Black Sand Samples

[alloy_II]

Samples from two different areas, once the weather improves - smelting will begin the top sample certainly shows promise, both by weight and microscope image.

For those interested in smelting the attached file is about the various flux's used and their purpose.

 

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[alloy_II]

If a fellow had several tons of the Hedley black sand an assay would have revealed the gold.

As i now see it, smelting both the gold and platinum together was not a very good idea.

As the lead button in being cupeled, you need a really high heat and the gold is likely to volatilize long before cupellation is complete.

Ball milling the black sand then subjecting it to a weak cyanide leach would have first removed the gold leaving the platinum behind. This could be smelted then cupeled.

Gold will surrender to a cold cyanide leach while platinum will not.

Yea this is cut n paste

A method for recovering platinum group metals from a catalyst material comprises leaching the material with a cyanide solution at a temperature greater than about 100° C. to form soluble platinum group metal-cyanide complexes

 

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[southfork]

If a fellow had several tons of the Hedley black sand an assay would have revealed the gold.

As i now see it, smelting both the gold and platinum together was not a very good idea.

As the lead button in being cupeled, you need a really high heat and the gold is likely to volatilize long before cupellation is complete.

Ball milling the black sand then subjecting it to a weak cyanide leach would have first removed the gold leaving the platinum behind. This could be smelted then cupeled.

Gold will surrender to a cold cyanide leach while platinum will not.

Yea this is cut n paste

A method for recovering platinum group metals from a catalyst material comprises leaching the material with a cyanide solution at a temperature greater than about 100° C. to form soluble platinum group metal-cyanide complexes

I just watched a video on this and the lead oxides were absorbed by the clay cupel. Just leaving a nice little gold bead.

 

[alloy_II]

With the platinum being greater than the gold content, I've reached the limits of my propane fired torch.

A gold alloyed with silver would have a lower melting point, similar reaction when using lead as a collector metal.

Any of the following metals maybe used as collectors, bismuth, lead, litharge, copper or silver.

Collectors highlighted in red can be cupeled, green most economic would be eclectically parting, silver dissolved with nitric leaving gold behind as brown powder.

A propane torch with oxygen from a cylinder would do the trick.

The melting point of pure gold is 1,948 degrees Fahrenheit or 1,064 degrees Celsius.

Platinum needs 1700C to melt so the furnace alone will not do it. The acetylene torch can generate the necessary heat if properly applied

 

[alloy_II]

Cupellation
The lead buttons are placed into a cupel. Cupels are made of bone ash and cement or magnesium oxide. The cupels are loaded into the cupellation kiln at 1750°F.

 

[alloy_II]

I just watched a video on this and the lead oxides were absorbed by the clay cupel. Just leaving a nice little gold bead.

The cupels are made from bone ash along with a binder, I'll be using a 50/50 bone ash, portland cement to make my own.

Five Kg bone ash ordered from a pottery supplier, in Canadian funds, our dollar has 25% less buying power than your American dollar.

Anyhow having the bone ash will allow me to make cupels in any size I need.

From smelting I now have several lead buttons to cupel.

 

[alloy_II]

What I discovered from using my custom flux blend similar to the Chapman's blend. The silica from the blend in addition to the native silica already present in the mill grind, thickened the melted flux into a gummy mixture.

Below some quartz I milled, from about a ton I had brought home from a BC prospecting trip.

Once my bone ash arrives, the lead button to the cupel.

Looking at the surface texture of the lead button it appears that oxygen was expelled during the cooling off - i suspect platinum.

Platinum $$$ looks good on paper, but in fact very difficult to sell, so it's not a metal I desire.

 

[alloy_II]

The top image is from the quartz, the pockets are very shiny no oxidation, while the lead button from the black sand I had to scratch through the oxide layer.

In British Colombia starting from Colemont running through the mountain range east to west running towards Hope is where you'll find platinum.

The Hedley black sand was transported east from Coalmont via the Similkameen River.

An assay from a sample taken from the ready mix plant where the gravels are washed showed 17 parts per million platinum.

I'm more interested in the black sand sample from Northern BC which is the provinces gold area.

Expand the top image, have a close look and see if you can indentify the presence of gold. As I mentioned earlier milled then cyanide leaching would extract the gold.

 

[alloy_II]

The Hedley button after a failed attempt of cupelling.

 

[alloy_II]

The iron bar I used to stir the quartz smelt, shiny material platinum and if you look closely you'll see some gold attached as well.

The function of the iron is to convert sulfides to release any gold present. Using an excess of iron will lead to a loss of gold and any other precious metals present.

Iron by alone maybe used as a collector, dilute sulfuric acid will convert the iron into iron sulfate leaving the precious metals behind.

Showing front and back.

 

[alloy_II]

After removing the sand and flux stuck to the inside of the ball mill did a remelt adding the mill scrapping's into the smelt.

Also added a bit more lead along with the two previous buttons, everything is now in the cone mold cooling off.

The problem with this commercially made cast iron mold is the walls a very thick and it takes a very long time to cool off.

Two lead buttons are now combined into one, I'm going to melt this in a melting dish then scrap off the dross before cupelling.

Open it too soon and you lose the lead which is still it the liquid state.

 

[alloy_II]

I'll have to live with the slag,, tried to remove it but some lead came out with it, so I added the bits back then super heated the lead hoping the slag would burn off.

Instead some nice colored oxides showed up, this if the junk that the bone ash cupel will soak up.

Always the optimist, but it sure does look like gold is starting to appear on the surface.

 

[alloy_II]

A bit of water to enhance the color.

 

[alloy_II]

Button from the quartz smelt, upsize the image have a close look for the small bits of gold.

 

[alloy_II]

I needed to obtain some zinc, couple of tire shops give me their wheel weights, came home with a couple hundred pounds.

Some are made of steel, easy to identify, as for the ones made from lead or zinc not so easy to tell them apart.

Zinc has a unique characteristic, it's lighter than lead and floats on top of the molten mass, zinc cools off faster than lead making it easy to just skim off the zinc.

AUDIBLE IDENTIFICATION
Lead can be differentiated from Zinc and Steel by tapping it against a hard object and listening to the sound. This works best with large and medium size WW but becomes less reliable with smaller ones. Holding the WW limp tap it against a heavy hard object (I use a large chunk of steel). Lead will make a dull thud, steel and zinc will make a higher pitch pinging noise.

 

[alloy_II]

Made three cupels last night, made a thick paste the formed this into a mold, soon learned I had added a tad bit more water than was needed.

The forms held their shape but need hear to dry them out, normally when you add water to Portland heat is generated. But with the 50 percent bone ash added this did not happen as expected.

The cupels are in the oven an low heat.

Next time I'll mix the powders on a cookie sheet and make it more doughy.

 

[alloy_II]

After an hour my cupels still have a significant amount of lead, either the bone ash is fully saturated and not able to absorb more oxides or the formula 50/50 isn't worth the paper it was written on.

Everything is cooling down, will examine the cupels tomorrow.

 

[alloy_II]

Couldn't wait until morning, turns out the formula contains too much Portland and not enough bone ash.

This button is from the quartz, the lead is no longer very malleable and it looks like I have some copper to contend with.

 

[alloy_II]

After an hour my cupels still have a significant amount of lead, either the bone ash is fully saturated and not able to absorb more oxides or the formula 50/50 isn't worth the paper it was written on.

Everything is cooling down, will examine the cupels tomorrow.

Leave the Portland out.

The method of making cupels is very simple and substantially the same at each institution. The bone ash is moistened, generally with water only, until it will cohere into a lump on gentle pressure in the hand. After being allowed to stand, it is fed into a mold, a plunger is applied to form the cupel, and the finished cupel is removed from the mold. Different styles of machines, both hand and power, are used to form the cupel and different pressures are applied.

 

[alloy_II]

I just watched a video on this and the lead oxides were absorbed by the clay cupel. Just leaving a nice little gold bead.

You'll soon learn it's not that easy to cupel lead containing metals which do not readily oxide.

During the smelt, lead will absorb every element below itself in the electromotive series. Some o these elements taken up by the lead will volatilize while others will turn into oxides and some which will not oxide such as copper,silver, gold and platinum group.

Copper appears to be a beast., had I added a sodium nitrate into the flux then the copper would have reported to the slag as an oxide.

The lead button below is going in for a remelt, new flux formula with sodium nitrate to remove the copper.

Sodium Nitrate

Some types of flux are good at oxidizing specific metals. Sodium Nitrate belongs to this class of flux elements. Sodium nitrate oxidizes metals like iron, copper, and zinc by liberating oxygen at a temperature of about 500oC.

Since this will be a small smelt, I'll use the induction furnace.

If it turns out that the quartz has sufficient gold I'm just going to ball mill it then use sodium cyanide to recover the gold.

In anticipation of this process have already obtained the zinc from old wheel weights, just have to do some sorting.

For obvious reasons I'll not be posting the cyanide process., for those interested in its use there's plenty of literature available.

 

[alloy_II]

In the real world e-waste in sent to a copper smelter to recover the precious metals.