Perchloric acid is a clear and odorless liquid that's stronger than sulfuric acid or nitric acid. It remains generally safe at room temperature at 70%-75% concentration. (Of course, it still needs to be housed and contained properly.) The real fun starts once you begin to heat it up.
The basis of many laboratory experiments involves heating perchloric acid. At that point, its oxidizing properties are amplified. Since it becomes explosive when heated, it must be handled with extreme care. Perchloric acid is a double whammy in a sense—it's an acid and it also produces perchlorates. (Perchlorates are salts that are sometimes referred to as crystals.)
Considerations for Proper Safety
All surfaces that make contact with perchloric acid should be cleaned thoroughly on a regular basis. Otherwise, even though it's not generally dangerous for people within the laboratory, it could pose a danger to maintenance people who clean the exhaust. (If you do a web search for 'perchloric acid accidents', you'll be quite surprised with the results.) If anyone happened to hit a surface where perchlorates (salts/crystals) had accumulated, it could literally blow up. That's why you really need to have a safe, effective cleaning and exhausting system. Perchlorates are water soluble, so these systems should always be cleaned periodically to remove any potentially dangerous buildup.
You also need to use the right types of materials when dealing with perchloric acid. Due to its corrosive properties, materials like copper, brass, bronze, high-nickel alloys, or aluminum aren't suitable. (For fun, try pouring perchloric acid onto aluminum and run like hell. It will burst into flames.) You also shouldn't use organic materials like cotton, wool, or wood. If you have an installation that's using perchloric acid and fume hoods, the facility shouldn't have wooden floors. Materials that are suitable for contact with perchloric acid are Teflon, neoprene, PVC, fiberglass (which we specialize in), and 3/16 stainless steel.
Fiberglass is recommended for the ducting that travels from the fume hood to the exhaust system in the roof. The fume hood should also be specifically dedicated for perchloric acid. It needs to have a wash down system, which has wash rings and spray nozzles within the ducting. They are periodically turned on after experiments in the hood to effectively and safely clean down the system. At the back of the fume hood is a catchment tank where the contaminated water is collected. Instead of sending the water into the municipal draining system, it's periodically removed, treated, and properly disposed.
MK Plastics is Solutions-Based
Being a solutions-based company means that we don't just provide a product for perchloric acid exhaust systems. We also help the engineers and owners to design a safe and efficient system. We often get requests with attached contract drawings sent to us asking to help design the system. The bulk of our work when it comes to these applications is sitting down with the engineers and designers at the facility to design the complete system for them. We also provide a startup sequence and help the owners start up the application in a safe and satisfactory way.
If you're interested in learning about how we can help design and build a system that meets your requirements, contact us today. We also have documentation to help owners gain a complete understanding about the systems we supply. We provide a complete package including wash down system, programmable timer, valves, exhaust fans, and the passive stack. The only thing we don't supply is the dedicated fume hood.