Washing and absorbing device and method for wet process phosphoric acid production tail gas

Abstract

The invention discloses a washing and absorbing device and method for wet process phosphoric acid production tail gas. Five-stage countercurrent washing absorbing modes of a mono-fluoro washing and absorbing tower, a venturi washing absorber, a difluoro washing and absorbing tower, a trifluoro washing and absorbing tower and a tail gas washing and absorbing tower are adopted, after washing and absorbing are performed, high-altitude emission is performed at 80 m high part, when the concentration of a washing and absorbing solution (mainly H2SiF6) of the mono-fluoro washing and absorbing tower is larger than or equal to 10%, the solution is drained to a tail gas washing and absorbing system defluorinated silica acid storage tank to be sedimented, a supernate is adopted as a raw material of a Na2SiF6 workshop and an anhydrous HF workshop after dissolved iodine in the supernate is recycled, and lower sedimentation silica gel is adopted as a raw material of a white carbon black workshop. The device has the advantages that the obvious wet process phosphoric acid production tail gas washing and absorbing effects are obvious, the recycling rate of fluorosilicone iodine resources in tail gas is high, the device automatic degree is high, and the operation and maintenance cost is low.

Description

technical field [0001] The invention relates to a device and method for scrubbing and absorbing tail gas from wet-process phosphoric acid production, and belongs to the field of phosphorus chemical production. Background technique [0002] As an important new chemical material, fluorosilicon materials are widely used in military industry, aerospace, petrochemical, electronic information, automobile, textile, medicine, agriculture, environmental protection, food, new energy and strategic emerging industries. After more than 50 years of development, my country's fluorosilicon material industry has formed a high-tech industry with complete categories, a complete industrial chain, and is highly related to other industries. At the same time, my country has become a major producer and consumer of fluorosilicon materials in the world. [0003] In nature, fluorine resources mainly come from natural cryolite, fluorite and phosphate rock. Among them, the amount of natural cryolite is...

AI Technical Summary

Problems solved by technology

[0008] (2) SiF in wet-process phosphoric acid extraction tail gas 4 High content, SiF 4 Form SiO at the gas-liquid interface with the moisture in the scrubbing absorbent 2 ·nH 2 The colloidal foam layer of O will reduce the SiF 4 The reaction speed with the moisture in the washing absorbent limits the continuous progress of the interface chemical reaction process

At the same time, SiO is precipitated in the liquid phase 2 ·nH 2 O colloid is easy to deposit on the inner wall of the absorption tower, the inner wall of the pipeline for absorbing the washing and circulating liquid and the nozzle, causing the blockage of the inner wall of the washing absorption tower and the pipeline, affecting normal production

[0009] (3) The raw material phosphate rock used in the production of wet-process phosphoric acid usually has high carbonate and organic components. During the extraction process of wet-process phosphoric acid, a large amount of foam will be generated, and a large amount of phosphogypsum and mineral powder particles will be entrained in the foam, and enter the Fluorine absorption system, these particulate matter are easily combined with H 2 SiF 6 The solution reacts to form insoluble scale, which causes the blockage of the washing absorption tower and the inner wall of the pipeline, affecting normal production

Theoretically speaking, the horizontal cross-flow (cross-flow) spray scrubber should be a good gas purification equipment. Its washing efficiency is very high, both above 99%, but it is not ideal in practical applications. The exhaust gas associated with silica gel is extremely Easy to clog packing system

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