Process for producing sodium bicarbonate from natural soda salts
OwnerRaymundo R. Lunainventor
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Abstract
Production of sodium bicarbonate from natural soda deposits that may occur as natural brines or solid soda salts is disclosed. The alkalinity in these natural soda deposits consists of carbonates and bicarbonates. The carbonates are converted to bicarbonates by reacting sodium carbonate with ammonium bicarbonate which acts as a carbon dioxide carrier until all the sodium carbonate is exhausted. The solubility of the sodium bicarbonate is lowered by the presence of non-alkaline sodium salts, e.g., sodium chloride. The regeneration of the cyclic reagent (NH.sub.3) is done using the sodium bicarbonate formed by the double decomposition of sodium chloride and ammonium bicarbonate giving a final soda free brine exempt of contaminants foreign to its original components.
Claims34
A carbonation process for the production of solid sodium bicarbonate from natural soda deposits, comprising:
- obtaining a solution of said deposits that contains sodium chloride, wherein this obtaining step comprises adding sodium chloride to the solution if said deposits lack natural sodium chloride;
- ammoniating soda brine from said deposits to form ammonium hydroxide;
- carbonating said ammoniated soda brine from said deposits to form ammonium bicarbonate;
- reacting said ammonium bicarbonate with sodium carbonate to form sodium bicarbonate and ammonium hydroxide;
- forming sodium bicarbonate and excess equivalents of ammonium chloride from the double decomposition reaction of ammonium bicarbonate and sodium chloride;
- determining the excess equivalents of ammonium chloride over the equivalents of sodium bicarbonate in the solution produced after the double decomposition reaction of ammonium bicarbonate and sodium chloride;
- adding an amount of solid sodium bicarbonate to the solution in an equivalent amount to said excess equivalents;
- and
- heating the solution, thereby recovering ammonia and carbon dioxide from the solution.
A process for the substantially total recovery of the alkalinity from soda brine as crystallized sodium bicarbonate without the need for evaporating said soda brine, said soda brine comprising sodium carbonate, sodium bicarbonate and other soluble salts, said process comprising:
- adding sodium chloride to said brine to bring the sodium chloride concentration of the brine to within the range 0.5 to 3.0 equivalents per liter;
- ammoniating said brine to form ammonium hydroxide by adding ammonia in an amount inversely proportional to the amount of sodium chloride in said brine, such that the amount of ammonia multiplied by the amount of sodium chloride is in the range of 1.5 to 3.0;
- and
- carbonating said ammoniated brine to form ammonium bicarbonate by adding carbon dioxide in the amount of one mole of carbon dioxide per mole of ammonia added, plus one mole of carbon dioxide for each mole of sodium carbonate in the brine per liter.
A process for the production of sodium bicarbonate from soda brine solution comprised of sodium carbonate and sodium chloride having a concentration in the range 0.5 to 3.0 equivalents per liter in water, said process comprising:
- a. adding said soda brine to an absorber tank;
- b. adding carbon dioxide and ammonia gases to said absorber, thereby forming a supersaturates solution of sodium bicarbonate, wherein the ammonia is added in an amount that is inversely proportional to the amount of sodium chloride in said solution, such that the amount of ammonia multiplied by the amount of sodium chloride is in the range of 1.5 to 3.0;
- c. precipitating at least some of said sodium bicarbonate, thereby forming a suspension of solid sodium bicarbonate;
- d. separating said solid sodium bicarbonate from said mother liquor;
- and
- e. recovering ammonia by returning less than 0.1 gram equivalents per liter of separated solid sodium bicarbonate to the mother liquor, and heating the mother liquor.
Dependencies are inferred from the claim text.