Arsenic precipitating agent for separation of gallium and arsenic and method for separation of gallium and arsenic from gallium and arsenic solution

Abstract

The present invention discloses an arsenic precipitator for separation of gallium and arsenic, comprising one or more of barium oxide, calcium oxide, magnesium oxide and cerium oxide, and the mass ratio of barium oxide, calcium oxide, magnesium oxide and cerium oxide is (3-8): (0-1): (0-1): (0-1). The present invention also provides a method for separating gallium and arsenic from a gallium and arsenic solution. The arsenic precipitator for separation of gallium and arsenic of the present invention mainly comprises one or more of barium oxide, calcium oxide, magnesium oxide and cerium oxide, has the advantages of low cost, non-toxicity, no operational risk, etc., the introduced impurity ions are easily removed by reaction with sulfate and carbonate, and has the advantages of good arsenic-gallium separation effect and high arsenic removal rate.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrometallurgy, and in particular relates to an arsenic precipitation agent and a method for recovering a gallium-arsenic solution. Background Art

[0002] Gallium is an important rare metal. Gallium and its compounds have excellent photoelectric and chemical properties. They are widely used in semiconductor materials, solar cells, alloys, chemicals, medical treatment and other fields. They are key raw materials for the development of modern high technology. Gallium arsenide is an important gallium compound. It is widely used in many optoelectronic fields such as remote control, mobile phones, DVD computer peripherals, lighting, etc. It is one of the most important applications of gallium. With the increasing global demand for gallium, the recovery of gallium from natural resources can no longer meet human needs. Therefore, the recovery of gallium from secondary resources has attracted much attention. The efficient and clean recovery of gallium secondary resources can be used to alleviate the contradiction between the supply and demand of gallium metal in the future. The production process of gallium arsenide devices has many steps and a low yield rate. Every year, its production and processing process generates a large amount of gallium-containing waste, in which the gallium grade is much higher than that of traditional gallium-extracting minerals, and it is an important raw material for recycled gallium.

[0003] At present, the gallium arsenide recovery process is mainly based on hydrometallurgy. First, the gallium in the gallium arsenide must be leached into the solution. However, due to the similar chemical properties of arsenic and gallium, both arsenic and gallium will be leached into the solution during the leaching process. Therefore, the arsenic and gallium in the leachate must be further separated in order to produce a purer gallium product. Gallium-arsenic separation is an important problem in the current gallium arsenide recovery process. Since both are amphoteric and soluble in both acid and alkali, it is impossible to directly separate gallium and arsenic by adjusting the pH of the solution.

[0004] At present, the commonly used gallium-arsenic separation methods in industry include solvent extraction, ion exchange and neutralization precipitation. For example, the invention patent CN108707927A discloses a method for recovering arsenic and gallium from gallium arsenide waste. The gallium arsenide waste is used as the anode for electrolysis, gallium is precipitated at the cathode, and the arsenic in the electrolyte is recovered by ion exchange. This method can realize the comprehensive recovery and utilization of gallium and arsenic, but the arsenic concentration is too high during electrolysis, which may produce toxic arsenic hydrogen gas. At the same time, the ion exchange method is relatively expensive and difficult to operate. The invention patent CN106498168A discloses a method for recovering gallium from oil-containing gallium arsenide slurry. Metal gallium is obtained by controlled potential acid leaching, extraction and arsenic removal, and liquid electrolysis. P204 is used as the extractant and a relatively pure gallium-containing solution is obtained by three-stage countercurrent extraction. A large amount of acid stripping and washing are required in this process, and the extraction operation is relatively cumbersome and costly. Invention patent CN108004409A discloses a method for separating and recovering gallium from gallium arsenide sludge. The method realizes the separation and recovery of gallium from gallium arsenide sludge through a specific process of alkaline leaching, neutralization, acid leaching for silicon removal and gallium precipitation. However, the multi-stage precipitation process is relatively cumbersome, and gallium and arsenic will co-precipitate under neutral conditions, making the separation of the two incomplete.

[0005] Therefore, the gallium-arsenic separation methods commonly used in the industry are often accompanied by high costs, complicated steps, poor separation effects, etc. The method of separating arsenic and gallium from gallium arsenide leaching solution still needs to be further improved. Summary of the invention

[0006] The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the above background technology, and to provide a precipitant for gallium-arsenic separation with low cost, simple steps and good separation effect, as well as a method for separating gallium-arsenic from a gallium-arsenic solution. In order to solve the above technical problem, the technical solution proposed by the present invention is:

[0007] An arsenic precipitator for gallium-arsenic separation comprises one or more of barium oxide, calcium oxide, magnesium oxide and cerium oxide, wherein the mass ratio of barium oxide, calcium oxide, magnesium oxide and cerium oxide is (3-8):(0-1):(0-1):(0-1).

[0008] In the above-mentioned arsenic precipitant for separation of gallium and arsenic, preferably, the arsenic precipitant contains barium oxide and at least one of calcium oxide, magnesium oxide and cerium oxide. More preferably, the arsenic precipitant contains barium oxide, calcium oxide, magnesium oxide and cerium oxide at the same time.

[0009] In the above-mentioned arsenic precipitator for gallium-arsenic separation, preferably, the arsenic precipitator also includes a dispersed solution, the dispersed solution is a hot alkaline solution (30-90°C) with a pH value>14, and one or more of barium oxide, calcium oxide, magnesium oxide and cerium oxide are dispersed in the dispersed solution to obtain a dispersed suspension with a mass concentration of 30-50%. Since the effective components of the arsenic precipitator of the present invention are slightly soluble or difficult to dissolve in alkali, directly adding the arsenic precipitator to the gallium-arsenic solution may cause flocculation and agglomeration, resulting in a smaller specific surface area, thereby reducing the arsenic removal efficiency. The present invention first uses a hot alkaline solution to prepare a dispersed suspension, which can make the effective components of the arsenic precipitator more evenly dispersed in the gallium-arsenic solution in the form of a colloidal precipitate, have a larger specific surface area, and have a better arsenic removal effect. The dispersed solution for preparing the suspension can be replaced by a primary gallium liquid obtained by a single filtration, which can be recycled.

[0010] In the above-mentioned arsenic precipitator for gallium-arsenic separation, preferably, the pH value of the gallium-arsenic solution is controlled to be > 14 when the arsenic precipitator is used. The use condition of the arsenic precipitator of the present invention is a strongly alkaline (pH>14) solution containing gallium and arsenic, generally an alkaline leaching solution of gallium arsenide waste. If the pH is too low, the gallium ions in the solution will be hydrolyzed and precipitated, thereby affecting the gallium-arsenic separation effect of the precipitator.

[0011] Our research shows that the arsenic precipitator with barium oxide as the single effective ingredient has an excellent arsenic removal rate after being dispersed in a hot alkaline solution. In the preferred scheme, the present invention adds barium oxide, calcium oxide, magnesium oxide and cerium oxide to a hot alkaline solution with a pH value>14 to generate a colloidal precipitate with a large specific surface area and a good adsorption and removal effect on arsenic. In addition, the present invention uses a mixed alkaline arsenic precipitator to remove arsenic, and by virtue of the property that arsenic can react with calcium, magnesium, barium and cerium ions to generate arsenate precipitates with a large solubility product, it has a good selective removal effect on arsenic. Preferably, the present invention uses a mixture of barium oxide and calcium oxide, magnesium oxide and cerium oxide. The microstructure of the arsenate complex salt formed by the mixture of these four substances is more stable, so the removal of arsenic by using a mixed arsenic precipitator is more excellent than that of a single component. This method avoids the use of a large amount of acid when using the traditional neutralization precipitation method, and also avoids the large loss of gallium in the solution during neutralization. It has a good effect on the separation of gallium and arsenic in the solution, and can make the precipitation of arsenic more complete.

[0012] As a general technical concept, the present invention also provides a method for separating gallium arsenic from a gallium arsenic solution, comprising the following steps:

[0013] (1) adding alkali (sodium hydroxide) to the gallium arsenic solution to adjust the pH value to >14, then adding the newly prepared arsenic precipitating agent mentioned above, and after the arsenic precipitation reaction, filtering and separating to obtain arsenic residue and primary gallium liquid;

[0014] (2) adding sulfate ions and / or carbonate ions to the primary gallium solution obtained in step (1) to carry out a decontamination reaction, filtering and separating, and collecting the filtrate to obtain a secondary gallium solution.

[0015] In the above-mentioned method for separating gallium arsenic from gallium arsenic solution, preferably, when the arsenic precipitation reaction is carried out under stirring conditions, the reaction temperature is controlled to be 30-90°C, the reaction time is 30-60min, the stirring speed is 200-300r / min, and the mass ratio of the amount of arsenic precipitation agent to arsenic in the gallium arsenic solution is (3-5):1.

[0016] In the above-mentioned method for separating gallium arsenic from gallium arsenic solution, preferably, after the arsenic precipitation reaction, stirring and aging treatment is carried out and then filtering and separating are carried out. During the stirring and aging treatment, the aging temperature is controlled to be 60-80°C, the aging time is 60-90min, and the stirring speed is 50-100r / min.

[0017] In the above-mentioned method for separating gallium arsenic from gallium arsenic solution, preferably, sodium sulfate and sodium carbonate are added to the primary gallium solution for reaction, and the mass ratio of the total amount of sodium sulfate and sodium carbonate to the excess arsenic precipitant is (1.5-2.5):1.

[0018] In the above-mentioned method for separating gallium arsenic from gallium arsenic solution, preferably, the impurity removal reaction is carried out under stirring conditions, the reaction time is controlled to be 10-30 min, and the stirring speed is 200-300 r / min.

[0019] In the above-mentioned method for separating gallium arsenic from gallium arsenic solution, preferably, after the impurity removal reaction, stirring and aging treatment is carried out and then filtering and separating are carried out. During the stirring and aging treatment, the aging temperature is controlled to be 20-40°C, the aging time is 10-30min, and the stirring speed is 50-100r / min.

[0020] In the above-mentioned method for separating gallium arsenic from a gallium arsenic solution, the method preferably comprises the following steps:

[0021] (1) First, sodium hydroxide is added to the gallium arsenic solution to adjust the pH value. In order to ensure that the gallium in the solution is not hydrolyzed and precipitated, the pH of the solution needs to be controlled to be > 14. After adjusting the pH, a newly prepared arsenic precipitant (dispersible suspension, which can be prepared from the primary gallium solution) is added. After a period of reaction, the solution is aged and filtered to separate the arsenic residue and the primary gallium solution.

[0022] (2) Sodium sulfate and sodium carbonate are added to the gallium solution obtained in step (1) to further purify the residual arsenic ions in the solution, such as Ba 2+ ,Mg 2+ , Ca 2+ These ions are easily precipitated by reaction with sulfate and carbonate, and filtered again to obtain a relatively pure secondary gallium liquid for subsequent gallium recovery.

[0023] The main reactions that occur during the process include:

[0024] XO+H 2 O=X 2+ +2OH - ;

[0025] 3X 2+ +2AsO 4 3- =X 3 (AsO 4 ) 2 ↓;

[0026] X 2+ +SO 4 2- =XSO 4 ↓;

[0027] X 2+ +CO 3 2- =XCO 3 ↓;

[0028] Wherein, X = Ba, Mg, Ca;

[0029] CeO 2 +2H 2 O=Ce 4+ +4OH - ;

[0030] 3Ce 4+ +4AsO 4 3- =Ce 3 (AsO 4 ) 4 ↓;

[0031] Ce 4+ +4OH - =Ce(OH) 4 ↓.

[0032] Preferably, the reaction conditions of the first stage precipitation of arsenic in step (1) are: temperature of 30-90°C, mass ratio of arsenic precipitant: arsenic is (3-5): 1 (the mass of arsenic precipitant refers to the mass of the effective component in the arsenic precipitant, excluding the mass of the dispersed solution), stirring reaction time of 30-60min, stirring speed of 200-300r / min, aging temperature of 60-80°C, aging time of 60-90min, aging stirring speed of 50-100r / min. Increasing the temperature can accelerate the precipitation reaction, but too high a temperature will lead to an increase in the ion solubility product, resulting in incomplete precipitation and a decrease in precipitation rate. In order to ensure the removal rate of arsenic, the amount of arsenic precipitant used needs to be higher than the theoretical amount, but in order to reduce the amount of precipitant used in the second stage precipitation, the excess coefficient of the arsenic precipitant should be reduced as much as possible under the premise of ensuring the precipitation rate.

[0033] Preferably, the reaction conditions for removing the impurity ions introduced by the arsenic precipitator by the second stage precipitation in step (2) are as follows: the mass ratio of the total amount of sodium sulfate and sodium carbonate to the excess arsenic precipitator is (1.5-2.5):1, the stirring reaction time is 10-30min, the stirring speed is 200-300r / min, the aging temperature is 20-40°C, the aging time is 10-30min, and the aging stirring speed is 50-100r / min. In order to prevent the introduction of new impurity ions into the system and ensure the purity of gallium in the subsequent recovery process, sodium sulfate and sodium carbonate need to be added as precipitants to remove excess arsenic precipitator ions.

[0034] Preferably, in the process of industrial long-line production, the primary gallium liquid obtained in step (1) can be used to prepare a dispersed suspension. The arsenic in the primary gallium liquid has been completely removed and contains some unreacted arsenic precipitant. At the same time, the pH value also meets the use requirements of the arsenic precipitant. Therefore, a small amount of primary gallium liquid can be used to prepare a dispersed suspension in each production cycle, thereby reducing the amount of arsenic precipitant, sodium hydroxide and industrial water.

[0035] The leaching of gallium arsenide needs to be carried out in a strong alkaline system. Since the properties of gallium and arsenic are relatively similar, the use of conventional neutralization precipitation method to separate and recover gallium arsenide alkaline leaching solution will cause the gallium therein to be neutralized and hydrolyzed and form a co-precipitation with arsenic, which is difficult to separate and results in a high gallium loss rate. However, the use of the precipitant described in the present invention can directly achieve gallium-arsenic separation in a strong alkaline solution, has a good gallium-arsenic separation effect, is low in cost, and has simple steps.

[0036] Compared with the prior art, the advantages of the present invention are:

[0037] 1. The main components of the arsenic precipitation agent for gallium-arsenic separation of the present invention are one or more of barium oxide, calcium oxide, magnesium oxide and cerium oxide, and it has the advantages of low cost, non-toxicity, no operational risks, etc. The introduced impurity ions are easily removed by reaction with sulfates and carbonates, and it has the advantage of good arsenic-gallium separation effect.

[0038] 2. In the method for separating gallium and arsenic from a gallium-arsenic solution of the present invention, the gallium-arsenic separation effect is good, the arsenic removal rate is high, the loss of gallium in the process is small, and the impurity ion content of the solution after purification is low, which is conducive to the further recovery of gallium.

[0039] 3. The method for separating gallium arsenic from a gallium arsenic solution of the present invention is simple to operate, has a short process, and has friendly operating conditions. It is easy to realize industrial application and can economically and effectively separate arsenic and gallium in the solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0041] Figure 1 The present invention is a process flow chart of the method for separating gallium arsenic from a gallium arsenic solution.

[0042] Figure 2 These are photos of the actual objects after adding arsenic precipitating agent at different temperatures in Example 1. DETAILED DESCRIPTION

[0043] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and meticulously below in conjunction with the accompanying drawings and preferred embodiments of the present invention, but the protection scope of the present invention is not limited to the following specific embodiments.

[0044] Unless otherwise defined, all the professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0045] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0046] The gallium-arsenic solution used in the following examples is an alkaline leaching solution of gallium arsenide waste, wherein the gallium concentration is 58.2 g / L and the arsenic concentration is 60.1 g / L.

[0047] Embodiment 1:

[0048] An arsenic precipitator for gallium-arsenic separation is prepared from barium oxide, calcium oxide, magnesium oxide and cerium oxide in a mass ratio of 3:1:1:1. Before use, the primary gallium liquid obtained in the previous process is used to prepare a dispersed suspension with a mass concentration of 50%.

[0049] like Figure 1 As shown, the method for separating gallium arsenic from a gallium arsenic solution of this embodiment comprises the following steps:

[0050] Take 500mL of gallium arsenic solution, add sodium hydroxide to adjust the pH value to >14. Then add the above-prepared dispersed suspension as an arsenic precipitant to the gallium arsenic solution, stir and react for 30 minutes at a temperature of 50°C and a mass ratio of arsenic precipitant to arsenic of 3:1, control the stirring speed to 200r / min, then age, control the aging temperature to 60°C, the aging time to 60min, the aging stirring speed to 50r / min, and filter and separate after aging to obtain arsenic residue and primary gallium liquid. In this step, the arsenic removal rate is 92.49%, and the gallium loss rate is 2.60%.

[0051] Sodium sulfate and sodium carbonate are added to the primary gallium liquid for stirring reaction, the mass ratio of the total amount of sodium sulfate and sodium carbonate to the excess arsenic precipitant is controlled to be 1.5:1, the stirring reaction time is controlled to be 10 minutes, the stirring speed is controlled to be 200r / min, and the stirring reaction is followed by aging treatment, the aging temperature is controlled to be 20°C, the aging time is controlled to be 10 minutes, the aging stirring speed is controlled to be 50r / min, and the sulfate precipitate and the secondary gallium liquid are obtained by filtration and separation after aging. In this step, the removal rate of impurity ions can reach 97.33%, and the concentration of gallium ions does not change significantly.

[0052] Sulfuric acid is added to the purified secondary gallium liquid to adjust the pH to 4, the precipitate is filtered and washed with water to remove impurities, and then dried. After drying, it is calcined in a muffle furnace at 700° C. for 2 hours to obtain gallium oxide with a purity higher than 99.9%.

[0053] like Figure 2 As shown, the arsenic precipitation temperature when the arsenic precipitation agent is added in Example 1 is changed, and the arsenic removal rates at 30°C, 50°C and 90°C are 90.23%, 92.49% and 92.86% respectively, and the gallium removal rates are 2.46%, 2.60% and 2.79% respectively. The separation effect is as shown in FIG. Figure 2 As shown by Figure 2 It can be seen that at 30°C, the sedimentation rate of the precipitate is slow; but as the temperature increases, the sedimentation rate accelerates, which is conducive to clarification and filtration; at 50°C, the arsenic removal effect is already good, and further increasing the temperature has little effect on the removal rate.

[0054] Embodiment 2:

[0055] An arsenic precipitator for gallium-arsenic separation is prepared from barium oxide, calcium oxide, magnesium oxide and cerium oxide in a mass ratio of 6:1:1:1. Before use, the primary gallium liquid obtained in the previous process is used to prepare a dispersed suspension with a mass concentration of 50%.

[0056] like Figure 1As shown, the method for separating gallium arsenic from a gallium arsenic solution of this embodiment comprises the following steps:

[0057] Take 500mL of gallium arsenic solution, add sodium hydroxide to adjust the pH value to >14. Then add the above-prepared dispersed suspension as an arsenic precipitant to the gallium arsenic solution, stir and react for 40 minutes at a temperature of 50°C and a mass ratio of arsenic precipitant to arsenic of 5:1, control the stirring speed to 250r / min, and then age, control the aging temperature to 70°C, the aging time to 60min, the aging stirring speed to 50r / min, and filter and separate after aging to obtain arsenic residue and primary gallium liquid. In this step, the arsenic removal rate is 99.29%, and the gallium loss rate is 11.24%.

[0058] Sodium sulfate and sodium carbonate are added to the primary gallium liquid for stirring reaction, the mass ratio of the total amount of sodium sulfate and sodium carbonate to the excess arsenic precipitant is controlled to be 2:1, the stirring reaction time is controlled to be 30 minutes, the stirring speed is controlled to be 200r / min, and the stirring reaction is followed by aging treatment, the aging temperature is controlled to be 20°C, the aging time is controlled to be 30 minutes, the aging stirring speed is controlled to be 50r / min, and the sulfate precipitate and the secondary gallium liquid are obtained by filtration and separation after aging. In this step, the removal rate of impurity ions can reach 99.01%, and the concentration of gallium ions does not change significantly.

[0059] Sulfuric acid is added to the purified secondary gallium liquid to adjust the pH to 4, the precipitate is filtered and washed with water to remove impurities, and then dried. After drying, it is calcined in a muffle furnace at 700° C. for 2 hours to obtain gallium oxide with a purity higher than 99.9%.

[0060] Embodiment 3:

[0061] An arsenic precipitator for gallium-arsenic separation is prepared only from barium oxide. Before use, the primary gallium liquid obtained in the previous process is used to prepare a dispersed suspension with a mass concentration of 50%.

[0062] The method for separating gallium arsenic from a gallium arsenic solution of this embodiment comprises the following steps:

[0063] Take 500mL of gallium arsenic solution, add sodium hydroxide to adjust the pH value to >14. Then add the above-prepared dispersed suspension as an arsenic precipitant to the gallium arsenic solution, stir and react for 40 minutes at a temperature of 50°C and a mass ratio of arsenic precipitant to arsenic of 5:1, control the stirring speed to 250r / min, and then age, control the aging temperature to 70°C, the aging time to 60min, the aging stirring speed to 50r / min, and filter and separate after aging to obtain arsenic residue and primary gallium liquid. In this step, the arsenic removal rate is 93.60%, and the gallium loss rate is 8.51%.

[0064] Sodium sulfate and sodium carbonate are added to the primary gallium liquid for stirring reaction, the mass ratio of the total amount of sodium sulfate and sodium carbonate to the excess arsenic precipitant is controlled to be 2:1, the stirring reaction time is controlled to be 30 minutes, the stirring speed is controlled to be 200r / min, and the stirring reaction is followed by aging treatment, the aging temperature is controlled to be 20°C, the aging time is controlled to be 30 minutes, and the aging stirring speed is controlled to be 50r / min. After aging, the sulfate precipitate and the secondary gallium liquid are separated by filtration. In this step, the removal rate of impurity ions can reach 99.13%, and the concentration of gallium ions does not change significantly.

[0065] Sulfuric acid is added to the purified secondary gallium liquid to adjust the pH to 4, the precipitate is filtered and washed with water to remove impurities, and then dried. After drying, it is calcined in a muffle furnace at 700° C. for 2 hours to obtain gallium oxide with a purity higher than 99.9%.

[0066] Embodiment 4:

[0067] An arsenic precipitator for gallium-arsenic separation is prepared from barium oxide, calcium oxide and magnesium oxide in a mass ratio of 8:0.5:0.5. Before use, the primary gallium liquid obtained in the previous process is used to prepare a dispersed suspension with a mass concentration of 30%.

[0068] The method for separating gallium arsenic from a gallium arsenic solution of this embodiment comprises the following steps:

[0069] Take 500mL of gallium arsenic solution, add sodium hydroxide to adjust the pH value to >14. Then add the above-prepared dispersed suspension as an arsenic precipitant to the gallium arsenic solution, stir and react for 40 minutes at a temperature of 90°C and a mass ratio of arsenic precipitant to arsenic of 4:1, control the stirring speed to 250r / min, then age, control the aging temperature to 70°C, the aging time to 60min, the aging stirring speed to 50r / min, and filter and separate after aging to obtain arsenic residue and primary gallium liquid. In this step, the arsenic removal rate is 96.34%, and the gallium loss rate is 8.59%.

[0070] Sodium sulfate and sodium carbonate are added to the primary gallium liquid for stirring reaction, the mass ratio of the total amount of sodium sulfate and sodium carbonate to the excess arsenic precipitant is controlled to be 2:1, the stirring reaction time is controlled to be 30 minutes, the stirring speed is controlled to be 200r / min, and the stirring reaction is followed by aging treatment, the aging temperature is controlled to be 20°C, the aging time is controlled to be 30 minutes, and the aging stirring speed is controlled to be 50r / min. After aging, the sulfate precipitate and the secondary gallium liquid are separated by filtration. In this step, the removal rate of impurity ions can reach 98.59%, and the concentration of gallium ions does not change significantly.

[0071] Sulfuric acid is added to the purified secondary gallium liquid to adjust the pH to 4, the precipitate is filtered and washed with water to remove impurities, and then dried. After drying, it is calcined in a muffle furnace at 700° C. for 2 hours to obtain gallium oxide with a purity higher than 99.9%.

[0072] Comparative Example 1:

[0073] An arsenic precipitator for gallium-arsenic separation is prepared from barium oxide, calcium oxide, magnesium oxide and cerium oxide in a mass ratio of 6:1:1:1. Before use, the primary gallium liquid obtained in the previous process is used to prepare a dispersed suspension with a mass concentration of 50%.

[0074] The method for separating gallium arsenic from the gallium arsenic solution of this comparative example comprises the following steps:

[0075] Take 500mL of gallium arsenic solution, add sodium hydroxide to adjust the pH value to >14. Then add the above-prepared dispersed suspension as an arsenic precipitant to the gallium arsenic solution, stir and react for 40 minutes at a temperature of 50°C and a mass ratio of arsenic precipitant to arsenic of 1:1, control the stirring speed to 250r / min, and then age, control the aging temperature to 70°C, the aging time to 60min, the aging stirring speed to 50r / min, and filter and separate after aging to obtain arsenic residue and primary gallium liquid. In this step, the arsenic removal rate is 16.67%, and the gallium loss rate is 5.92%.

[0076] Comparative Example 2:

[0077] An arsenic precipitator for gallium-arsenic separation is prepared only from calcium oxide. Before use, the primary gallium liquid obtained in the previous process is used to prepare a dispersed suspension with a mass concentration of 50%.

[0078] The method for separating gallium arsenic from a gallium arsenic solution of this embodiment comprises the following steps:

[0079] Take 500mL of gallium arsenic solution, add sodium hydroxide to adjust the pH value to >14. Then add the above-prepared dispersed suspension as an arsenic precipitant to the gallium arsenic solution, stir and react for 40 minutes at a temperature of 50°C and a mass ratio of arsenic precipitant to arsenic of 5:1, control the stirring speed to 250r / min, and then age, control the aging temperature to 70°C, the aging time to 60min, and the aging stirring speed to 50r / min. After aging, filter and separate to obtain arsenic residue and primary gallium liquid. In this step, the arsenic removal rate is 58.42%, and the gallium loss rate is 1.11%.

[0080] Comparative Example 3:

[0081] An arsenic precipitation agent for gallium-arsenic separation is prepared by directly mixing barium oxide, calcium oxide, magnesium oxide and cerium oxide in a mass ratio of 6:1:1:1.

[0082] The method for separating gallium arsenic from the gallium arsenic solution of this comparative example comprises the following steps:

[0083] Take 500mL of gallium arsenic solution, add sodium hydroxide to adjust the pH value to >14. Then add the prepared solid arsenic precipitant directly to the gallium arsenic solution, stir and react for 40 minutes at a temperature of 50°C and a mass ratio of arsenic precipitant to arsenic of 5:1, control the stirring speed to 250r / min, then age, control the aging temperature to 70°C, the aging time to 60min, the aging stirring speed to 50r / min, and filter and separate after aging to obtain arsenic residue and primary gallium liquid. In this step, the arsenic removal rate is 82.49%, and the gallium loss rate is 5.64%.

Claims

1. A method for separating gallium arsenic from a gallium arsenic solution, characterized in that: The following steps are involved: (1) adding alkali to a gallium arsenic solution to adjust the pH value to >14, then adding an arsenic precipitator, and after the arsenic precipitation reaction, filtering and separating to obtain an arsenic residue and a primary gallium solution; the arsenic precipitator is a dispersed suspension having a mass concentration of 30-50% obtained by dispersing barium oxide in a dispersed solution, or the arsenic precipitator is a dispersed suspension having a mass concentration of 30-50% obtained by dispersing barium oxide and at least one of calcium oxide, magnesium oxide and cerium oxide in a dispersed solution, and the mass ratio of barium oxide, calcium oxide, magnesium oxide and cerium oxide is (3-8): (0-1): (0-1): (0-1); the dispersed solution is a hot alkaline solution having a pH value >14, and the mass ratio of the arsenic precipitator to the arsenic in the gallium arsenic solution is (3-5): 1; (2) Adding sulfate ions and / or carbonate ions to the primary gallium liquid obtained in step (1) to carry out impurity removal reaction, filtering and separating, collecting the filtrate, and obtaining a secondary gallium liquid.

2. The method for separating gallium arsenic from a gallium arsenic solution according to claim 1, characterized in that: When the arsenic precipitation reaction is carried out under stirring conditions, the reaction temperature is controlled to be 30-90°C, the reaction time is 30-60min, and the stirring speed is 200-300r / min.

3. The method for separating gallium arsenic from a gallium arsenic solution according to claim 1, characterized in that: After the arsenic precipitation reaction, stirring and aging treatment is carried out and then filtering and separation is carried out. During the stirring and aging treatment, the aging temperature is controlled to be 60-80°C, the aging time is 60-90min, and the stirring speed is 50-100r / min.

4. The method for separating gallium arsenic from a gallium arsenic solution according to any one of claims 1 to 3, characterized in that: Sodium sulfate and sodium carbonate are added to the primary gallium solution for reaction, and the mass ratio of the total amount of sodium sulfate and sodium carbonate to the excess arsenic precipitant is (1.5-2.5):

1.

5. The method for separating gallium arsenic from a gallium arsenic solution according to any one of claims 1 to 3, characterized in that: The impurity removal reaction is carried out under stirring conditions, the reaction time is controlled to be 10-30min, and the stirring speed is 200-300r / min.

6. The method for separating gallium arsenic from a gallium arsenic solution according to any one of claims 1 to 3, characterized in that: After the impurity removal reaction, the mixture is subjected to stirring and aging treatment and then filtered for separation. During the stirring and aging treatment, the aging temperature is controlled to be 20-40°C, the aging time is 10-30min, and the stirring speed is 50-100r / min.

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