Method for concentrating and purifying dilute acid by using waste heat of smelting flue gas and device thereof

Abstract

The invention provides a method for concentrating and purifying dilute acids by using the waste heat of smelting flue gas and a device thereof. When the flue gas generated during the smelting of non-ferrous metals is applied to the acid production, a waste dilute acid generated by power waves (with a concentration ranging from 20% to 30%) is delivered to a dilute acid tank, pumped to a concentration tower through a horizontal-type dilute acid pump and sprayed downwards to contact with the smelting flue gas of a temperature ranging from 200 DEG C to 280 DEG C, which oppositely flows from a flue gas inlet pipe; the water is heated to evaporate through the waste heat of the flue gas, so that the dilute acid is concentrated and simultaneously sulfur trioxide (SO3) and dust in the flue gas are washed off; the resulting acid fog is captured by a fog capturing layer and finally falls into the produced concentrated acid; the concentrated acid enters a concentrated acid storage tank through a concentrated acid discharge port; and the dust settles at the front part of the storage tank. The method reduces the working pressure of the power waves and reduces the corrosion to the equipment in the next procedures; achieves the purpose of recovery and reutilization of sulfur resources; doesn't need lime to neutralize the waste acid, so as to avoid the formation of a large amount of gypsum residues and reduce the expenses for waste acid treatment; adapts to the fluctuation of concentration of SO3 in the flue gas, so as to ensure the stability of the dilute acid washing process and improve the washing effect.

Description

technical field [0001] The invention belongs to the field of non-ferrous metallurgy, and relates to a processing method for auxiliary products. Specifically, the flue gas produced in smelting is sent to acid production after being subjected to electric dust collection, and the heterogeneous dilute acid produced in the flue gas purification process is evaporated by utilizing the waste heat of the flue gas It is a method to increase the concentration of acid, remove impurities contained in concentrated acid, and obtain commercial acid. Background technique [0002] The non-ferrous metal smelting flue gas is cooled and purified for acid production, and dirty acid (dilute acid) is produced during cooling and purification. The traditional method is to sulfide the dilute acid and neutralize it with lime milk to the emission standard, and then use it internally or discharge it. [0003] This dirty acid treatment process is a countermeasure to make the flue gas dilute acid washing p...

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Problems solved by technology

[0003] This dirty acid treatment process is a countermeasure to make the flue gas dilute acid washing process go smoothly. There are many defects in this dirty acid treatment process: ① affected by the SO in the flue gas 3 Constraints of content, SO 3 ② The sulfuric acid in the sewage acid is not effectively used, and the sulfur resource is wasted; ③ A large amount of lime is used in the neutralization of the sewage acid, resulting in a lot of gypsum slag, which increases the cost of sewage acid treatment

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