I was walking ... ok you dont need to know the details.

 

I have a jar of metalic powder that i found in a garage. It was used to make reflective paint so i asumed Al ... So to test my theory i put a pinch into HCl but nothing happened so now i am lead to believe that it is not Al. I tested it with a magnet. Its not magnetic. It is grey in colour and is quite heavy (i will work out its density and post it later)

 

Any suggestions as to how i can find out what it is ???

Much appreciated

flame test?

Mmm good idea ...

 

I could not perform the flame test (out of gas).

 

I did another test with HCl , using less diluted acid (30%). It reacted slowly and the acid/powder mix is now a dark green colour.

I`st of all you don`t mention what color the powder is, is there a reason for that?

 

a green soln does however narrow it down somewhat, now try using sodium hydroxide

Edited November 18, 200817 yr by YT2095
multiple post merged

It is a grey/silver metalic powder.

I didnt observe any reaction between it and a strong NaOH soln after 20 min.

It has a density of 3.08 g/ml

 

Something to consider, it might be an aloy.

 

P.s my density might be slightly off (i used a scale that only has one decimal).

thnx

i suspect your density is wonky. A powder isn't the same volume as a solid. Also your powder might not be entirely dry or free of oxides and other contaminants

So what colour flame does it give in a bunsen then?

I couldnt perform a flame test because i dont have gas for my bunsen burner!!

if it didn`t react with the NaOH then it`s not Alu, another idea would be to crystalise your green soln and look at them under the microscope, their shape and color can be very revealing.

I dont have a microscope lying around and its going to take me a day or so to crystalise the green stuff so il keep you posteed.

I couldnt perform a flame test because i dont have gas for my bunsen burner!!

 

a candle or any other flame should work too

My best guess right now is chromium powder, in which case when you crystalise the green stuff then dehydrate it, it should turn purple.

I did what the flashman said and it turned light green/yellow then upon more heat went brown and then black??

Odd, that sounds more like nickel but that should have been magnetic as the powder.

sounds like Copper to me, perhaps a Brass, especially the chlorides then oxides.

perhaps it`s been coated with something?

 

try dissolving in Nitric acid, and then add a a weak chloride soln to this, look for a white PPT, I`v seen Silver (alloyed with copper) have this effect.

did all the powder dissolve when you did the HCl addition?

No not all the powder disolved (it could just be that the acid lost some acidity though)! I gree that it may be a aloy of copper but i dought it contains any silver (baught it for quite cheep).

 

It was slightly affected by a strong magnet (when i moved the magnet close i saw the particles moving a bit) but not enough for the powder to "slick" to the magnet.

 

What chloride soln should i add to the nitric HNO3 metal mix (chloride that i got from the HCl and metal mix)?

 

Thanx

a simple salt water soln would provide the chloride needed.

if it goes cloudy white, then it likely contains silver.

Thanx to all but im not gonna go further with this seach. What ever it is it doesnt seem to be very usefull to me and i dont have time to deal with it now, so thanx for all the help.

Titanium Dioxide, calcium carbonate Are used in commercial reflective paints according to their MSDS sheets.

Titanium Dioxide, calcium carbonate Are used in commercial reflective paints according to their MSDS sheets.

 

Yea - TiO2 as a white pigment and CaCO3 as a filler. The reflectivity would come from metalic particulates.