Improvements in the Electrowinning of Chromium ''2

Improvements in the eleetrowinning of chromium from trivalent or "chrome alum" solutions, made since publication of a previous paper, are disclosed. El imination of sodi-um sulfate from the electrolyte and ehaages in cell design have decreased the cost of electrowinning chromium metal. Details of the new cell design and data obtained with a 120-pound-per-day cell are discussed. The sensitivity of laboratory-size cells to certain critical impurities and other vari-ables tends to obscure the possibilities of this type of electrolyte. Research in pilot-plant cells has shown that proper cell design and operation on a sufficiently large scale can largely overcome the sensitivity of chromium sulfate electrolytes to impurities and, to a lesser extent, to pH and other variables