Patent ID: 9475712
Filing Date: 2016-10-25
CPC Classification: B01D,C01B,C01D,C02F

Claim Text:
1. A method for treating wastewater from a coal to chemical or coal to liquid process, comprising: converting coal to chemical or liquid and producing a wastewater; concentrating the wastewater to form a salt solution; directing the salt solution comprising an alkali metal, chloride, and sulfate to a hydrous salt crystallization unit and crystallizing hydrated sulfate salts to form hydrated sulfate salt crystals comprising sulfate and at least one alkali metal, and a hydrous salt crystallization unit solution; melting the hydrated sulfate salt crystals to form an aqueous sulfate solution; directing the aqueous sulfate solution to a sulfate crystallization unit and crystallizing anhydrous sulfate salts from the aqueous sulfate solution to form sulfate salt crystals comprising sulfate and at least one alkali metal, and a sulfate crystallization unit solution; directing at least a portion of the sulfate crystallization unit solution to the hydrous salt crystallization unit; directing at least a portion of the hydrous salt crystallization unit solution or at least a portion of the sulfate crystallization unit solution to a chloride salt crystallization unit and crystallizing chloride salt from the hydrous salt crystallization unit solution or the sulfate crystallization unit solution to form chloride salt crystals comprising chloride and at least one alkali metal, and a chloride salt crystallization unit solution; and directing at least a portion of the chloride salt crystallization unit solution to the hydrous salt crystallization unit.