continuos ore roaster
- Thread starter danec
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Shouldn't be much of a deal to build. A slowly rotating steel tube on a slight incline should do it. Tube could run on two sets of rollers, perhaps even water cooled.danec said:
The ball mill I built was a continuous feed. How fast material (and water) was introduced determined how long the material remained in the mill. I was well pleased with the outcome.
Harold
philddreamer
Well-known member
dtectr
Well-known member
From google Books 2 excellent resources
"A practical manual of minerals, mines, and mining" by Henry Osborn.
"australian mining and metalurgy" Donald Clark.
One or both of these address the roasting of sulfide rich ores. One large mind in particular had a multi level oven. They were in the form of extremely shallow arches brick lined, with constantly rotating rakes, with access by the workers to rake and turn the ore as needed. An issue is the liberation and ignition of sulfur- it actually aided the roasting process in their set ups but I can see it becoming a safety issue for the small scale miner. If they could be collected safely, the fumes could be used to make sulfuric acid if one knew how, which I do not. At one time, the majority of the sulfuric acid produced was from the mining industries. The australian operations used it to make their own ferrous sulfate, as well as an oxidizer for creation of chlorine gas for their leach tanks. This was, of course, prior to their conversion to cyanide.
But they still did batches, though they were big ones. If I remember correctly from Ammen, the presence of even small amounts of unreacted sulfides could result in loss of values.
The ore needed to be milled to sand-like size prior to roasting so maybe you could incorporate harolds trommel-type design as a pre roast step. Either way, you need to be absolutely certain that all ore is sufficiently roasted and as we are generally processing smaller deposits whose chemical makeup can vary considerably trying to set a given amount of roast time in a continuous feed operation may result in more work down the road.
Just my tuppense (I bet that's more british than australian), mate!
G'day
"A practical manual of minerals, mines, and mining" by Henry Osborn.
"australian mining and metalurgy" Donald Clark.
One or both of these address the roasting of sulfide rich ores. One large mind in particular had a multi level oven. They were in the form of extremely shallow arches brick lined, with constantly rotating rakes, with access by the workers to rake and turn the ore as needed. An issue is the liberation and ignition of sulfur- it actually aided the roasting process in their set ups but I can see it becoming a safety issue for the small scale miner. If they could be collected safely, the fumes could be used to make sulfuric acid if one knew how, which I do not. At one time, the majority of the sulfuric acid produced was from the mining industries. The australian operations used it to make their own ferrous sulfate, as well as an oxidizer for creation of chlorine gas for their leach tanks. This was, of course, prior to their conversion to cyanide.
But they still did batches, though they were big ones. If I remember correctly from Ammen, the presence of even small amounts of unreacted sulfides could result in loss of values.
The ore needed to be milled to sand-like size prior to roasting so maybe you could incorporate harolds trommel-type design as a pre roast step. Either way, you need to be absolutely certain that all ore is sufficiently roasted and as we are generally processing smaller deposits whose chemical makeup can vary considerably trying to set a given amount of roast time in a continuous feed operation may result in more work down the road.
Just my tuppense (I bet that's more british than australian), mate!
G'day
You might want to try milling instead of roasting. I have some experience with roasting and it can be very difficult and expensive. I'm not sure what size your PM is or how your recovering after roasting but fine milling can bypass the roasting step. I would take it down to 200-300mesh. At this size you could gravity separate even sulfides if there are any left. So I would grind, gravity separate then roast the concentrate if needed. The last step would be recovery from the concentrate which could be done different ways.
If your determined to roast large amounts of material then a continuous roaster is the best way. There is a large propane torch used in the northeast for melting ice. They are cheap, hand held and put off alot a of heat. I would mount this at the end facing the opening of a slanting 4-5 inch wide pipe. Have the pipe rotate while slowly feeding material through it. I started to build one myself until I learned that fine milling can bypass roasting.
If your determined to roast large amounts of material then a continuous roaster is the best way. There is a large propane torch used in the northeast for melting ice. They are cheap, hand held and put off alot a of heat. I would mount this at the end facing the opening of a slanting 4-5 inch wide pipe. Have the pipe rotate while slowly feeding material through it. I started to build one myself until I learned that fine milling can bypass roasting.
rookieminer
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I read in my metallurgy of gold book by T.K. Rose and W.T. Merloc, that roasting ore can cause considerable loss of gold by volatilisation. I could be remembering it wrong, but I'm pretty sure that's what it said.
Feel free to correct me if I'm wrong.
rookieminer
Feel free to correct me if I'm wrong.
rookieminer
prospect88
Member
rookieminer said:
This is very true, I had some sulphides that I roasted and in a stainless steel pot over a propane burner sent in for an assay and they results were much much lower than the original material.P
P88
prospect88
Member
How much material are you wanting to feed through this roaster?
P88
P88
Rotary kiln.
They make these:
http://www.metso.com/miningandconstruction/mm_pyro.nsf/WebWID/WTB-041108-2256F-95C90
They make these:
http://www.metso.com/miningandconstruction/mm_pyro.nsf/WebWID/WTB-041108-2256F-95C90
There is some good information in The Metallurgy of Gold by T. K. Rose. It is an old book and the copyright is expired, so it is available for free on the internet.
Dave
Dave
Paul goldbugg
Member
I was just reading about microwave pretreatment for sulfide ore before you grind. Interesting subject
Southfork
Well-known member
Gold Refining Methods good information here
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I lack detail - plan on trying it to process a fair quantity ofsulfide ore: pulverize it, dampen it, add small amount of fertilizer, stir periodically, and after some considerable time bacteria will reduce the sulfides.
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A calciner, looks like a tube mill, but lined with fire bricks, would have a capacity to roast a good amount of ore. We have bought some 7' diameter x 30' long, for $5,000 US at auctions. We stripped the fire bricks, cut windows, and installed screen sections, making a really good trammel for a low price. Calciners usually go for a low price as they are not in high demand. A smaller one could be built out of any thick walled tubing from around 2' in diameter and up, with around a 12' minimum length. You didn't mention quantity to run per hour, so we don't know what size you need to run per hour.
The technique mentioned by Jobinyt, requires an expensive, heavy autoclave. Better have some deep pockets for that technique.
I don't know what country you live in, but open air roasting is by far the cheapest, but most polluting method. If you either scrub, or convert the sulphur to Sulphuric acid (bonus), you will be looked upon with much more favor.
The heavier losses of Au, are usually caused by too large of a grind size, causing the sulphide particles to explode into the surrounding open ( open air roasting).The temperature for roasting is around 800 F, so losses by evaporating the PMs should be nil.
The technique mentioned by Jobinyt, requires an expensive, heavy autoclave. Better have some deep pockets for that technique.
I don't know what country you live in, but open air roasting is by far the cheapest, but most polluting method. If you either scrub, or convert the sulphur to Sulphuric acid (bonus), you will be looked upon with much more favor.
The heavier losses of Au, are usually caused by too large of a grind size, causing the sulphide particles to explode into the surrounding open ( open air roasting).The temperature for roasting is around 800 F, so losses by evaporating the PMs should be nil.
If you use the search function and go back through old posts there is a very good cyclonic roasting setup that allows the capture and scrubbingf exhaust gases.
It may not be simple but it can be adapted easily for a continuous feed
It may not be simple but it can be adapted easily for a continuous feed
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Autoclave - not my understanding - months of patience is my understanding - careful to keep things damp - not wet - and very little fertilizer. Advantages: low cost; such a slow release (outside/open air) of sulfur oxides seems better than the concentrated release from roasting. More for small scale rather than industrial processing. I suspect sustained use of a roaster will attract regulator attention and cause visible local environmental damage; more likely to produce health problems.
In summary, I suspect OP has an awkward amount of material: too much for my suggestion, too little for a proper industrial process - and that's just the first step in recovery. Obtaining a roaster hardly seems the biggest hurdle faced, so, I suspect OP, to move forward, to gain some experience - with the process end-to-end - as cheaply as possible, might be better off experimenting than by roasting some significant quantity of material.
In summary, I suspect OP has an awkward amount of material: too much for my suggestion, too little for a proper industrial process - and that's just the first step in recovery. Obtaining a roaster hardly seems the biggest hurdle faced, so, I suspect OP, to move forward, to gain some experience - with the process end-to-end - as cheaply as possible, might be better off experimenting than by roasting some significant quantity of material.
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How does the ball mill rotation drive work? Trying to visualize power transmission from large pulley locations.
Which fertilizer you use?
