Zinc oxide desulfuration technology

Abstract

The invention discloses a zinc oxide desulfuration technology, which comprises the following steps of: reversely contacting sulfurous flue gas with a zinc-oxide-contained absorption solution in an absorption tower so as to remove sulfur from the sulfurous flue gas; conveying the desulfurated absorption solution into a settling tank and carrying out settling so as to obtain solid impurities and a supernatant; stirring and pulpifying the supernatant and a zinc-oxide-contained absorbent in a pulpifying tank, and then, conveying the mixture back the absorption tower; subjecting the solid impurities and a waste acidic solution to reacting in an acidifying tank so as to produce SO2 and acidified serous fluid; reversely contacting the acidified serous fluid with air in a sulfur dioxide desorption tower so as to desorb the SO2 from the acidified serous fluid and obtain SO2-desorbed serous fluid; and carrying out acid making by using the produced SO2. According to the zinc oxide desulfuration technology disclosed by the embodiment of the invention, the cost for raw materials in each system is saved, and no waste gas, waste liquid and waste solid are discharged in the whole system, so that the totally-closed operation is realized, and the requirements on environmental protection are met. In addition, the technology is simple, the process is short, further, the operation is convenient, and the continuous operation can be realized.

Description

technical field [0001] The invention relates to a zinc oxide desulfurization process. Background technique [0002] The traditional zinc oxide desulfurization process is as follows: a slurry containing zinc oxide (ZnO) or pure ZnO mixed with water and sulfur dioxide (SO 2 ) flue gas contacts, reacts, and generates zinc sulfite (ZnSO 3 ), ZnSO 3 After the precipitate is filtered by the filter press, the formed filter residue is sent to the roasting workshop; there are also ZnSO 3 In the case of oxidizing air blowing, the oxidation reaction occurs, and ZnSO is finally generated 4 , containing ZnSO 4 , ZnSO 3 , ZnO and the mixed solution of impurities, after being filtered by a filter press, the filtrate contains a large amount of ZnSO 4 , is sent to the leaching section of the wet system. After the filter residue is dried, it is sent to the slag treatment system or roasting section of the zinc smelter. [0003] The overall chemical reaction equation is as follows: [...

AI Technical Summary

Problems solved by technology

[0007] (1) ZnSO 3 The viscosity is relatively large, and the ZnSO in the circulating fluid 3 It is easy to deposit in equipment and pipelines, causing scaling and clogging of pipelines, and it is very difficult to clean up after scaling;

[0008] (2)ZnSO 3 Oxidized to ZnSO 4 A large amount of oxidizing air is required for oxidation, and the energy consumption is relatively high. The oxidation effect is controlled by many factors, and the oxidation efficiency is difficult to control;

[0009] (3) Since a large amount of filter residue is filtered out, and the filter residue is difficult to achieve a very low moisture content, if the filter is not well filtered, the filter residue is often like mud, which makes the operating environment of the first floor of the filter press workshop very poor, and these filter residues are transported outside During the process, it is impossible to achieve fully enclosed transportation, causing secondary pollution to the factory area;

[0010] (4) to ZnSO 4 The solution is separated from the slag, or the ZnSO in the slurry 3 To filter out, a filter press is required, and in order to operate continuously, the filter press has to be used one at a time, so that workers have to be arranged to operate and arrange the filter cloth, the filtered residue has to be transported away, and a filter press has to be built. Machine workshop, the entire system occupies a large area, and the operating costs and investment are large;

[0011] Generally speaking, since tail gas desulfurization does not produce any benefits for enterprises, the lower the investment and the simpler the equipment, the better. However, the traditional zinc oxide desulfurization process, from zinc oxide pulping to subsequent filter press filtration, all The scale of the system is not large, but to make the entire process run stably and reliably, the operating environment is good, and the degree of automation is high, the auxiliary facilities such as electricity and instruments must be complete, and the investment often exceeds the company's expectations.

As a result, a lot of equipment can be saved if it can be saved, and if it can be simplified, it will be simplified. As a result, there is no very good demonstration project for the zinc oxide desulfurization process, and it cannot be widely promoted.

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