Sciencemadness Discussion Board

What ELSE is in the sulfur?

jgourlay - 1-12-2008 at 12:03

Last night I opened up a bag of gardening sulfur. It LOOKED like sulfur, but sure as heck didn't SMELL like sulfur. It smelled more like an insecticide of some type.

Label: Active ingredients Sulfur 90%. Inactive Ingredients: Other 10%.

Any idea of what the "other" is, and any methods for getting rid of it?

JohnWW - 1-12-2008 at 13:27

Because much technical-grade sulfur comes from deposits in sedimentary rocks (into which superheated steam is injected to melt the sulfur which then rises under pressure to the surface where it is collected in tanks), it is liable to contain dust derived from sedimentary rocks, such as limestone, dolomite, gypsum, and silica. The other main source of technical-grade sulfur is from mining volcanic fumaroles (e.g. like Mt. Etna) in which it is deposited from the vapor as a yellow sublimate; this would contain dust derived from igneous rocks such as basalt and andesite. But as for your sulfur smelling like an insecticide, - that sounds like deliberate adulteration with something else.

[Edited on 2-12-08 by JohnWW]

Klute - 1-12-2008 at 14:42

I remember trying to purify garden-grade sulfur it was hell, lots of brown/black residu very difficult to seperate, and the sulfur would cristallize much too quickly from the boiling xylene to offer a decent seperation. <you might want to try washing with a minimum amount of water, that removed at least part of the red shit, and the other inorganics and rocks dust shouldn't be a true problem for most uses of technical sulfur. Something like a acetone wash might remove any added pesticides or such.

watson.fawkes - 1-12-2008 at 14:43

You can distill liquid sulfur. If using ordinary lab glass, you can cool the still head with moving air. Alternately, you could build a still out of steel pipe.

chemkid - 1-12-2008 at 17:51

It sounds like most of the above impurities would be easily eliminated with a quick rinse with HCl and water. Sulfur is insoluble in just about everything, so we can use that to our advantage.

chemkid

JohnWW - 1-12-2008 at 19:54

The stuff is soluble in CS2, to the extent of 24 parts in 100 parts CS2 at 0ºC and much more soluble at higher temperatures, although this solvent is toxic and inflammable.

not_important - 1-12-2008 at 23:25

The two common additives to gardening or agricultural sulfur are clay, used as acoating to reduce fire danger, and wetting agents - detergents - to make it easy to mix with water for spraying.

The wetting agents can be removed by repeated washings with plain water, if not removed they can react with the sulfur when heated forming H2S and highly unsaturated organics and even carbon. Clay can be mostly removed by drying the sulfur, but not heating very hot, then melting the dry sulfur at a temperature as little above its melting point as possible, and leaving it molten for some time to allow the clay to settle out.

Some sulfur also has CaSO4 in it, from mining it. A lot of sulfur now comes from desulfurisation of natural gas and petroleum, this may contain trace amounts of organic compounds.

jgourlay - 3-12-2008 at 10:38

Got it.

Wash it. Melt it. let it sit. Recrystallize it?

Someday before I die I want to go the place where you can walk up to the cave with your geologists hammer, whang out a chunk, and just drive home.

I also want to visit the place, mentioned in Agricola, where you can walk up with a cup to the pool of mercury and collect all you want.

not_important - 3-12-2008 at 17:28

One of the board members lives in a location in Canada near some plant that produces sulfur as a byproduct, and has said that the railroad line tracks often have large piles (in the lab sense of large) of sulfur here and there along them. I'm near a glass works, and can get both white sand and soda ash similarly.

UnintentionalChaos - 3-12-2008 at 17:47

I have made pure-enough-for-simple-experiments sulfur from the garden variety, but it's a lot of work. I washed it with a ton of water until the water remained clear, dissolved in boiling xylene (giving a lot of gray-brown junk in a clear yellow liquid) and filtered through very, very fine stainless steel mesh (none of the gray-brown junk visibly passed through). Upon cooling, tons of long yellow crystals seperate from the solution, which were filtered, rinsed with cold xylene, and then 50/50 methanol/ethanol and allowed to dry.

There is still some junk in it, but not a lot. And it no longer smells like fertilizer. It smells like proper sulfur.

[Edited on 12-3-08 by UnintentionalChaos]

Mumbles - 3-12-2008 at 18:30

It's common for the 10% to be a clay for the reasons already stated. Separation can be as easy as adding it to a beaker of water. The clay will hydrate and fall to the bottom, while the sulfur will float so I have heard. I'm unsure about this, as sulfur seems to be denser than water. I suppose it doesn't hurt to try just a little bit.

Ketone - 4-12-2008 at 12:12

Heh, that's really strange.. Never had any difficulty with this myself.

I've separated sulfur from garden sulfur supposed to be 80% biosulfur, "green", and to be used against some kind of mildew or something - it did NOT look like sulfur though, but very fine dirt - by simply dumping it in water, waiting for the sulfur to sink to the bottom (all the brown stuff seemed to dissolve in the water or atleast be suspended in it - doesn't matter) then decant the (now brown) water, add water, then decant and repeat until the water was clear.

Then I simply let the sulfur and a little remaining water sit in an improvised petridish until the water evaporated.
I was left with a yellowish coating which was scraped off and dried with low heat..

After all was done I got a yellow powder that looks like, smells like, and burns like - sulfur.
I can't say for certain if it's completely clean of course, but it IS clear of whatever the brown stuff was (I reckon dirt) and most importantly, it WORKS. Still have some of it, and I've used it for stuff like gunpowder to S2Cl2 with no problem.

This "separation" was one of the first things "chemical" I ever did, quite a long time ago now, and as you can see- shit easy to do..

Sounds to me like you should try to find some "green" sulfur so to speak, as it seems they don't dilute it with as much crap as the "normal" sulfur you've bought so far..

jgourlay - 8-12-2008 at 08:20

Unintentional: what is the safe way to boil Xylene? I'm imagining "oops!!!" KABOOM!

jgourlay - 20-4-2009 at 12:11

Folks, can I some safety hints on Unintentional's method? Also, I up in the thread is the idea of distilling sulfur.

That to me says it must be "sulfur gas", which indicates high temp/high pressure. Can I get further clarification, esp. w/regard to technique.

Either that, or a good place to buy sulfur cheap?
Quote: Originally posted by UnintentionalChaos  
I have made pure-enough-for-simple-experiments sulfur from the garden variety, but it's a lot of work. I washed it with a ton of water until the water remained clear, dissolved in boiling xylene (giving a lot of gray-brown junk in a clear yellow liquid) and filtered through very, very fine stainless steel mesh (none of the gray-brown junk visibly passed through). Upon cooling, tons of long yellow crystals seperate from the solution, which were filtered, rinsed with cold xylene, and then 50/50 methanol/ethanol and allowed to dry.

There is still some junk in it, but not a lot. And it no longer smells like fertilizer. It smells like proper sulfur.

[Edited on 12-3-08 by UnintentionalChaos]

UnintentionalChaos - 20-4-2009 at 15:04

Quote: Originally posted by jgourlay  
Folks, can I some safety hints on Unintentional's method? Also, I up in the thread is the idea of distilling sulfur.

That to me says it must be "sulfur gas", which indicates high temp/high pressure. Can I get further clarification, esp. w/regard to technique.

Either that, or a good place to buy sulfur cheap?

Quote: Originally posted by UnintentionalChaos  
I have made pure-enough-for-simple-experiments sulfur from the garden variety, but it's a lot of work. I washed it with a ton of water until the water remained clear, dissolved in boiling xylene (giving a lot of gray-brown junk in a clear yellow liquid) and filtered through very, very fine stainless steel mesh (none of the gray-brown junk visibly passed through). Upon cooling, tons of long yellow crystals seperate from the solution, which were filtered, rinsed with cold xylene, and then 50/50 methanol/ethanol and allowed to dry.

There is still some junk in it, but not a lot. And it no longer smells like fertilizer. It smells like proper sulfur.

[Edited on 12-3-08 by UnintentionalChaos]


How not to kill yourself while working with hot xylene? easy! no open flames and do it in a ventilated space. I did this outside for the ventilation part (man, does it smell). A long time ago, I had boiling xylene go up in a very sooty fireball due to stupidity, so I've more than learned my lesson. I have some big, thick silicone gloves for handling the hot-but-not-outrageouslly-hot vessels.

I would actually use toluene if you can get it, as some xylene has ethylbenzene in it, which can form some H2S on heating with sulfur.

not_important - 20-4-2009 at 17:45

Quote: Originally posted by jgourlay  
Folks, can I some safety hints on Unintentional's method? Also, I up in the thread is the idea of distilling sulfur.

That to me says it must be "sulfur gas", which indicates high temp/high pressure. Can I get further clarification, esp. w/regard to technique.

Either that, or a good place to buy sulfur cheap?



At ordinary pressure sulfur boils at 444.7 C, which is pretty hot. As a minimum you'll need to well insulate the still, being able to heat the upper section is even better. Generally done under a slow stream of CO2, to keep air and water out of the hot sulfur. This is heating mantle or sand bath territory, unless you're doing it on a pretty small scale.

Air condenser and let the liquid sulfur collect in something you can either remove the solidified block from or melt it out of. If you use a descending air condenser feeding into a container that you can insulate a bit, the collected sulfur can be kept liquid, pouring it out into shallow dishes when done. Again a flow of CO2 through the still into the collection section helps reduce SO2 and H2S formation and so on.

You want to remove as much organic material, such as the wetting agents in 'wettable sulfur', before doing any serious purification. As already mentioned, washing with water several times does OK. After that allow the sulfur to air dry. If it has clay added, just barely melting the dry sulfur and allowing the clay to settle, and/or filtering it through hot fine wire mesh, will remove much of the clay.

U.C. has covered using flammable solvents. Again, a way to warm the filtering apparatus is handy at keeping it from clogging from sulfur dropping out of solution.