I would like to ask how to handle a mixed gas of sulfuric acid, nitric acid, and hydrochloric acid
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There is an existing cleaning production line that requires the use of sulfuric acid, hydrochloric acid, and nitric acid to clean workpieces at elevated temperatures; the acidic vapors are collected through exhaust hoods and then treated by spraying with NaOH solution. Is this approach feasible? Are there any other better ways? Please give me some advice! Thank you first.
It is possible to use alkaline solutions for neutralization, such as ammonia water and Na2CO3
This post was last edited by blueseabreeze on 2011-8-26 08:47. They are all strong acids; using bases or basic salts are viable solutions. It mainly depends on what your ultimate goal is for handling these three gases. Those upstairs suggested using ammonia, but I disagree with that. Although ammonia is alkaline and can react with certain substances, it evaporates easily and ends up in the mixed gas. Carbon dioxide produced by sodium carbonate will also enter the mixed gas. So it also depends on what the homeowner’s ultimate goal is. So, what the original poster said isn’t very clear either.
Reply to 3# blueseabreeze Thank you for your reply! Is sodium carbonate used to save costs? The carbon dioxide produced as a byproduct of the reaction is to be discharged; my goal is to ensure that, after purification, it meets environmental standards and can be released into the atmosphere. If it is only a case of acid-base neutralization, sodium hydroxide would be more appropriate.
The amount of gas emitted will not be very large, and it is difficult to control the amount absorbed by NaOH; it is recommended to use a weak base for absorption.
Reply to 5# A Sha: Using a 15% sodium hydroxide solution, with a pH meter and a dosing pump for control – there shouldn’t be any major problems.
Reply to 6# evident: Regardless of the substance used for absorption, solid materials will be formed, and their recycling and disposal also need to be taken into consideration. Ammonia water is recommended, as it makes it easier to handle the material after absorption.
Reply to 7# A Shan: Ammonia! It needs to be carefully considered; it has not been used before, and transportation, storage, safety, working environment, and daily management all need to be taken into account together. Are there any good resources on this convenience?
When NaOH is absorbed, solids are formed, and it is indeed necessary to consider the recovery and disposal of these solids. If the volume of gas is high, it can easily cause blockages in the packing or the circulation pump
Ammonia water is good; the product can be used as fertilizer.
Is it needed for recycling? ? A condenser will suffice if needed; otherwise, an alkaline scrubber will do.