Separation of complex potassium salts from brine evaporites
AssigneeN L Industries, Inc.
InventorAbraham Sadan
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Abstract
Evaporite minerals comprising mixtures of relatively coarse salts are treated in a manner such that certain of said salts are converted by recrystallization to very finely divided form and then separated from the coarse salts by size classification such as elutriation, the treatment being especially useful in a process for the recovery of potassium sulfate from marine evaporite mixtures such as kainite and halite.
Claims6
Process for separating kainite from a mixture of salts comprising essentially kainite and sodium chloride characterized by relatively coarse crystals comprising:
- slurrying said mixture of salts in a MgCl.sub.2 brine, heating the slurry to temperatures above about 80.degree.C. for a predetermind period of time such that said kainite only of said mixture of salts is converted by recrystallization to relatively fine crystals of langbeinite and carnallite in said slurry and thereafter subjecting the slurry to a particle size dependent separation process whereby the fine recrystallized langbeinite and carnallite are separated from the remaining relatively coarse crystalline salts.
In a process for producing potassium sulfate from salt deposits derived from naturally occurring brines wherein said salts comprise essentially a mixture of kainite and sodium chloride of relatively coarse crystal size the improvement comprising:
- adding said mixture of salts to a brine of from 28 to 32% MgCl.sub.2 to form a slurry of about 50% solids, separating the sodium chloride from the kainite by heating said slurry to a temperature above 80.degree. to as high as 120.degree.C. for from one to two hours such that the kainite is converted by recrystallization to the potassium salts langbeinite and carnallite of relatively fine crystal size, separating these potassium salts from the relatively coarse sodium chloride crystals by elutriation, recovering the potassium salts substantially free of sodium chloride and then treating said potassium salts to recover the potassium values as potassium sulfate.
Dependencies are inferred from the claim text.