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Author Topic: Calling all chemistry geeks!
Grummash

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Icon 1 posted November 22, 2008 06:02      Profile for Grummash     Send New Private Message       Edit/Delete Post   Reply With Quote 
Now - let's be clear on one thing - this isn't a necro, it's an update ok? [Wink]

I think that after all the input I have received from you guys, I should at least let you know how things went. Errrr....welll....they didn't go at all actually. [Frown]

here is my starting material, the 10 or more years old clump of crystals gone all manky in its box:

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Even when I took the crystals out of the box, they were still pretty grotty:


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So here is my first attempt, showing the lovely little seed crystal I picked out which subsequently dissolved in what I thought was a saturated solution!


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When that attempt produced no crystals I boiled the solution down to 125ml and let it cool. All I got was thick layer of blue sand at the bottom of the jar! Not even worth the bother of photographing. [Frown]

So, I may boil it up again when the disappointment has passed, or I may just leave it on the shelf for another 10 years. [ohwell]

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...and yet, across the gulf of space, minds immeasurably superior to ours regarded this earth with envious eyes...

Posts: 2335 | From: Lancashire,UK | Registered: Aug 2005  |  IP: Logged
TheMoMan
BlabberMouth, a Blabber Odyssey
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Icon 1 posted November 22, 2008 06:31      Profile for TheMoMan         Edit/Delete Post   Reply With Quote 
___________________ Grummash I maybe wrong on this but speed is not your friend. Bring your solution to temp again and let it slowly cool for days getting down to room temp.

When softening hardened tool and die steel our cooling rate was 25 degrees F per hour from 2300 deg. faster than that and it did not anneal. Internal steel grain structure is not unlike crystals if it went to small grains it was glass hard.

If I were to try your project. I would put your solution in a baggy in a large water bath and slowly cool the whole thing. Think the kitchen tool item a double boiler. Then let the water evaporate. SLOWLY time is your friend.

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Those who would give up essential liberty to purchase a little temporary safety deserve neither liberty nor safety.


Benjamin Franklin,

Posts: 5848 | From: Just South of the Huron National Forest, in the water shed of the Rifle River | Registered: Sep 2002  |  IP: Logged
ASM65816
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Icon 5 posted November 22, 2008 10:54      Profile for ASM65816   Author's Homepage     Send New Private Message       Edit/Delete Post   Reply With Quote 
quote:
October 30, 2008, 16:28
I'd use some good clean water, distilled and bottled, not from the tap. Tap water's got stuff that's fine for you but could potentially poison your crystal lattice ....

November 10, 2008, 09:22
As the water dissolves you should have ... and whatever other minerals were in the water.

from a "Crystal Growing" article
Adding any ionic crystal to a supersaturated solution will start precipitation by giving the solution a seed. Even dust will act as a seed.

How many "microscopic" paper fibers are in your solution? I didn't see you mention filtering the solution to remove dust or any other unwanted materials (but maybe I just skimmed the posts).

I assumed that the "blue sand" could be the result of 30,000 seed particles (like paper fibers or dust).

Is a coffee filter sufficient for removing unwanted particles?

EDIT: Have you considered electricity (anode/cathode) usage in crystal growth?

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Once a proud programmer of Apple II's, he now spends his days and nights in cheap dives fraternizing with exotic dancers....

Posts: 1035 | From: Third rock from sun. | Registered: Mar 2001  |  IP: Logged
Grummash

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Icon 1 posted November 22, 2008 13:26      Profile for Grummash     Send New Private Message       Edit/Delete Post   Reply With Quote 
MoMan - on my last attempt the solution was cooled by just pouring it into a jar and putting the jar on the shelf. The room I keep the jar in is usually about 17 degrees C, so it took however long 125ml of hot liquid takes to cool in those conditions. I certainly didn't try to chill it in any way.

I have been thinking about your suggestion regarding cooling the liquid slowly. Next time I may try sitting the jar of solution in a big pan of hot water so that only the surface of the solution is in contact with air at room temperature. If I use a pan that holds 4 litres, that should take a while to cool to room temperature and should slow the cooling of the solution. I may give that a whirl next weekend.

ASM - the 'blue sand' is a thick layer of tiny Copper Sulphate crystals, not the lump of big crystals I was aiming for. [Frown]

If the problem is microscopic particles/ fibres acting as seeds, then I don't have any kit that could filter the liquid at that level. And I haven't thought about using electricity so far......I took on this little project because I thought it was simple! [ohwell]

I guess we will have to see what happens next time, but for now the jar can stay on the shelf!

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...and yet, across the gulf of space, minds immeasurably superior to ours regarded this earth with envious eyes...

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Xanthine

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Icon 1 posted November 22, 2008 16:29      Profile for Xanthine     Send New Private Message       Edit/Delete Post   Reply With Quote 
In the lab we clean our solutions of dust and debris using 0.22 micron filters and a vacuum funnel. I have no idea where you'd find that stuff outside a lab supply catalog.

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And it's one, two, three / On the wrong side of the lee / What were you meant for? / What were you meant for?
- The Decemberists

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TheMoMan
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Icon 1 posted November 22, 2008 18:05      Profile for TheMoMan         Edit/Delete Post   Reply With Quote 
___________________ Grummash __ For your purposes a plastic kitchen strainer and two layers of coffee filter should do.

Copper Sulfate being an ionic salt will be in solution as a Copper ion and a Sulfate ion loosely tied to seven water molecules all behaving as ions. So for your crystal to grow to a very large one you must give the ones you want to attach to each other to have plenty of time to find the right place to land. Think of them as swimming and their speed is controlled by temp. the warmer the faster they move.

As the water molecules evaporate out of the solution the number of good collisions will increase. So if you have a way of keeping the solution at say 50C until the water evaporates out you will get a better molecule or grain. Eventually the water will leave and all that is left will be the blue-vitroil.

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Those who would give up essential liberty to purchase a little temporary safety deserve neither liberty nor safety.


Benjamin Franklin,

Posts: 5848 | From: Just South of the Huron National Forest, in the water shed of the Rifle River | Registered: Sep 2002  |  IP: Logged


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