Nitrogen-oxides-containing exhaust gas comprehensive utilization method

Abstract

The invention discloses a nitrogen-oxides-containing exhaust gas comprehensive utilization method which is characterized by subjecting nitrogen oxides and potassium chloride solution to reaction in anabsorption tower rapidly to obtain potassium nitrate, converting chloridion into hydrogen chloride, subjecting hydrogen chloride, volatile nitric acid and unabsorbed nitrogen oxides to reaction to form aqua regia, and oxidizing waste diamond segments further to recover useful substances. The method includes the steps of 1, subjecting industrial exhaust gas containing nitrogen oxides and potassiumchloride solution to reaction to obtain potassium nitrate; 2, carrying out gas stripping at a certain temperature to blow out diluted hydrochloric acid and oxynitride and then convert them into aquaregia; 3, subjecting aqua regia and waste diamond segments to oxidation-reduction reaction to recover diamonds and heavy metal elements. By using replacement reaction and oxidation-reduction reactionfully, exhaust gas is utilized effectively through the method. Accordingly, the method has the advantages of good convenience in operation, environmental protection, energy conservation and the like,and is worthy of wide application and promotion.

Description

technical field [0001] The invention belongs to the comprehensive treatment technology of waste gas in chemistry, chemical industry, medicine and environmental protection industries, and in particular relates to a method for comprehensive utilization of nitrogen oxide tail gas. Background technique [0002] With the improvement of people's awareness of environmental protection, the emission standards of industrial tail gas are becoming more and more stringent. For example, the discharge of nitrogen oxides and sulfur dioxide must meet the standards. At present, there are three methods for the treatment of nitrogen oxide tail gas in factories. The first is the catalytic reduction method, which uses platinum or copper-chromium as the catalyst and ammonia as the reducing agent to treat the exhaust gas. This method requires huge equipment and precious metals as the catalyst, and the cost is very high. Generally, manufacturers seldom use it; the second is solid-phase adsorption. R...

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Problems solved by technology

For example, sodium nitrate and potassium chloride are used for metathesis reaction. Changsha Design and Research Institute of Chemical Industry has adopted multi-step reaction and purification to obtain potassium nitrate with high purity (CN201510747903.0). Expensive, so the profit margin is limited; Shandong Changle County Nitrate Factory utilizes dilute nitric acid to produce potassium nitrate (CN92106421.7), and its condition is 70-105 ℃, under negative pressure 300-400mm-Hg, reaction conversion is more than 3 hours, in fact This condition has decomposed a large amount of nitric acid, and the use of negative pressure concentrated salt solution consumes a lot of energy, and washing with a large amount of tap water during impurity removal will dissolve a large amount of potassium nitrate and reduce the yield.

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