Sciencemadness Discussion Board

Magnetic Hotplate Stirrer Advice

MrMario - 4-2-2016 at 11:20

Hello Sciencemadness-forum,

This is my first post so correct me if i'm breaking any rules. First, I would like to say that this forum is full of great topics which help me alot, thanks!

I'm an Advanced beginner in Chemistry, almost fully understand most basic inorganic chemistry and now beginning to learn inorganic chemistry with reactions schemes, ect.

Now as a hobbiest and not professional chemist it's sometimes hard to obtain very common used lab chemicals (This is a good thing, so that people with no knowledge don't do harm).
I know how to obtain many usefull materials OTC and now i'm looking for a good Magnetic Hotplate Stirrer that can for example be used for the distillation of Sulfuric Acid from Drain Cleaner/Battery Acid and maybe many other usefull chemicals.

Do you guys have any advice for a good Hotplate Stirrer that is suitable to reach high temperatures and boil Sulphuric Acid for example? Some people on the net create their own specialized heating mantle to do this, but i would like to buy a complete hotplate that can do all.

Also, some hotplates advertise that they can heat up to 550 degrees. Is that the surface of the hotplate or how high you can heat a substance?

Thanks in advance!:)

MrMario

chemrox - 4-2-2016 at 14:07

I just lost the "spin" part of my Spin-Master. Damn! It was the right size and and provides continuous heat adjustment. Is it worth the hassle of taking it apart i should I just wait for the right ebay offering?

MrMario - 4-2-2016 at 14:14

Is the magnet completely missing or is it still in the hotplate, maybe you can do some DIY fixing with a harddrive magnet?

JJay - 4-2-2016 at 15:32

Quote: Originally posted by MrMario  
Hello Sciencemadness-forum,

This is my first post so correct me if i'm breaking any rules. First, I would like to say that this forum is full of great topics which help me alot, thanks!

I'm an Advanced beginner in Chemistry, almost fully understand most basic inorganic chemistry and now beginning to learn inorganic chemistry with reactions schemes, ect.

Now as a hobbiest and not professional chemist it's sometimes hard to obtain very common used lab chemicals (This is a good thing, so that people with no knowledge don't do harm).
I know how to obtain many usefull materials OTC and now i'm looking for a good Magnetic Hotplate Stirrer that can for example be used for the distillation of Sulfuric Acid from Drain Cleaner/Battery Acid and maybe many other usefull chemicals.

Do you guys have any advice for a good Hotplate Stirrer that is suitable to reach high temperatures and boil Sulphuric Acid for example? Some people on the net create their own specialized heating mantle to do this, but i would like to buy a complete hotplate that can do all.

Also, some hotplates advertise that they can heat up to 550 degrees. Is that the surface of the hotplate or how high you can heat a substance?

Thanks in advance!:)

MrMario


That's the surface of the hotplate.

MrMario - 4-2-2016 at 15:43

Quote: Originally posted by JJay  

That's the surface of the hotplate.


Do you know what kind of surface temperature a hotplate needs to achieve to boil Sulphuric acid, because alot of heat will get lost?

chemrox - 4-2-2016 at 19:16

Quote: Originally posted by MrMario  
Is the magnet completely missing or is it still in the hotplate, maybe you can do some DIY fixing with a harddrive magnet?

Good ideas! I'll disassemble to where I can see it. The mag seems dead but I need to do more checking and it's late here.. longass day. Why would the mag be dead for example? I really like the size/dimensions of the unit. I would prefer other than Al surface...but alas that would be too dear to change.

[Edited on 5-2-2016 by chemrox]

Herr Haber - 4-2-2016 at 19:38

Quote: Originally posted by MrMario  
Quote: Originally posted by JJay  

That's the surface of the hotplate.


Do you know what kind of surface temperature a hotplate needs to achieve to boil Sulphuric acid, because alot of heat will get lost?


If I had to distill sulphuric acid I'd rather go for a heating mantle.
Considering you'll have to reach 300° for a while, I would be especially concerned about the vessel. A little vacuum if possible may help lower the temperature therefore the risks. In any case, you'll lose some SO3 in the process too though that should be neglegible.
Either way, hotplate or heating mantle, be extra paranoïd with the quality of the glassware you'll be using.

Also, one beginner mistake I made and I urge you to avoid: dont use the extra thick for heavy use glassware. It might seem like a good idea but dilatation of thicker glassware will make it more dangerous. I'm saying that out of the bottom of my head but I'm pretty sure I read this somewhere here in SM.

At some point I was wondering if I shouldnt buy some quartz glassware for "extreme" temperatures.

MrMario - 5-2-2016 at 01:30

Quote: Originally posted by Herr Haber  
Quote: Originally posted by MrMario  
Quote: Originally posted by JJay  

That's the surface of the hotplate.


Do you know what kind of surface temperature a hotplate needs to achieve to boil Sulphuric acid, because alot of heat will get lost?


If I had to distill sulphuric acid I'd rather go for a heating mantle.
Considering you'll have to reach 300° for a while, I would be especially concerned about the vessel. A little vacuum if possible may help lower the temperature therefore the risks. In any case, you'll lose some SO3 in the process too though that should be neglegible.
Either way, hotplate or heating mantle, be extra paranoïd with the quality of the glassware you'll be using.

Also, one beginner mistake I made and I urge you to avoid: dont use the extra thick for heavy use glassware. It might seem like a good idea but dilatation of thicker glassware will make it more dangerous. I'm saying that out of the bottom of my head but I'm pretty sure I read this somewhere here in SM.

At some point I was wondering if I shouldnt buy some quartz glassware for "extreme" temperatures.


So i guess it would be a better option to go for vacuum distillation, considering the risks at high temperatures.Since I really don't want to have any boiling sulphuric acid explosion :)

@Chemrox My magnetic stir bar once demagnitezed due long incorrect spinning. I don't know for sure, but some heat and wrong spinning can render it unusable.