RU1788057C - Method of recovering vanadium and molybdenum from solutions by adsorption - Google Patents

Abstract

Usage: relates to methods for processing molybdenum, vanadium-containing pulps. Essence: the extraction of vanadium and molybdenum is carried out on a strongly basic resin, followed by elution. After adjusting the pH within 1.2-1.6, solutions containing both metals are passed for 0.5-1 hours through a strongly basic ion-exchange salt (such as AM-pore, AB, etc.), on which molybdenum is adsorbed. Vanadium is sorbed on a new portion of salt after alkalizing the resulting solution to a grH of 2.5-2.8. 1 tab.

Description

The invention relates to the metallurgy of rare metals, and in particular to methods for processing molybdenum-, vanadium-containing pulps,

A known method for the extraction of molybdenum from sulfuric acid solutions after neutralizing them with lime to a pH of 1.2-1.5 sorption on anion exchange resins.

There is a known method for isolating molybdenum and vanadium, in which hydrochloric acid solutions of molybdenum and vanadium are passed through a ion exchange resin in salt form at pH 1.5-7, the resin is treated with 1-4 ammonia solution and ammonium vanadate crystals are isolated from the resulting solution.

The closest technical solution selected as a prototype is a method in which the following steps are provided: the pH of an aqueous solution containing molybdenum and vanadium is adjusted in the range of pH 1.5-7. Then, the solution is brought into contact with a strongly basic ion-exchange salt, said ion-exchange salt is eluted with 1-4 solutions

, the obtained ammonium vanadate is crystallized and separated from the vanadium-molybdenum solution formed by elution.

A disadvantage of the process is that only pure vanadium compounds are obtained.

It is an object of the invention to selectively recover from solutions containing molybdenum and vanadium with a high recovery of molybdenum and vanadium.

The essence of the method lies in the fact that the solution after leaching of ash from sulfuric acid from burning oil shale, having a pH of 1, and filtration, are made alkaline with lime to a pH of 1.2-1.6. then the solution is cooled to a temperature of 50 ° C and served on the sorption extraction of molybdenum. Sorption is carried out in two stages. The volume of a strongly basic resin of the AM-pore type (AB-17 and others) is calculated so that, at a given passage speed, the solution is in contact with the resin for no more than 0.5-1 hours. In this case, molybdenum is adsorbed on

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resin in an amount of 98.5-99.5% of that contained in the solution, and vanadium remains almost completely in solution. After the molybdenum is extracted, the resulting solution is made alkaline with lime to a pH of 2.5-2.8 and fed to the sorption extraction of vanadium using a resin of the same grade AM-pore (or AB-17). Moreover, the recovery of vanadium on the resin is 98.5-99.5%. Molybdenum is eluted with a 15% sulfuric acid solution with the addition of 0.5 nitric acid, vanadium with a 10% HC solution saturated with Oh. The elution of metals can be carried out with alkali solutions and other possible methods.

The choice of pH limits for the sorption of molybdenum and vanadium, as well as the sorption time, was made experimentally (see table). At pH values less than 1.2, the molybdenum capacity of the resin decreases, at pH values of 1.6 a parallel sorption of vanadium is observed, up to 17-20%.

At a sorption time of less than 0.5 hours, a decrease in the value of sorption of molybdenum to 70-80% of that contained in the solution is observed; at a sorption time of more than 1 hour, sorption of vanadium in an amount of 12 -5% is observed. ..

. The method selectively achieves a high degree of recovery of molybdenum and vanadium even with a five-fold excess of the concentration of vanadium compared to molybdenum.

Example. This method of separation of molybdenum and vanadium was tested in laboratory and then in laboratory-enlarged conditions for sulfuric acid solutions obtained in the process of acid leaching of ash and other products of the processing of oil shales of the Dzhamskoye field (coke, slag). These solutions

had a pH of 1 and contained 112.5 mg / dm of molybdenum and 575 mg / dm of vanadium. Sorption was carried out on an AM-pore resin with a solution flow rate of 4 volumes per 1 volume of resin per hour. At a pH of 1.2–1.55, the extraction of molybdenum per resin was 98.8 vanadium — less than 3%; vanadium was well sorbed at a pH of 2.5–2.8 (vanadium recovery 98.3–98.9%) after alkalizing the solution lime.

Molybdenum was eluted from the AM pore resin with a 15% sulfuric acid solution supplemented with 0.5% nitric acid. The recovery was 84.2% vanadium and was stripped with 10% sodium hydroxide solution. The recovery amounted to 88%.

Using the proposed method of conducting the process of separation of vanadium and molybdenum provides, in comparison with existing methods, the following advantages:

a high degree of extraction of molybdenum (98.5-99.5) and vanadium (99.5-99.8) from the solution is achieved;

in connection with the low sorption of vanadium by the proposed method at a pH of 1.2-1.55 (0-1.8) compared with molybdenum, metal compounds are obtained in high purity, i.e. high selectivity of the process is observed

Claims (1)

SUMMARY OF THE INVENTION A method for extracting vanadium and molybdenum from sulphate solutions by sorption on a strongly basic anion-exchange sorbent, characterized in that, in order to selectively recover molybdenum with a high degree of extraction of molybdenum and vanadium, sorption is carried out in two stages: at the first stage, at pH 1.2 -1.6 for 0.5-1 hours with the extraction of molybdenum and the second at pH 2.5-2.8 with the extraction of vanadium. The sorbability of molybdenum and vanadium on the resin AM-pores from the pH of the solutions and the time of sorption