red color after calcining

[cad]

Boy i dont seem to be able to get past this point. After I my nitric reduced pregnant solotion with a bright yellow or orange color in a clear filtered solution using ammonium chloride i get a oarange/ yellow pricp. I then dry to a powder slowly and smash it in a morter and pestle in from of a fume removing device i use for essay work. Then i take the powder usually orange and put in a bowl on my hot plate and slowly heat to calcinate up to the max heat of the plate (slowly looking for only white smoke) The material starts turning black and i can see metalics if i believe there is more chlorine in material i put it in a small paragon oven and continue to heat looking at the color and fumes. with the heat in place the powder looks black with a slight bit of brown or red granules mixed in. When cooled it takes on a red or crimsin color witch i put on a filter paper and try to wash a bit. but it still is mixed up.

I then re- refine first in nitric acid tp remove any pd reduce the nitric filter etc. left over in the beaker in the beaker there is a very very fine red or crimson color that is dificult to filter but after a few times i get a yellow or golden clear solution.


The tails and crimson colored powder i put in ar and then filter again (ar does not completly remove the crimson fine powder) And it takes very fine repeated filtering to remove the powder to get a clear solution and i start all over again. this time the material after calcification is more clean black.


Is there another process that i can try or any ideas on what is going on.


Thanks for any ideas you have.
Carl

 

[butcher]

what are you processing? what values do you think were dissolved originally?
was this ore?
It sounds as though you were after PGM's, if so How does heating the solution change the picture?

the question seems vague to me without details of your process.

 

[cad]

I am processing ore.

The first thing is a fine grit
the next is to put it in AR. filter and reduce by evaporation three or for times no silver or much of anything to filter but i do anyway to get a clear but have a general color

let it rest, filter all sediments ( the color of the pregnante solution is yellow or orange)

heat up solution till it almost boils and add ammonium chrolate and pricipitate (orange color mostly)

all along i use stanus to see what is there.

I let the pricipitaion dry and calcinate on hot plate first.

then the proplem starts (perhaps some kind of contaminante) but the material does not completely turn to a gray,black or white material. there is a red or brown color mixed in with the metalics that i canot at this point separate.

perhaps i am doing something wrong!!

Carl

 

[butcher]

Ore is a complex mix, and you may or may not have sucsess with using aqua regia as a leach method.

I would take the sample powder, neutralize with sodium hydroxide, wash out the salt water well, then mix with a flux and collector metal like lead oxide and cupel this, then part the button and see if this red mud has values.

Edit more thought: how are you concentrating your ore so that it is mostly just values, did you roast the ore concentrate well before leaching, what process are you using to eliminate the base metals, if you are just directly treating a mineral with acids without much pretreatment you can have anything in this soup?

 

[Lou]

The red is probably iron oxide.

In any case, if you precipitate the Pt with ammonium chloride and calcine it, you can dissolve away any iron oxide produced with HCl or H2SO4 or HNO3. If it's Pd, be sure to use only HCl.

Then redissolve the purer PGM in aqua regia or HCl-Cl2 and then go through the steps all over again.

 

[cad]

Thanks for your ideas!

I have not yet used the HCL-CL2 method yet I have heard it mentioned here and am not sure of the ratio or the the potency of the the cl2.

I do not pick up any magnetics on the mixer bar.

The red powder does not disolve in AR I am trying to use a flux mix that contains litarge and cupeling it but have not come up a large enough bead to part out.

I have used sodium thiosufate leach before but am not sure of how to collect the potential values yet. Can you prisip. with regular chemicals.

i have tried useing ammonium hydroxide and hydrozine sulfate but i do not get any reactions perhaps the hydrozine is not potent enough. (any ideas)

please let me know any other ideas nd i will keep you posted with my experiments,

again thanks for sharing!

Carl

 

[Barren Realms 007]

Thanks for your ideas!

I have not yet used the HCL-CL2 method yet I have heard it mentioned here and am not sure of the ratio or the the potency of the the cl2.

I do not pick up any magnetics on the mixer bar.

The red powder does not disolve in AR I am trying to use a flux mix that contains litarge and cupeling it but have not come up a large enough bead to part out.

I have used sodium thiosufate leach before but am not sure of how to collect the potential values yet. Can you prisip. with regular chemicals.

i have tried useing ammonium hydroxide and hydrozine sulfate but i do not get any reactions perhaps the hydrozine is not potent enough. (any ideas)

please let me know any other ideas nd i will keep you posted with my experiments,

again thanks for sharing!

Carl

When using the thiosulphate in an acid solution raise your PH to 6-7 and you PM's should drop out. If using in a base solution lower your PH to 6-7 and you PM's should drop out.It will have more of a tendancy to remove base metals from what you are processing when used as a base solution.