Poor quality of Ferrous Sulphate

[hrushi]

Hi Guys

I have processed some gold, up to filtration all was going great.
For precipitation I used Ferrous Sulfate which unfortunately was of worst quality (got it from local supplier).
Powder precipitated was very fine and some kind white-grey slurry was formed on top.
Couldn't filter using vacuum pump had to gravitational filtration.
I have attached images.




How should I proceed?
Thanks
Hrushi

 

[FrugalRefiner]

My first thought would be to redissolve the precipitate, then drop again with something different, like SMB, or a better quality ferrous sulfate.

Dave

 

[hrushi]

Thanks Dave

Grey slurry is oily and sticky.
Should I dry it or burn it or directly put everything into AR.
As few filter paper is there I have to burn them and put them in AR.

Hrushi

 

[Lino1406]

Suggestion: take sediment sample and boil in HCl

 

[Johnny5]

Suggestion: take sediment sample and boil in HCl

Agreed.

I don't know if this will help, but many years ago I bought a 50lb bag of ferrous sulfate at a fertilizer store. It wasn't pretty, but it was cheap. After dissolving in distilled water I would filter the solution using a funnel plug, and I never had a problem dropping values.
However if you are going for ultra pure 999+ , I would not suggest using ferrous sulfate.

 

[Geo]

For better quality gold, it's always better to do a second refine and drop with different precipitants. The OP didn't say what the starting material was. Is there a chance that there is silver in the mix? I don't think the ferrous sulfate is the problem unless it is a fertilizer that contains calcium and even that wouldn't cause the gray mass in the photos. I would suggest taking a sample and boiling it in water to see if any is soluble in just water. Next, try a sample in dilute HCl. If neither of these improves the appearance, simply redissolve the whole mass and precipitate using a different precipitant.