PROCESS FOR PREPARATION OF PURIFIED PHOSPHORIC ACID

• Main Authors: TAKAHASHI A, SUGAHARA Y, SYOJI S, NAITO H, NOSHI Y
• Format: Patent
• Language: English
• Published: 11.12.1976
• Edition: 2
• Subjects: CHEMISTRY; COMPOUNDS THEREOF; INORGANIC CHEMISTRY; METALLURGY; NON-METALLIC ELEMENTS

1452136 Phosphoric acid MIZUSAWA KAGAKU KOGYO KK 23 Nov 1973 [25 Nov 1972] 54592/73 Heading C1A Phosphoric acid is prepared by mixing phosphate rock with sulphuric acid to give a solid granular phosphate rock-sulphuric acid reaction product having a transfer index E of 0À8-2À8 and selectively extracting the phosphoric acid component from the reaction product using an organic solvent. The transfer index is defined by the relationship where (P 2 O 5 ), (CaO), (SO 3 ) and (F-fluorine) are the respective weight percentages in the reaction product and (M) is the sum of the weight percentages of Al 2 O 3 , SiO 2 , Fe 2 O 3 , MgO and alkali metal oxides, the quantity E being, for all practical purposes, the percentage of water in the composition. The organic solvent may be an aliphatic alcohol. where n is an integer of 1-3, m is 0 or 1, R1 is an aliphatic hydrocarbon residue having 2 to 8 carbon atoms, whose carbon chain is optionally interrupted by an ether-type oxygen atom and R2 is a H atom or an alkyl group of up to 4 carbon atoms. The preferred organic solvent is butanol and the organic solvent may contain water in an amount of at most x parts by weight where x = y-z, z is the weight of water present in the phosphate rock and y is that weight of water which if present in the rock would give a transfer index of 0À8. Other organic solvents mentioned include organic sulphoxides, organic phosphates, organic amines and quaternary organic ammonium salts.