Method and device for recycling iodine from cooling water in first cooling tower used in yellow phosphorus production and used cooling tower

Abstract

The invention relates to the technology of recycling iodine in yellow phosphorus production, especially to a method and device for recycling iodine from cooling water in a first cooling tower used in yellow phosphorus production and the used cooling tower. The method includes sending the cooling water in the first cooling tower used in yellow phosphorus production to a settlement aeration tank to overflow to an oxidation tank, adding an oxidizing agent to oxidize to iodate, analyzing, and absorbing by a reducing agent. The method can improve the recovery rate of iodine. The modified cooling structure can make the cooling water in the first cooling tower perform settlement processing in the settling tank preferentially, which can reduce the circulation volume of the solution absorbed circularly, reduce the energy consumption, shorten the processing period of recycling iodine and reduce the recovery cost. Moreover, the liquid with high density from the first cooling tower is recycled preferentially, the recovery rate of iodine is improved, the enriching step of recycling iodine in yellow phosphorus production is avoided, and the cost is reduced.

Description

technical field [0001] The invention relates to the technical field of iodine recovery from yellow phosphorus production, in particular to a method and device for recovering yellow phosphorus to produce iodine in the cooling water of a first-stage cooling tower and the cooling tower used. Background technique [0002] In the iodine recovery process, the most typical and earliest method is the blowing method, which was first proposed by the Japanese Isai Chemical Industry Company. The specific process is to acidify the clarified brine to pH=2-3, The chlorine gas is mixed and then enters the blowing tower, and the elemental iodine replaced by the chlorine gas is vaporized by the air flow, and the iodine vapor in the air flow is introduced into the absorption tower and absorbed by an iodine solution dissolved in sulfur dioxide. The iodide solution flows out from the bottom of the tower with a concentration of 50-100g / L and keeps the iodide solution recirculating, then the solut...

AI Technical Summary

Problems solved by technology

[0003] But, for the yellow phosphorus production process, it only needs to consume millions of tons of phosphate rocks every year in China, and there is unavoidable iodine element in these phosphate rocks, and in the current prior art, although there are Publication No. CN101318624A "Method for Extracting Iodine from Circulating Water of Iodine-Containing Yellow Phosphorus Plant" adopts the process of extracting iodine by blowing out method, but because yellow phosphorus wastewater is a complicated system, it contains many factors that affect the extraction of iodine element, such as rare metal Elements, heavy metal elements, etc. are very easy to form complexes with iodine simple substance, so that the blowing efficiency is very low, and then the wastewater produced by yellow phosphorus production must be pretreated before iodine can be extracted. The reports on the technical literature of extracting iodine from the yellow phosphorus production process make the waste gas generated in the yellow phosphorus production process be discharged, which not only causes a waste of resources, but also brings serious pollution to the environment

Images