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Non-Chemical Filtering

Gold Refining Forum

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timsiggins

Well-known member
Joined
Oct 4, 2021
Messages
50
Hey Guys,

one thing about filtering that bugs me is that stuff gets caught in the filter, aka you are filtering gold foils and specks of gold get caught in the filter so you have to throw the filter into the AR and let it dissolve, has anybody found any type of membrane filters that you can use clean and use again. I would only use it when I know I have pure material, anything that I have question of it being dirty, I would use a reg filter and then just keep it. Then process them with the rest of my filters. what do you guys think?
 
Try a Buchner with calendered polypropylene clothe, usually sold as filter cloth. Go online to see who sells the cloth in your area. There are a lot of manufacturers of these cloths and they all have different pore sizes.

Cloths are rated in porosity by airflow rates through them, I have no idea what the relationship in the US is between airflow rates and porosity. I do know that they are rated in cubic feet/minute but the rest of the world only rates them in metric units.

These cloths will last virtually forever provided you do not put them into aqua regia.

Deano
 
I'm not sure I completely understand the problem. Filtering is done for different reasons at different stages of the recovery and refining processes. The main purpose of each stage, however, is to remove the solids from whatever you just dissolved. How you process the solution and the solids is just the next step in the process. If you have gold foils in the filter just thoroughly incinerate the filter and the solids. If you were dissolving gold and still have foils in the filter, then you didn't finish the dissolving process.
 
After reading it again I have to say I still don't see the problem. You mentioned putting the filter and solids in AR. That is the most effective way to put the gold into solution and dispose of the remaining solids (including the filter). The filter will be completely consumed by the AR.
 
@FrugalRefiner thanks for the name I was looking at those on eBay but didn't know what they really where used for, ya they are expensive maybe I will put it on my Christmas list

Also Thanks @Deano I will look at that too
 
A Büchner funnel with a sintered glass disc would work, but they can get pricey.

Dave
Be careful, as I tried using one for gold. I loaded it up with silver chloride without realizing what I was doing. Now its pretty much shot since it dried in there.
 
After reading it again I have to say I still don't see the problem. You mentioned putting the filter and solids in AR. That is the most effective way to put the gold into solution and dispose of the remaining solids (including the filter). The filter will be completely consumed by the AR.
I read it as they want to be able to re-use the filter rather than have it be consumed in AR or incineration.
 
I'm not sure I completely understand the problem. Filtering is done for different reasons at different stages of the recovery and refining processes. The main purpose of each stage, however, is to remove the solids from whatever you just dissolved. How you process the solution and the solids is just the next step in the process. If you have gold foils in the filter just thoroughly incinerate the filter and the solids. If you were dissolving gold and still have foils in the filter, then you didn't finish the dissolving process.
I have a question, I am making a test and have dissolved some filtered gold from AP, together with the filter in AR, should the filter dissolve completely in AR? Also how long should I let it in, I have added nitric just a little at a time.
Meanwhile the filter started to become mushy, I kept stirring.
 
Last edited:
Be careful, as I tried using one for gold. I loaded it up with silver chloride without realizing what I was doing. Now its pretty much shot since it dried in there.
Try sucking ammonia through the sintered plate as it will dissolve the Silver Chloride to clean it.

They sound great in concept but do seem to plug up.
 
I have a question, I am making a test and have dissolved some filtered gold from AP, together with the filter in AR, should the filter dissolve completely in AR? Also how long should I let it in, I have added nitric just a little at a time.
Meanwhile the filter started to become mushy, I kept stirring.
Question why did you put a filter from AP, in the AR were the particles to small to come off the filter when dry.

Depending on the filters you used the answer is there should be fiber goo, I have no better name for it ......
I have herd there are filters that are designed to dissolve but have never used any of this kind.

Well if all the gold in in solution and the filter is goo.............Now you filter the whole mass again.
Once the solution has passed through this filter you need to rinse the goo of the filter until all the color/AR is washed through the filter.

One issue I see is you added more nitric acid so that most likely will now have to be dealt with.

Now you can do your preferred gold drop method on this filtered AR.

Now is this 100% effective, I do not think so.
That is why you save this filter with the goo in it for later processing of all your filters.
 
Question why did you put a filter from AP, in the AR were the particles to small to come off the filter when dry.

Depending on the filters you used the answer is there should be fiber goo, I have no better name for it ......
I have herd there are filters that are designed to dissolve but have never used any of this kind.

Well if all the gold in in solution and the filter is goo.............Now you filter the whole mass again.
Once the solution has passed through this filter you need to rinse the goo of the filter until all the color/AR is washed through the filter.

One issue I see is you added more nitric acid so that most likely will now have to be dealt with.

Now you can do your preferred gold drop method on this filtered AR.

Now is this 100% effective, I do not think so.
That is why you save this filter with the goo in it for later processing of all your filters.
Thanks, due to the specific type of small ribbons I had I went with AP when I probably should have process with AR from the beginning because it was very hard to wash the material afterwards and had clinging problems of the recipients I used for washing everything well. I used coffee filters. I will wash the filter goo as well. I am keeping everything for the stockpot. I have only added nitric bit by bit.
 
Question why did you put a filter from AP, in the AR were the particles to small to come off the filter when dry.

Depending on the filters you used the answer is there should be fiber goo, I have no better name for it ......
I have herd there are filters that are designed to dissolve but have never used any of this kind.

Well if all the gold in in solution and the filter is goo.............Now you filter the whole mass again.
Once the solution has passed through this filter you need to rinse the goo of the filter until all the color/AR is washed through the filter.

One issue I see is you added more nitric acid so that most likely will now have to be dealt with.

Now you can do your preferred gold drop method on this filtered AR.

Now is this 100% effective, I do not think so.
That is why you save this filter with the goo in it for later processing of all your filters.
i did some decanting and tried to filter the remaining water and used a different type of coffee filter and discovered a lot of the very fine gold passes through. Of course I am not throwing anything away but this is something to consider. You trust a filter and it lets you down eventually. I am keeping even that filtrate test everything over and over
 
I have found that storing and processing filters several times helps me. They catch what they catch and I’ll leach it out at a later date if it’s something I want. The filters do a great job of separating things so they can be sorted correctly.

I use poor mans so the cost to re run some suspect filter media is very low. Never hurts to be certain before they get discarded.
 
Question why did you put a filter from AP, in the AR were the particles to small to come off the filter when dry.

Depending on the filters you used the answer is there should be fiber goo, I have no better name for it ......
I have herd there are filters that are designed to dissolve but have never used any of this kind.

Well if all the gold in in solution and the filter is goo.............Now you filter the whole mass again.
Once the solution has passed through this filter you need to rinse the goo of the filter until all the color/AR is washed through the filter.

One issue I see is you added more nitric acid so that most likely will now have to be dealt with.

Now you can do your preferred gold drop method on this filtered AR.

Now is this 100% effective, I do not think so.
That is why you save this filter with the goo in it for later processing of all your filters.
I am not sure I have answered you first question, yes the gold was so fine and I could not get it off the sides of the containers and beakers I have used during first phase and second to filtration, they became very small some of the fine particles were floating, it was very difficult, I had to use filter paper to wipe and then water spray .... In this case I believe now that using directly AR would have been better due to the ribbons ends small size and the clinging problem as well as the washing difficulty being so many I had to wash everything several time in a bigger bucket so .. more gold clinging to the bucket......
 
I have found that storing and processing filters several times helps me. They catch what they catch and I’ll leach it out at a later date if it’s something I want. The filters do a great job of separating things so they can be sorted correctly.

I use poor mans so the cost to re run some suspect filter media is very low. Never hurts to be certain before they get discarded.
what exactly do you use for filtering? What kind of poor man's filter?
 
I just use a few different sized coffee filters depending on the amount o be filtered.

As for the super fine stuff I try and get it all but there is a point where your chasing 10 cents in gold.
 
Does anyone here use celite for extremely fine particle filtering, I seen Nilered use it, but I don't know if it would hold up under extremely high/low Ph solutions. Can it be cleaned and reused?, if not then it's probably not cost effective to use it.
 

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