Smelting in India

Gold Refining Forum

Help Support Gold Refining Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

gaurav_347

Well-known member
Joined
Nov 17, 2013
Messages
169
Dear Members,

The process being used is for black sands but this process can also be used for ic ash and mlccs.

In the video the person mentions 'mercury' but he means litharge! The later stage uses a bone ash hearth to absorb the lead leaving only a silver dore which contains all the precious metals.

This process is harmful unless performed under proper fume control systems with proper safety measures.

The round balls are a mixture of black sands/ ic ash ,dried cow manure(to provide extra heat) soda ash, borax and litharge which are then placed over a cuploa typle furnace powered by coal.Lead is also added from top to get better collection of pm's.



[youtube]http://www.youtube.com/watch?v=cNFhN5DojWE[/youtube]

Regards,
Gaurav
 
I think the whole process they done wrong, as-far-as safety goes. Just too much to address other than "DON"T DO IT this way. Do some research and learn the right way.

Ken
 
They are doing the equivalent of a fusion assay on a larger scale. It would be interesting to hear the ratio of black sands to the other components, including the manure which is a carbon source to act as a reducing agent.

In the US we use white bread flour as the carbon source. But that is in the land of overweight Americans, in a country where so many are starving I guess they feed the flour to the livestock to fatten them up (or some kind of grain) and use the by product in its place.
 
Dear All,

I came across the process through a friend who is a fellow E-waste Recycler. Under no circumstances I am performing this in my plant. I do have all the necessary pollution control equipments approved by the state pollution control board. There are certainly other ways to do the process but some of the recyclers have been using this process to recover pms from chips and ics with excellent recovery.

Regards,
Gaurav
 
There is no question the process works, but the long time impact to the health of the people and nature could be severe. Doing this in any western country would have you shut down as soon as the government finds out and there would be a hefty bill for cleanup and probably heavy fines too.

Göran
 
Sir,
I do understand the consequences of lead poisoning and that no western country would allow this . Every country has their own legal system and how they operate in their own way.

Let's say if you had to make this process safer what changes would you make?

Regards,
Gaurav
 
gaurav_347 said:
Sir,
I do understand the consequences of lead poisoning and that no western country would allow this . Every country has their own legal system and how they operate in their own way.

Let's say if you had to make this process safer what changes would you make?

Regards,
Gaurav
I know the laws of man can differ from place to place and it wasn't long since we started to take care of the environment here. When I was a boy the copper smelter 150 km from me was so bad that the cartilage in the nose of the workers got dissolved and the nose practically collapsed. It was so common there that it was named "Rönnskärs-nose". Today it is a clean operation.
As I understand it, India is going through the same transformation from a rural to an industrial country that we did a couple of generations back, just a lot faster.

I'm no expert on environmental technology, but we have a number of sulfide mines in my area so I can tell you what the mines around here are doing.

Depending on the ore type the tailings from the washing could contain a lot of harmful metals like lead, copper, cadmium, arsenic and so on. The tailings are collected in a water proof lined dam and any fluids coming off is treated in a water treatment plant. Storage below the water level reduces oxidation and prevents too much leaching of toxic substances. At the end of operation the dam is filled up and a water proof lining added to the top so any rain water doesn't get mixed in the dam. Drainage pipes are added in the bottom so the water level can be controlled and any dissolved metals can be treated before letting it out.

The gases from the smelting operation is filtered, first with a filter removing solid particles (cyclone, electrostatic filters...) and then chemically scrubbing sulfuric acid from the smoke.

The slag can be deposited in the tailings dam.

The led that was burned off from the silver goes somewhere, probably absorbed in the large melting dish or collected as slag. It should be taken care of too. If rich enough it can be collected and sent off to a led smelter to be recycled or it could be put in the dam too. (Don't quote me on that though.)

This is what I think a sustainable and reasonable environmental friendly operation would look like for gold ore. But as I wrote, I'm no expert on environmental engineering, just relaying what I have seen here in my area.

To incinerate electronics is a whole different matter, there are plastics and a whole lot of different compounds that makes a toxic mess when incinerated. In that case afterburner, filtering and scrubbing the gases becomes vital to not poisoning your neighborhood.

Göran
 
gaurav_347 said:
Sir,
I do understand the consequences of lead poisoning and that no western country would allow this . Every country has their own legal system and how they operate in their own way.

Let's say if you had to make this process safer what changes would you make?

Regards,
Gaurav

Gaurav, try to read few threads made by this member:
http://goldrefiningforum.com/phpBB3/memberlist.php?mode=viewprofile&u=6862

He does something similar of what you are asking about.
 
Seeing the equipment they currently use it is apparent that they are a low budget operation and will not be purchasing any equipment with chemical controllers and dosing pumps.

The first thing they should do is place an exhaust hood over their melt furnace and their cupellation setup. This will not treat the fumes but it will at least get the fume away from the workers and up over the roof height. Sheet metal hoods and ducting should generate an effective draft from the heat of the process. If I could only do one thing, this would be it.

A moderately effective wet scrubber could be (actually should be) connected to the exhaust on the roof to wet scrub the fume of particulates and likely a good amount of the lead. Unfortunately this cannot be driven by thermal currents, the fume will need to be fan driven and the scrubber liquid will need to be recirculated from the sump with a high flow pump. The water running off from the scrubber sump overflow can be used in their riffle tables before it is collected for treatment.

Water can be recycled until the lead builds up to levels where it can be precipitated by caustic treatment. Unfortunately Lead will drop from the solution at a pH of 10 but much over 10 and it begins to go back into solution. The down side is this method is not effective at getting Lead much below 10 PPM. All of the testing can be done with lead test strips and pH test strips to control this process.
 
I was wondering about there gravity separation.
I have never seen such viscus slime put through a sluice.
is there a better way to produce abetter concentrate to work with.
I have been working with centrifugal classifying but have not had much success.
 
4metals said:
Seeing the equipment they currently use it is apparent that they are a low budget operation and will not be purchasing any equipment with chemical controllers and dosing pumps.

The first thing they should do is place an exhaust hood over their melt furnace and their cupellation setup. This will not treat the fumes but it will at least get the fume away from the workers and up over the roof height. Sheet metal hoods and ducting should generate an effective draft from the heat of the process. If I could only do one thing, this would be it.

A moderately effective wet scrubber could be (actually should be) connected to the exhaust on the roof to wet scrub the fume of particulates and likely a good amount of the lead. Unfortunately this cannot be driven by thermal currents, the fume will need to be fan driven and the scrubber liquid will need to be recirculated from the sump with a high flow pump. The water running off from the scrubber sump overflow can be used in their riffle tables before it is collected for treatment.

Water can be recycled until the lead builds up to levels where it can be precipitated by caustic treatment. Unfortunately Lead will drop from the solution at a pH of 10 but much over 10 and it begins to go back into solution. The down side is this method is not effective at getting Lead much below 10 PPM. All of the testing can be done with lead test strips and pH test strips to control this process.

Sir,

We have exhaust hoods placed over our incinerator ,copper melting furnace, incinerator and a cupellation setup. All these fume hoods are connected to a wet scrubber, the same being described by you. I would be trying this process in the coming week and post my results here. We have around 100 plus kgs of ics which are already incinerated ,pulverized, sieved and magnetics removed. I will be smelting these ashes with litharge, borax, soda ash and flourspar in the melting furnace and pour of the smelt in the cone mold. Process this dore on a bone ash hearth and see the results .I will start with 5 kgs of ic ashes first and go from there.

Regards,
Gaurav
 
Smack said:
Gaurav,
Make sure to take some pictures for us. :G

Sir,

Surely I will do that and post the pics here. Here are some pictures of the setup.

Regards,
Gaurav
 

Attachments

  • IMG_20160927_171409.png
    IMG_20160927_171409.png
    358.3 KB · Views: 1,206
  • IMG_20160927_171708.png
    IMG_20160927_171708.png
    436.7 KB · Views: 1,206
  • IMG_20160524_182921.png
    IMG_20160524_182921.png
    416.9 KB · Views: 1,206
4metals said:
Gaurav,

Remember to save your slags for another melt with additional thinning flux. Again, poured into cone molds.

Sir,

Should lead or litharge be added again to this flux when re smelting slags?

Thanking you
Gaurav
 
Slags are remelted to recover beads of metal that never collected in the pool of metal you recovered in the first melt with litharge. The slag remelts are usually done with a thinning flux made with fluorspar borax and soda ash.
 
Sir,

Thank you for clearing out my doubts. I have one last question before I proceed ahead.While searching the forum I came across various threads related to smelting of ic ash. Kurtak and You mentioned that while smelting you should smelt the ic ashes with fluxes constituting of 50% soda ash 50% anhydrous borax and some flourspar and a collector metal. Now let's say for example I want to smelt one kg of ic ash. For example The formula would be 1kg ic ash + 2/3 kgs of soda ash borax flux(50/50) and some fluorspar. I am a little confused about using litharge. What quantity should be used here? Also what is the difference between lead oxide and litharge and which should be used for smelting ic ash. Do i even i have to use lead metal as a collector metal even after using litharge? I do understand the chemistry mentioned in the thread "smelting" as posted by you. I would be grateful if you give your insight on this.

Thanking you,
Gaurav
 
Back
Top