Tail gas desulfuration adopting zinc oxide method in smelting industry

Abstract

The invention belongs to the technical filed of environmental protection, and particularly relates to tail gas desulfuration adopting a zinc oxide method in smelting industry. The tail gas desulfuration adopting a zinc oxide method in smelting industry comprises the following steps of: preparing a serous fluid-increasing smelting tail gas pressure-absorbing procedure-oxygenation procedure-plate frame pressure filtration procedure-acid decomposition procedure; the quantity of absorbing towers can be determined according to the temperature of tail gas to be processed and sulfur dioxide content, and a primary-level absorbing tower is used when the sulfur dioxide content of the tail gas is in the range of 0-6000 mg / Nm3; and a secondary-level absorbing tower is used when the sulfur dioxide content of the tail gas is in the range of 6000-12000 mg / Nm3, and a third-level absorbing tower is used when the sulfur dioxide content of the tail gas is in the range of 12000-24000 mg / Nm3. The air oxidation is realized in the absorbing tower, ZnSO3.5H2O which is easy to crystallize is oxidized to be ZnSO4, the quantity of the crystals is greatly reduced, the phenomena of sedimentation and choking are greatly relieved, and the abrasion to the circulating pump and a pipeline is relieved; and the waste acid generated by a smelting industry is utilized, part of waste fluid or waste acid is reused, and the clean production and work is promoted.

Description

technical field [0001] The invention belongs to the technical field of environmental protection, in particular to desulfurization of tail gas in zinc oxide smelting industry. Background technique [0002] The zinc oxide method is to use zinc oxide-containing materials to prepare absorption slurry, which is in contact with low-concentration sulfur dioxide flue gas in the absorption equipment, sulfur dioxide dissolves into the liquid phase, and uses the reaction of zinc oxide and sulfur dioxide in the liquid phase to generate zinc sulfite Its crystals, in which part of zinc sulfite is oxidized to zinc sulfate. Zinc sulfite can recover sulfur dioxide and Zn through acid decomposition or air oxidation. 2+ . In the liquid phase, fluoride ions are removed by limestone powder, and chloride ions are removed by copper slag. [0003] (1) Absorption process [0004] In the absorption tower, the zinc oxide slurry and the SO in the flue gas 2 The following main reaction occurs [0...

AI Technical Summary

Problems solved by technology

[0036] (1) Due to the large amount of ZnSO in the circulating fluid 3 ·5H 2 O crystals exist, causing severe wear and tear on system piping and pumps

[0037] (2) Since the circulating fluid contains ZnO dust and ZnSO 3 ·5H 2 O crystals, easy to deposit, block equipment and pipelines

[0038] Due to the above shortcomings, none of the established projects in the smelting industry are operating normally

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