Calcium Carbonate → Carbon Dioxide

Participants

Reaction Steps

FIG. 2 depicts a process in which calcium hydroxide is used to adjust the pH of the pretreated feedstock. Like reference numbers indicate identical or similar processing steps as in FIG. 1A. FIG. 2 is similar to FIG. 1A, except that, according to this embodiment, the calcium carbonate-containing stream 24 is subjected to calcination in a lime kiln 25. Calcination of calcium carbonate in lime kiln 25 produces calcium oxide and carbon dioxide. The calcium oxide becomes hydrated by the addition of water to form an aqueous solution of calcium hydroxide 29. The resulting calcium hydroxide-containing stream 29 is then the stream used for the neutralization 6. If the calcium carbonate-containing stream 24 additionally contains magnesium carbonate, stream 29 will contain magnesium hydroxide.

Provenance & Evidence