Silver chloride conversion question

[stefano]

I want to make this for the first time.
I had 340 g of solder balls from IC`s. There was too some plastics adherent at the solder balls and a lot of tiny gold plated IC-pins adherent at the solder balls.
For the past two years i treated these solder balls with used HCl-solutions to dissolve the tin and the lead little by little, like a stock pot.
After the metals had all dissolved, i had eliminated the formed lead chloride with hot water washes and following cooling the solution down to 0°C and in this way precipitating the lead chloride. I did this until there was no more precipitated lead chloride in the down cooled water. Then i rinsed the mud ( now 50 ml of volume ) in the buchner funnel with 500 ml hot water and one drop every 7 seconds to eliminate as much as possible lead chloride which could remain in the mud.
I want to recover the silver in the mud and using it for inquarting. Now i want to convert the silver chloride ( now dark grey color ) with NaOH into oxide/hydroxide at pH 9, then rinsing with water, then drying the mud and then incinerating the mud to eliminate plastics, carbon, and converting possible insoluble tin chlorides which had possibly formed in the long dissolving for over two years. Then i want to do another HCl-wash to dissolve and eliminate these chlorides.
Then i want to repeat the rinsing and NaOH treating to convert possible new silver chloride formations.
Now my question. Had i to do the silver chloride conversion to silver with the methods of dilute H2SO4/iron, or NaOH/sugar, or is it sufficient when i incinerate the material to converting the silver oxide/hydroxide to silver with heat?
Second question. Can i use the converted silver directly for inquarting, or is it necessary to dissolve the silver in nitric and precipitate it with copper, and then use it for inquarting ?

 

[lazersteve]

You have gone above and beyond cleaning the silver chloride. At this point simply:

1) put the chloride in an oversized heat resistant container (4+× the chloride volume).

2) Cover the chloride with water to twice it's settled volume.

3) Add pelletized lye with stirring until all chlorides turn brown/black without any visible white or purple.

4) Slowly add a saturated solution of very hot tap water and white cane sugar (normal sugar) with stirring between each addition. This water/sugar must be saturated.

5) Go slow, stir, add until heavy silver cement settles quickly to bottom of reaction vessel.The conversion reaction is very fast and generates heat.

6) Settle and decant off straw colored lye/water solution.

7) Rinse gray/green Ag throughly with water and settle/decant.

8) Rinse with diluted HCl (10-15%), stir, settle, decant

9) Repeat step 7.

10) Collect Ag powder in 4-5 coffee filters and wring out all liquid with gloved hands.

11) Melt the clean Ag powder with a light sprinkle of soda ash in a clean melting dish or air dry after step 10 and use for inquarting as is.

The entire process will only take a 30-45 minutes and produces 100% purity (on xrf) Ag from any relatively clean feedstock of AgCl.

Steve

 

[lazersteve]

As a side note. If gold was present it will be recovered on the first use of the Ag for inquarting with the other Au.

Subsequent recover/refining of the Ag will be 100% purity with proper filtering techiques.

Steve

 

[stefano]

Thanks at lazersteve for his detailed answer.

Now i have another silver chloride problem. I have stored for over a year wet mud which is covered with very dilute HCl. The mud is the remaining of the lazersteve HCl/H2O2 method to dissolve MLCC´s and recover the Pd.The mud had from the beginning of the recovery always the same color ( yellowish-white ) and didn't dark in the light. I made yesterday a test with a little volume of this mud and treated it with dilute ammonia. A part of the mud dissolved ( i think it is AgCl, because it precipitated again with adding of HCl ), and a part of yellowish powder remained undissolved.
Now i want to recover the silver chloride for using it for inquarting. If possible i want to avoid the use of ammonia because of possibly dangers of forming explosives.
Now my question. Is it possible to treat this mixture with the silver chloride conversion methods like NaOH/sugar or H2SO4/iron, and then following a leach in HNO3/water to dissolve the silver ?
Or have i to separate the silver chloride first from the unknown yellowish powder with another method (ammonia or other ) ?

 

[lazersteve]

Wash with very hot water 3 times with vigourous stirring followed by settling between each wash.

Do your lye/sugar conversion (it will be dirty).

Wash the product of the conversion throughly with hot water again until wash wayer pH is near 7.

Melt with equal parts soda ash or use directly to inquart with soda ash.

The base metal contaminates will end up in the inquarting nitric acid liquid or be filtered off with the Au solids and separated from the Au with AR.

Each cycle like the above will produce cleaner Ag.

Steve

 

[kernels]

Thanks for your great answers here Steve.