Alkali for a wet scrubber.

[Justincase]

I have a small scrubber only eight feet tall with a 100l reservoir.
it draw's by water driven Venturi effect ranging form a large low pressure high volume aspirator to several smaller store bought high vacuum unit's I use for evaporation.
Being that my little shed is wedged under some very large tree's I am concerned about leek's.
By my judgment I am loosing just over a liter every two day's of running.Still working to improve the seal's but high pressure spray's in a tight compartment is hard to contain properly.
If The spray head's did not need adjustment from time to time I would seal the hole thing shut.
I am keeping the hole thing as carefully monitored as possible so the liquor is never to strong an alkali.
Is there a more suitable compound to use for P.H. adjustment than sodium hydroxide.
Lime is a bit to insoluble and would clog the spray heads.
I may have to rebuild with a simple pipe and hole system.
My objective was to go as over the top as possible for what little Au I get in.
Regards
J

 

[Geo]

Sodium carbonate. It's not as strong as sodium hydroxide but breathing a mist of either is very dangerous. Is the leak inside or in the exhaust?

 

[Justincase]

Sodium carbonate. It's not as strong as sodium hydroxide but breathing a mist of either is very dangerous. Is the leak inside or in the exhaust?

The hole unit is outside at the back of the shed well away form every thing else.
No mist escapes only dripping form where water has been pressed into the seal..
I will look at sodium carbonate thank you.
Some thing's like Dolomite Lime which is about about 50% calcium carbonate and 40% magnesium carbonate, giving approximately 22% calcium and at least 11% magnesium are quite good for the soil.A plant enjoys about an ounce in ever four or five liter's of organic mulch.
But again it is a little bit insoluble.

 

[NobleMetalWorks]

Instead of neutralizing the acidic water, I recover the water when it becomes mildly acidic for another process. Instead of using a venturi system, I am using a more traditional method when the gas is forced through water, then through plastic ball media under spray nozzles so that any gas that is acidic rises through the plastic chaff and is captured by the water droplets that collect on the chaff, which then is knocked down into the reservoir. And this under a nitrogen blanket.

I am not suggesting going through the trouble of switching over to another system, but if you have anything you can use the mildly acidic solution for, it might be better, instead of neutralizing the solution, to recover and use it for another process, such as leaching or dissolving base metals, etc.

Scott

 

[4metals]

The trouble with recovering the water is plain water doesn't cut it to knock down NOx fumes. So the fumes are passing through more than raising the pH of your liquid.

Unless it is sealed and you are adding O2.

 

[Lou]

You could probably make a venturi scrubber using compressed air (think 100-200 psi) off a rotary screw compressor (figure about 10K to start new) and plain water. That will give you a weak nitric acid solution. Probably need multi stages and it probably wouldn't fly because venturi scrubbers are better for particulates.

Anyway, I suggest you get a packed bed scrubber with Lan-pak and switch to 20 g/l alkali sodium sulfite/thiosulfate, pH 10-12, ORP @ -30/40

NO2 problem solved. NO, however, suggestion is to use peroxide.

Lou

 

[NobleMetalWorks]

Yes, I am using compressed O and N. I purchased the scrubber from the University of Florida where it was being used to scrub NOx. Here are a few pictures prior to installation. When I get a chance I will take more pictures.

https://www.dropbox.com/s/4qvdaq4usvdqsru/$(KGrHqF,!icFB9-HblPKBQn67bpqJg~~60_57.JPG?dl=0

https://www.dropbox.com/s/wlxpz73i7wzi344/$T2eC16Z,!zQE9s3stvlkBQn7!y7NlQ~~60_57.JPG?dl=0

Scott

 

[Justincase]

Thanks chaps very interesting and helpful.
I did experiment with using salt water ice to cool a bubbler down to -2 or -3c which did seem to reduce the amount of visible NO2 in the glass piping very considerably.
What it produced was quite usable for digestion's and would put any little bit's of value back in my loop, but I stopped for the small lot's I tend to process as acid is much cheaper than my time.
4f 100L of my little unit is all reservoir which gas is injected with enough force to disperse into very small bubble, The second 4f 70L is sealed directly on top and is filled with odd shaped high-density polyethylene bit's (old milk jug's)which seem to increase the surface aria and be resistant to chemical reaction.
I am looking at better alternative's Lan-pak and sodium sulfite/thiosulfate look like very good improvement's I will take a closer look.
O2 is another thing I have been considering for my digestion vessel's but I think I would need a substantial increase of material to process before that would become worth while.
The other addition I am planning is an auto P.H. control. There are a good number of controller's and pump's that are meant for large fish habitat. They use a small reservoir of highly concentrated alkali solution which is very similar to the professional lab controllers but much cheaper.