how to build an acid resistant hood & scrubber _hood_

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Repeating the same information here will only serve to fragment the forum content further.

Steve
 
It looks like I will have to buy one of these
I would also like to how our veteran refiners protected themselves from all these dangerous chemicals
Thanks
http://www.grainger.com/Grainger/NORTH-BY-HONEYWELL-Respirator-Hood-4GM52?Pid=search
# Supplied Air System Accessories
 
Hi Guys
The fume hood is working
For one thing I still have to buy a Plexiglas for the front of the fume hood and I didn't like the fact that there is the smell of acid in that room.
I am a freak when it comes to clean air and my whole shop smells clean but that room is not what I would like it to be.
I have heard of a lot of people dying or getting cancer from doing this profession so I don't want to take any chances.
 
This might sound a bit bizarre but I am going to spend over a $1,000 to buy a suit with an oxygen tank.
 
Hi Barren
Thanks for your reply
I think the system is working well but no matter what happens when nitric reacts with the other acids and other metals there is deadly fumes in the air.
In that room I don't have windows so it becomes more of a problem
I have worked with nitric and cyanide before and these things become a part of the air and when I was younger I didn't care much about those issues but now I do.
I know that Harold and GSP have worked for years but maybe their conditions were different.
If anyone has any additional help to make this profession safer I would like to hear from them.
Thanks again
 
You may want to add an additional ventilator that simply sucks air and blows it outside, just to keep the atmosphere clean.

If that is not an option, and you aren't working with huge quantities, then the addition of H2O2 to the digestion is a valuable option for NOx free digestion with nitric acid.

If the above two are not to your liking, then dissolving a fine powder with HCl and sodium chlorate elliminates the NOx entirely and makes for much easier scrubbing.

I would avoid working in a closed room without ventilation. It can easily kill you or someone else, or at least severely damage your health. :shock:
 
golddie said:
Hi Barren
Thanks for your reply
I think the system is working well but no matter what happens when nitric reacts with the other acids and other metals there is deadly fumes in the air.
In that room I don't have windows so it becomes more of a problem
I have worked with nitric and cyanide before and these things become a part of the air and when I was younger I didn't care much about those issues but now I do.
I know that Harold and GSP have worked for years but maybe their conditions were different.
If anyone has any additional help to make this profession safer I would like to hear from them.
Thanks again
Click to expand...

If I remember you said you didn't have a fron on your hood. Put a piece of plexigalss over the front and see ifthat will help some. Or set you up a table outside and do certain things outside. But to spend a $1,000 dollars for a suit HMMMM.
 
Hi HAuCl4
Thanks for your help
I have the fume hood and the scrubber system and plus another blower working as an extra ventilation system.
I have separated the refining part from the whole shop so that the entire place does not get the acid in the air.
The acid smell stays in that room but I am not happy with the quality of the air in there, maybe if it was someone else they would not be bothered but I am bothered by that.

AP= Acid Peroxide = 2 Parts Muriatic Acid, 1 Part 3% Hydrogen Peroxide. Dissolves
base metals, slowly dissolves gold when heated. If gold is present drop with SMB, NO
urea needed.
Click to expand...

Do I have to boil this mixture until everything dissolves and its like Aqua Regia

HCl-Cl= Clorox Method = 4 Parts Muriatic, 1 Part Clorox (added in small increments).
Used to dissolve gold foils and powder. Drop gold with SMB, NO urea needed.
Click to expand...

When you say HCl and sodium chlorate is this what you mean

I don't know if I did right or wrong but I made the back part of the shop the refining room and
it has a window but with the system there I am not able to open it.
If I leave the door open to the reffing room than the acid smell will be less over there and more in the other parts of the shop
Thanks again
 
I have only scanned this post but from what little I have read I believe your problem is not enough fresh air intake. I also agree that you need to close off part or all of the front of your hood.

I built a crude fume hood 4 months ago 60"L x 30"D x 39"H with a front opening of 46" x 30". I am using 2 - 120 cfm bathroom exhaust fans made of all plastic except for the motor and each vented thru the roof with 4" ducting. I also keep 1 of these fans running 24 hrs. a day.

I put a piece of 1/4" plexiglass on the front with crude hinges and barrel bolts to keep it held down and used 1/4" x 3/4" closed cell foam weather stripping to seal the edges. I kept the bottom 10" of my hood open.
I am also in a small 9" x 9'-6" room but I do have a window.

Now for my point :). If I close off my window and open my hood front and rely on drawing all my fresh air from my house I have the same problems you do. When I close my hood front the fume control gets better. However, if I just crack open my window, I can actually feel the air drawing in and will sometimes even howl if it's not open enough. I then get no noticeable fumes at all in my room until I do something outside the hood. But I still don't get any fumes in my house.

I can only assume my system must be keeping control of most of my fumes in my little room because I have had several pieces of raw steel beside my hood for a month or so and I have no signs of any oxidation or on any of my tools.

I am working on a small scrubber system that I can incorporate into my hood and will eventuly build a bigger and better hood system once I'm happy with my scrubber results. In the mean time I keep things small and use lots of watch glasses. :)
 

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Take a look at this thread for the nitric+peroxide. Forget I mentioned HCl+sodium chlorate, you may get into trouble with that. It's like HCl-clorox but much stronger.

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=55&t=764

You must have leaks in your system. Can you open the window on the back and ventilate that way?. I also hate HCl stink. :x

What I mean is push air through the now closed window with an extractor, sucking it from the door that leads to the front of the shop through a grid in the door. That way there would be permanent circulation.
 
HAuCl4 & Emmjae
Thanks for your help
I will have to try those things that you are recommending.
I cant bring air from the back because that is where the scrubbed fumes are going out and I will only be bringing in bad air.
The idea of bringing in air from the front of the shop makes sense.



Thanks goldenchild
I dont know how many you have but they are very helpful, II think you have the one about making nitric acid and this one and if you have more I would like a link to it.

I have looked at this thread and watched the video made by goldenchild
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=55&t=764
1) 35 percent H2o2 (Hydrogen peroxide)[makes up 49 percent of the total weight of the entire mixture]
2) Ethylene Glycol (found in anti freeze coolant)Prestone and main ingredient should be Ethylene Glycol[makes up 22 percent of the total weight of the entire mixture]
3) 70 percent nitric acid[makes up 29 percent of the total weight of the entire mixture]

He dissolves copper in this mixture as experiment
If I wanted to dissolve gold I guess I would place it in there instead of the copper.
Than the gold goes in there and how do I cement the gold in the liquid
Is this right or am i doing something wrong
Thanks again
 
I have a blower I am thinking of placing where I have marked new fan. I will make a hole and bring air from the front of the shop to the refining room without getting air from the outside because the front window is kind of far and the air in the shop is clean.
I will also have the Plexiglas soon and I will also have to check around the entrance and exit holes for leaks.
I used duct tape with plastic to make the connections to the pipes
How is that for idea
http://img140.imageshack.us/f/61484804.jpg/
 
golddie said:
I have a blower I am thinking of placing where I have marked new fan. I will make a hole and bring air from the front of the shop to the refining room without getting air from the outside because the front window is kind of far and the air in the shop is clean.
I will also have the Plexiglas soon and I will also have to check around the entrance and exit holes for leaks.
I used duct tape with plastic to make the connections to the pipes
How is that for idea
http://img140.imageshack.us/f/61484804.jpg/
Click to expand...

You got to stop drawing these pictures and learn to take pictures and post them. They will tell so much more of a story.
 
Before I spent a $1000 on a space suit I would get the fume hood working properly. Think how miserable that suit will be on a 95 degree day.

Your blower has a 9"diameter inlet, what size duct tube are you using?
 
http://img703.imageshack.us/f/81461484.jpg/
I tried to post this picture to test and as you can see the size is very small, its 100 pixels by 100 pixels and the story is the same
I looked here for answers
http://goldrefiningforum.com/phpBB3/viewtopic.php?t=24
and I did this with photoshop and not that ifran program could that be the reason why I cant upload it
 
http://img199.imageshack.us/i/42059188.jpg/
qst42know
Here i drew a sketch of the plan
Thanks
 
You also have to determine when to change out the scrubbing liquid to lower the TDS and restore efficiency. It's a learning curve.
Click to expand...
What is TDS and it is possible that I didnt have enough scrubbing liquid in the scrubber because I didnt think it was important
 

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