Device and method for removing free ammonia from mixed slurry of ammonium sulfate and calcium carbonate

Abstract

The invention discloses a device and a method for removing free ammonia from mixed slurry of ammonium sulfate and calcium carbonate, and belongs to the technical field of deamination. The method adopts the following technical scheme: feeding mixed slurry of ammonium sulfate and calcium carbonate to a deamination tank; and heating the slurry to be in a boiling state by steam under a negative pressure condition, and then feeding the generated mixed gas into a condenser; conveying an absorption liquid to an ammonia tank after the generated ammonia gas is absorbed by the absorption liquid in a hydraulic ejector. By adopting the technical scheme, the removal rate for removing the free ammonia from the slurry is over 90%, the removed free ammonia is recycled to prepare ammonium hydroxide, and the recovery rate can be up to 100%. In addition, a sulfuric acid does not need to be added in the technical scheme, the moisture content of the mixed slurry is reduced in deamination, the problem of unorganized emission of ammonia in the process of preparing ammonium sulfate from phosphogypsum is solved, the production intensity of a filter separator in the process for preparing ammonium sulfate from phosphogypsum is improved, ammonia consumption of the system is reduced, the production cost is reduced, and the production and operation environment is improved.

Description

technical field [0001] The invention belongs to the technical field of ammonia removal, and in particular relates to a device and a method for removing free ammonia in mixed slurry of ammonium sulfate and calcium carbonate. Background technique [0002] At present, the solid waste treatment of phosphogypsum is a common problem in the domestic phosphorus chemical industry. According to the national "Twelfth Five-Year" development plan, in 2015, my country's annual industrial by-product phosphogypsum will reach 80 million tons. The current comprehensive utilization rate is only about 20%. [0003] Using phosphogypsum to produce ammonium sulfate is a route for resource utilization of phosphogypsum. As early as 1914, I.G.Farben Industries proposed the process of making ammonium sulfate from gypsum. India's Chavanka Fertilizer and Chemical Company (FACT) researched and developed the Chavanka process for producing ammonium sulfate from phosphogypsum, and in 1960 Established a f...

AI Technical Summary

Problems solved by technology

[0007] (1) Free ammonia cannot be completely recovered

The mixed slurry containing free ammonia is filtered first, the filter cannot be completely sealed, and the ammonia gas cannot be completely recovered, which increases ammonia consumption and affects production costs

[0008] (2) Fugitive discharge of ammonia affects the operating environment

Due to the high temperature of the slurry in the filtration process, free ammonia escapes, and the free ammonia in the mixed slurry in the filtration section is in a state of unorganized discharge. The ammonia content in the on-site operating environment is high, which affects the operation of workers.

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