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Topic: spent acid recovery  (Read 2865 times)

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Offline Surabh K.t

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spent acid recovery
« on: October 24, 2018, 08:56:57 AM »
How to concentrate a 10% w/w sulfuric acid solution which contains 5 % w/w organics (M.wt>150), 5%w/w NaHSO4 and rest water to an 80% w/w sulfuric acid solution.
Note: This has to be done on an industrial level not lab scale.

Offline wildfyr

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Re: spent acid recovery
« Reply #1 on: October 24, 2018, 09:21:30 AM »
So the organics are not volatile?

Anyways, the primary way to go from a 10% H2SO4 solution to an 80% H2SO4 solution is by evaporating the water. Usually with heat.


The one other option is to use an ion exchange column to sequester sulfate ions, then you acidify the column with another (cheaper) acid and H2SO4 is released.

Offline Surabh K.t

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Re: spent acid recovery
« Reply #2 on: October 24, 2018, 09:54:19 AM »
All I know is that the organics are soluble. Also we cant directly remove water as concentrated sulfuric acid will char the organics. Ion exchange column would be too expensive for a commercial process.

Offline wildfyr

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Re: spent acid recovery
« Reply #3 on: October 24, 2018, 11:10:11 AM »
Well I work in a commercial process, and we use acid recovery via ion exchange resin on the hundreds of kg scale per exchange column. Our is for phosphoric acid, but I think our sister factories do it for sulfuric as well.

You could extract the organics with an immiscible solvent like ethyl acetate.

Offline Surabh K.t

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Re: spent acid recovery
« Reply #4 on: October 24, 2018, 02:11:32 PM »
Thank you for your help. If you don't mind can you suggest me which anion exchange resin would be best suitable for the job. Moreover after regenerating H2SO4 with the cheaper acid how should i regenerate the resin?. Also i have read that the efficiency of the resin decreases over time. How often is one required to replace the resin bed?

Offline wildfyr

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Re: spent acid recovery
« Reply #5 on: October 24, 2018, 02:59:52 PM »
I'm sorry, I really don't know what resin you should use, it is highly dependent on the application. For instance, having some organic material could change the game. I suggest you get small amounts of a bunch of diferent ones and try them out in little lab columns. Also, talk to the manufacturers, they are true experts in this field. They are trying to sell you something, but if you can get an actual scientist on the phone instead of a rep, you'll probably get honest answers to all these questions, and probably higher quality ones that I can give.

The manufacturers often will provide specs on how many cycles the resin will reasonably last.


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