# Make a vacuum scrubber. Step by Step!



## saadat68 (Nov 8, 2016)

Hi
I want to start making a vacuum scrubber. I have some questions that ask here and make a good scrubber with you.
Thanks for your help

Tomorrow for first step I will buy some PVC or UPVC pipe. each 90 cm with 9 cm diameter and I think its enough for 0.5 liter Nitric use per day. right?

I want to make scrubber units like these images. 






I will use plastic connections





Which are safer and better? 1 or 2 ?
I think 1 is better. Can open and close, but 2 is safer, I stick it with PVC glue.
What do you think?


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## 4metals (Nov 8, 2016)

The proper size of the scrubber tube is determined by the flow through the scrubber. How are you providing vacuum? What is the flow rate of the vacuum pump or the Venturi you are using? 

On my iPhone I didn't see the pictures, if those connectors on the cap are metal that will not work for more than 1 job. It must be all plastic. 


Sent from my iPhone using Tapatalk


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## saadat68 (Nov 9, 2016)

4metals said:


> The proper size of the scrubber tube is determined by the flow through the scrubber. How are you providing vacuum? What is the flow rate of the vacuum pump or the Venturi you are using?
> 
> On my iPhone I didn't see the pictures, if those connectors on the cap are metal that will not work for more than 1 job. It must be all plastic.
> 
> ...



I said I will use plastic connectors. they are just models. I want to use a vacuum pump 2.5 CFM 

Need some advise about second question. I want to go to the shop today. Thanks guys 
Which are safer and better? 1 or 2 ?
 I prefer buy 1 but is it safe ?


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## Barren Realms 007 (Nov 9, 2016)

saadat68 said:


> 4metals said:
> 
> 
> > The proper size of the scrubber tube is determined by the flow through the scrubber. How are you providing vacuum? What is the flow rate of the vacuum pump or the Venturi you are using?
> ...




#1 would be better because it will seal better on the pipe, if the threads are the same.
It will also give better access to the inside of the chamber and less chance of vaccum leak.


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## 4metals (Nov 9, 2016)

We backwards American seem to love a system based on some ancient kings shoe size so i had to convert your much more practical metric figures into our archaic feet and inches to make sense of it.

So; a 3.5" diameter by 35" long cylinder has a volume of 1.45 gallons ((Pi x ((3.5/2)^2)*35)/231 = US Gallons (231 is the number of cubic inches in a gallon, a handy number for those of us practicing the archaic system to know)

For a scrubber to be effective a retention time of 8 seconds is desirable.

Your scrubber will evacuate all of the air through your cylinder in 0.58 minutes which is 34.8 seconds and sufficient retention time for scrubbing. So 1 should do the trick but 2 would be better because a bubble through scrubber is less efficient than an air to surface film scrubber. Plus one cylinder of peroxide, another of caustic, and even a third of water would be ideal. 

In either case, safe means it is safe to be exhausted out of the work space not safe to discharge into the work space.


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## saadat68 (Nov 9, 2016)

Thanks 
I bought 3 pipe and 6 PVC socket and finally 6 connections model 1 ( because I did not see your advise and went to shop, Also I check them and think they are strong enough. They have O-ring too  Tomorrow I will give my connections and add an image from them

Pipe and sockets:


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## 4metals (Nov 9, 2016)

If the O Ring isn't Vyton or teflon, it won't last long. I would glue them.


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## saadat68 (Nov 9, 2016)

4metals said:


> If the O Ring isn't Vyton or teflon, it won't last long. I would glue them.


I think they are silicone O-rings. we can easily open and check it and if it destroyed buy another and change it  in this system we can check all of connections very easy. 
Also we can change O-rings to teflon O-rings.

Good tip :idea: - Thanks
I wanted to buy some O-rings for other connections and don't know I must buy teflon or Vyton


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## autumnwillow (Nov 10, 2016)

saadat68,

What will you be processing in nitric?

edit to add:

if you are going to use it everyday. make another entry point for dosing(scrubber maintenance) with a pvc gate valve.
another gate valve for draining is ideal. mine doesn't have this feature yet. heh


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## saadat68 (Nov 10, 2016)

autumnwillow said:


> saadat68,
> 
> What will you be processing in nitric?
> 
> ...


I want to add valve too! 8) Don't want model 1 for draining.
Today I want to shop and he doesn't provide my connections. So I can buy model 2.
Do you think model 2 is better ? like 4metals?


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## autumnwillow (Nov 10, 2016)

I would prefer model 1 if you can get a teflon O ring for it and get a really good seal. Just in case something happens you can open it up to fix or clean it. If you can't get a good seal go for model 2.

What will you be digesting in nitric?


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## saadat68 (Nov 11, 2016)

autumnwillow said:


> I would prefer model 1 if you can get a teflon O ring for it and get a really good seal. Just in case something happens you can open it up to fix or clean it. If you can't get a good seal go for model 2.
> 
> What will you be digesting in nitric?


Silver from silver oxide batteries


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## 4metals (Nov 11, 2016)

If you have the silver oxide powder, often obtained by splitting the batteries so the silver oxide falls out, why do you dissolve in nitric? Silver oxide breaks down to silver metal when you melt it.


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## autumnwillow (Nov 11, 2016)

Well I think you can convert silver oxide to silver powder directly without using nitric. Search the forums. 

If you are after pure crystals it would be best to create a silver cell. Also available in this forum.


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## saadat68 (Nov 11, 2016)

Yes I thought to it. But it has other metals too like Zinc and a little* Hg* :shock: 
Also I can't find a post about other ways. Just there is leaching with Nitric acid

Can I melt it and then refine it with silver cell ?
Maybe need searching in patents


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## autumnwillow (Nov 12, 2016)

Are you sure there is mercury? 
That's highly toxic. Do not melt. Separate it away first. 

Silver cell info can be found in this forum.


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## Palladium (Nov 12, 2016)

How much of this are you trying to run and how often?


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## saadat68 (Nov 12, 2016)

autumnwillow said:


> Are you sure there is mercury?
> That's highly toxic. Do not melt. Separate it away first.
> 
> Silver cell info can be found in this forum.


Yes they have some Hg


Palladium said:


> I hammer mill, screen, two hot water rinses ( boil ), then nitric, drop with copper, and then the cell. Batteries are fairly easy. If you don't do the water washes you are out for problems. The water washes remove the hydroxides from the equation. Most of the zinc will follow the hydroxides into solution. The nitric consumption will be cut by 50-75% by doing the water washes. The material is easy to run if you follow the steps and the nitric consumption is really low compared to other types of feed stock. How much of this are you trying to run and how often?


Thanks I know I must wash them but didn't know it reduces 50% acid. It is very good
Maybe can collect 500 Kg mix batteries in year
How much water do you consume per 1 Kg batteries for rinsing ?


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## 4metals (Nov 12, 2016)

You are worried about generating waste? That is a good sign. 

From people I have spoken to who have been to the Middle East, the thing they speak of most is the dry heat. With an excess of dry heat a solar evaporator can take care of a small refiners waste waters easily.


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## saadat68 (Nov 12, 2016)

4metals said:


> You are worried about generating waste? That is a good sign.
> 
> From people I have spoken to who have been to the Middle East, the thing they speak of most is the dry heat. With an excess of dry heat a solar evaporator can take care of a small refiners waste waters easily.


I don't worry about water waste. It is not much. and water is cheap here (0.1$ per 1000 liter)
South of Iran have dry heat. middle of Iran is not bad. I am living here. And north of Iran is like Europe:
http://cdn.fararu.com/files/fa/news/1391/5/8/20787_119.jpg


https://www.google.com/search?q=mazandaran&sa=X&biw=1093&bih=510&tbm=isch&tbo=u&source=univ&ved=0ahUKEwil5cSPsqTQAhXKPxoKHd9XCLcQsAQIJw


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## 4metals (Nov 13, 2016)

> I don't worry about water waste. It is not much. and water is cheap here (0.1$ per 1000 liter)



Waste water and water waste are 2 different things. When you use a lot of water because your faucet leaks it may cost you extra to pay for your water use. In refining we refer to waste water as water we have used in a process which is now contaminated and we have to eliminate the contamination before we get rid of the water. The more rinse water you use in refining, the more waste you have to treat. That is why I said it was good that you have concerns about generating waste. Apparently I got that wrong!


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## patnor1011 (Nov 14, 2016)

saadat68 said:


> Maybe can collect 500 Kg mix batteries in year
> How much water do you consume per 1 Kg batteries for rinsing ?



And how many from those 500kg of mixed batteries do you think will be silver oxide batteries?


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## saadat68 (Nov 15, 2016)

patnor1011 said:


> saadat68 said:
> 
> 
> > Maybe can collect 500 Kg mix batteries in year
> ...


60 percent (Tested it )
Do you recycle silver oxide batteries?
If yes, How much silver do you get from 1 Kg silver oxide batteries ? (Just silver oxides)


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## g_axelsson (Nov 15, 2016)

There is two articles at the end of the references at http://goldrefiningwiki.com/mediawiki/index.php/Silver_oxide_batteries with some compositions of batteries.

The composition will vary depending on the size, date of manufacturing, brand... and so on. Keep track of the numbers when you refine and you can build up a good data set to do statistics on. The more data you have the better prognosis you can make.

Let us know how it goes.  

By the way, there are fake silver oxide batteries out there.

Göran


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## saadat68 (Nov 21, 2016)

I couldn't make a scrubber yet. I can't find suitable PVC connections
What do you think about this design? this can solve many of my problems. *each column* is like* U* and will make with PVC pipes. 
Can I make my scrubber like this ?!


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## butcher (Nov 21, 2016)

If the U tube has a closed top on the right side gas would displace the liquid. If the top on the right side was open gas escapes...


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## saadat68 (Nov 22, 2016)

Yes I close it


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## saadat68 (Dec 4, 2016)

This is my design (One column): 8) 





Now I'm waiting for receiving some connections


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## patnor1011 (Dec 4, 2016)

It will not work.


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## autumnwillow (Dec 4, 2016)

Why won't it work? It seems ok to me.


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## butcher (Dec 4, 2016)

I may be confused what that is or its purpose, if it is suppose to be a venturi for draft it would not work.
You need a venturi action, that design does not create a venturi.

https://www.google.com/search?q=venturi&espv=2&biw=954&bih=871&source=lnms&tbm=isch&sa=X&ved=0ahUKEwj8sfi4hNzQAhUqxVQKHdCkCzYQ_AUIBygC

If it is suppose to be a scrubber Column I cannot see it working.

Can you explain how you believe it will work?


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## saadat68 (Dec 5, 2016)

patnor1011 said:


> It will not work.


Why?


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## saadat68 (Dec 5, 2016)

butcher said:


> I may be confused what that is or its purpose, if it is suppose to be a venturi for draft it would not work.
> You need a venturi action, that design does not create a venturi.
> 
> https://www.google.com/search?q=venturi&espv=2&biw=954&bih=871&source=lnms&tbm=isch&sa=X&ved=0ahUKEwj8sfi4hNzQAhUqxVQKHdCkCzYQ_AUIBygC
> ...


Hi
As I said I want to make my columns like U. It is a vacuum scrubber with 3 column like U. Why you say it doesn't work?


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## g_axelsson (Dec 5, 2016)

In the previous drawing it looked like you were to draw the gas around the U-bend with it filled with water. Every bend is needing around 0.1 kg/cm2 in under pressure, in other words for three bends you need to pump down to (1.0-0.3) = 0.7 kg/cm2 vacuum just to get the air around the bend.

You can't suck air down through water, the only way to get it around the bend is to suck up enough water in the outlet so the water level on the inlet sinks down to be level with the U-bend and air starts to bubble up on the outlet side.

What is the limit of vacuum attainable with your vacuum pump and what is the flow rate at 0.7 kg/cm2 vacuum (0.3 kg/cm under pressure)?

Göran


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## saadat68 (Dec 5, 2016)

g_axelsson said:


> In the previous drawing it looked like you were to draw the gas around the U-bend with it filled with water. Every bend is needing around 0.1 kg/cm2 in under pressure, in other words for three bends you need to pump down to (1.0-0.3) = 0.7 kg/cm2 vacuum just to get the air around the bend.
> 
> You can't suck air down through water, the only way to get it around the bend is to suck up enough water in the outlet so the water level on the inlet sinks down to be level with the U-bend and air starts to bubble up on the outlet side.
> 
> ...



Thanks All
I thought that design is better( need fewer connections and longer columns) and didn't know the pump can not suck air in this way
OK, I back to conventional design. just use 3 pipe as 3 columns :


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## Palladium (Dec 5, 2016)

If you're going to scrub fumes from an open air hood you need a tower designed scrubber where the naoh solution trickles over your packings and draws air over the packings. If you're using a sealed reactor system you can draw the fumes through a flooded column scrubber like you are proposing. If this is for the batteries only and you are using nitric only you can use a 15 gallon stainless drum with a removable top for your reactor and use a flooded column system under vacuum with no problem.


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## saadat68 (Dec 5, 2016)

Palladium said:


> If you're going to scrub fumes from an open air hood you need a tower designed scrubber where the naoh solution trickles over your packings and draws air over the packings. If you're using a sealed reactor system you can draw the fumes through a flooded column scrubber like you are proposing. If this is for the batteries only and you are using nitric only you can use a 15 gallon stainless drum with a removable top for your reactor and use a flooded column system under vacuum with no problem.


Thanks
I want to use vacuum scrubber for batteries but I will add PC scraps to my business after 2 or 3 month

I want to use some pipes for connecting columns ( instead of hose )
For columns I use 3 pipes with 90 mm diameter *and for connect them together I want to use pipe with 40 mm diameter. I solve many of my problem this way. 
Is it OK? 40 mm diameter isn't high for example for vacuum pump or ...? :?: *


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## autumnwillow (Dec 7, 2016)

Make one, fill one with water and use your vacuum pump. If you hear it bubble and check the suction if it doesn't have that much resistance then you are good to go. Don't forget the scrubbing media (bioballs, scrap pvc, etc)

And you will us this scrubber for a closed reaction vessel correct? Like 4metal's design with a filtering flask? If so yes, this will work.
If you are planning to use this system for the entire fume hood then it will not work.

Its your drawing that confused the members.

Edit to add:
It seems that the U design is okay to me. I'm not sure what the other members are thinking why won't it work. As long as the liquid level is correct it should work.

Remember that retention time is important for the scrubber to work. It should pass slowly thru those columns in order for it to treat the fumes. A scrubbing media will help but if your vacuum pressure is too high then it will not work. If your vacuum pressure is too low then your reaction vessel will leak.

This is why I recommend you making a bleeder valve so you can adjust the flow. Its very easy to make.
Its just Tee fitting connected to the vacuum pump w/ 1 gate valve for flow adjustment and 1 inlet valve for the scrubber system.

One more reason for you to use a bleeder valve is because the vacuum pressure will need to go into an equilibrium after you turn off the pump. Tendency is it will push out once you turn off the pump.


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## saadat68 (Dec 7, 2016)

OK
Understood 
Thanks
My biggest problem is limitation in PVC connections. I can not find some of them so I change my design again and again


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## Palladium (Dec 7, 2016)

Use the PVC pipe and caps to make the columns. Then tap each cap and thread it for a barb with threads. Put a barb in the top and bottom of the columns and connect the columns with flexible PVC tubing.


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## saadat68 (Dec 10, 2016)

This is my last design!
Can someone confirm it ? Is it OK ?
Thanks


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## autumnwillow (Dec 19, 2016)

So many fittings, that probably costed you a lot, but you are already there.
Test it yourself. I have provided the guidelines.


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## saadat68 (Dec 29, 2016)

autumnwillow said:


> So many fittings, that probably costed you a lot, but you are already there.
> Test it yourself. I have provided the guidelines.


Thanks I wait for some connections 
I will add some images after finish it 8)


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## saadat68 (Dec 29, 2016)

*I want to destroy my scrubber! It is big ( 3 columns with 100 cm height ) and I fear put that in my workshop  3 columns full of NaOH   
I really fear 

Can I make 6 column ( each on 50 cm ) instead of three column ? I think it is safer :? *


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## autumnwillow (Dec 30, 2016)

If the vacuum is working, just use supports to hold the vessels well and safety buckets for each.


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## saadat68 (Dec 30, 2016)

I destroy it
I really fear. prefer to make a smaller one.


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