The advantage is you will have 99.99% pure gold, but the disadvantage is there is 10% gold loss unrecoverable.
The purity claim is accurate but the gold loss is grossly inaccurate. Every cell has some losses, losses up the stack, losses from dripping valuable solution, losses from pieces of cathode dislodging and being lost. But in total I cannot imagine them to be in excess of 1/10th of 1%. And a lot of that is recoverable.
As Martijn pointed out things like anode stubs and values in solution could cause the number to climb, but if you do not understand the basics of electrolytic refining you shouldn't be doing it.
Refining with a Wohlwill cell requires a feedstock approaching 99% pure gold. That means the electrolytic cell feedstock needs to be refined to at least 99% pure first before it goes into the cell. This is either done with Miller chlorination, which comes with it's own issues like gold retention in the chlorides or by aqua regia or inquartation and parting.
The reason I do not like a gold cell is from a management standpoint. First off, the electrolyte requires something on the order of 60 grams of gold per liter. The smallest cell I ever worked with was 10 gallons. At todays gold price that means $146,000 worth of gold remains in the electrolyte while processing and you only recover that when you do a cell cleanup, which can be 2 to 4 times a year.
But the biggest turn off for me is lot accountability. With a gold cell you are daily adding new anodes and scraping and melting 9999 gold off the cathodes. But at the end of the day you do not know how profitable you were. The only way to know the profitability of a cell is when you break it down and recover all of the anode stubs and gold in solution and gold that fell off the cathode and is on the bottom of the tank. Add all of that up calculating ounces in and ounces out plus all of the gold from the cleanup and a few times a year you are certain of how well the cell performed. From a management perspective that is too long.
Small to medium sized refineries have a hard time assuring themselves that their workers or partners aren't walking out the door with metals. Larger refineries have additional overhead simply because of the security they have to put in place to cut down on these losses. When you refine classically with aqua regia, you know the ounces in based on assay and within 24 hours you know the ounces out. This quick turn around deters theft because the boss knows what to expect and doesn't have to wait a few months before he knows if all of the values came out as predicted.
In the right situation a gold cell is great, the losses are minimal and if your production is great enough, and the security is good enough, it will spit out 9999 gold daily. And if by some un-imaginable method, your unrecoverable losses are 10%, you will quickly be out of business.
