Silver chloride

[snoman701]

That silver chloride is not ready to melt. First, it's not washed well enough.

When silver chloride clumps, the outer particles will convert using sulfuric/iron method, but the particles on the inside of the surface will not. You absolutely have to crush all of those little chunks to expose the silver chloride to sulfuric acid. This is why tumbling with scrap steel is so beneficial. It acts like a ball mill.

I can also tell you from experience that ball bearings are not the best material to tumble it in, if you are tumbling in a bucket. Lou's posts specifically state that punch blanks are good...and I can see why. In a bucket, if angled and rotated, you end up with silver chloride caking in to the corners. The punchings would be able to get in to the corners and break up the cake.

 

[saadat68]

Good trick I didn't know that
Thanks
After crushing I see some white traces
http://uupload.ir/files/57ey_img_20180907_160005.jpg


How I must wash these powders? In filter paper or in bucket? With decant or without decant?
I can't find posts about this with search box

Thank you

 

[vjodhani]

Molten silver can absorb more than its volume of oxygen when it is molten and it spits it all out when it cools. That is why it has all of the holes.

Because this was dry silver chloride adding the carbonate and grinding it fine so there was good contact between the silver chloride and the carbonate the molten silver will absorb all of the gasses and there is not much you can do to stop it.

What you can do, is remelt the silver and prevent the silver from exposure to oxygen while it is in the furnace and while it is poured into the mold. This is usually done by using a flame over the furnace to burn the oxygen over the crucible holding the molten silver so it is not available to the molten silver to be absorbed. Additionally pouring through a flame into your mold further eliminates the potential for any oxygen to be absorbed, once the bar skims over solidifying, the flame can be shut off. The flame is not hot enough to prevent the silver from solidifying. If the silver cannot absorb any oxygen it has none to spit and the bars are much nicer.

What 4metals says is actually correct about blowing a torch to cut oxygen supply gives good surface finish.Also if you want to prevent blowholes u can blacken the mould with D.A. Cylinder (Acetylene gas) and preheat.This reduces blowholes as well as gives good surface finish.Trial and tested million times.

 

[ION 47]

Molten silver can absorb more than its volume of oxygen when it is molten and it spits it all out when it cools. That is why it has all of the holes.

Because this was dry silver chloride adding the carbonate and grinding it fine so there was good contact between the silver chloride and the carbonate the molten silver will absorb all of the gasses and there is not much you can do to stop it.

What you can do, is remelt the silver and prevent the silver from exposure to oxygen while it is in the furnace and while it is poured into the mold. This is usually done by using a flame over the furnace to burn the oxygen over the crucible holding the molten silver so it is not available to the molten silver to be absorbed. Additionally pouring through a flame into your mold further eliminates the potential for any oxygen to be absorbed, once the bar skims over solidifying, the flame can be shut off. The flame is not hot enough to prevent the silver from solidifying. If the silver cannot absorb any oxygen it has none to spit and the bars are much nicer.

to protect the silver melt from oxygen, it is enough to put a few pieces of charcoal into the crucible (on which the meat is fried in the grill). When you pour metal, the flame of propane will help.