# Freezing Cons "Fines" for Recovery of PMs



## MurrayEnt (Jan 17, 2011)

:idea: Freezing Cons for Recovery. 

One of the areas I’ve become really good at is recovering “fines” or cons from salvaged E-waist. I recalled a period during my youth where my mother would hang out our cloths during the winter to dry. We would often go out the next day and bring them in, pants would be stiff as a board! This freeze drying method was all we had at the time as we did not own a dryer. I got to thinking ….. :roll: 

We all have had our problems with collecting the fines in our solutions. I happen to live in a cold part of the country and thought I would try this experiment. I washed a lot of my fines recovered from E-waist in standard tap water placing the contents in a flat bottomed disposable container. The water was murky as it often is when you shake up the materials but with all good things gravity helps us out and the materials will settle out on the bottom of the container. The heavier materials first, then the lighter materials in a sedimentary fashion. 

I set the container outside in the cold. You can do the same by placing it in the freezer. (Just make sure everyone is aware that you did this!) The water and contents in the container will freeze solid over time. The next day, I cut the container open. (you can use a flat container with a lid) Taking a chisel, I began to ice sculpture the block of ice removing the cleared water and tossing it until I began trimming into the collected fines. You can trim all the way down into the fines. Any ice that had traces of fines in it, I set aside as I continued to “shave” the ice. With the layering of the materials, it’s possible to selectively shave off sections that look the most promising. By open air freeze / drying of your fines sample, you can complete this process and recover nearly all of the materials from your solution. Allot of times, I will dry and torch the materials. Silver, lead, etc. will melt together leaving the other higher temperature PMs available for further recovery. 

I never throw away any of my wash water. The same principle applies to this salvage as well. You can even freeze diluted acid and ammonia. Just remember to wear your rubber gloves when working with these samples. 

Donated by: Michael Murray Ent.


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## Harold_V (Jan 18, 2011)

Welcome to the forum.

I see some serious holes in your process. The same thing can be accomplished by allowing solutions to settle, then siphoning off the barren liquid. Certainly you can see that screwing around for hours with ice, trying to be selective, isn't productive. 

One thing really troubles me. Your suggestion that you can melt anything and expect other elements to remain behind isn't true. Molten metals are typically strong solvents of other metals, and will dissolve them readily, even if the temperature of the molten mass is below the melting point of other values. 

Harold


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