Talk:Cement kiln

From Wikipedia, the free encyclopedia

I have opened up a new article for this, allowing reference from product related articles. The existing article on Portland cement references Kiln, which refers only to ceramics kilns, and which would become unweildy if extended to include every piece of equipment that is called a "kiln". I will expand this article shortly, and welcome other informed contributions.LinguisticDemographer 16:11, 1 October 2006 (UTC) I have now added a bunch of text. I am aware that the text is hard to understand without diagrams and pictures. I'll remedy that when I get a moment.LinguisticDemographer 01:59, 2 October 2006 (UTC)

[edit] Emissions section

Following incorporation of the "Emissions" article, I have tidied it up a bit. I took out the sentence:

"Investigations have shown that their (i.e. "dioxins and furans") emissions are independent of the type of input materials used and cannot be influenced by process technology measures."

I removed it because it's patently untrue on both counts. Clearly, some materials (e.g. those containing halogens) are more likely to produce D&F than others, and many plants are in fact using process technology (involving control of temperature profiles) to control them. Maybe "investigations" did show this, but obviously other investigations show the contrary. . . .LinguisticDemographer 11:27, 28 June 2007 (UTC) p.s. There is no citation in this section. It appears to be based on the report of a very comprehensive research project performed by VDZ a while back. I thought the original article mentioned it, but I can't find it in the "history". If anyone can pin it down, it would be helpful. . . .LinguisticDemographer 11:42, 28 June 2007 (UTC)

[edit] Stoichiometry

This is a wonderful article, but in the beginning section explaining what happens to the rawmix as the temperature of the kiln rises, the chemical reactions given don't seem stoichiometric.

When dolomite decomposes, I would think the proper equation would be:

   CaMg(C03)2) --> MgO + CaCO3 + CO2  or

   CaMg(C03)2) --> MgO + CaO + 2CO2        (I don't know which is correct)

When limestone combines with silicate, I would think the equation would be:

   2CaCO3 + SiO2 --> Ca2SiO4 + 2C02
 

When limestone decomposes into calcium oxide, the equation should be:

   CaCO3 --> CaO + C02

The stoichiometry is important because it shows where the carbon dioxide comes from. As mentioned in the article, cement manufacture is a major source of carbon dioxide emissions: 60% of total emissions comes from the limestone calcification process.

I didn't want to make these changes myself, because I am not an expert in these matters. Others more knowledgeable than me should make the edits.

Mhklein (talk) 20:21, 13 March 2008 (UTC)