Method for selectively separating perrhenic acid radical through two-section capacitive deionization process

Abstract

The invention discloses a method for selectively separating a perrhenic acid radical through a two-section capacitive deionization process. The method comprises the following steps of: introducing a to-be-adsorbed solution containing the perrhenic acid radical into a first-section capacitor, and adsorbing the to-be-adsorbed solution by active carbon in an anode region under slot voltage of 1.8-3.0V; and introducing the to-be-adsorbed solution into a second-section capacitor, and adsorbing the to-be-adsorbed solution by active carbon in anode region under slot voltage of 1.8-3.0V. The invention further discloses a device for selectively separating the perrhenic acid radical through the two-section capacitive deionization process. The method for selectively separating the perrhenic acid radical through the two-section capacitive deionization process is good in selectivity, has a selective adsorption rate of 93% or more on ReO4<->, and has adsorption smaller than 1% on other ions such as SO4<2->, Cl<-> and NO3<->. The adopted adsorption material is low in price, the active carbon is a common carbon material, is low in price, is simple to manufacture, and is convenient to purchase; and relative to other carbon materials, implementation cost of the technical scheme is reduced.

Description

technical field [0001] The invention belongs to the field of recovery and utilization of scattered elements, and in particular relates to a method for separating perrhenate from sewage. Background technique [0002] Rhenium (Re) is the latest important element discovered in the rare element (RSE) group. It belongs to a kind of precious rare metal element, and its content in the earth's crust is very small. However, rhenium has high hardness, corrosion resistance, wear resistance and good Ductility, has a wide range of applications in defense and aerospace, ultra-high temperature emission, thermionic materials for special lamps, etc. Because the content of rhenium in the earth's crust is very small, the price of rhenium and its compounds is very expensive, making it more practical to recycle and reuse. In weak acid or weak base solution, rhenium is the heptavalent anion ReO 4 - Existence, such as ammonium perrhenate and potassium perrhenate, are generally extracted in the ...

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Problems solved by technology

The precipitation method is mainly sulfide precipitation, which belongs to the traditional process, but the sulfide salt has strong activity and cannot selectively extract rhenium. Heavy metals, especially copper, arsenic, antimony, bismuth, etc., are precipitated at the same time as rhenium, and more than 90% of rhenium enters the arsenic filter cake. Part of it is lost with the discharge of wastewater, and the amount of arsenic filter cake residue is large. This method has complex rhenium recovery procedures and low rhenium recovery rate; solvent extraction is widely used in the preparation of ammonium rhenate products, but there are cumbersome steps, many chemicals, poor operating environment, Problems such as low recovery rate of rhenium; ion exchange operation is simple, but there are problems such as small saturated adsorption capacity, low recovery rate, short service life, frequent replacement, and increased production costs; large-scale application has not been realized; liquid membrane method It is still in its infancy, and the specific industrial production practice is not yet mature

The size of the ions affects the distribution of the electric double layer on the electrode surface, which in turn affects the selectivity

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