Process for the recovery of soda ash
OwnerWilliam C. Copenhafer, David E. Smithinventors
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Abstract
A process for the production of soda ash by withdrawing an aqueous mining solution containing dissolved sodium carbonate and at least about 1 wt % sodium bicarbonate from an underground alkali source; stripping CO2 gas from the withdrawn aqueous mining solution, to convert sodium bicarbonate dissolved therein to sodium carbonate; co-crystallizing sodium carbonate monohydrate and sodium sesquicarbonate by evaporation of water from the CO2-stripped aqueous mining solution, without co-crystallization of anhydrous sodium carbonate, to form a slurry of crystalline solids in an aqueous liquor; recovering crystalline solids from the slurry; and calcining the recovered crystalline solids to produce soda ash.
Claims31
A process for the production of sodium carbonate-containing crystalline solids comprising:
- (i) providing an aqueous solution containing sodium bicarbonate;
- (ii) converting a portion of the sodium bicarbonate in the aqueous solution to sodium carbonate to provide a sodium carbonate concentration in the bicarbonate-depleted solution such that a resulting crystallization step provides crystals of both sodium carbonate monohydrate and sodium sesquicarbonate;
- (iii) co-crystallizing sodium carbonate monohydrate and sodium sesquicarbonate crystalline solids from the bicarbonate-depleted solution, to avoid co-crystallization of anhydrous sodium carbonate, by evaporation of water at a temperature of at least about 50° C. and below the invariant point of the bicarbonate-depleted solution to form a slurry of crystalline solids in an aqueous liquor;
- and
- (iv) recovering the sodium carbonate monohydrate and sodium sesquicarbonate crystalline solids from the slurry.
A process for the production of sodium carbonate containing crystalline solids, comprising:
- (i) obtaining an aqueous solution containing at least about 1 wt % sodium bicarbonate from an alkali source;
- (ii) converting at least a portion of the sodium bicarbonate in the aqueous solution to sodium carbonate by removing CO2 from the aqueous solution to provide a modified solution containing increased sodium carbonate content in relation to the remaining sodium bicarbonate content in the modified solution, such that upon evaporative crystallization ofthe modified solution, crystals of sodium carbonate monohydrate and crystals of sodium sesquicarbonate precipitate;
- (iii) co-crystallizing sodium carbonate monohydrate crystals and sodium sesquicarbonate crystals in bimodal form from the modified solution containing increased sodium carbonate content below an invariant point of the modified solution to avoid co-crystallization of anhydrous sodium carbonate, by evaporation of water at a temperature of at least about 50° C. and below the invariant point of the modified solution to form a slurry of crystalline solids in an aqueous mother liquor;
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- (iv) separating the crystalline solids from the mother liquor to recover the crystalline solids.
In an in situ solution mining process of a sodium bicarbonate containing ore wherein the resulting mine brine is treated to convert at least a portion of the sodium bicarbonate content to sodium carbonate to produce a process stream having significant sodium carbonate content and sodium bicarbonate content, comprising carrying out a conversion step on the mine brine to produce a process stream with a sodium carbonate content and a sodium bicarbonate content such that a resulting crystallization step at a temperature below the invariant point provides crystals of both sodium carbonate monohydrate and sodium sesquicarbonate.
Dependencies are inferred from the claim text.