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zoas23
09-03-2015, 05:24 PM
Hi!

A simple question (and thanks for everyone's tolerance with my ongoing questions).

A crucible made of stone is "cured" with Borax (sodium borate) to melt metals...

http://s22.postimg.org/oeytznrld/Captura_de_pantalla_2015_09_03_a_las_14_39_26.png

... but what happens with herbal calcinations? should the crucible be "cured" with borax or such thing may actually contaminate the salts?

JDP
09-03-2015, 06:09 PM
Hi!

A simple question (and thanks for everyone's tolerance with my ongoing questions).

A crucible made of stone is "cured" with Borax (sodium borate) to melt metals...

http://s22.postimg.org/oeytznrld/Captura_de_pantalla_2015_09_03_a_las_14_39_26.png

... but what happens with herbal calcinations? should the crucible be "cured" with borax or such thing may actually contaminate the salts?

It is not even absolutely necessary to "cure" crucibles with borax. The only thing such a treatment does is to form a thin layer of "glass" to seal up the pores of the crucible, but you can just go ahead and use the crucibles as they are for most operations (like melting metals, which usually use some borax or any other flux anyway.)

Regarding calcination of plants: unless you heat them too strongly and melt the alkaline salts left in the ashes, it won't have any appreciable effect on the crucible walls. However, for calcining plants it is better to use wide calcining pots or dishes rather than tall and narrow crucibles like the ones usually employed for melting metals. The objective here is to get rid of most of the combustible carbon (in the form of gaseous oxides of carbon) and leave the non-combustible byproducts behind, so the more oxygen that comes in contact with the heated plant-matter the better it will be to get rid of the combustible carbon content.

zoas23
09-03-2015, 10:45 PM
Thank you for your kindness, JDP.

My intention is to calcinate herbal salts after they were separated from the ashes by leeching.
The pores may make a small amount of the ashes stay there and in the long run make it become a "dirty" crucible.
That's why I thought of Borax, but I am not 100% sure about how Borax will behave...

Will it react in any way with the salts?
Will it "melt again" and get mixed with the salts?
DO I face the risk of getting salts mixed with (undesirable) Borax?

JDP
09-04-2015, 12:19 AM
Thank you for your kindness, JDP.

My intention is to calcinate herbal salts after they were separated from the ashes by leeching.
The pores may make a small amount of the ashes stay there and in the long run make it become a "dirty" crucible.
That's why I thought of Borax, but I am not 100% sure about how Borax will behave...

Will it react in any way with the salts?
Will it "melt again" and get mixed with the salts?
DO I face the risk of getting salts mixed with (undesirable) Borax?

Well, it depends on how strongly you heat the salts. If you heat them enough to melt them then they will react with both the borax glass and the walls of the vessel because molten alkaline salts react with silicates. Also, borax has a relatively low melting point, so it is not the most ideal thing for what you want. It would be better to use a high temperature glaze.

zoas23
09-04-2015, 06:59 PM
Well, it depends on how strongly you heat the salts. If you heat them enough to melt them then they will react with both the borax glass and the walls of the vessel because molten alkaline salts react with silicates. Also, borax has a relatively low melting point, so it is not the most ideal thing for what you want. It would be better to use a high temperature glaze.

Thank you so much, JDP.
The minutes you devote to answering my silly questions save me from HOURS of frustration, mistakes, bad choices, etc.
infinite gratitude.