Absorption carbon dioxide, after sulfur

Ammonia is readily absorbed by potassium carbonate solutions. Sulfur dioxide and hydrogen cyanide, both acidic compounds, are also readily absorbed by hot carbonate solutions. After absorption, these compounds react further forming a variety of compounds, such as sulfates, thiosulfates, thiocyanates, polysulfides, and elemental sulfur, which accumulate in the solution. 

After the system described above was devised, the Onahama smelter was expanded, and a commercial magnesia-base absorption system developed by the company was applied to the reverberatory furnace gases (27). As described (27), the process is essentially the same as the Chemico-Basic process (33) although equipment details are not reported. The magnesium sulfite is decomposed in a rotary kiln in the presence of added carbon. The magnesia is returned to the absorption process, and the rich kiln gas stream (13-15% sulfur dioxide) is sent to a sulfuric acid plant. 

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