Talk:Blue lava

Article Confused on if flame is blue from emission spectra or black body radiation

First the article claims "When sulfur burns, it produces a neon blue flame" but then it says "These gases produce a very hot flame when oxidized, which results in a blue flame, as hotter temperatures produce fires that are bluer in appearance" and draws parallels to black body radiation. My gut (and background in chemistry) says this is almost certainly not black body radiation, but I'm haven't dug into the geology or looked for any sources on blue lava. Somebody should take a look. Mallonna (talk) 22:55, 17 May 2021 (UTC)

It is wrong, relies on poor sourcing, and violates WP:SYNTHESIS. I've removed it.

For a flame to be blue in color due to pure thermal processes (black-body radiation), by Wien's Law, it would have to have a temperature of at least 6440 C. This is far hotter even than an acetylene flame at 3330 C; in spite of what you sometimes read in half-researched sources, the blue color of an acetylene flame is not a thermal effect. The ignition temperature of sulfur is just 168 C and the operating temperature of sulfur-burning furnaces, used in sulfuric acid manufacture, is just 1093 C, far below blue heat. Again, not a thermal effect. Something in a sulfur flame (likely some intermediate free radical) has characteristic emission bands in the blue part of the spectrum, but after a considerable time trying to Google up a reliable source, it looks like it may not actually be known what the blue chromophore in sulfur flames is.

This admittedly not terrible reliable source states that "Bizarrely, the temperatures are insufficient to create a blue hue" which is right (except it's not bizarre; it's pretty common).

Anyway, the statement had to go. --Kent G. Budge (talk) 16:16, 1 August 2021 (UTC)