[How2] Recover gold from mass finishing effluents

We are finishing lot of gold jewllery by mass finishing methods using
plastic media. These plastic media contains quartz, silica, Silicone
carbide, aluminium oxide or zirconium as abrasives. We use different types
at different stages. All the affluent is collected for refining and sent
to a refiner. However my experience is that recovery is only 70%. For e.g.
if I have lost 10 gms of 22 carat gold in the process, 8.33 gms should be
recovered from efflluent. Instead of that I get 5.5gms to 5.8 gms, which
is quite low. I dont know where the balance gold has gone. Is it with the
refiner or is it lost somewhere else?


Here is a suggestion or two. 1. next time split your refining into two
lots and send to different refiners. see if they come out the same. 2. pull
a sample and send in to an independent lab for assey to see what quantity
of gold you have per lb. 3. find and honest refiner and stick with him