Method for extracting iodine from iodine containing circulation water of yellow phosphorus factory

Abstract

The invention discloses a method for extracting iodine from the iodine-containing recycled water of a yellow phosphorus plant; the iodine is extracted from the recycled water generated from yellow phosphorus production process, wherein, the content of iodine in the recycled water is 80-140mg / L, the content of phosphorus in the recycled water is 100-400mg / L, compound oxidant is added into the recycled water for oxidation reaction, ionic iodine is oxidized into molecular iodine, air is used for blowing molecular iodine out, then SO2-containing acidic solution is used for absorbing, the pH value of absorption liquid is between 1-6, then hydrogen peroxide is added to separate iodine out and filtration and separation are carried out to obtain finished iodine. The recycled water from the yellow phosphorus plant with iodine content of below 140 mg / L is usually selected as raw material for extracting iodine; the method and the compound oxidant proposed by the applicant after tests can extract the iodine with low content in the recycled water and can expand the select range of the raw material for extracting iodine, and optimum compound oxidant proportion and production technique are also provided by the tests.

Description

Technical field: [0001] The invention relates to a method for extracting iodine from circulating water of an iodine-containing yellow phosphorus plant, and belongs to the technical fields of iodine extraction, environmental protection and chemical industry. Background technique: [0002] At present, most industrial iodine manufacturers in my country use high-grade iodide-containing brine, brine, or kelp soaking solution (iodine content: 200-300mg / L) as raw materials to produce industrial iodine. Most of the processes used are ion exchange resin methods. That is to say, the high-grade iodide-containing bittern, brine, or kelp soaking liquid is acidified with acid, and chlorine gas is introduced to make iodine free and precipitate, and then adsorbed by polystyrene ion exchange resin. There are two methods of desorption: one is elution with sulfite solution, and then potassium chlorate is used to precipitate iodine, centrifuged, and crude iodine is melted and refined by sulfuric...

AI Technical Summary

Problems solved by technology

[0011] The object of the present invention is to: provide a kind of method that extracts iodine from the circulating water of iodine-containing yellow phosphorus plant; This method mainly carries out effective iodine separation to the circulating water of low-iodine-containing yellow phosphorus plant that cannot be processed by other methods, and uses hydrogen peroxide and sulfur dioxide As a raw material for production, it is more convenient and safe; it not only solves the problems of waste discharge and environmental pollution, but also provides a new raw material for iodine production, so that waste can be turned into treasure, and at the same time it can overcome the problems of existing technologies. technical issues