I always found Thum cells complimentary to Möebius cells. The stub butt ends could be put into Thum cell. I was at lower voltage of 1.7-1.9 V and maybe 70 A/sf for the vertical vs 3.7-3.9 V and 40-60 A/sf for the horizontal. Problem with Thums is the floor space they take up, but you can always build them up instead of out I suppose.
I have also done titanium anode hooks that go in the mold and can be used to hang the anodes. These conduct better than stainless. If I had an autoclave then, I would have taken the leftover stub and just dissolved in nitric acid/oxygen overpressure because it saves 25% of the nitric used in the best case to dissolve silver and is effectively NOx fume free and 1:1 Ag:HNO3 vs 1:4/3 or more. The Ti hook can be rinsed off and tossed in a drying oven, while the nitric gets the gold and junk filtered out (sent for burning with the bag) while the solution gets used for electrolyte.Some TiO2 ends up in the slimes because the silver eats the titanium by alloying a small amount. Heating the hooks red hot seems to prevent the alloying somewhat without producing too much resistance to current flow.
Insofar as electrolyte is concerned, this is perhaps one area where I had an active interest, both in preparing large volumes of electrolyte with oxygen pressure oxidation (as used at RMC and at OPM) and maintaining it. I certainly agree that concentration, conductivity, impurity profile, temperature and pH are all critical parameters that should be kept as close to steady state as possible. There is not terrible ohmic heating in silver cells if current densities are not so high as mudville describes. Without active cooling/heat exchange, you sacrifice production and a modicum of electrolyte volume management for the crystal rinse waters that get returned after countercurrent wash/decantation. I never had to cool my cells but I have been to facilities where they do.
Now, as to impurities management, I should start by saying that my actual scientific training was in polymer science and for a time I used to make a bit of polymers (i.e. suspension polymerization for ion exchange resins etc.) so I have always had an interest in using these technologies in a silver cell. And they can in fact be used!
I can say that it is almost entirely possible to maintain silver concentrations and copper, nickel, cobalt and palladium in the electrolyte through the use of resins. Zn hopefully is already largely removed during furnacing. Residual elements like Sn and Pb and some Ag as Ag2O typically just end up as their oxides in the anode bag and can be largely blown from the silver if a reverb or TBRC is used up front. The resin itself ignores the silver and binds the Cu and Ni(Co). The preference for which is contingent on pH. Both of these can be eluted with ammonia to regenerate the resin and then NaOH added and the solution boiled to return the ammonia for reuse and give the Ni/Co/Cu as a feed to the copper/nickel refiner.
I know about that which mudville speaks on the Russian resin but I think people that know just use any weak base anionite resin. I have my own version that I use and like it very much but not in silver duty (though it can be used in a cell and has a very high capacity of about 6 oz Pd/kg of resin in nitric acid conditions and is fully elutable with ammonia water giving [Pd(NH4)4]+2). My opinion on improvements to the best run silver refinery possible is that the converting furnace is a TBRC with removable flue to reprocess the silver mist/condensate. This produces an anode feed that is 98-99% and provides a feedstock slag that can be sent for copper recovery where trace payable silver gets paid back to the refiner. Much of the Cu, Al, W/Mo, Sn, Pb, Sb, Zn and even some Se/Te can be removed.
These anodes should be cast into tapered molds with a stout titanium hook such that they more or less anodically erode in an even fashion, and the butts can be dissolved for electrolyte makeup, under pressure. I have never liked shot under pressure due but bulk solids behave better. The electrolyte is managed by continuous circulation of electrolyte through resins, the first one to fetch the Pd, the second to fetch Cu. Periodically, the pH is adjusted and Ni/Co can be removed onto the same resin. This resin is still very expensive but price will hopefully go down...
