Process for the production of cement
A process for the production of cement which includes the calcination of calcium carbonate-containing raw meal in a calciner heated by combustion of a carbon-containing fuel with a gas including oxygen and from 0 to 80% by volume of carbon dioxide, and substantially free of nitrogen, and isolating the gas produced by combustion and calcination in the calciner.
1. A process for the production of cement, the process comprising: calcining calcium carbonate-containing raw meal in a calciner heated by combustion of a carbon-containing fuel with a gas comprising oxygen and from 0 to 80% by volume of carbon dioxide, and substantially free of nitrogen, and isolating the carbon dioxide gas produced by combustion and calcination in the calciner.
2. The process according to claim 1 , wherein the combustion is effected with a gas comprising from 90 to 100% of oxygen.
3. The process according to claim 1 , wherein the raw meal is introduced into the calciner at a plurality of points.
4. The process according to claim 1 , wherein the supplied gas is introduced into the calciner at a plurality of points.
5. The process according to claim 1 , wherein oxygen and carbon dioxide in the supplied gas are introduced separately into the calciner.
6. The process according to claim 1 , wherein the effluent gas comprises at least 90% of carbon dioxide.
7. The process according to claim 1 , wherein the level of calcination in the calciner is controlled to 80% or more by weight leaving up to 20% residual carbon dioxide in the meal.
8. The process according to claim 1 , wherein the calciner is operated at a reduced gas pressure of less than 1 millibar relative to the gas pressure in the kiln.