Sciencemadness Discussion Board - Help - What have I??

Help - What have I??

m1tanker78 - 5-1-2011 at 14:18

Hi, I'm new to this board and to chemistry in general. Please help me determine what substance I have.

First off, I was attempting to make a small batch of zinc chloride possibly mixed with some ammonium chloride. I started off with a small quantity (~ half liter) of 31% solution of muriatic acid. Since I didn't have any zinc pieces, I began adding small pieces of galvanized steel, allowing the zinc to completely fizzle off and then some. The fizzling never ceased when adding fresh pieces of galv although it did slow drastically. I ran out of galv pieces so decided to try killing 2 birds with 1 stone (produce a bit of ammonium chloride and neutralize the solution) by adding around half a cup of 'clear' ammonia solution. I realize the ammonia solution is very weak but still didn't want to overdo it.

IIRC, the solution was a sort of greenish gray color at the time. I let the solution sit overnight and found that there was a layer of brownish white froth on top, dark green liquid underneath, and a layer of dark precipitated material on the bottom. I scooped out the froth and let the solution sit on my bench for a couple of days.

Today, I scooped out what little froth was left and removed the steel pieces I'd left in. I now have a neon green colored liquid and dark precipitate at the bottom.

I realize I probably failed at my original objectives since it seems both zinc chloride and ammonium chloride crystals and solutions are white and clear, respectively. Is the solution tinted green because I accidentally made ferrous chloride (among other things)?

I really don't want to throw this solution out after I sacrificed all that steel

-Tom

plante1999 - 5-1-2011 at 14:43

I is very simple, iron disolve in HCl to form FeCl2 witch will oxidize with air to iron hydroxide and oxide, i dont think you coul retrive sommewath with this solution,you can filtrate the iron oxide.

[Edited on 5-1-2011 by plante1999]

m1tanker78 - 6-1-2011 at 17:30

Thanks plante.

So you think the solution is pretty much useless? Just so you know, I'm trying my hand at making a homemade brazing/welding flux. According to what I've read, iron powder is a common additive which is why I didn't sweat the iron content to begin with. I'm not trying to reinvent the wheel, just gain a better understanding of it.

I tested the solution for ph and it came up slightly acidic so added in a bit more household ammonia solution. This effectively neutralized the solution and formed a thin layer of viscous liquid on top of the solution along with a jelly like blueish-white substance. I read somewhere a while back that adding a base to ferrous chloride forms a type of jelly but can no longer find that text. The jelly dissipated after I shook the solution but the viscous layer immediately re-formed. The main liquid component of the solution changed from neon green to dull brown.

I passed a magnet underneath the container and was able to pull up quite a bit of dark powder (iron) from the layer of muck at the bottom. What is that viscous layer at the top? Should I heat the solution to see what happens?? If I decide to toss the solution but keep the iron powder, how would I go about storing it and keeping it from oxidising? I live in an extremely hot/humid region.

What are my options here??

-Tom

DougTheMapper - 6-1-2011 at 18:07

Not that this is my area of expertise, but I think Zn can form various amine complexes. This could explain some of the crazy color changes and opacity.

m1tanker78 - 6-1-2011 at 19:02

Thanks Doug! I'll look into that.

bbartlog - 7-1-2011 at 05:16

The green color is (was) surely FeCl2.
I don't know what compound(s) you ended up with; however I would suggest (at least if you are in the USA, or have ready access to US coins) that zinc pennies are a better way to make ZnCl2. You need to grind off a small patch of the copper coating (takes a fraction of a second on a bench grinder... I ended up making two small spots on opposite rims of each penny when I did it), at which point the zinc will readily react with HCl, leaving behind a paper-thin copper shell. This works properly only with post-1982 pennies as the earlier ones are essentially all copper.

blogfast25 - 7-1-2011 at 10:52

Quote: Originally posted by bbartlog

I don't know what compound(s) you ended up with; however I would suggest (at least if you are in the USA, or have ready access to US coins) that zinc pennies are a better way to make ZnCl2.

Even better: zinc casings of spent no-frills batteries. Carefully prise off the steel protective casing first, the underlying casing is relatively pure zinc. Since as it’s rather thin you can cut through it with a sharp knife, small hacksaw or a strong pair of scissors. Then remove the paper and battery electrolyte. Flatten and sand down or wash the inside parts of the zinc casing, so you have little or no electrolyte black gunge sticking to it.

Dissolve in strong HCl, filter and carefully evaporate the remaining solvent. This will give you a mix of zinc chlorides and zinc hydroxy chlorides, depending a bit on evaporation/crystallisation conditions. That should be the basis for a decent flux...

Note: dissolving zinc in acid evolves hydrogen; do this away from open flames.

[Edited on 7-1-2011 by blogfast25]

ScienceSquirrel - 7-1-2011 at 10:58

If you want zinc sheet make friends with a local roofer.
Round here it is used for flashings etc and they always have off cut pieces that they will give you.
Even run of the mill zinc is very pure.

m1tanker78 - 7-1-2011 at 21:41

Quote: Originally posted by bbartlog

The green color is (was) surely FeCl2.
I don't know what compound(s) you ended up with; however I would suggest (at least if you are in the USA, or have ready access to US coins) that zinc pennies are a better way to make ZnCl2. You need to grind off a small patch of the copper coating (takes a fraction of a second on a bench grinder... I ended up making two small spots on opposite rims of each penny when I did it), at which point the zinc will readily react with HCl, leaving behind a paper-thin copper shell. This works properly only with post-1982 pennies as the earlier ones are essentially all copper.

Thanks for the suggestion. That crossed my mind but I had quite a bit of galvanized steel laying around so thought I'd strip the zinc off (I have to do so anyway before welding on it). I didn't think the iron contamination would be much of a problem in the HCL solution but hey, I learned something. I'm going to start gathering up pennies to do a very small batch. I figure I shouldn't have that much of a problem with copper in the solution if I pickle the pennies in a separate HCL solution just before I grind and dunk them. I'm also going to hit up the municipal battery drop-off center and see if I can scrounge some batteries for zinc casings, carbon rods, etc...

Sedit - 7-1-2011 at 23:48

Take a bunch of pennys and stack them up. Hit them with a blowtorch and the Zinc will just melt right out of the casing quickly into a puddle. I also seen a web page where someone just tossed a bunch in an old pot and stuck it on the stove. After they melted he just poured it out into water.

vulture - 8-1-2011 at 09:44

Quote:

Not that this is my area of expertise, but I think Zn can form various amine complexes. This could explain some of the crazy color changes and opacity.

Zinc complexes are colorless unless the ligand or the anion is colored because of its filled d shell.

[Edited on 8-1-2011 by vulture]

m1tanker78 - 9-1-2011 at 00:28

Thanks for the replies; loads of good ideas...

@blogfast25: What would be the ideal way to evaporate the remaining liquid? Boil, low heat/reduced pressure, evap in air?

@science squirrel: Unfortunately around here, the only kind of roofing sheet that contains zinc is in the form of galvanized steel.

@sedit: I considered melting the zinc out of the copper plate but figured there'd be some alloying taking place (or copper contamination in the zinc at best). I'll still give it a try and see what happens. I realize that zinc melts at a much lower temp than copper but recall plating some pennies with zinc years ago. When heated, the zinc alloyed with the copper to form brass. I have a small aluminum foundry so if this works out, I'll just *pretend* to deface a thousand or so pennies in a seperate crucible

As for the amine complexes, I'm going to google that and learn something new

peach - 9-1-2011 at 03:24

Blogfast is onto the winning solution here, battery casings.

I was going to suggest the same thing.

Zinc lantern batteries (the kind that look like a brick with springs on the top) have a seriously decent amount of zinc in the casings.

If you crack the plastic casing off, you'll find big D cell like cells inside to harvest.

I did this with sulphuric, to produce the sulphate and one lantern battery will give you around 140g of the salt - and it seems like it may be extremely clean zinc, particularly when compared with the other sources you have available.

Mine came out pristine white, as did Arthur Dent's who did it with hydrochloric. If there was iron in the casings, it'd be tinted green or yellow respectively.

Using sulphuric to dissolve metals can be annoying as, if you add a bit too much or don't leave it to fully react, you'll end up with concentrated sulphuric at the bottom as you try to boil it down. That needs boiling off (at over 300C), and just a a few drops will produce clouds of white fumes for aaaaaaaaaaaaaages, which can't be done inside and looks a bit odd outside (people will cough if they breath it in before it dilutes down as well).

A rough guide!

To produce my salt, I pulled the casings off with some pliers and then used an old toothbrush to physically scrub every visible traces of the paper separator and black paste off - you want them nice and clean!

I then put them in a clean jar with a little battery acid and gave them a swirl to wet them all, and left them for a few minutes. They will start to fizz (effervesce). This is the acid attacking the zinc but, more importantly, attacking any engrained or invisible muck on their surfaces - pickling them.

Empty the acid out and rinse them with clean water - to wash away any muck that's been etched off.

Weigh the casings and add the corresponding amount of acid to turn that weight of zinc into the salt. With sulphuric, I used about 10% less than I needed to, to try and make sure I didn't have much left when boiling it off later.

Add the acid to the casings, top the jar up with water, cover with cling film, leave somewhere warm and wait.

I left mine for about two months because I was busy with fixing the house. When you return, the casings will have corroded away (with some left). Filter, keep the filtrate, boil it down. I had ZERO problems with fuming since it'd all gone for all intents.

Using battery acid is good, when compared with drain acid, because it's usually cleaner (the concentrated drain sulphuric will often have dyes or organic muck burnt into it, the battery acid doesn't).

Different batteries

Both Zinc lanterns and alkaline cells use the manganese / zinc chemistry - with a different electrolyte.

I don't know how true this is of other brands, but Energizer's alkaline batteries have the zinc present as a small blob of paste in the centre. There is not a lot there and getting it out and working with it is likely going to be hard work compared to the lanterns.

I have a bunch of photos of this on my friendface profile, I'll send you a link in a second.

m1tanker78 - 9-1-2011 at 10:27

@Peach: Thanks for the link as well as the good info. I'm kicking myself for throwing away all those D cells I pulled out of lantern batteries!! I'd tear them apart, remove the carbon rod and chuck the rest in the garbage can, thinking there was nothing else of value left over :mad:

. I did a magnet test on the casing and sure enough, it was ferrous (steel) but next batch of lantern bats, I'll dig a little deeper and see if I strike gold (um, zinc that is).

I attempted a small batch of zinc chloride with notched pennies. I used regular old ~31% muriatic for this. The pennies fizzled vigorously where I'd notched them. It became apparent that it was going to take a LONG while since I only made tiny notches. After a while, I got impatient and heated a few more pennies with a propane torch. I have oxy/acetylene but would've been overkill.

As expected, the inside melted before the outter Cu shell. What I didn't expect was to see the torch flame momentarily go green - indicating that at least some of the copper was most likely oxidizing and burning off. Shortly after the green flame disappeared, the coin became a gray blob. I tested one of these blobs in a seperate container with a little bit of muriatic. The blob reacted with the HCL almost voilently and finished dissolving in a matter of a few minutes. There was a thin chewed-up disc left behind as well as some copper-looking grains at the bottom. I decided to toss a couple of these blobs into the HCL with notched pennies. That effectively put an end to ~3 hours waiting for either the zinc to dissolve or acid to neutralize. The ph quickly changed from highly acidic to a hair below neutral (very, very slightly acidic) and the fizzling had almost completely stopped.

I'll update later - I have to run!

Tom

m1tanker78 - 12-1-2011 at 10:58

Update...

I finally got around to tearing some carbon zinc batteries apart and cleaning up the zinc casings. I obviously put the carbon rods aside for later use. Most of the batt's I disassembled had their zinc casings almost completely chewed-up. I suppose they quickly deteriorate once they're completely discharged. A couple of the casings looked pristine - maybe they hadn't been completely discharged and/or didn't sit for a long period of time. Regardless, the casings had quite a bit of electrolyte residue on them so I let them sit in a solution of DH2O and dawn soap which I very slightly acidified to try and dissolve the electrolyte as well as clean up some of the oxydized zinc.

After I meticulously rinsed the casings, I dunked them (one at a time) into a container of 31% HCL. It was very obvious that there was STILL(!!!) some soap residue left over. I had a miniature volcano of corrosive suds - heck, just one more stain on the concrete. When the zinc stopped reacting with the acid, I took the jar over to my heat lamp setup to slowly evaporate the excess water. To my surprise, the solution seemed to come back to life as it warmed up. The vapor was horribly acrid! After a while I had to remove the heat; didn't want my neighbors thinking I was running a meth lab! I saturated the solution with zinc pieces and let it sit overnight.

The following morning, I inspected the solution and noted that the zinc fragments were still intact and there wasn't any reaction taking place. The liquid (hopefully zinc chloride) has a hint of a smoked grey tint. The solution smells 'metallic'; hard to explain. I filtered out the zinc fragments and tested the solution on both rusted and freshly ground-to-base-metal steel. The liquid didn't seem to perform terribly well on either test.

I may end up throwing this solution out since I got excellent results with another flux project I had going in parallel. I'll perform some tweaks and tests and report back (if anyone's interested).

Tom

peach - 12-1-2011 at 11:59

This is why I'm hesitant to use soap on any of my glass if I can do it with solvent, base or acid instead.

The detergents in them are far more effective than a lot of people think. They're thickened up and formulated to make them spreadable and get them into every corner possible.

If a tiny bit of them is left, you'll see it appear later.

If you're cleaning something like a beaker, put your hand over the top and shake it like beyonce

Repeat two or three times with fresh water giving it swirls under the tap between each. You need to keep going until the bubbles burst as they would for a cup of water alone, and then give it a few more quick rinses to be sure. Also think about where you leave it to dry. You want to turn it upside down, and not have the rim in anything else (e.g. if it's touching the surface, someone may have left detergent on there earlier).

I would suggest if you repeat this, you don't wash the casings the way you did. Once you have all the big lumps of paste and paper scraped off, give them going over with an old tooth or nail brush to scrub them clean. Then dunk them in some sulphuric or hydrochloric for a few minutes giving them a swirl, then rinse them and inspect to check you haven't missed any hidden bits of muck.

That will dissolve the paste and gunk away nicely, by eating the surface off the zinc.

Repeat if in any doubt of cleanliness, you're only loosing tiny amounts of zinc, but gaining more in purity.

I would also recommend you throw away the very tops of the casings, where the can is crimped. There are almost always specks of paste / separator hidden inside the rolled crimp, and getting them out is not worth it for the amount of zinc you'll loose by cutting them off.

Arthur Dent - 12-1-2011 at 13:36

As stated by Peach, the Zinc casings should be free of any impurities before the big dip.

I usually unroll the casings with a pair of needlenose so that I literally peel off the entire casing into a foot-long "strip" of zinc. With careful work while holding the bottom with a pair of vise-grips, this should give you a fairly flat strip and prevent the inner paper envelope with the MnO2 from breaking up. 3/4 of the way down the battery, just carefully twist and pull up the battery innards, trying to keep the paper envelope and battery crud in one piece (patience is required).

Next with a small hard-bristle brush, wash both sides of the Zn strips with water (soap is okay, as long as you rince well). Then I do a quick dip in some "sacrificial" hydrochloric acid just to completely remove traces of soap and electrolyte, then I rince again with cold water. A last wash of the strips in a jar filled with acetone should give you perfectly clean Zinc. (you can skip that last part if you wish).

The final step is dropping the zinc parts in smaller portions in some new, clean, concentrated HCl. The reaction does fizz a lot at first, and when it subsides, just leave the zinc pckling in the acid for a few days, in a WELL VENTILATED AREA. When all of the zinc is dissolved, add an excess of zinc and leave it for a few more days. When some of the zinc will not dissolve, this means that most of the HCl is reacted and you should have a fairly concentrated solution of the ZnCl2.

If your zinc is too corroded, it will be hard to clean-off and there will be all sorts of residues of K and other grudge that will dissolve along in the acid. It's not necessary to have brand new batteries, but long dead batteries might not be the best candidates.

Robert

m1tanker78 - 13-1-2011 at 17:40

For the record, no soap in the future unless absolutely necessary. Also, I think I'll stick to pennies for ZnCl2 but still collect the battery cases.

One batch of Zn chloride I made was with pennies (see above). The only visible contamination that resulted were some copper flakes sitting at the bottom of the solution; easily filtered off with a coffee filter. I'll try dunking a zinc case or two in some 30% sacrificial HCl to see how well it cleans them.

As for making a soldering/brazing/welding flux, I learned that ZnCl2 on its own isn't particularly good for soldering anything practical except galvanized steel which I've always been able to do with commercial cleaning products

I've always been curious to develop a flux which would allow me to soft solder steel without the flux fizzling off or running like the devil when I heat it. I was able to develop a very interesting flux which I'm going to turn my attention to now.

The problem with joining galvanized steel is that the strength of the joint is at the mercy of the steel-zinc joint. The zinc-solder-zinc joint may very well withstand a crapload of force but that doesn't mean a thing if the zinc plating easily separates from the base metal.

Tom

peach - 14-1-2011 at 03:22

True.

It's interesting to hear you're after fluxes.

There is a site on the web if you google around for soldering aluminium that sells kits - a stick and a flux - for doing it sans AC welding gear; with a gas torch instead. I think the site is geared towards guys doing repairs on their planes or building parts for them, so they can solder the airframe.

To clean the casings, I went with sulphuric. Like robert, I'd peeled the casings off and had some long strips of it, which I chopped up with the wire cutters on the pliers before washing so there was a lower chance of contaminating them after they'd been washed; as I'd been using the same needle pliers to take the batteries to bits.

I put all the chopped up bits (about a palms worth) into a big olive jar (I think it was a 500g one that'd already been washed like crazy over the months with acids, bases and solvents), dropped them in and put just enough battery strength sulphuric in to make a puddle at the bottom.

Then gave it a good swirl and shimmy for the five or ten minutes to jiggle the strips around and coat them all. That saves using lots of acid for a wash and they will be fizzing away.

[Edited on 14-1-2011 by peach]

m1tanker78 - 16-1-2011 at 13:24

Quote: Originally posted by peach

True.

It's interesting to hear you're after fluxes.

There is a site on the web if you google around for soldering aluminium that sells kits - a stick and a flux - for doing it sans AC welding gear; with a gas torch instead. I think the site is geared towards guys doing repairs on their planes or building parts for them, so they can solder the airframe.

To clean the casings, I went with sulphuric. Like robert, I'd peeled the casings off and had some long strips of it, which I chopped up with the wire cutters on the pliers before washing so there was a lower chance of contaminating them after they'd been washed; as I'd been using the same needle pliers to take the batteries to bits.

I put all the chopped up bits (about a palms worth) into a big olive jar (I think it was a 500g one that'd already been washed like crazy over the months with acids, bases and solvents), dropped them in and put just enough battery strength sulphuric in to make a puddle at the bottom.

Then gave it a good swirl and shimmy for the five or ten minutes to jiggle the strips around and coat them all. That saves using lots of acid for a wash and they will be fizzing away.

[Edited on 14-1-2011 by peach]

Thanks Peach, I just bought a quart of 98% sulphuric acid. I have to admit that I'm a little intimidated by it but I'll still be giving this a try...

Harbor Freight sells aluminum brazing rods that have mixed but mostly good reviews. I haven't tried the stuff personally (yet).

As it turns out, the soap residue didn't seem to affect the end product at all. I'm still working on another flux that makes it easy to soft solder galvanized steel, clean and even rusty steel, copper, brass and even ALUMINUM(!!!). I'm using plain old solid core plumbing solder, not any special filler with exotic alloys. No pre-cleaning of any of the materials. I have yet to try it out on stainless steel. I nearly crapped my pants when I saw that plumbing solder wet and flow on aluminum...

Tom

peach - 17-1-2011 at 03:18

Quote:

I nearly crapped my pants when I saw that plumbing solder wet and flow on aluminum...

I've had one of these AC/DC sets from ESAB before, but had to sell it to cover the mounting tuition fees and cost of tile adhesive needed to tidy the house up :mad:

They are fairly expensive, and being able to do simple work with fluxes and solders would be great. Particularly with an aluminium filler - I'd be hesitant of using lead solders on it in terms of strength.

Battery acid will work fine for your casings. I have both the concentrated and battery acid strength. Whilst looking at ways people at home could make this special glow paint I'm trying to produce, I looked at using boiling 98% acid and found it was far worse in terms of simplicity, safety and the end result.

A good thing about using lower concentration sulphuric is that the acid is more disassociated when mixed with water and, concentrated sulphuric off the shelf is often mixed with dye when I buy it. Other guys have mentioned getting it and it being nearly black. This is because the strong sulphuric will dehydrate anything organic it touches during handling / bottling / storage, turning it to carbon and staining the acid. The lower concentrations can do this, but they are much less prone to it and it takes a lot longer.

Battery acid sold in the refill packs, in my experience, never has any dye in it or visible staining. The reason for the lack of dye is likely due to it being on the way to a car battery (important), as opposed to a drain (people put shit down the drain everyday

).

Tool porn

m1tanker78 - 17-1-2011 at 11:05

Quote: Originally posted by peach

Quote:

I nearly crapped my pants when I saw that plumbing solder wet and flow on aluminum...

I've had one of these AC/DC sets from ESAB before, but had to sell it to cover the mounting tuition fees and cost of tile adhesive needed to tidy the house up :mad:

).

Tool porn

I only use lead-free solder. I came dangerously close to buying a Miller AC/DC tig rig. Looking back, I'm glad I didn't because I'd still be paying on it. It would complete my small shop, though. I currently have 4 arc welders, 1 mig (no gas at the moment), a plasma cutter which I hardly ever use, an oxygen/acetylene rig, and propane for the small stuff. My first arc welder was one I built from a scapped microwave oven.

Here's the sulfuric acid I bought:

http://www.youtube.com/watch?v=-bweWvb0wws

According to the guy in the video, it seems pretty clean and fairly concentrated. I was originally going to buy battery acid from the auto parts store thinking it should be cleaner.

peach - 17-1-2011 at 15:34

I spent so long pining for an AC set, sitting on the ESAB site going all dreamy eyed. But then, most laboratory gear is stainless, which only needs the DC and it's faaaaar cheaper to get a DC only set than one that'll do aluminium as well.

I bought a welder when I was 14, a Clarke MIG set. Then a Harris MX oxy / acetylene torch when I was 16. I also bought the stack of iron ladle lining bricks around then and set about building a furnace to make an attempt at melting iron. Then a Thermal Arc 400 amp DC set when I was 17/18, then that ESAB not that long ago.

Sold the Thermal Arc, and the ESAB. The cost of the darn cylinders is a kick in the balls too! I have an argon one for chemistry, that costs enough on it's own. Adding the oxygen and acetylene ones would be painful.

I actually just had a scary incident with one of them, for the first time. I picked up a fairly new looking X size (waist height) argon, opened the stem and felt gas jet across my hand. So the stem is a bit leaky for a start. I then tried opening the regulator. Nothing..... but 3000psi on the gauge. It's going sticky, and I only just bought the thing.

I'd like one of those Matheson Monel regulators so I can use the reactive gases straight from the cylinders. A snap at $2k.

You can always concentrate up battery acid by boiling it down, if short on supplies.

You'll know it's ready when the lady of the manor comes in waving a rolling pin at you because the house is filling with white smoke that's making everyone cough.

[Edited on 17-1-2011 by peach]

m1tanker78 - 18-1-2011 at 12:30

Quote:

I also bought the stack of iron ladle lining bricks around then and set about building a furnace to make an attempt at melting iron.

Interesting. Did you ever get that iron melting/smelting operation going? I have a small foundry that I use to melt aluminum. In spite of its small size, it can easily handle over 10 pounds of aluminum. I need to make or get some green sand so I can actually put it to good use. So far I've only been pouring ingots.

Tom

peach - 19-1-2011 at 04:40

I didn't.

I was only 16 at the time and doing it entirely on my own - my dad died when I was 9 or 10, so I didn't have any supervision or help with the welding, cylinders, crucibles or lathe.

At the time, the garage was in a terrible state, the roof was leaking so much there was mould all over the inside and it'd keep raining in there even when it's stopped outside. The thing was absolutely jammed full and even at that age I realised, "this is going to go wrong", envisaging myself tripping up with a a litre or so of molten iron.

I used to be up on the roof on a regular basis, painting it with bitumen and putting tarpaulins over it. None of it worked. It had a flat, bitumen felt roof, and it was bubbled / cracked to bits.

I ended up taking it down myself. On doing so, I discovered sails, yes the things from boats, had been used to line the roof - it was quite clearly a makeshift build.

I had bags of both green sand and petro (oil) sand for pouring aluminium into. The petro bond stuff is incredible. It's like play dough it's so fine and soft.

If you're not in the mood for building your own muller, it's worth buying a bag of petrobond just to see what it's like.