Method and apparatus for recovering iodine in yellow phosphorus production first stage cooling tower cooling water

Abstract

The present invention relates to the technology of recovering of iodine in yellow phosphorus production, and particularly relates to a method and an apparatus for recovering iodine in yellow phosphorus production first stage cooling tower cooling water; the yellow phosphorus production first stage cooling tower cooling water is sent into a sedimentation aeration tank for sedimentation aeration treatment, supernatant overflows into a sedimentation impurity removal tank in overflowing manner, impurities in the supernatant can be removed by sedimentation by addition of sulphurizing salt, iodide ions and iodine element all remain in the solution, the yellow phosphorus production is not affected, during the sedimentation aeration treatment process in the sedimentation aeration tank, the iodine element is separated, and then the iodine element dissolved in the solution is recovered by subsequent oxidation, desorption, absorption, iodine precipitation, filtration and drying steps, so that yellow phosphorus production system cooling water discharge and processing capacity can be reduced, and by absorption tower circulating absorbing processing, the iodine recovery rate can be improved, and the cost is reduced.

Description

technical field [0001] The invention relates to the technical field of iodine recovery in yellow phosphorus production, in particular to a method and a device for recovering yellow phosphorus to produce iodine in cooling water of a first-stage cooling tower. Background technique [0002] There are two main methods for extracting iodine in wet-process phosphoric acid. One is to add some oxidant to wet-process phosphoric acid, which may be one or more of strong oxidants such as chlorine gas, potassium permanganate, potassium chlorate, or hydrogen peroxide and vanadium pentoxide. Mixing, iodine from the free state I - Oxidize into iodine molecules, then add carbon tetrachloride and other extractants, fully stir to extract iodine molecules into the organic phase, separate the organic phase and acid liquid phase, and evaporate carbon tetrachloride by vacuum distillation at a certain temperature and pressure Obtain crude iodine; the 2nd, add some kind of oxidizing agent in wet-pr...

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Problems solved by technology

[0004] But, in spite of this, the iodine extraction process in the prior art can not satisfy the situation that iodine exists in various aspects and various substances in the living environment, and then the universality of the process of iodine recovery is relatively weak. For this reason, Some researchers have aimed at the method for extracting iodine from iodine-containing phosphorus plant circulating water. The publication number of its patent is CN101318624A. The impurity composition is relatively complex, and it contains a variety of impurities that affect the precipitation of iodine, such as rare metals, heavy metals, etc., which are very easy to form complexes with iodine, which makes it difficult to separate iodine, which reduces the recovery rate of iodine and the iodine content. For this reason, the wastewater from the yellow phosphorus plant needs to be pretreated, resulting in higher costs and high energy consumption for wastewater treatment in the yellow phosphorus plant

[0005] At the same time, the researcher searched and consulted the relevant prior art, and found no relevant technical literature on the treatment plan for extracting iodine from the cooling water of the primary cooling tower during the yellow phosphorus production process.

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