Love gold refining, not so much silver

[4metals]

I believe I read about adding the Karo first in Lowen's book. It works either way, but adding the syrup first does make it tumble smoother.

The reaction still proceeds the same way. The syrup does not reduce the silver chloride it does reduce silver oxide. When you add the caustic first, the batch converts to silver oxide. Then as the syrup goes in, the silver is reduced proportional to the amount of syrup added. When you add the syrup first, the silver is reduced as the caustic is added, again proportional to the caustic add rate as the reduction only takes place on silver oxide.

With larger batches, 100+ ounces, it is visibly better with the syrup first. Small lots may not be as obvious.

 

[goldenchild]

With larger batches, 100+ ounces, it is visibly better with the syrup first. Small lots may not be as obvious.

This is the first thing that I thought of if you were to add syrup first. Are the visual indicators the same? Adding karo first, are we still looking for the color change to black? I have a couple of ounces of AgCl that I am just about done recovering and would like to try this 1. karo 2. lye

 

[4metals]

Adding the syrup gives no color indication as it doesn't react until there is silver oxide to react with. It may appear to mix more fluidly. (if fluidly is indeed a word!)

The caustic tends to fizzle when it goes in and if the syrup is well blended into the mix, it instantly goes from silver chloride to silver oxide to silver metal. When all of the caustic is added, there is enough to reduce all of the silver if you use the formulas I gave. When the reaction is complete the silver has a grey metallic luster to it.

I can't say this enough.... mixing is everything, if the silver chloride does not contact the caustic it remains silver chloride, or if you added the Karo first that's sweet silver chloride!

My idea of mixing is using one of these stationary mixers. http://www.mcmaster.com/#catalog/117/495/=c5dm5i
found at the bottom of the McMaster catalog page.