SU1691307A1 - Method of recovering rare earth members from aqueous solutions - Google Patents

Abstract

This invention relates to methods for extracting rare earth elements from. aqueous solutions and allows to increase the degree of extraction and concentration of rare-earth elements, as well as reduce the duration of the process when they are extracted from acidic aqueous solutions. In the chamber of the flotation machine, 1 l of an acidic (nitro-salt or sulphate) solution containing 50 mg / l is placed. In a solution with a pH of 1-2 at a temperature of 10-60 ° C, with a vigorous stirring, a 0.07-0.13% solution of the sodium salt of dialkylphosphonic acids is added at the rate of 3 mol per 1 mol of rare earth elements. The solution is purged with air for 10 minutes. A precipitate containing rare earth elements that has floated to the surface is separated from the solution. Extraction of rare-earth elements in the sediment was 96% with a concentration ratio of 4800. 1 Cp f-ly, 1 tab. ate

Description

The invention relates to methods for extracting rare earth elements from aqueous solutions and can be used in the preparation of compounds of rare earth elements (REE) from poor ores, as well as in the processing of apatites and phosphorites.

The purpose of the invention is to increase the degree of extraction and concentration of rare-earth elements and to reduce the process time when extracting rare-earth elements directly from acidic aqueous solutions.

PRI me R 1. In the chamber of a 136B-FL flotation machine, 1 l of a sulphate solution containing 50 mg / l of lanthanum is placed.

A 0.1% aqueous solution of sodium dioctylphosphate at the rate of 3 mol per 1 mol of lanthanum is introduced into the solution with a pH of 1 and a temperature of 10 ° C with vigorous stirring. The solution is purged with air (air flow rate of 300 ml / min) for 10 minutes. The lanthanus-containing product floating on the surface is removed with a scraper. As a result, the degree of release from the solution delivered 96%, and the concentration ratio was 4800.

EXAMPLE 2 The conditions of the process are similar to those in Example 1, with the exception of: solution — nitrate. Collector — sodium dinonyl phosphinate, pH of solution 1.5, temperature 35 ° C.

ABOUT

Yu

with

about vj

As a result, the degree of release of lanthanum from the solution was 96%, and the concentration ratio was 4800.

Example 3. The conditions of the process are similar except for: the solution is hydrochloric, the collector is sodium didecylphosphate; pH of solution 2, temperature 60 ° C.

As a result, the degree of release of lanthanum from the solution was 96%, and the concentration ratio was 4800.

Experimental data obtained in the process of studying the effectiveness of the proposed method and the prototype method when changing parameters in a wide range are summarized in table.

The whole process of separating REE, including the operations of introducing the collector, blowing water with air and simultaneously removing the pop-up sublate, takes 10 minutes.

By this method, the flotation extracts that part of the REE, which is bound by the collector to the sparingly soluble compound. The use of dialkylphosphonic acids with a hydrocarbon chain length of less than 8 carbon atoms as a collector of sodium salts does not lead to the formation of a hardly soluble precipitate with a recoverable element. Sodium salts of dialkylphosphonic acids with a carbon chain containing more than 10 carbon atoms are poorly soluble in water, which sharply reduces their collective ability,

Introduction to a solution containing rare earth elements less than 3 mol of the collector per 1 mol of metal does not ensure the binding of the entire recoverable element contained in it to a hardly soluble product. Excess collector (more than 3 mol per 1 mol of the extracted metal) leads to hydrophilization of the colloidal sediment particles, which causes their incomplete extraction from solution.

In extremely acidic environments (pH C1), the collector is in an acid form, which makes it difficult for it to interact with metal cations. The decrease in the degree of release of REEs from solutions is associated with the presence of negative charge in metal-containing sediment particles that are poorly fixed on the surface of negatively charged air bubbles. Using a collector solution with a concentration of less than

0.07% entails a significant dilution of treated water, which creates certain difficulties. In a solution with a collector concentration of more than 0.13%, potassium salts of dialkylphosphonic acids with

the length of the hydrocarbon radical of 8-10 carbon atoms exists in micellar (poorly soluble) form, which significantly reduces their collective properties.

Excess solution temperature

60 ° C increases the solubility of the resulting precipitate, thereby reducing the recovery rate. When the temperature of the solutions is below 10 ° C, the interaction of the extracted element with the collector and coagulation of particles

sublat slowing down. In this case, it is necessary to significantly increase the time of agitation of the solutions and the time of their flotation treatment.

Thus, when implementing

the invention increases the degree of extraction of rare-earth elements from acidic solutions by 2–4 times, the degree of concentration - by 76–150 times, and decreases by 2–4 times the duration of the process compared to

with the prototype method.

Claims (2)

1. A method for extracting rare earth elements from aqueous solutions, including introducing a collector reagent into the solution, blowing the solution with air and separating the precipitate formed, characterized in that, in order to increase the degree of extraction of rare earth elements and reduce process time when extracting directly from acidic aqueous solutions, 0.07-0.13% aqueous solutions of dialkylphosphinic acid sodium salts containing 3 to 10 carbon atoms in the alkyl chain as 1 mole as the reagent-collector are used rare earth elements and extraction lead from solutions at pH 1-2. 2. A method according to claim 1, characterized in that the extraction is carried out at 10-60 C. The proposed method