How pure is silver produced by electrorefining?

Silver produced through electrorefining typically achieves a purity of "three-nines fine," which corresponds to 99.9 percent silver. In some instances, the process can yield "four-nines fine" silver, reaching a purity level of 99.99 percent.1

This high level of purity is attained by casting doré metal into anodes and subjecting them to electrolysis in a silver-copper nitrate solution, using either the Moebius or Thum Balbach systems.1