Borax only without anything

[j2000]

Hi, i have gold powder (sure it's not pure gold).
I have melting with electric furnace with graphite crucible.

I melt around 1150c/2102F, and hold until 30 to 60 minuite.
I use general borax only because very hard to find chemical thing on my location....and i try from 1part of gold powder: 2 part borax, to 1:3, 1:4, 1:5, 1:6 (borax part ).
After melting, i can see much gold extract from that powder…

In the picture, this is from broken crucible, i can see much gold (sorry for the bad pic), but all separated condition, i mean the gold not gathered together to be 1 pcs gold…
I just confused, this problem about borax or i must use special borax ?

I also order hank chapman borax, but not yet arrived…as i know hank chapman borax already to go composition borax....

Regards

Joel

 

[nickvc]

The powder looks good to me but the amount of flux is way too much.
Heat your powder in the crucible which has a light coating of flux already applied to the insides. If the powder won't melt either the temperature isn't hot enough or else you need more insulation for the furnace. The already melted flux will need thinning down and ideally the molten flux should be poured into a cone mould. 4metals has posted some good mixes for thinning fluxes but it depends on what's available to you locally as to what you use. The colour of the flux indicates to me you have values still trapped in it and if your furnace won't get hot enough to melt the gold try a gas torch and a melting dish with again decent insulation to retain the heat. Melting is another part of recovery and refining that isn't as easy as it looks especially if you don't have the correct equipment and some electric furnaces really are rubbish for our needs.

 

[Geo]

There's one of two things that come to mind. Either that's not borax (at least no borax i have ever seen) or that's not gold powder. I've seen borax look like that when melting copper powder but not gold. fluxing should be done for several different processes (assays,smelting) but melting doesn't necessarily require fluxing. After initially coating the crucible with borax, no more is needed for melting gold powder. A thin layer can be re-applied several times before the flux needs to be stripped and a fresh coat applied. Stripping old flux can be hard on the crucible or melting dish if not properly applied and maintained.

 

[butcher]

j2000,
My thoughts, that powder if it was gold would melt to look like gold even without borax, I suspect the powders to have a high iron or other metal content.

I would try a couple of things, one would be to take the powders and try to separate the gold from them chemically to get the gold out before melting. the other would be to melt with a flux (not just borax) and a collector metal (like silver) and then separate the gold from that metal chemically.

Being powders already, I feel that separating the gold from them while they are powders would be easier to deal with, but then again how the powders react to acid may change that.

If you can get an assay on the powders you would have a better idea of what you are dealing with (chemically either in a leaching process or in a smelting process (or melting process), knowing what the powders are composed of can give you a better Idea of what may or may not work chemically with acids or the fluxing processes, it can also help you later to see if you are getting the gold or leaving it behind...

When we melt the more pure gold we do not use borax as much for its fluxing character as we do to help the gold from sticking to the dish.

The brown powders do look like a gold powder, but looks alone can be deceiving.

 

[j2000]

The powder looks good to me but the amount of flux is way too much.
Heat your powder in the crucible which has a light coating of flux already applied to the insides. If the powder won't melt either the temperature isn't hot enough or else you need more insulation for the furnace. The already melted flux will need thinning down and ideally the molten flux should be poured into a cone mould. 4metals has posted some good mixes for thinning fluxes but it depends on what's available to you locally as to what you use. The colour of the flux indicates to me you have values still trapped in it and if your furnace won't get hot enough to melt the gold try a gas torch and a melting dish with again decent insulation to retain the heat. Melting is another part of recovery and refining that isn't as easy as it looks especially if you don't have the correct equipment and some electric furnaces really are rubbish for our needs.

Thanks Nick,
You mean my borax (flux) is too much...?
Thanks for test solution to apply lil borax and see powder really molten or not...it's make sense...
Actually, in electric furnace i can't see totally condition the powder molten or not...but your suggest i want to try it....

I have victor torch for acetylen and oxygen, but i still don't have crucible for torch...still waiting arrived, i already order it on ebay....

 

[j2000]

j2000,
My thoughts, that powder if it was gold would melt to look like gold even without borax, I suspect the powders to have a high iron or other metal content.

I would try a couple of things, one would be to take the powders and try to separate the gold from them chemically to get the gold out before melting. the other would be to melt with a flux (not just borax) and a collector metal (like silver) and then separate the gold from that metal chemically.

Being powders already, I feel that separating the gold from them while they are powders would be easier to deal with, but then again how the powders react to acid may change that.

If you can get an assay on the powders you would have a better idea of what you are dealing with (chemically either in a leaching process or in a smelting process (or melting process), knowing what the powders are composed of can give you a better Idea of what may or may not work chemically with acids or the fluxing processes, it can also help you later to see if you are getting the gold or leaving it behind...

When we melt the more pure gold we do not use borax as much for its fluxing character as we do to help the gold from sticking to the dish.

The brown powders do look like a gold powder, but looks alone can be deceiving.

Thanks Butcher, it's not totally gold...but much gold...
I can see the gold after melting, put all on the water when still melting...
After it, i wash with hot water around 1 hour with citric acid, the borax dissolve on water, but the gold only around 1percent (heave gold) maximum in the bottom of water...
The rest and really make me confused...Very much GOLD also floating in the water...very very tiny...like cosmetics powder floating in the water (acid).
I wait until 24 hour, the powder still floating...
FYI, the water color is YELLOW,.

The heavy gold in the bottom (1 percent), almost no iron when i check it...

I am still waiting my chapman borax arrived...i hope i can catch more gold with this flux...

 

[rickbb]

Where did the gold powder come from?

What percentage of the powder is gold?

What do you think the rest of the powder is?

You need to know these things before you can make up a flux of any kind. Assuming that you even need a flux at all.

 

[butcher]

The reason I suspect a high iron is the color of the powders, they could be high in gold content also, but if most of the color came from gold you would not be having the trouble you are having melting it, knowing the source of the powders and what they are composed of would be a big part of your puzzle, iron may also be were that yellow color is coming from in the water, if this is one of the oxides of iron you may have a hard time dissolving it, how are you determining that you do not have much iron in the powders?

Are these powders from an ore? if so have they been roasted, if roasted do you smell SO2 gas evolving from them...

At this point all we have is some powders and guessing, at what possible approach to take to try and get that gold, knowing what the powders are would at least give some clue.

 

[tnitrato]

I agree with butcher advice, it would be nice to purify chemically (AR, etc) your gold before melting.

If you need small amounts of PURE borax, and cant find it, you can easily purify the comercial/suspect grade into a purer one.

Sodium borate is easily soluble in hot water. Filter this solution while hot to remove solid impurities and add caustiously/slowly a slight excess hydrochloric acid in that solution, cool it below 0°C. It would precipite much of the boric acid, since it has much lower solubility in cold water (about 2.5g per 100mL water - 0°C).

Na2B4O7·10H2O + 2 HCl ----> 4 H3BO3 + 2 NaCl + 5 H2O

Filter boric acid, dry it and re-dissolve completely on hot tap or distilled water, re-filter if there is any debris or undissolved material. Gentle boil and go adding baking soda (NaHCO3) slowly until there is no more fizzing.

Boric acid is a very weak acid, and sodium bicarbonate a weak base, but hot water drives the reaction by removing carbon dioxide.. Actually sodium bicarbonate is not stable in hot water because it loose its CO2 giving more alkaline soidum carbonate that reacts more easily with boric acid, giving off more CO2:

2NaHCO3(aq) ---> Na2CO3 + H2O + CO2
4 H3BO3 + Na2CO3 + 4H2O ----> Na2B4O7*10H2O + CO2
-------------------------------------------------------------------
2NaHCO3 + 4 H3BO3 + 3H2O -----> Na2B4O7*10H2O + 2CO2

You can evaporate some of this solution and cool it to get borax crystals, then dry it or give it a recrystallization to get an even purer borax.

You can see the 1° process (borax to boric acid) here (p. 208):
http://library.sciencemadness.org/library/books/synthetic_inorganic_chemistry_blanchard_5thed1937.pdf

This DIY purification is only recommended if you cant buy the pure product or that is very expensive.
If plan to do, remember to always wear protective clothes and goggles and read MSDS (material safety data sheets) of every substance to understand the risks associated with these chemicals.

 

[kurtak]

I agree with butcher here --- LOTs of iron - based on the color of the slag

Kurt

 

[butcher]

tnitrato,

Thanks for the well written post on purifying borax, Thanks.

 

[Palladium]

A picture of the dish AFTER the melt would help.

 

[sharkhook]

tnitrato,

Thanks for the well written post on purifying borax, Thanks.

I agree, I had never heard of way to purify borax. But I am newer here than most, Thanks.

 

[j2000]

Where did the gold powder come from?

What percentage of the powder is gold?

What do you think the rest of the powder is?

You need to know these things before you can make up a flux of any kind. Assuming that you even need a flux at all.

As my customer said: Gold in the powder it's around 5-25 percent maximum, this job about trust...so my customer trust to me, and share profit to me depend on my finishing result...

As my customer said, the rest is iron, gypsum, and another...my job is just collect gold bead, not refine it to 99 percent.

My customer don't permit to me IF i use hard chemical, so that's why i only borax, some type flux from usa for melting, and pour to the wating and wash with hot water only or water plus Nitric Acid only...
The said this for my safety...and healthy environment

Thanks

Joel

 

[j2000]

The reason I suspect a high iron is the color of the powders, they could be high in gold content also, but if most of the color came from gold you would not be having the trouble you are having melting it, knowing the source of the powders and what they are composed of would be a big part of your puzzle, iron may also be were that yellow color is coming from in the water, if this is one of the oxides of iron you may have a hard time dissolving it, how are you determining that you do not have much iron in the powders?

Are these powders from an ore? if so have they been roasted, if roasted do you smell SO2 gas evolving from them...

At this point all we have is some powders and guessing, at what possible approach to take to try and get that gold, knowing what the powders are would at least give some clue.

U r absolutely right butcher, i just suspect from you: "yellow color is not gold" and i forget gold cannot dissolve by Citric Acid (i use) only...
but the Citric Acid really dissolve the iron...all black part is gone...and the water color to be yellow...
This is really puzzle to me...hopely problem resolved asap...

This powder is from my customer, they cannot tell me where is from...the just tell me the powder the processing with chemical thing...and they need help from me for melting it...coz they don't have experience for melting it...
When i melt, and i pour to the water, there's blink of gold (yellow) but the major parts is black...before i don't doubt it's iron, i think reaction with my borax...
When i use Citric Acid (not nitric acid) with hot water, the parts of black is totally gone...and the color of water to be yellow to almost green...
But iam sad, too much acid make the gold floating in the water, need 3 days to wating the very very tiny powder of gold sink to the bottom...

Thanks Butcher...

 

[j2000]

I agree with butcher advice, it would be nice to purify chemically (AR, etc) your gold before melting.

If you need small amounts of PURE borax, and cant find it, you can easily purify the comercial/suspect grade into a purer one.

Sodium borate is easily soluble in hot water. Filter this solution while hot to remove solid impurities and add caustiously/slowly a slight excess hydrochloric acid in that solution, cool it below 0°C. It would precipite much of the boric acid, since it has much lower solubility in cold water (about 2.5g per 100mL water - 0°C).

Na2B4O7·10H2O + 2 HCl ----> 4 H3BO3 + 2 NaCl + 5 H2O

Filter boric acid, dry it and re-dissolve completely on hot tap or distilled water, re-filter if there is any debris or undissolved material. Gentle boil and go adding baking soda (NaHCO3) slowly until there is no more fizzing.

Boric acid is a very weak acid, and sodium bicarbonate a weak base, but hot water drives the reaction by removing carbon dioxide.. Actually sodium bicarbonate is not stable in hot water because it loose its CO2 giving more alkaline soidum carbonate that reacts more easily with boric acid, giving off more CO2:

2NaHCO3(aq) ---> Na2CO3 + H2O + CO2
4 H3BO3 + Na2CO3 + 4H2O ----> Na2B4O7*10H2O + CO2
-------------------------------------------------------------------
2NaHCO3 + 4 H3BO3 + 3H2O -----> Na2B4O7*10H2O + 2CO2

You can evaporate some of this solution and cool it to get borax crystals, then dry it or give it a recrystallization to get an even purer borax.

You can see the 1° process (borax to boric acid) here (p. 208):
http://library.sciencemadness.org/library/books/synthetic_inorganic_chemistry_blanchard_5thed1937.pdf

This DIY purification is only recommended if you cant buy the pure product or that is very expensive.
If plan to do, remember to always wear protective clothes and goggles and read MSDS (material safety data sheets) of every substance to understand the risks associated with these chemicals.

Thanks very much Tnitrato...
Could you please tell me what is kind of borax in this thread:
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=48&t=20145&p=205736&hilit=kind+of+borax#p205736

Regards

Joel

 

[Palladium]

I still think you should inquart with silver and remove that with nitric, wash, and melt. It's a simple nice procedure that would solve a lot of your problems and you wouldn't lose near as much gold as you are now dealing with slag, plus you can recover the silver you use and what is in the jewelry also. That's a nice little added bonus. Your accountability with that procedure will be about 98-99 percent for gold recovered and your purity should be about 98-99 percent and melt real nicely or at least nicer than it is now.

 

[j2000]

A picture of the dish AFTER the melt would help.

U mean picture of the crucible after i pour it to the water?

Or this picture when i melt the powder with too much borax around 1 powder : 4 borax and i pour it to the water.

 

[j2000]

I still think you should inquart with silver and remove that with nitric, wash, and melt. It's a simple nice procedure that would solve a lot of your problems and you wouldn't lose near as much gold as you are now dealing with slag, plus you can recover the silver you use and what is in the jewelry also. That's a nice little added bonus. Your accountability with that procedure will be about 98-99 percent for gold recovered and your purity should be about 98-99 percent and melt real nicely or at least nicer than it is now.

Yes it's very possible now...
I have to try it 1 month ago...but with borax only...the result is: the gold powder still separate...not all collected with silver...

But i will try again since my chapman and flourspar arrived in my workshop...hehehe

Thanks very much palladium...

Regards

Joel

 

[Palladium]

A picture of what you melted it in. The colors of the oxides will give some indication to the contaminates.