Regeneration process and regeneration device for heavy metal containing nitric acid waste liquor

Abstract

The invention discloses a regeneration process and regeneration equipment for heavy metal containing nitric acid waste liquor. The regeneration process comprises the following steps of: evaporating nitric acid by virtue of an evaporative crystallization device under the action of negative pressure, condensing and recycling the nitric acid steam to obtain regenerated nitric acid; mixing heavy metal nitrate, which is recycled by a discharging system of the evaporative crystallization device, with concentrated sulfuric acid, stirring the mixture, cooling the mixture to room temperature, and filtering the mixture to obtain a heavy metal sulphate product in suction. The regeneration equipment comprises an evaporating device, a condensing and cooling device, a cooling and crystallizing device, a suction-filtering device and a horizontal ejection vacuum device, wherein the evaporating device, the condensing and cooling device and the cooling and crystallizing device are communicated in sequence. The regeneration process is high in nitric acid recovery rate, almost free of secondary pollution, capable of recycling the heavy metal to the greatest extend and high in market value of the recycled product. And the complete equipment is easy to manufacture, install, maintain and repair, low in energy consumption, and high in economical benefits and environment-friendly benefits.

Description

technical field [0001] The invention relates to the field of nitric acid waste liquid treatment, in particular to a regeneration process and regeneration equipment for the heavy metal-containing nitric acid waste liquid. Background technique [0002] Because nitric acid has no corrosive effect on stainless steel parts, it is widely used in the removal of coatings on workpieces, such as copper coating, nickel coating, zinc coating, etc. The exhausted nitric acid removal solution is very difficult to handle because it contains a large amount of total nitrogen. The treatment of nitric acid waste liquid in the industry is mainly acid-base neutralization, after sedimentation and extraction of heavy metals, and then denitrification treatment, which not only consumes a lot of chemicals, but also consumes a lot of energy, which is easy to cause secondary pollution. Other methods such as oxalic acid replacement and regeneration of nitric acid are simple in process, but have low econ...

AI Technical Summary

Problems solved by technology

It is very difficult to deal with the invalid nitric acid removal solution because it contains a large amount of total nitrogen

The treatment of nitric acid waste liquid in the industry is mainly acid-base neutralization, after sedimentation and extraction of heavy metals, and then denitrification treatment, which not only consumes a lot of chemicals, but also consumes a lot of energy, which is easy to cause secondary pollution

Other methods such as oxalic acid replacement and regeneration of nitric acid are simple in process, but the economic benefit is low

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