Atmospheric pressure absorption process and device for nitrogen oxide gas

Abstract

The invention mainly relates to the field of industrial waste gas treatment, especially applicable to the hydrometallurgical production field that needs to use nitric acid as an oxidant to generate nitrogen oxide "waste gas", specifically an atmospheric pressure absorption process for nitrogen oxide gas and a device, comprising the following steps: (1) Nitrogen oxide gas and pure oxygen are fed into the absorber under normal pressure; (2) The absorption liquid in the absorber circulates to absorb the nitrogen oxide gas; (3) The absorption liquid After reaching a certain concentration range, return to the reactor for reuse. The invention has the advantages that: after the nitrogen oxide gas produced by the reactor enters the system, the nitrogen oxide gas is completely absorbed, and at the same time, the by-produced nitric acid is returned to the reactor for production, and waste gas is basically not discharged. In the whole production and absorption system, nitric acid acts as a catalyst, and the consumption of nitric acid is finally converted into the consumption of oxygen. Only a small amount of nitric acid is supplemented in the production process, which greatly reduces the cost of leaching.

Description

technical field [0001] The invention mainly relates to the field of industrial waste gas treatment, especially applicable to the hydrometallurgical production field that needs to use nitric acid as an oxidant to generate nitrogen oxide "waste gas", specifically an atmospheric pressure absorption process for nitrogen oxide gas and devices. Background technique [0002] Metal sulfide ores such as molybdenite and nickel-molybdenum ore are mostly produced by fire, and are further processed after high-temperature combustion. During the fire process, a large amount of exhaust gas such as sulfur dioxide and carbon dioxide will be produced, and heavy metals may also be carried out, causing serious environmental pollution. In addition, fire production may also result in low yield of active ingredients or lower product value due to ion complexation at high temperature. If these minerals use the wet high pressure oxygen leaching process, the disadvantages are: difficult operation and...

AI Technical Summary

Problems solved by technology

During the fire process, a large amount of exhaust gas such as sulfur dioxide and carbon dioxide will be produced, and heavy metals may also be carried out, causing serious environmental pollution.

In addition, fire production may also result in low yield of active ingredients or lower product value due to ion complexation at high temperature

If these minerals use the wet high pressure oxygen leaching process, the disadvantages are: difficult operation and maintenance, expensive equipment, and difficult to scale production

Another example is to use metal and nitric acid to react to produce catalyst-grade nitrate. The nitrogen oxide gas produced is usually reduced to nitrogen with urea or catalytically reduced to nitrogen. These methods waste resources and are costly; into nitric acid, the disadvantages of which are expensive equipment, difficult production control, and difficulty in large-scale production

[0003] The strong oxidizing property of nitric acid is very effective for some difficult-to-leach materials, but because the absorption of nitrogen oxide gas produced after adding nitric acid is difficult, it causes serious environmental pollution, and the price of nitric acid is high, and the nitrogen oxide gas that escapes is consumed The addition of nitric acid increases the production cost, making the production process with nitric acid abandoned

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