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Don't know why you're being downvoted when you have provided the answer. "In their search for a new process for producing cyanides for cyanide leaching of gold
by soperj 3y ago
Don't know why you're being downvoted when you have provided the answer.
"In their search for a new process for producing cyanides for cyanide leaching of gold, Frank and Caro discovered the ability of alkaline earth carbides to absorb atmospheric nitrogen at high temperatures."
- philipkglass 3y agoI didn't downvote, but the Wikipedia article does not explain how nitrogen unmixed with oxygen was obtained from the atmosphere. This 1913 book on calcium cyanamide manufacturing explains: https://archive.org/details/cyanamidmanufact00pran/page/4/mode/2up https://archive.org/details/cyanamidmanufact00pran/page/4/mo... Nitrogen is obtained either by fractional distillation of liquid air, or by means of the copper oxide process. In the latter, air is passed through a red-hot mass of finely divided copper, suspended in asbestos or other inert material. The copper combines with the oxygen and allows the nitrogen to pass through. The copper oxide is easily recovered for use by reduction in situ with a suitable gas, such as natural gas. The nitrogen used must be pure and dry, otherwise, at high temperatures, there is destruction of the carbon pencils, and of calcium carbide, according to the following reactions ...
- actionfromafar 3y agoSo, very energy intensive either way! I was thinking, surely they couldn’t be distilling air in large quantities in the early 20th century. But, yes! The other, copper reduction method also sounds pretty intense.
- leblancfg 3y agoWhat a great link. Love that Archive reference book. Cheers!