Production of sodium bicarbonate by reversion of soda-type feed salt
AssigneeIntermountain Research and Development Corporation
InventorsWilliam C. Copenhafer, Henry A. Pfeffer, III, Francis Rauh
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Abstract
Sodium bicarbonate is produced by introducing solid sodium carbonate, sodium sesquicarbonate, and/or Wegscheider's salt into a reversion slurry, saturated with respect to bicarbonate and containing at least 10 wt. % solids, to effect rapid and complete conversion of the feed solids to crystalline sodium bicarbonate which is recovered from the slurry. Carbon dioxide is introduced into the reversion liquor to maintain its composition at a relatively constant value, preferably in a region of the Na.sub.2 CO.sub.3 --NaHCO.sub.3 --H.sub.2 O phase diagram that minimizes the equilibrium partial pressure of CO.sub.2 vapor above such liquor.
Claims28
A continuous method for the production of sodium bicarbonate, which comprises
- intoducing granular solid sodium sesquicarbonate or sodium carbonate or Wegscheider's salt, as a solid feed or as a concentrated aqueous slurry feed containing greater than 5 wt % solids, into an aqueous reversion slurry saturated with respect to sodium bicarbonate and containing at least about 10 wt. % sodium bicarbonate solids, to effect rapid and direct reversion of the crystalline feed salt to crystalline sodium bicarbonate, without resorting to cooling crystallization;
- withdrawing a portion of the aqueous reversion slurry and separating crystalline sodium bicarbonate from the aqueous reversion liquor, the bicarbonate being substantially free of solid feed salt;
- recycling aqueous reversion liquor, that remains after recovery of the bicarbonate product, to the aqueous reversion slurry;
- adjusting the bicarbonate content of the reversion liquor, via introduction of carbon dioxide to convert soluble carbonate to bicarbonate, to maintain a relatively constant composition in the aqueous liquor portion of the reversion slurry;
- and, further,
- maintaining the temperature of the aqueous reversion slurry at a relatively constant value, that is the same as or higher than the temperature of the recycled reversion liquor being reintroduced to the slurry.
Dependencies are inferred from the claim text.