Method for producing ammonium phosphate by using low-grade low-concentration raffinate acid

• Main Authors: TANG CHUN, JIN LING, JIANG YILAN, ZHOU CHUNYOU
• Format: Patent
• Language: English
• Published: 24.02.2016
• Subjects: CHEMISTRY; COMPOUNDS THEREOF; INORGANIC CHEMISTRY; METALLURGY; NON-METALLIC ELEMENTS

The invention discloses a method for producing ammonium phosphate by using low-grade low-concentration raffinate acid. The method includes the steps that the low-grade raffinate acid with the P2O5 concentration of 22-24% is conveyed into a washing system of an ammonium phosphate device as washing liquid to circularly absorb ammonia and dust in tail gas, when the neutralization degree of the raffinate acid washing liquid is 0.6-0.9, the raffinate acid washing liquid is conveyed to a concentration device and is concentrated through heating until the P2O5 concentration is 26-30%, and concentrated slurry and strong phosphoric acid are mixed and then produce an ammonium phosphate product in a neutralization reactor. The low-grade low-concentration raffinate acid is used for absorbing ammonia and the dust in the tail gas of the ammonium phosphate device and then is concentrated through heating, the problem that an acid-insoluble scale layer difficult to clear is prone to generation in the concentration process of the low-grade low-concentration raffinate acid can be solved, and the cost of producing ammonium phosphate by using the low-grade low-concentration raffinate acid is substantially reduced; the usage amount of washing water needed by a tail gas treatment system of the ammonium phosphate device can be reduced, and the production cost of the whole ammonium phosphate device is further reduced.