Talk:Cement kiln emissions

Emission of HCl and HF
The wording seems to imply that there is no actual evidence that these gases are not emitted, but that this is merely inferred from the alkalinity of the exhaust gas environment. However, this inference is incorrect. Ammonia that may be present as salts, or as a decomposition product of nitrogen-bearing organics, competes with other alkaline materials for chloride, and a low temperature cycle involving ammonium chloride or ammonium fluoride may be set up in certain conditions. Because these reversibly decompose, they may be emitted as salt fume, or as an ammonia/HX mixture, depending on partial pressure and temperature. It is commonly observed as a bluish hazy plume close to the exhaust stack. On dilution, clearly hydrogen chloride or fluoride will be present. This can cause very significant HCl emissions. It's interesting to note that the article says that false halide results may be obtained due to ultra-fine solids passing the gas-sampling filter. However, because of the above mechanism, the results may not (entirely) be anomalous. Where debatable results are obtained by the standard "wet" analysis (which can't distinguish between solid chloride salts and HCl) hydrogen chloride can be unabiguously identified by Fourier Transform Infrared analysis of the entire gas stream. This technique has shown substantial HCl emissions at numerous plants, where a suitable combination of chloride in fuels and nitrogen in raw materials is present.

LinguisticDemographer 22:46, 16 March 2007 (UTC)

There being no substantiation in the last 10 weeks, I have deleted these conjectural and, in fact, incorrect statements. There is also no justification for the "10% aromatics" claim, since the sources of any hydrocarbons in kiln gas emissions are infinitely variable, and this number may be anywhere between zero and 100%.

LinguisticDemographer 16:34, 31 May 2007 (UTC)