Nouran Alaa
Member
We built a refinery gold small factory scale, 4kg per day in an italian impianti closed tumbler attached to it a precipitator. Aqua regia was used to recover the gold.
First Time:
Our first time I had zero experience and throughout the process the technician lead us blind. We put 4102 grams of unrefined gold and we were expecting 3494.57 grams, we only recovered 3478.90 grams with a loss of 15.67 grams.
The technician insisted that the machines normally "eat" the gold in their first run.
All machine parts were thoroughly washed, no water was thrown out and we let the water sit for 3 days with 3kg of caustic soda and the refiltered the water to see if there is still any water inside.
Second time:
In both times the gold purity ranged between 999.1 to 999.5 which pretty satisfactory but the losses were unbearable.
After doing some research here are some mistakes, I think our technician did:
1- He added all the urea all at once and then he directly added the SMB and waited for the bubbles to settle and then filtered directly.
2- The addition to caustic soda was unnecessary to the resting water after all the process was done.
3- He let the gold in the tumbler for 3.5 hours only which might be low time but the purity was of 999.1 was not bad.
4-He did not measure very accurately the amounts of chemicals
for each Kilo of gold he used:
3Liters of HCL
1 Liter of HNO3
900 grams of urea dissolved in 2L/kg of water
670 grams of SMB dissolved in 3L/kg of water
he added all the HCL at once and the titrated the HNO3 till it was fully poured into the tumbler (approximately 20 mins)
We tried to recover these losses:
we collected all the gold in all the waters
we burned any gloves or cotton used throughout the process
we burned the filter papers used
We recovered the silver and did fire assay analysis on it
At the end: 12.75 grams were fully recovered and 17 grams remained lost.
We suspected that the issue might be the technician or the fire assay performed in the beginning. to fix this issue:
1- We hired a different experienced technician
2- we used gold that was analyzed by our fire assay lab and another external lab were both gave the same values.
Third Time:
4992.62 grams of gold were admitted to the tumbler and 3796.14 grams were expected but only 3774.64 were recovered.
21.51 grams losses the highest so far.
we ran into some operational issues where:
1- the precipitator's capacity was so small it couldnt hold all the amount of gold so we had to empty some of it into 2 buckets using a rubber pipe which was thoroughly washed after.
2- The Precipitator was leaking but the leak was instantly noticed and any leakage was collected (not yet recovered but the leakage was around 10mls of fluid so it wont be holding 21 grams of gold that's for sure)
3- I did not like the washing technique of the technician as i I felt there was a lot of splashing drops everywhere but where then all wiped with cotton and also yet to be recovered.
Chemicals used and technique:
1-15 liters of HCl added all at once and 5 liters of HNO3 were then titrated for 30 mins.
2-The tumbler was operated for 6 hours and then the gold was recovered.
3-in the precipitator tank the urea was added whilst the filter was pumping the gold solution from the tumbler (2.5 kg of urea was used)
4- The SMB was then added (3kg of SMB) and the gold in the buckets (from the issue we rand into was also readded again to the precipitator and filtered.
We are planning on doing a recovery cycle were all waters are refiltered and materials (gloves, cotton, ... etc) are burned and refined to see how much we will recover.
I still cant put my hand on where all the losses are coming from. I will be glad to clarify any issues and please excuse my English and terminology as they are not my first language.
First Time:
Our first time I had zero experience and throughout the process the technician lead us blind. We put 4102 grams of unrefined gold and we were expecting 3494.57 grams, we only recovered 3478.90 grams with a loss of 15.67 grams.
The technician insisted that the machines normally "eat" the gold in their first run.
All machine parts were thoroughly washed, no water was thrown out and we let the water sit for 3 days with 3kg of caustic soda and the refiltered the water to see if there is still any water inside.
Second time:
| 3976.58 grams of gold entered the tumbler. |
| 3027.88 grams of gold were expected to be recovered after the full process. only 3015.57 grams were recovered with 12.31 grams losses |
After doing some research here are some mistakes, I think our technician did:
1- He added all the urea all at once and then he directly added the SMB and waited for the bubbles to settle and then filtered directly.
2- The addition to caustic soda was unnecessary to the resting water after all the process was done.
3- He let the gold in the tumbler for 3.5 hours only which might be low time but the purity was of 999.1 was not bad.
4-He did not measure very accurately the amounts of chemicals
for each Kilo of gold he used:
3Liters of HCL
1 Liter of HNO3
900 grams of urea dissolved in 2L/kg of water
670 grams of SMB dissolved in 3L/kg of water
he added all the HCL at once and the titrated the HNO3 till it was fully poured into the tumbler (approximately 20 mins)
We tried to recover these losses:
we collected all the gold in all the waters
we burned any gloves or cotton used throughout the process
we burned the filter papers used
We recovered the silver and did fire assay analysis on it
At the end: 12.75 grams were fully recovered and 17 grams remained lost.
We suspected that the issue might be the technician or the fire assay performed in the beginning. to fix this issue:
1- We hired a different experienced technician
2- we used gold that was analyzed by our fire assay lab and another external lab were both gave the same values.
Third Time:
4992.62 grams of gold were admitted to the tumbler and 3796.14 grams were expected but only 3774.64 were recovered.
21.51 grams losses the highest so far.
we ran into some operational issues where:
1- the precipitator's capacity was so small it couldnt hold all the amount of gold so we had to empty some of it into 2 buckets using a rubber pipe which was thoroughly washed after.
2- The Precipitator was leaking but the leak was instantly noticed and any leakage was collected (not yet recovered but the leakage was around 10mls of fluid so it wont be holding 21 grams of gold that's for sure)
3- I did not like the washing technique of the technician as i I felt there was a lot of splashing drops everywhere but where then all wiped with cotton and also yet to be recovered.
Chemicals used and technique:
1-15 liters of HCl added all at once and 5 liters of HNO3 were then titrated for 30 mins.
2-The tumbler was operated for 6 hours and then the gold was recovered.
3-in the precipitator tank the urea was added whilst the filter was pumping the gold solution from the tumbler (2.5 kg of urea was used)
4- The SMB was then added (3kg of SMB) and the gold in the buckets (from the issue we rand into was also readded again to the precipitator and filtered.
We are planning on doing a recovery cycle were all waters are refiltered and materials (gloves, cotton, ... etc) are burned and refined to see how much we will recover.
I still cant put my hand on where all the losses are coming from. I will be glad to clarify any issues and please excuse my English and terminology as they are not my first language.
with his tall tales of gold. This is funny
Why people in middle east and close countries use it everywhere, hard to say 
