| 摘要 |
PURPOSE:To improve the rate of calcination and causticity by using MgCO3 in place of CaCO3 in a method in which CaCO3 is fed to a calciner attached to the side wall of the waste liquor combustion section of a soda recovery boiler. CONSTITUTION:Highly concd. waste liquor is sprayed and burned in the bottom combustion section of a recovery boiler 10, and produced smelted matter flows down into a soda dissolving tank 16. MgCO3-base powder is fed to an MgCO3 calciner 22 attached to the side wall of a lower part of the boiler 10 from a feeding inlet 15. Most of MgO formed by calcination in the calciner 22 in accordance with equation I is dropped into the tank 16 through an opening 24 connecting the calciner 22 to the tank 16. In the tank 16, the smelted matter (Na2CO3 and MgO) dissolves in water fed beforehand to the tank 16, and NaOH as chemicals for digesion is prepd. by a reaction represented by equation II. The NaOH is fed to an NaOH circulating system through a white liquor tank 19.
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