Electrochemistry Copper Nitrate Cell

[ericrm]

kurt,from what i read, glass melt at 1600deg celcius , did you manage to lower the melting point enuf so it can be melt in a regular furnace?

 

[jonn]

Try adding Borax Kurt, you will be surprised at it's color once cooled. The tin will report first.

 

[kurt]

Thanks John – will give it a try – I just referred to fluxes in my assaying book & it list’s both soda ash & borax as complexing fluxes (meaning they cause both oxidation & reduction in the crucible) & it list’s ferric oxide & potassium nitrate as oxidizing fluxes which is why I asked

But then in the description on each flux it says soda ash will cause “some” oxidation – were as for borax it says – this is an oxidizing flux

I used soda ash without borax on that first smelt for two reasons (1) soda ash tends to run more fluid then borax & without having any fluorspar for thinning I wanted my flux as fluid as possible to reduce metal balling up in the slag (2) soda ash brakes down in water borax doesn’t - so with soda ash in the flux you can brake the slag down in water & pan out any metal that balls up in the slag --- you still need to do some crushing but the more you can brake the slag down in water the easier the crushing.

Eric – yes – silica (glass) has a high melt point (1775 C for pure silica) but in combination with different fluxes it’s melting point is reduced (the flux acts as a solvent)

Silica is used as a flux – in combination with other fluxes – in both smelting & assaying to form the slag – the silica combines with the metal oxides & bases so they are retained in the slag & not carried down with the metal

So yes – the glass (from fiber glass in CBs) will melt in any furnace we use for melting our metals when used in combination with other fluxes (if it will melt gold it will melt glass combined with other flux) & the glass is actually beneficial in the smelt --- borax will dissolve silica at assay temperatures (1850 F)

Fluxing is a science in its own – one I am still learning - any good fire assay book is a good place to start learning about fluxing

Kurt

 

[kurt]

Kurt, you're replacing the Borax with fiberglass? From where?? Did you forget to incinerate?

Yes I incinerated first - after incineration you end up with ash (from burned plastics & resin) the fiber glass (which doesn't burn or melt at incineration temps) and of course your metals --- so I didn't ad fiberglass in place of borax - I just didn't use any borax figuring the existing fiberglass would work in place of borax

Kurt

 

[jonn]

Thanks Kurt, you pose some very good questions. My feedstock is usually different than yours, I have more copper and less tin. I think you're on to something good here and would be very interested to know how this turns out for you. Every time I had fiberglass in the crucible it would float to the top and create a sticky mess which would not melt. Adding borax has always solved the problem. Please keep us posted as to what flux combination works best for you. It would certainly solve a lot of problems for everyone. Thanks, Jonn.