Method for extracting iodine from blanching waste water of fresh kelp

Abstract

A method for extracting iodine from blanching waste water of fresh kelp comprises the steps as follows: adjusting the pH value of the blanching waste water, adding an oxidant into the blanching waste water, blowing out the iodine in the blanching waste water by using air, absorbing the iodine in the blown out air by using a solution, analyzing the iodine in the absorption solution, and removing residual oxidant in iodine waste water. The invention overcomes the defects that cannot be overcome in the traditional kelp ion-exchange iodine extraction process through the adoption of the air blowing method, and solves the heating problems in the traditional air blowing method in virtue of the characteristic of high temperature of the blanching waste water of fresh kelp, reduces process cost, realizes economical and efficient extraction of iodine from the blanching waste water of fresh kelp, and achieves the iodine extraction rate above 80 percent. The invention discloses a reduction acidification oxidation method to solve the speed problem of iodine analysis adopting a NaOH solution as an absorption solution and improve quality. Besides, the invention adopts a quantitative reaction method and removes the residual oxidant NaNO2 in the waste water after iodine extraction, thereby solving the problem of environmental pollution caused by the oxidant in the traditional process.

Description

Technical field: [0001] The invention belongs to the technical fields of environmental protection and chemical industry, and in particular relates to a method for extracting iodine from fresh kelp blanching wastewater. Background technique: [0002] Kelp processing is one of the pillar industries in my country's aquaculture industry. The annual output of kelp is about 800,000 tons, of which about 500,000 tons are processed into salted kelp after blanching and salting. volume of high-temperature hot water for blanching treatment, and the total amount of blanching wastewater produced by fresh kelp processing is about 80,000-100,000 tons per year. During this process, some active ingredients in the fresh kelp will dissolve in the blanching water, and the iodine content in it can reach 300-800ppm. However, this part of the blanching water has high temperature, high impurities, and poor water quality. It wastes resources and pollutes the environment. [0003] The traditional iod...

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved in the present invention is to provide a method for extracting iodine from fresh kelp blanching wastewater; use the air blowing method to extract iodine in fresh kelp blanching wastewater, to overcome the poor water quality of fresh kelp blanching wastewater, many impurities, Strong production seasonality and other shortcomings that cannot be solved by the traditional kelp iodine extraction process. At the same time, the high temperature of fresh kelp blanching wastewater is used to solve the heating problem of the traditional air blowing method, reduce process costs, and realize economical and efficient iodine in fresh kelp blanching water. Extraction; for the problem that the iodine resolution rate produced by NaOH solution as the absorption solution is difficult to control and iodine is not easy to crystallize, a reduction acidification oxidation method is proposed to solve the problem of iodine resolution rate, so that iodine can produce crystallization and improve the quality of iodine products; the present invention also Using a quantitative reaction method, the residual oxidant NaNO in the wastewater after iodine extraction is reduced 2 Removal to solve the problem of environmental pollution caused by oxidants in traditional processes