shattering vesel

[elfixx]

I tryed to boil down batterie acid to obtain concentrated sulphuric acid. I used pyrex mesuring cup on a spiral coil electric hot plate, first try I putted the cup directly on the plate and upped the temp step by step over 30min till I reached the max temp. One minute later my vesel shattered to pieces. Second try I used a ceramic plate to cover the coil and sit the pyrex onto it and I haven't been able to reach boiling after a hour so I removed the ceramic then sitted the pyrex directly onto the plate and it immediatly shattered. Is it possible those mesuring cup cannot stand heat at all or is it my plate which give to much direct heat? Could a coffee pot withstand the direct heat or do I need pyrex lab beaker and will a pyrex beaker stand such a direct heating? or what could I use to cover the plate without loosing all the heat?
I dont have much choice to produce some nitric since the only other source of this acid I founded is a small water treatment shop who can sell me 500ml bottle for 50$(CAD) + they are closed at the moment for the holydays

 

[Platdigger]

I have used a coffee pot on a propane burner to boil down sulfuric.
Randy

 

[butcher]

pyrex measuring cups should not be heated, use coffee pot, on hot plate and do not change temperatures fast (thermal shock).I use cofee pot alot with much sucsess, no glass can handle thermal shock, the thick glass is not made for heating, and can be dangerous to try. also I use fiberglass trays under my hot plate,or my other jars to catch any spills and to keep things cleaner, as all my processing is done under a tarp outdoors in woods on my property.
you can make nitric acid with fertilizer KNO3, or NaNO3 and sulfuric acid. see poormans for cold or distilling nitric for more purity, buying nitric can use up any profit you may get, also most electronic gold or fine material can be done without nitric.

 

[elfixx]

thx for those precious info. And i'm not in processing electronic scrap for now. Atm i'm on a karat jewelry job, I bought a few once of karat jewelry for resonable price (65-70% market value). But now i'm guessing if I should try to sell or just refine one of the pieces. It's a set of one neclace and a bracelet made of white and yellow 14k gold incrusted with 1.06 carat of SI2 round brilliant diamond weigting 55g in mint condition. I even got the aparasal proving it as been paid 3476$usd in 2003 at birks. Anyone got a idea where I could sell this? lets just say it could be way more profitable to sell it somewhere for half its value instead of refining the 32g of gold and maybe 1g of Pd it contain..

 

[qst42know]

Finished jewelery in good condition is often worth more than the scrap value it contains. I wouldn't take long to run it on eBay and find out.

You likely will not get appraised price but you may even consider wholesaling it to a retail jeweler as considerable labor went into its creation.

 

[skykinghunter]

I tryed to boil down batterie acid to obtain concentrated sulphuric acid. I used pyrex mesuring cup on a spiral coil electric hot plate, first try I putted the cup directly on the plate and upped the temp step by step over 30min till I reached the max temp. One minute later my vesel shattered to pieces. Second try I used a ceramic plate to cover the coil and sit the pyrex onto it and I haven't been able to reach boiling after a hour so I removed the ceramic then sitted the pyrex directly onto the plate and it immediatly shattered. Is it possible those mesuring cup cannot stand heat at all or is it my plate which give to much direct heat? Could a coffee pot withstand the direct heat or do I need pyrex lab beaker and will a pyrex beaker stand such a direct heating? or what could I use to cover the plate without loosing all the heat?
I dont have much choice to produce some nitric since the only other source of this acid I founded is a small water treatment shop who can sell me 500ml bottle for 50$(CAD) + they are closed at the moment for the holydays

 

[junkelly]

What I have done is to fill a steel dish, such as a muffin pan, with sand. Then sit your glass beaker in the sand 'bath'. The sand acts as a buffer, taking a long time to heat up or cool down. It buffers the shock that your glassware may face when exposed to direct heat. It also helps to use a broken piece of tile inside the beaker as a 'boiling stone'.

-junkelly

 

[goldsilverpro]

Just because a container is Pyrex, it doesn't mean that it will take heat, especially direct heat, like the electric burner you set it on. At the temperature needed for cooking sulfuric, even thin heatable Pyrex, like beakers and coffee pots, can break if you put them directly on a burner.

The sand bath, mentioned by junkelly, is the safest way to do it. I use a cast iron skillet with about 1.5" of sand in it. I sink the beaker about .5" into the sand and pile a little sand up around the beaker. It takes awhile to get hot, but once it's hot, it stays very hot.

Even when dissolving something, I always put the beaker in a 5 quart, white, flat-bottomed, Corning Ware dish and place the dish on the hotplate. Saves a lot of grief.

 

[Noxx]

Pyrex cups (for cooking) are no longer made of pyrex.

I would strongly recommend using laboratory glassware. Beakers are cheap and work well.

 

[Harold_V]

I would strongly recommend using laboratory glassware. Beakers are cheap and work well.

That advice also promotes the appearance of professionalism. That can spell the difference between acceptance and rejection if one is seeking customers. Just a thought to keep when you're trying to convince someone that you know what you're doing.

Harold

 

[Noxx]

Exactly !

Also, if you afford thick lab glassware go for it. You wouldn't want your beaker holding $10'000 worth of gold to break during use.

But take this into consideration. You WILL likely break glassware during handling/heating. It may not be your fault but you should have a set-up to catch any spills/leaks. I designed my fume hood for this reason. If any glassware would break, nothing would be lost since the floor of the fume hood is sealed with windows sealant I think...

 

[elfixx]

All noted once again thx for those helpfull info