Slagging off silicon

[Ayham Hafez]

I remember from old thread @kurtak mention that silicon will be alloyed with copper when smelt E-waste so we should slag it off, I make a search about how we can do that but didn't find any method rather than using NaOH, but as in Smelting thread, NaOH is not a flux and should not be used, so what is the proper way to slag off silicon when smelt E-waste?

 

[FrugalRefiner]

Ayham, you've used silicone in both your thread title and your post, but I believe you mean silicon.

Silicon is an element and is used in making ceramics and is the basis of the actual "chip" in integrated circuits.

Silicone is a synthetic oil or rubber-like substance. Silicone caulk is a common form.

You may want to try your searches again with silicon instead of silicone.

I'm going to change the title of this thread to Slagging off silicon.

Dave

 

[Ayham Hafez]

Ayham, you've used silicone in both your thread title and your post, but I believe you mean silicon.

Silicon is an element and is used in making ceramics and is the basis of the actual "chip" in integrated circuits.

Silicone is a synthetic oil or rubber-like substance. Silicone caulk is a common form.

You may want to try your searches again with silicon instead of silicone.

I'm going to change the title of this thread to Slagging off silicon.

Dave

Appreciated, I found in the forum how to slag silicon, simply by just adding silica in fair amount, mentioned also by @kurtak in another thread.

 

[kurtak]

Appreciated, I found in the forum how to slag silicon, simply by just adding silica in fair amount, mentioned also by @kurtak in another thread.

Could you please provide a link to that post/thread - I would like to re-read what I posted

I remember from old thread @kurtak mention that silicon will be alloyed with copper when smelt E-waste so we should slag it off,

But yes - silicon will alloy with copper & as well with gold or silver - especially if copper is involved in the dore metal (smelt)

I don't have time right now to post a detailed post - but ------

the reason silicon can/will alloy with copper (as well as silver & gold) is because silicon (Si) is a pure element whereas silica (SiO2) is not --- silica is silicon plus 2 oxygen atom

So the reason silica helps to slag off silicon is that in the smelt oxygen from the silica is donated to the silicon allowing the silicon to combine with the silica & other flux ingredients (borax, soda ash etc.) thereby "helping" the silicon to slag off

Adding some lime to the smelt (flux) will better improve the slagging off of the silicon as the lime complexes with both the silicon & silica turning them to "lime glass" which helps prevent the silicon from alloying with the metals in the smelt

In other words - the silicon & silica (as lime glass) are better "take up" in the other flux ingredients (borax & soda ash)

Kurt

 

[Ayham Hafez]

Could you please provide a link to that post/thread - I would like to re-read what I posted


But yes - silicon will alloy with copper & as well with gold or silver - especially if copper is involved in the dore metal (smelt)

I don't have time right now to post a detailed post - but ------

the reason silicon can/will alloy with copper (as well as silver & gold) is because silicon (Si) is a pure element whereas silica (SiO2) is not --- silica is silicon plus 2 oxygen atom

So the reason silica helps to slag off silicon is that in the smelt oxygen from the silica is donated to the silicon allowing the silicon to combine with the silica & other flux ingredients (borax, soda ash etc.) thereby "helping" the silicon to slag off

Adding some lime to the smelt (flux) will better improve the slagging off of the silicon as the lime complexes with both the silicon & silica turning them to "lime glass" which helps prevent the silicon from alloying with the metals in the smelt

In other words - the silicon & silica (as lime glass) are better "take up" in the other flux ingredients (borax & soda ash)

Kurt

https://goldrefiningforum.com/threads/smelting.23680/page-9#post-353135

In same page at the end you mentioned to post a solution for using excess amount of soda ash so it will not eat the crucible and will help to get metal from slag by boiling it with water, did you share the solution in another thread?

 

[Ayham Hafez]

Could you please provide a link to that post/thread - I would like to re-read what I posted


But yes - silicon will alloy with copper & as well with gold or silver - especially if copper is involved in the dore metal (smelt)

I don't have time right now to post a detailed post - but ------

the reason silicon can/will alloy with copper (as well as silver & gold) is because silicon (Si) is a pure element whereas silica (SiO2) is not --- silica is silicon plus 2 oxygen atom

So the reason silica helps to slag off silicon is that in the smelt oxygen from the silica is donated to the silicon allowing the silicon to combine with the silica & other flux ingredients (borax, soda ash etc.) thereby "helping" the silicon to slag off

Adding some lime to the smelt (flux) will better improve the slagging off of the silicon as the lime complexes with both the silicon & silica turning them to "lime glass" which helps prevent the silicon from alloying with the metals in the smelt

In other words - the silicon & silica (as lime glass) are better "take up" in the other flux ingredients (borax & soda ash)

Kurt

Regard using lime, can I use hydroxide calcium which used as a building products instead cause I can't find oxide calcium in my local market? I read that lime is a combination between oxide and hydroxide calcium so both materials included in calcium hydroxide building product

 

[goldshark]

Regard using lime, can I use hydroxide calcium which used as a building products instead cause I can't find oxide calcium in my local market? I read that lime is a combination between oxide and hydroxide calcium so both materials included in calcium hydroxide building product

Calcium oxide can be made, by heating Limestone to 1850+F, until glowing white. The simplest technique is to take 2" gravel size Limestone, equal parts charcoal or coal, put in a cylindrical refractory chimney looking device, then ignite from the bottom. There are many Youtube videos on how to do this.
Using Calcium Hydroxide ( slaked lime, or has water added to it ), will create a lot of boiling action in the smelt, due to evolution of CO2, the gas you eliminate when making CaO (quicklime or Calcium Oxide ).
Calcium Oxide will readily absorb CO2 back from the atmosphere, much like Sodium Carbonate, so it is best to make either a fresh supply for immediate use, or store in an air tight container.
If there is a Marble quarry close by, it is an excellent source of 99.9% Calcium Carbonate. I am lucky enough to have a quarry facility nearby, so I just acquired a 5 gallon bucket full, just for this purpose. Also a stone and tile fabricator, which deals in Marble, may have some waste available very cheaply, if not free.

 

[Ayham Hafez]

Calcium oxide can be made, by heating Limestone to 1850+F, until glowing white. The simplest technique is to take 2" gravel size Limestone, equal parts charcoal or coal, put in a cylindrical refractory chimney looking device, then ignite from the bottom. There are many Youtube videos on how to do this.
Using Calcium Hydroxide ( slaked lime, or has water added to it ), will create a lot of boiling action in the smelt, due to evolution of CO2, the gas you eliminate when making CaO (quicklime or Calcium Oxide ).
Calcium Oxide will readily absorb CO2 back from the atmosphere, much like Sodium Carbonate, so it is best to make either a fresh supply for immediate use, or store in an air tight container.
If there is a Marble quarry close by, it is an excellent source of 99.9% Calcium Carbonate. I am lucky enough to have a quarry facility nearby, so I just acquired a 5 gallon bucket full, just for this purpose. Also a stone and tile fabricator, which deals in Marble, may have some waste available very cheaply, if not free.

Thanks @goldshark , I think I can get benefits of producing calcium oxide from calcium carbonate with smelting and with naturalizing stockpot.

Sodium carbonate powder is available and much cheaper than calcium hydroxide, I think I can simply produce calcium oxide by heating calcium carbonate powder in a crucible without charcoal, when want to use calcium oxide for naturalizing stockpot I will just add some water to it to convert it to calcium hydroxide

 

[Yggdrasil]

Thanks @goldshark , I think I can get benefits of producing calcium oxide from calcium carbonate with smelting and with naturalizing stockpot.

Sodium carbonate powder is available and much cheaper than calcium hydroxide, I think I can simply produce calcium oxide by heating calcium carbonate powder in a crucible without charcoal, when want to use calcium oxide for naturalizing stockpot I will just add some water to it to convert it to calcium hydroxide

Frankly your post is confusing me a bit.
If you are talking on neutralizing your stockpot, you are doing this as in a step to treat your waste right?

Fort treating your waste any carbonate or Hydroxide will do it only needs to be a high pH substance.
Sodium Carbonate, Sodium Hydroxide or Calcium Hydroxide will do, Calcium Hydroxide (Slaked Lime) is usually cheapest.

 

[Ayham Hafez]

Frankly your post is confusing me a bit.
If you are talking on neutralizing your stockpot, you are doing this as in a step to treat your waste right?

Fort treating your waste any carbonate or Hydroxide will do it only needs to be a high pH substance.
Sodium Carbonate, Sodium Hydroxide or Calcium Hydroxide will do, Calcium Hydroxide (Slaked Lime) is usually cheapest.

Calcium carbonate has ph of 9 not like calcium hydroxide which is 12.5.

My main question is about using calcium oxide, I just thought loudly, said to my self to produce calcium oxide from calcium carbonate to use it for fluxing IC-chips and for naturalizing waste acids

 

[Yggdrasil]

Calcium carbonate has ph of 9 not like calcium hydroxide which is 12.5.

My main question is about using calcium oxide, I just thought loudly, said to my self to produce calcium oxide from calcium carbonate to use it for fluxing IC-chips and for naturalizing waste acids

Again, you men neutralizing, yes?
The Hydroxides may be a bit too strong when you start to get close neutral, so using both Carbonates and Hydroxides might be beneficial.

 

[Ayham Hafez]

Again, you men neutralizing, yes?
The Hydroxides may be a bit too strong when you start to get close neutral, so using both Carbonates and Hydroxides might be beneficial.

Apologize for my weak English spelling, yes neutralizing.

Did you test using calcium carbonate for neutralizing acids, if its effective I will just use it since its very cheap comparing with calcium hydroxide.

 

[Yggdrasil]

Apologize for my weak English spelling, yes neutralizing.

Did you test using calcium carbonate for neutralizing acids, if its effective I will just use it since its very cheap comparing with calcium hydroxide.

No I have used only NaOH, but it is hard to control and it is rather expensive.

 

[Ayham Hafez]

No I have used only NaOH, but it is hard to control and it is rather expensive.

As you mentioned its expensive and hard to control and make filtration very hard

 

[Yggdrasil]

Apologize for my weak English spelling, yes neutralizing.

Did you test using calcium carbonate for neutralizing acids, if its effective I will just use it since its very cheap comparing with calcium hydroxide.

You just quoted my reply without new information?
Calcium Hydroxide is less aggressive and slower working so some has reported that it is better to use.
But all is here in the thread, dealing with waste.
You have read it have you not?

 

[Ayham Hafez]

You just quoted my reply without new information?
Calcium Hydroxide is less aggressive and slower working so some has reported that it is better to use.
But all is here in the thread, dealing with waste.
You have read it have you not?

Sorry I quoted your reply and posted before add my reply, then edited.

Yes I read it, I stopped using NaOH because of what you have mentioned, and calcium hydroxide much better and cheaper in same time, will try to test calcium carbonate if its like calcium hydroxide then it will be better because of its low price

 

[MH36]

Could you please provide a link to that post/thread - I would like to re-read what I posted


But yes - silicon will alloy with copper & as well with gold or silver - especially if copper is involved in the dore metal (smelt)

I don't have time right now to post a detailed post - but ------

the reason silicon can/will alloy with copper (as well as silver & gold) is because silicon (Si) is a pure element whereas silica (SiO2) is not --- silica is silicon plus 2 oxygen atom

So the reason silica helps to slag off silicon is that in the smelt oxygen from the silica is donated to the silicon allowing the silicon to combine with the silica & other flux ingredients (borax, soda ash etc.) thereby "helping" the silicon to slag off

Adding some lime to the smelt (flux) will better improve the slagging off of the silicon as the lime complexes with both the silicon & silica turning them to "lime glass" which helps prevent the silicon from alloying with the metals in the smelt

In other words - the silicon & silica (as lime glass) are better "take up" in the other flux ingredients (borax & soda ash)

Kurt

Could you by chance post a detailed information about this silicon/silicone topic please? I am very interested in this specific aspect...obviously when you get the time to write such a post

 

[goldshark]

Thanks @goldshark , I think I can get benefits of producing calcium oxide from calcium carbonate with smelting and with naturalizing stockpot.

Sodium carbonate powder is available and much cheaper than calcium hydroxide, I think I can simply produce calcium oxide by heating calcium carbonate powder in a crucible without charcoal, when want to use calcium oxide for naturalizing stockpot I will just add some water to it to convert it to calcium hydroxide

Just so we are on the same page, yes, you can use Calcium Hydroxide as a flux. The only problem is the excess gas production, which could lead to a boil over in the furnace. Boil overs are a mess, leading to problems until you change the refractory bricks.

 

[Yggdrasil]

Could you by chance post a detailed information about this silicon/silicone topic please? I am very interested in this specific aspect...obviously when you get the time to write such a post

Silicon is a hard brittle semi metal looking like Silver. https://en.wikipedia.org/wiki/Silicon
Silicone is a colorless Polymer often used as rubber, lubricant sealant and more. https://en.wikipedia.org/wiki/Silicone

 

[Ayham Hafez]

Just so we are on the same page, yes, you can use Calcium Hydroxide as a flux. The only problem is the excess gas production, which could lead to a boil over in the furnace. Boil overs are a mess, leading to problems until you change the refractory bricks.

BTW, because of aggressive fluxes I built a furnace that don't use refractory bricks or crucible, molten material only contact with refractory cement, till now I make 4 smelts and it looks great, here a photos of it