processing with Hcl/Clorox

[robertismo]

Hello Guys/Gals,

I know this topic has been covered extensively. However, i cannot seem to find info on when to stop adding drops of bleach. Am i supposed to keep adding until there is no longer a reaction (fizzing). This is the first i have attempted to dissolve with this method and it seems like the reaction is not subsiding after what seems like half the volume of Hcl. If this has been covered can someone please direct me to the search term as i have not been able to find this info.

Thanks,
Rob W

 

[joubjonn]

it depends on what your trying to dissolve. if it's gold powder or foils? if it's larger pieces, even wires from IC's this method takes a bit longer to work to the point that you saturate the solution with salts.

basically if it's foils or powder I add small amounts, stir, wait 10-15minutes and add more if I still see material. your not going to find an exact amount to add on the forum. it's a bit different then AR, works slower and depends on amount of HCl, temperature, how clean the material is, how big the gold particles are, etc.

and I'm just guessing you have removed base metals before trying this method right?

 

[joubjonn]

I find it also helps to add a little bit of heat just a little. too much and the Cl gas will come out too fast. like 80f or so is good for me. I have used this method twice for IC gold wires after nitric and incineration and it takes awhile to dissolve those little wires. I think next time AR will be my choice. HCl/Bleach works a lot better with foils that are microns thick

 

[robertismo]

Thanks for the response. I'm actually processing the black powder from my sulfuric cell. I have used ceramic fiber to filter the solution through a funnel. So i then put the entire wad into a beaker and added the Hcl (enough to cover the wad). So as i have been adding the Clorox, it has dissolved the gold (used stannous chloride to test), but i can't visually tell if ALL the gold is dissolved . Therefore i wasn't sure if i should continue adding Clorox until there is no longer a reaction. Thanks.

 

[Anonymous]

I guess the question you're asking is whether the reaction takes place instantly or not. If it helps, it doesn't, so don't keep adding your chlorine liquid for the sake of it.

Put some in, and let it do its thing for a while before adding more mate. If it's powder that you're dissolving, then swirling or stirring is a great way to help the reaction take place. You'll see the powder disappearing as it's taken into solution so add more only when you're sure that it's going no further.

Having said that, it's not really difficult to get rid of the chlorine if you put too much in but for speed and simplicity I would treat it as I've suggested above.

Hope that helps.

Jon

 

[lazersteve]

The end point of the Clorox addition occurs when the black powder is all dissolved. It is very common for additional material to remain after all of the black is dissolved. Typically the remaining powder is gray,, yellow, or off white.

The key to using Clorox is to be patient and stir the heck out of the reaction. If you are making large clouds of choking chlorine gas, you are adding way too much Clorox.

Steve