Sciencemadness Discussion Board

Phosphors from CRT's - large amount recovered - What can be done?

RogueRose - 1-1-2018 at 05:42

So let's say someone has about 30lbs of phosphor from the inside of CRT's, both TV's and monitors and maybe 3-4lbs of phosphor from HPS/MH bulbs. It seems there is a wide variation of composition between what makes up these phosphors from some rare earth minerals, to silver to many common elements. the funny thing is that after looking a a VERY long list of about 400+ types of phosphor, I don't think I ever saw the big "P" on the list anywhere (bummer). I was thinking that phosphorus could be made from this stuff.

I'm wondering if during a recycling process, is it OK to collect it all from all sources into one location and then send the collected powered out for processing? Seeing that it is near impossible to tell the composition by looking at it (and models change the type used between runs sometimes), there aren't many options when dealing with this.

Does anyone have any interesting facts, thoughts or ideas on CRT/light bulb phosphors?

Radium212 - 1-1-2018 at 06:56

Well if you've mixed them together that's buggered any chances of selecting certain phosphors. But if you have just the CRT phosphors you could use them in homemade CRTs, or maybe spinthariscopes. Yeah, build a little spinthariscope. How much would you charge for say 5g of a zinc sulphide phosphor, just out of curiosity.

Radium212 - 1-1-2018 at 06:58

Oh and be careful about the light bulb phosphor. It may be contaminated with mercury.

unionised - 1-1-2018 at 07:36

I doubt there's much market for 2nd hand phosphors, especially wen they are mixed up.

Most phosphors don't contain phosphorus and, if even they did, it would be easier and cheaper to get phosphorus from bone ash.

RogueRose - 1-1-2018 at 08:05

Is all the phosphor in CRT's (TV's and Monitors) the same? I looked on Wiki and they listed A LOT of phosphors and there were maybe 4-6 for CRT's if I remember correctly. Also the HPS/MH had almost the same number of types as well and it depended upon the color that was wanted from the light.

I don't have the phosphor but the person processing them does. I can contact them and see what they have and if they are seperating CRT and bulb phosphor.

unionised - 1-1-2018 at 08:23

Quote: Originally posted by RogueRose  
Is all the phosphor in CRT's (TV's and Monitors) the same?

No.

Radium212 - 1-1-2018 at 10:03

I suppose you might be able to flog them on eBay or something. Mixing them together was a bad move though. And where the hell did you get all this?

RogueRose - 1-1-2018 at 10:52

A guy who does recycling has been collecting it from CRT's for about 3 years.

AS far as making phosphorus, I know of two sources of P in my area. Bone ash and Triple Super Phosphate (0-45-0) which is a calcium based fertilizer. Actually there is also something called soft rock phosphate which is about 0-13-0 to 0-20-0 and is calcium based as well. It's almost the same price as the triple so it seems a no brainer.

IDK how phosphorus is extracted in any way, but I know that the bone ash has MUCH less P than the triple super phosphate.

Can the triple phosphate be used to make P? I'm guessing it can be used to make H3PO4 and I'm guessing P can be made from that. P is one compound i've never really read up on.

PirateDocBrown - 1-1-2018 at 12:07

You can use CaH2PO4.H2O (triple "super" phosphate) to make P. But there are several caveats:

1)You need high temps. Carbothermal reactions can work, or thermite types, done in an air-excluded environment. Since glass will melt at these temps, you need a metal retort.

2) You need a means of capturing the P underwater. It will be white P, formed at these temperatures. Otherwise, it will burn immediately. Take all other precautions for white P, as well.

3) Presence of hydrogen in your reactants will cause the formation of pyrophoric phosphene gas, PH3. This stuff robs you of your product, is toxic as hell, and stinks, to boot. To avoid its formation, make your reactants anhydrous, and choose ones that have no hydrogens. So you will need to convert your CaH2PO4 to something else. Many have used Na3PO4, anhydrous.

4) What you get will likely be rather dirty. You should have in mind uses for the product that are tolerant of such contamination, or have planned some means of purifiying your product.

Radium212 - 2-1-2018 at 03:04

Maybe you could purify your dirty product through dissolution in carbon disulfide?

Does anyone have any interesting facts, thoughts or ideas on CRT/light bulb phosphors?

Sulaiman - 2-1-2018 at 04:53

Just to repeat Radium212's comment about Spinthariscopes;
https://en.wikipedia.org/wiki/Spinthariscope


IF you have access to a radioactive source such as Am
AND a x10 or more eyepiece or magnifying glass, even better a microscope etc.
then I really recommend making a Spinthariscope
quick, easy, pretty.
By varying the distance between source and screen the image changes from a few random stars (tiny bursts of light) to a boiling cloud (in 2D only) ... I think worth seeing.

I imagine the effect with mixed phosphours could be quite psychedelic ... sellable
(I've never heard of a Color Spinthariscope)

EDIT: removed 'usb' from 'usb microscope' as I have not actually tried with a usb microscope, and the lightb levels are probably too low.
Also, I forgot to mention;
if you do make a spinthariscope you need to use it in a really dark room after many minutes of dark-adaptation ... up to 30 minutes.

[Edited on 2-1-2018 by Sulaiman]