# Neutralizing Hydrochloric Acid



## Traveller11 (May 22, 2011)

Hello
I need a little help here. I have seen instructions for doing what I want to do here but I would like to make sure I am going to do something the correct, safe way.
I have discovered here, exposed by ocean erosion, a layer of cemented gravel and sand that appears to be a leftover from glacial melting of the last Ice Age. It looks like a two foot thick layer of black asphalt and, as the ocean waves erode it, black sand is seen deposited below it.
I attempted to break some chunks of it up with a cement mixer so I could determine if they had any PM's in them. They broke up somewhat but it appears it would take a few days to completely remove all the oxidized iron (manganese?) from the fine PM's. I took the material from the cement mixer, put it in a jar and added acetic acid to it. This worked marginally well but did not really produce the desired results.
Sooo, I tried a fresh lump of this material in a fresh jar and carefully covered it with 38% muriatic (hydrochloric) acid wearing, of course, all of my PPE's. Now THIS produced some results. This weird black foam immediately filled most of the jar. With a wooden stick I was easily able to break the lump up into sand. I think I'll leave it sealed in the jar for a day or two just to get the maximum effect from the HCl.
How do I neutralize the acid when I wish to begin processing this sand? Also, as HCl is kind of expensive in bulk and not that nice to work with, is there a milder, cheaper acid that would work well in a plastic cement mixer to break this material down? Should I be looking at building some kind of small ball or rod mill and use that to scarify this material? This is assuming, of course, I find enough PM's in the HCl treated material to warrant further investigation.
Open to suggestions
Bob


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## element47 (May 22, 2011)

HCl is among the cheaper chemicals available, typically from pool supply shops. Maybe there aren't that many swimming pools in Canada, eh? 

Neutralizing the acid is also cheap; Bicarbonate of Soda (= sodium bicarbonate) is an inexpensive way to go. Add until fizzing stops. Keep away and upwind from any fumes generated, you might get some chlorine. 

It's hard to say whether you have anything valuable in your sea-junk. HCl will react to most base metals and will react to calcium carbonate seashells.


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## Traveller11 (May 22, 2011)

element47
Thanks for the reply. Just to make sure, Bicarbonate of Soda is the same thing as Baking Soda, right? And would I simply pour it in as a powder?
I seriously doubt that there is a vast amount of PM's in this stuff, too. However, I would kick my butt if there were something substantial there and, for the lack of a bit of experimenting, I passed it up. I was panning the stuff I had in acetic acid. Mostly there was sand, black sand and then this very fine (200-300 mesh) powder that seemed to separate from the rest of the material. I think if there's gold, it will be this fine stuff and it is a matter of getting the black coating off of it.
Yes, HCl is cheap enough but I don't think it would be economical for the volume I would need. That is why I was thinking of a combination of a milder acid with a mill for scarifying. Maybe diluted HCl ?
Regards
Bob


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## element47 (May 22, 2011)

Sodium bicarbonate = Baking SODA yes, baking *POWDER*, no, though it, too, would work. POWDER is probably somewhat more expensive. Usually Arm & Hammer brand in the yellow box, don't know if that is sold in Canada, but I'd be surprised if it was not. Usually baking POWDER is sold in red containers, at least here in the states. 

search google images for "baking soda".


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## Cody Reeder (May 23, 2011)

I would just try poring off the acid and washing your sand with water. you might even be able to re use your acid a few times.

but personaly I would go at it (black sand below outcrop)with a gold pan and see if I could find any colors (gold flakes).


edit: I just read that you panned it. and your problem is grinding it up? I would say ball mill or rock crusher is needed but first take some of your concintrates and do an assay to see if you have anything worth prusuing. and could you poast a photo or two?


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## Traveller11 (May 23, 2011)

Cody
It's not so much a matter of grinding it up. It's more like you had a bucket full of old nuts and bolts all glued together with oxides (manganese and iron, I think). All I want is something that will remove the oxides and let me see if they are concealing anything ultrafine and valuable.
There are black sand deposits on the beach below these outcrops that definitely have gold in them. All of this gold is -120 mesh and very flaky as is common with glacial gold.These deposits are usually formed during the Pacific storms we get here in the winter. Although somewhat rich, I want to see if the outcrop is even richer; kind of like the motherlode. 
I'll borrow a camera and post some pics for you.
Regards
Bob


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## Cody Reeder (May 25, 2011)

I see so the gold is in the matrix between the rock's and you just want to free it up. I think that it would be nice to know how much the outcrop contains over all and maybe it would be worth mining it like regular hard rock.

I beleve that manganese oxide gives off clorine when you add hydrocloric to it and if thats the case it may disolve some of your gold but you should be able to smell clorine. 

I still think that you could just poor off the acid and not have to neutralize it. but if you do have to dispose of it, baking soda or lime would do just fine.

well sounds like a fun project, after all if you can see the gold no matter how fine, its definatly worth something. I will watch out for those pics. 8)


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## Reno Chris (May 25, 2011)

OK - here is something about beach placers that is true pretty much world wide. Yep, the gold is fine, but the beach sands themselves are very, very low grade - as a whole, they contain very little gold. However, during storms and other periods of very strong wave action you get a pull of the waves across the shore and like in a sluice box, the light materials are washed away, leaving behind on the beach bands of black sand and other heavy materials, including gold. These are natural concentrations and can have significant gold - on some really rich beach placers, in just the right conditions, you can sometimes see the gold among the back sand there is so much of it. Still a sample of the un-concentrated beach sand only a few yards away would be almost barren. 

Because your sample after treatment with HCl was blonde sand, not black sand I am not all that surprised that it did not show any gold. Some inland sand deposits in Oregon and elsewhere in places where the ocean has stranded old beach sands - they have preserved bands of black sand layers from ancient storms that had the same concentration process - these inland black sands have the same good gold content as the black sand produced by modern storms. On the other hand, the blond sands on the old deposits are pretty much just as barren as the blond sands on the beach today. 

Chris


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## Cody Reeder (May 27, 2011)

I admit that the closest thing I have been to the beach is the shore of the great salt lake or the old water line of lake boniville (which my parents house is built upon). i wonder if their are any of those ancient beach placers on the boniville water line...


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## Dirtdiggaler (Aug 14, 2011)

I save the ashes from my wood stove in a plastic container after i'm finished with my acids and leaches I dump them in the ashes and it neuteralises them.


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## Geo (Aug 15, 2011)

crushed limestone dust is cheap,you can get it at any quarry that mines limestone. where i live a whole pickup load is about $15.


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