A method for extracting and separating gallium for purification

Abstract

The invention discloses an extraction and separation method for purifying gallium. The method first extracts and separates impurities such as iron, zinc, copper, and cobalt from a gallium-containing acidic solution with an alkaline extractant, then uses an acid-alkaline composite extractant for a second extraction, and then washes the organic phase with water to separate aluminum and other metals; then uses an acid-alkaline composite extractant for a third extraction, gallium is enriched in the organic phase, and other impurities remain in the raffinate, and the gallium-containing organic phase is stripped to obtain a high-purity gallium product. The extraction and separation method of the present invention has a simple process; only three steps of extraction are used to solve the separation problem of high-content aluminum in crude gallium, and gallium purification is achieved. Since the investment in extraction equipment is small and the energy consumption of the extraction process is low, the extraction and separation method of the present invention has low cost.

Description

Technical Field

[0001] The invention relates to the field of wet extraction and separation of gallium, and in particular to an extraction and separation method for purifying gallium. Background Art

[0002] Gallium and its compounds are widely used in the semiconductor field. High-purity gallium is the main raw material of the semiconductor industry. Gallium compounds represented by gallium arsenide and gallium nitride are widely used in optical systems, microwave communications, high-speed large-scale integrated circuits, solar cells, etc. Gallium is an important rare metal. There is no independent mineral of gallium in nature. It is usually associated with ores such as bauxite and sphalerite, and the gallium content in these ores is very low. Generally, hydrometallurgical processes are used to extract gallium from the leachate or leaching residue of these ores. The sodium aluminate solution obtained from the Bayer process of smelting bauxite can be used to obtain crude gallium through resin adsorption, extraction, precipitation, electrolysis and other processes, and high-purity gallium can be obtained through crystallization, vacuum distillation, evaporation, electrolysis and other processes.

[0003] Among the numerous gallium purification technologies, resin adsorption and solvent extraction are considered to be the simplest technologies and are therefore widely used in gallium purification production practices. However, chelating resins that can selectively adsorb gallium are relatively expensive, and the resin adsorption method takes a long time to reach adsorption equilibrium, and the adsorption and desorption times required to purify gallium are also very long. Extractants with strong gallium extraction capabilities, such as the hydroxyquinoline extractant Kelex 100, can only be used to extract gallium from alkaline solutions, and the extractant is highly water-soluble, easily volatile and deteriorates, and has a short service life, resulting in a high gallium purification cost. Summary of the invention

[0004] The invention provides an economical, environmentally friendly and easy-to-operate extraction and separation method, which can achieve gallium purification by composite treatment and three-step extraction of commonly used extractants, and overcome the shortcomings of existing extraction and separation technologies.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] A method for extracting and separating gallium for purification comprises the following steps:

[0007] (1) The crude gallium is fully dissolved with hydrochloric acid and nitric acid solution, then added to the first extraction tank, and extracted and separated with an alkaline-extractant to obtain an organic phase enriched with iron, zinc, copper, cobalt and other ions;

[0008] (2) sending the raffinate obtained in step (1) into a second extraction tank, performing a second extraction with an acidic-alkaline composite extractant for 5-10 min to obtain an aluminum-enriched organic phase, and washing the organic phase with water;

[0009] (3) The washing liquid and the raffinate obtained in step (2) are mixed and sent to a third extraction tank, and an acid-alkaline-kerosene composite extractant is used for a third extraction. The extraction time is 10-30 minutes, and an organic phase enriched in gallium and a raffinate containing other impurity ions are obtained;

[0010] (4) The organic phase obtained in step (2) and step (3) is stripped with a 0-2 mol / L hydrochloric acid solution to obtain a solution containing aluminum and a solution containing high-purity gallium, respectively. The solution containing high-purity gallium can be used to prepare high-purity metallic gallium by electrolysis or crystallization.

[0011] In the extraction separation method, the crude gallium in step (1) can be metallic gallium with a purity of 97-99.99%, or a gallium salt with a purity of 70-99.99%.

[0012] In the extraction separation method, the alkaline extractant in steps (1)-(3) is N235 or N1923, etc.; the acidic extractant in steps (1)-(3) is P204, P507, CA12, CA100 or C272, etc.

[0013] The extraction separation method of the present invention has the following beneficial effects:

[0014] (1) Using commonly used, low-cost acidic and alkaline extractants to replace the more expensive and short-lived hydroxyquinoline extractants to separate and purify gallium-containing raw materials, greatly reducing the cost of gallium purification;

[0015] (2) The extraction and separation method of the present invention is applicable to gallium raw materials of various purities (70-99.99%) and various forms (solid or liquid), and has a wide range of applications;

[0016] (3) The extraction and separation method of the present invention has a simple process. The first step is to extract and remove impurities such as iron, zinc, copper, and cobalt. The second step is to extract and remove aluminum. The third step is to enrich gallium and leave other impurities in the raffinate. The crude gallium obtained from bauxite smelting usually has a high aluminum content. The extraction and separation method of the present invention solves the problem of separating high-content aluminum in crude gallium through only three extraction steps and realizes the purification of gallium. Since the investment in extraction equipment is small and the energy consumption of the extraction process is low, the extraction and separation method of the present invention has a low cost. DETAILED DESCRIPTION

[0017] The present invention is described in detail below with reference to the embodiments, but the present invention is not limited to the following embodiments. Example 1

[0018] A method for extracting and separating gallium for purification comprises the following steps:

[0019] (1) The crude gallium with a purity of 99% is fully dissolved in a hydrochloric acid solution, and then added to the first extraction tank, and extracted and separated with an extractant composed of 20% N235-20% 2-octanol-60% kerosene for 5 minutes to obtain an organic phase enriched with iron, zinc, copper, cobalt and other ions;

[0020] (2) The raffinate obtained in step (1) is fed into a second extraction tank, and a second extraction is performed using an extractant composed of 20% CA12-25% N235-55% kerosene. The extraction time is 5 minutes to obtain an organic phase enriched in aluminum, and the organic phase is washed with water;

[0021] (3) The washing liquid and the raffinate obtained in step (2) are mixed and sent to a third extraction tank, and a third extraction is performed using an extractant composed of 20% CA12-25% N235-55% kerosene. The extraction time is 30 minutes to obtain a gallium-enriched organic phase and a raffinate containing other impurity ions;

[0022] (4) The organic phase obtained in step (2) is stripped with water, and the organic phase obtained in step (3) is stripped with 0.5 mol / L hydrochloric acid solution to obtain aluminum-containing solutions and high-purity gallium-containing solutions, respectively, wherein the purity of gallium in the high-purity gallium solution reaches more than 99.999%, and after electrolysis, metallic gallium with a purity of more than 99.9999% is obtained. Example 2

[0023] A method for extracting and separating gallium for purification comprises the following steps:

[0024] (1) Gallium nitrate with a purity of about 80% is fully dissolved in a nitric acid solution, and then added to a first extraction tank, and extracted and separated with an extractant composed of 10% N1923-20% 2-octanol-70% kerosene for 5 minutes to obtain an organic phase enriched with iron, zinc, copper, cobalt and other ions;

[0025] (2) The raffinate obtained in step (1) is sent to a second extraction tank, and a second extraction is performed using an extractant composed of 30% CA100-20% N235-50% kerosene. The extraction time is 10 minutes to obtain an organic phase enriched in aluminum, and the organic phase is washed with water;

[0026] (3) The washing liquid and the raffinate obtained in step (2) are mixed and sent to a third extraction tank, and a third extraction is performed with an extractant composed of 30% CA12-20% N235-50% kerosene. The extraction time is 20 minutes to obtain a gallium-enriched organic phase and a raffinate containing other impurity ions;

[0027] (4) The organic phase obtained in step (2) is stripped with a 0.5 mol / L hydrochloric acid solution, and the organic phase obtained in step (3) is stripped with a 1 mol / L hydrochloric acid solution to obtain a solution containing aluminum and a solution containing high-purity gallium, respectively, wherein the purity of gallium in the high-purity gallium solution reaches more than 99%, and after electrolysis, metallic gallium with a purity of more than 99.99% is obtained. Example 3

[0028] A method for extracting and separating gallium for purification comprises the following steps:

[0029] (1) Gallium chloride with a purity of 97% is fully dissolved in a hydrochloric acid solution, and then added to a first extraction tank, and extracted and separated with an extractant composed of 20% N235-20% 2-octanol-60% kerosene for 5 minutes to obtain an organic phase enriched with iron, zinc, copper, cobalt and other ions;

[0030] (2) The raffinate obtained in step (1) is sent to a second extraction tank, and a second extraction is performed using an extractant having a composition of 25% C272-30% N235-45% kerosene. The extraction time is 10 minutes to obtain an organic phase enriched in aluminum, and the organic phase is washed with water;

[0031] (3) The washing liquid and the raffinate obtained in step (2) are mixed and sent to a third extraction tank, and a third extraction is performed using an extractant composed of 20% CA100-20% N235-60% kerosene. The extraction time is 25 minutes to obtain a gallium-enriched organic phase and a raffinate containing other impurity ions;

[0032] (4) The organic phase obtained in step (2) is stripped with a 1 mol / L hydrochloric acid solution, and the organic phase obtained in step (3) is stripped with a 1.5 mol / L hydrochloric acid solution to obtain a solution containing aluminum and a solution containing high-purity gallium, respectively. The purity of gallium in the high-purity gallium solution reaches more than 99%, and after electrolysis, metallic gallium with a purity of more than 99.99% is obtained.

Claims

1. A method for extracting and separating gallium for purification, characterized in that: The following steps are involved: (1) The crude gallium is fully dissolved with hydrochloric acid or nitric acid solution, then added to a first extraction tank, and extracted and separated with an alkaline extractant to obtain an organic phase enriched with iron, zinc, copper and cobalt ions; The crude gallium is metallic gallium with a purity of 97-99.99%, or a gallium salt with a purity of 70-99.99%; (2) sending the raffinate obtained in step (1) into a second extraction tank, performing a second extraction with an acidic-alkaline composite extractant for 5-10 minutes to obtain an aluminum-enriched organic phase, and washing the organic phase with water; (3) The washing liquid and the raffinate obtained in step (2) are mixed and sent to a third extraction tank, and a third extraction is performed using an acidic-alkaline composite extractant for 10-30 minutes to obtain a gallium-enriched organic phase and a raffinate containing other impurity ions; (4) The organic phase obtained in step (2) and step (3) is stripped with a 0-2 mol / L hydrochloric acid solution to obtain a solution containing aluminum and a solution containing high-purity gallium, respectively, wherein the solution containing high-purity gallium is used to prepare high-purity metallic gallium by electrolysis or crystallization.

2. The method for extracting and separating purified gallium according to claim 1, characterized in that: The alkaline extractant in step (1) is N235 or N1923; The acidic extractant in the acidic-alkaline composite extractant in steps (2)-(3) is CA12, CA100, P204, P507 or C272, and the alkaline extractant is N235 or N1923.