt it in a thick crucible (I make mine out of jewelry investment built up around a Coors crucible) and bring it up to 900C and slowly let it cool. Emphasis on slowly. Please note that any more than 900C and you can decompose the investment, which makes for a stinky SO2 experience.

From my experience, the longer it cools (hours), the better the crystalline product will be. When it drops to near its melting point (271.3C) open the furnace to let the atmospheric oxygen in and kill the blanket gas-and you get your vivid colors. Some crystals can get rather large (egg size and beyond) using this method.

Alternatively, you can get one of those party balloon helium tanks for cover gas and get it very hot on a gas stove (a porcelain crucible can be used).

Oh another great thing about those bismuth pellets, they make superb ball mill media. Virtually no static, they're hard, and they last pretty long (I've ground iron oxide with them and they're still fine).

neutrino - 22-7-2005 at 17:13

The thing about ebay is that all sellers are very honest and reputable. The only thing to choose by is price.

900*C? Crucibles are usually rated for temperatures much higher than that.

Do you get any nucleation around the crucible-bismuth boundary with that method? I'm working with small batches of bismuth (~40 cc) and can't really afford any of those because they approximately halve the maximum crystal size.

How well does part balloon helium work?

You must have impure grinding media; my Bi can be dented with a fingernail.

I guess I should give another update about my tinkerings. My hotplate broke a while ago, I spent weeks trying to fix the damn thing, gave up, and got a new one a few days ago. I discovered that boric oxide doesn't work (despite its semi-fluidity at these temperatures). That's about it for now.

Fleaker - 22-7-2005 at 18:36

In regards to the crucible, the gypsum/cristobalite coating is for insulation more than anything else. I want to keep the bismuth in a molten state and without agitation as long as possible. Basically I dip a large 100mL porcelain crucible into jeweler's investment (for casting gold/silver etc). Why not more than 900C? Sure the crucible can take 1200C easily, but that is pushing it for the calcium sulfate which at that temperature decomposition can occur. Trust me, when it decomposes, it release a ridiculous amount of sulfur dioxide (and at those temperatures probably trioxide as well).

So you're having problems with nucleation at the point of contact with the 'crucible' walls and bismuth eh? I don't know what could cause that as I've not had that problem. Maybe a 4M sulfuric acid wash would clean up the glass. I'm guessing that some residue or maybe microscopic oxide on the walls is providing the impetus for nucleation at that area.

Party balloon helium, from what I've heard is decent to use, but it is really ineffective as a cover because it is so light and doesn't properly blanket the melt. I seem to recall that it's not just helium but a mixture of a few other gases.

12AX7 - 22-7-2005 at 19:33

Balloon helium is diluted because people inhale it. Go to a welder's supply, theirs also lifts better!

The bismuth I have is listed as 4n5 (IIRC) and makes brittle crystals. (To be fair it's from Lou here so probably the same stuff he buys.) Obviously it isn't impure because it makes crystals, and apparently the same goes for yours? Maybe you have lead?

Tim

Fleaker - 22-7-2005 at 19:52

Yep, and if you need more Tim, I've still got about a kilo and a half yet to use. Guess I should've shipped that out with the kaowool...oh well.

Very pure metals can be purchased from Alfa Aesar if you have a good reason for wanting to buy it. They specialize in high end, 4N+ metals (and most other useful elements).

neutrino - 23-7-2005 at 04:28

True, but they're usually very expensive.

Why do you heat all the way to 900*C?

edit: One more question: is there a better way to separate the crystals from the liquid Bi than simply shaking?

[Edited on 23-7-2005 by neutrino]

Fleaker - 26-7-2005 at 21:19

In my opinion, 900C is overkill, and I only do it so the metal and the crucible are fully 'soaked' and can then cool for a long period of time thus generating a larger crystal.

There was a guy on ebay (I think he was German) that was making spectacular crystals 8cm in breadth by heating to high temperatures in inert gas. I emailed him but received no reply. I could argue with results like his, but thus far I've failed to emulate his crystal growing procedure.

A better method than shaking? Hm, I do not know. Shaking seems risky (bismuth is rather fragile), and probably painful from the splatter.

neutrino - 27-7-2005 at 06:04

Well-formed crystals tend to stay together without much problem, although malformed ones fly apart. The only thing that separates the two types is how they’re nucleated.

Yes, burns are painful, but as a former pyro, I hardly notice them anymore.

For the most part, the drops flying around are very small and don't cause much damage.

BismuthGuy - 17-10-2011 at 12:29

http://www.youtube.com/watch?v=y3xCGP_9PdU&feature=feedu

http://www.youtube.com/watch?v=GoHtQURTxJI&feature=relat...

Been making different bismuth objects for awhile and can pretty much make any size crystal using seeds and a large stainless steel pot. The trick is to buy enough of the bismuth.

However I am more interested in the theories behind manipulating the oxidized layer to generate the wanted colors.

Has anyone experimented with introducing different amounts of oxygen into the crystal as it is removed from the molten liquid? (Although I would advise not using any high concentration of oxygen around the molten liquid lol)

[Edited on 17-10-2011 by BismuthGuy]

[Edited on 17-10-2011 by BismuthGuy]

BismuthGuy - 17-10-2011 at 12:36

Thinking about it a little more when watching Bismuth change(Usually its lighter then progressively gets darker)... It might be better to reduce the amount of oxygen in the air to get the neon rainbows until it dries.

With that said how might one go about doing that?

Plexy glass box with rubber arms to work with a layer of zink metal ?

hmm...

[Edited on 17-10-2011 by BismuthGuy]