Selenium from Copper Refinery Slimes Baked with Nitre and Precipitated by Sulfur Dioxide (Betterton and Lebedeff, US 2,378,824)

The selenium in copper ore ends up in the mud under the anodes of a copper refinery. Older works fused the mud with nitre and lost selenium as fume. Betterton and Lebedeff only baked a wet paste below fusion, so almost all the selenium turned water-soluble and stayed put. Result: selenium precipitated from the leach as a powder; 96.2 % of it made soluble in the bake. Source: Betterton and Lebedeff, US 2,378,824 (American Smelting and Refining, 1945), Example I. Unknown: the slimes, as nothing here makes them yet. Not given: leach water, how much gas, washing and drying. Picture drawn by Youblob.