Device and method for high-quality recovery of fluorine from wet-process phosphoric acid tail gas

Abstract

The invention discloses a device and a method for high-quality recovery of fluorine from wet-process phosphoric acid tail gas. The device comprises a venturi scrubber, wherein a circulating tank is arranged at the bottom of the venturi scrubber, the circulating tank and the venturi scrubber are connected to constitute a scouring water internal circulating pipeline, a discharge port of the circulating tank is connected with a filter device, and a filtrate outlet of the filter device is connected to a fluorosilicic acid storage tank and the circulating tank; a tail gas outlet of the circulatingtank is connected with multi-stage scrubbing towers, and a tail gas outlet of the last-stage scrubbing tower is connected to a chimney. The tail gas scrubbing process further comprises multi-stage countercurrent scrubbing besides scrubbing by the venturi scrubber; furthermore, clear water or recycled water subjected to defluorination treatment is adopted in the countercurrent scrubbing process, fluorine content of water is low, so that fluorine in the tail gas is sufficiently scrubbed, and the requirement of up-to-standard discharge of the tail gas is met; according to the method, the high-quality fluorosilicic acid solution is recovered, fluorine resources are sufficiently utilized, environmental pollution caused by fluorine emission is avoided, economic benefit and social benefit are remarkable, and the method can be popularized and applied.

Description

technical field

[0001] The invention relates to the technical field of wet-process phosphoric acid tail gas treatment, in particular to a device and method for high-quality recovery of fluorine in wet-process phosphoric acid tail gas. Background technique

[0002] Wet-process phosphoric acid plays a dominant role in the production process of phosphoric acid. In the process of wet-process phosphoric acid production, the dihydrate method of producing phosphoric acid by sulfuric acid method has simple process, mature technology, stable operation and strong ore adaptability (my country's low-grade phosphorus Large ore reserves, less rich ore) and other advantages have prompted more than 80% of phosphoric acid in my country to be produced by the dihydric process. Because phosphate rock contains about 3% (w / w) fluorine element, in the production process of dihydrate phosphoric acid, the tail gas escaped from the extraction reaction tank contains a certain amount of fluorine (genera...

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