Process for preparing alkali metal phosphate

Patent · Tue Jun 14 04:00:00 EDT 1988

OSTI ID:6834649

Hall, R E; Brochu, D P

A continuous method for producing alkali metal phosphates from wet process phosphoric acid is described comprising the steps: (a) contacting crude aqueous phosphoric acid with a solvent consisting of normally liquid trialkyl phosphate in the presence of sulfuric acid in at least one countercurrent flow extraction unit to form a solvent solution of phosphoric acid and an aqueous raffinate phase, (b) mixing the solvent solution of phosphoric acid from (a) with an aqueous basic alkali metal salt in which the ratio of alkali metal to phosphorus in the mixture is greater than 1, (c) continuing the mixing until the phosphate values have been transferred from the solvent to the aqueous medium, (d) settling the mixture from (c) whereby there if formed a two-phase system consisting of (1) an aqueous solution of the alkali metal phosphate, and (2) a stripped solvent layer containing entrained alkali metal phosphate, (e) extracting the solvent layer (d) with water to remove entrained alkali metal salt thereby giving an aqueous solution of the salt and salt free solvent, (f) recovering the alkali metal phosphates, and (g) recycling the stripped solvent to the extraction unit.

• Assignee: FMC Corp., Philadelphia, PA
• Patent Number(s): US 4751066
• OSTI ID: 6834649
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360601* -- Other Materials-- Preparation & Manufacture
ALKALINE EARTH METAL COMPOUNDS
AQUEOUS SOLUTIONS
CHEMICAL PREPARATION
DISPERSIONS
EXTRACTION
HYDROGEN COMPOUNDS
INORGANIC ACIDS
MIXING
MIXTURES
OXYGEN COMPOUNDS
PHOSPHATES
PHOSPHORIC ACID
PHOSPHORUS COMPOUNDS
SEPARATION PROCESSES
SOLUTIONS
SOLVATION
SOLVENT EXTRACTION
SOLVENTS
SULFURIC ACID
SYNTHESIS