Method and device for preparing sodium chlorite through comprehensive method chlorine dioxide process

Abstract

The invention discloses a method for preparing sodium chlorite through a comprehensive method chlorine dioxide process. According to the reaction principle, the method includes the steps of firstly, conducting sodium chlorate electrolysis according to the chemical equation NaCl+3H2O->NaClO3+3H2; secondly, conducting hydrochloric acid synthesis according to the chemical equation H2+Cl2->2HCl; thirdly, generating chlorine dioxide according to the chemical equation NaClO3+2HCl->NaCl+ClO2+1 / 2Cl2+H2O; fourthly, preparing sodium chlorite according to the chemical equation 2ClO2+2NaOH+H2O2->2NaClO2+2H2O+O2. A preparation device mainly comprises an electrolytic cell, a sodium chlorate reactor, a hydrochloric acid synthesis furnace, a reboiler, a chlorine dioxide generator, a chlorine dioxide absorption stripping tower, a chlorine dioxide stripper and a sodium chlorite preparation tower. When sodium chlorite is prepared through the method and the device, the product cost is low, yield is high, no side products are discharged, no waste acid or solid waste is discharged, environment pollution is reduced, and the advantages of being economical and environmentally friendly are achieved.

Description

technical field [0001] The invention relates to the field of sodium chlorite production, in particular to a method and a device for preparing sodium chlorite with a comprehensive chlorine dioxide process. Background technique [0002] Chlorine dioxide is a strong oxidant. Stable chlorine dioxide is internationally recognized as a safe and non-toxic green disinfectant. It is also a good paper bleaching agent and is widely used. However, chlorine dioxide has strong oxidizing properties, instability, and high-concentration explosiveness, which greatly restricts its production, packaging, and transportation. Sodium chlorite is a solid chlorine dioxide with superior performance, which has the superior performance of stable chlorine dioxide liquid, and also overcomes the short effective release period of stable chlorine dioxide liquid preparations, inconvenient transportation and storage, etc. shortcoming. Sodium chlorite product has two forms of solid crystal and aqueous soluti...

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Problems solved by technology

[0004] (1) Mathieson method: The method has low investment and is easy to operate. The disadvantage is that the production cost is high, sodium chlorate and sulfur dioxide need to be purchased, the reaction efficiency is low, and a large amount of by-products, thenardite and waste acid are produced.

[0005] (2) R1 method: 3NaClO 3 +4SO 2 +3H 2 O→2ClO 2 +Na 2 SO 4 +NaCl+3H 2 SO 4 , the production cost of this method is high, sodium chlorate, sulfur dioxide and sulfuric acid need to be purchased externally, the by-product acid Glauber's salt and waste acid need to be neutralized again, and there is a lot of waste water and waste gas

[0006] (3) R2 method: 2NaClO 3 +2H 2 SO 4 +2NaCl→2ClO 2 +2Na 2 SO 4 +Cl 2 +2H 2 O, the production cost of this method is high, and sodium chlorate, sulfuric acid, and sodium chloride need to be purchased externally, resulting in a large amount of by-products and waste acid discharge

However, the disadvantage of this method is that sodium chlorate, hydrogen peroxide, and sulfuric acid need to be purchased, so the production cost is high, and the by-product neutral Glauber's salt is also discharged

[0010] In summary, the process of preparing sodium chlorite with chlorine dioxide by reduction method needs to purchase multiple raw materials when preparing chlorine dioxide, the production cost is high, and a large amount of by-products are produced or a large amount of waste acid is discharged

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