Preparation method of gallium trichloride

Abstract

The invention provides a gallium trichloride preparation method, which comprises: S1, mixing gallium-containing waste with carbon, and carrying out preheating treatment to obtain an intermediate; s2, the intermediate is subjected to vacuum melting treatment under the condition that the vacuum degree ranges from 1000 Pa to 3000 Pa, and gallium is obtained; and S3, performing chlorination treatment on the gallium obtained in the step S2 to obtain gallium trichloride. The preparation method of gallium trichloride provided by the invention has the advantages that the steps are simpler and more convenient, the process flow is short, the impurity removal effect is good, gallium trichloride with the purity of 7N-8N can be obtained, and large-scale production or industrial production can be realized.

Description

Technical Field

[0001] The invention belongs to the technical field of inorganic synthesis, and specifically relates to a method for preparing gallium trichloride, and in particular to a method for preparing gallium trichloride in a short process. Background Art

[0002] Gallium trichloride is an ideal precursor for the production of gallium-derived compounds and can be widely used as a catalyst in the synthesis of organic gallium compounds and semiconductor raw materials. In addition, due to its special properties, trivalent gallium and its derivatives are also widely used in the field of biomedicine.

[0003] At present, the preparation methods of gallium trichloride mainly include: gallium compound method, gallium oxide double decomposition method and gallium replacement method. Among them, the gallium compound method prepares gallium trichloride by burning gallium and chlorine, including gallium one-step chlorination method and gallium two-step chlorination method; the gallium oxide double decomposition method uses gallium oxide and chlorine-containing compounds to undergo double decomposition reaction to prepare gallium trichloride; the gallium replacement method uses metallic gallium and hydrogen chloride to prepare gallium trichloride. It can be seen that the current preparation methods of gallium trichloride all require metallic gallium as the starting material, and the purity of metallic gallium will directly affect the purity of gallium trichloride. Therefore, the existing process generally requires the extraction of crude gallium, which is further processed into high-purity gallium, and then high-purity gallium is used as a raw material to prepare gallium trichloride, and the process is relatively complicated.

[0004] In summary, it is urgent to find a method for preparing gallium trichloride with a short production process and high purity. Summary of the invention

[0005] In view of this, the object of the present invention is to provide a method for preparing gallium trichloride, wherein the production process of the preparation method is short and the purity of the product is high.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] The present invention provides a method for preparing gallium trichloride, which comprises the following steps;

[0008] S1: Gallium-containing waste is mixed with carbon and then preheated to obtain an intermediate;

[0009] S2: subjecting the intermediate to vacuum melting treatment at a vacuum degree of 1000-3000 Pa to obtain gallium;

[0010] S3: Chlorination treatment is performed on the gallium obtained in step S2 to obtain gallium trichloride;

[0011] Wherein, the vacuum melting process includes a first vacuum melting process and a second vacuum melting process in sequence;

[0012] The temperature of the first vacuum melting treatment is 500-800 oC, time is 2~4 hours;

[0013] The temperature of the second vacuum melting treatment is 1200~1400 o C, time is 0.2~1 h.

[0014] Preferably, the composition of the gallium-containing waste includes: 60~70 wt% iron oxide, 2~8 wt% PbO, 5~10wt% CaO, 5~10 wt% MnO, 2~5 wt% MgO, and a combination of any one or more of Na2O, Al2O3, TiO2, V2O5, Cr2O3, SiO2, CuO, NiO, chlorides or sulfides with a total amount less than 10 wt%.

[0015] Preferably, the gallium content in the gallium-containing waste is 100-400 g / t.

[0016] Preferably, the carbon is selected from coke and / or graphite.

[0017] Preferably, the carbon content accounts for 0.5-5 wt% of the total mass of the gallium-containing waste and carbon.

[0018] Preferably, the preheating treatment is performed at a temperature of 200-400° C. and for a time of 1-2 h.

[0019] Preferably, the purity of gallium obtained in step S2 is 6N~8N.

[0020] Preferably, the chlorine source used in the chlorination treatment is any one or more of chlorine gas, hydrogen chloride or ammonium chloride.

[0021] Preferably, the chlorination treatment is carried out in an inert atmosphere.

[0022] Preferably, a cooling step is further included after the chlorination treatment.

[0023] Preferably, the gallium trichloride obtained in step S3 has a purity of 7N~8N.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention provides a short process for producing gallium trichloride by vacuum smelting of low gallium-containing waste. The method has simple steps. After mixing gallium-containing waste with carbon, preheating treatment, vacuum melting treatment and chlorination treatment are sequentially performed, and the production process is short. Among them, the preheating treatment can remove chlorides and sulfides in the raw materials to reduce corrosion to subsequent equipment; in the vacuum melting treatment, in the first vacuum melting process at a low temperature, low-melting-point substances are reduced and volatilized with the flue, thereby achieving the purpose of removal; then in the second vacuum melting process at a high temperature, all gallium is volatilized, and the gallium at this time is in gaseous form, and the gallium purity can be as high as 6N~8N, so that after chlorination treatment, gallium trichloride with a purity of 7N~8N can be obtained.

[0026] It can be seen that the preparation method of gallium trichloride provided by the present invention not only has simpler steps and a shorter process flow, but also has a good impurity removal effect, and can obtain gallium trichloride with a purity of 7N~8N, which is conducive to large-scale production or industrial production. DETAILED DESCRIPTION

[0027] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Based on the problem that the prior art uses high-purity gallium as a raw material to prepare gallium trichloride, the process is relatively complicated, the present invention provides a method for preparing gallium trichloride, which comprises the following steps;

[0029] S1: Gallium-containing waste is mixed with carbon and then preheated to obtain an intermediate;

[0030] S2: subjecting the intermediate to vacuum melting treatment at a vacuum degree of 1000-3000 Pa to obtain gallium;

[0031] S3: Chlorinate the gallium obtained in step S2 to obtain gallium trichloride.

[0032] In the present invention, the gallium-containing waste used as a raw material is preferably steelmaking refining dust, whose components include: 60~70wt% iron oxide, 2~8wt% PbO, 5~10wt% CaO, 5~10wt% MnO, 2~5wt% MgO, and a total amount of less than 10wt% of any one or more of Na2O, Al2O3, TiO2, V2O5, Cr2O3, SiO2, CuO, NiO, chloride or sulfide combination; preferably includes 65~70wt% iron oxide, 2~6wt% PbO, 5~8wt% CaO, 5~8wt% MnO, 2~4wt% MgO, and a total amount of less than 8wt% of any one or more of Na2O, Al2O3, TiO2, V2O5, Cr2O3, SiO2, CuO, NiO, chloride or sulfide combination. In the present invention, the gallium content of the gallium-containing waste is a trace amount, specifically 100-400 g / t, preferably 200-400 g / t, and more preferably 300-400 g / t.

[0033] In the present invention, the gallium-containing waste is preferably first mixed with carbon. Wherein, the carbon is used as a reducing agent. After being added, the iron oxide can be reduced to iron in the subsequent high-temperature vacuum smelting process, and the oxidized gallium can be reduced to elemental gallium, so as to dissociate the gallium element dissolved in the iron oxide, and facilitate the subsequent separation of gallium and iron to improve the purity of gallium. In some embodiments of the present invention, the carbon can be selected from coke and / or graphite, and the carbon content accounts for 0.5~5 wt% of the total mass of gallium-containing waste and carbon, preferably 0.8~3 wt%, and more preferably 1~2 wt%. It should be noted that the carbon content is controlled here because insufficient carbon content will result in a lower degree of reduction, but too much carbon will result in a waste of resources. In summary, the carbon content needs to be controlled within the above range, and the carbon content accounts for 0.5wt%~5wt% of the total material mass.

[0034] According to the present invention, after the gallium-containing waste is mixed with carbon to obtain the carbon-containing gallium-containing waste material, it is preferably preheated, and the purpose of the preheating is to remove chlorides and sulfides in the gallium-containing waste to reduce their corrosion to subsequent vacuum melting equipment. In some embodiments of the present invention, the temperature of the preheating is 200-400°C, preferably 250-300°C; the time is 1-2 h, preferably 1.2-1.5 h. The preheating can be carried out in a rotary kiln or a muffle furnace.

[0035] Then, according to the present invention, the intermediate obtained after the preheating treatment is subjected to vacuum melting treatment. In the present invention, the presence of carbon in the intermediate during the vacuum melting treatment can play a reducing role, which will not be described in detail here.

[0036] In some embodiments of the present invention, the vacuum melting treatment includes a first vacuum melting treatment and a second vacuum melting treatment in sequence; the temperature of the first vacuum melting treatment is relatively low, specifically 500-800 o C, preferably 600~700℃; the residence time is 2~4 h, preferably 2.5~3 h. Among them, the residence time depends on the temperature of the first vacuum melting treatment. Generally, the higher the temperature, the shorter the residence time. Conversely, the lower the temperature, the longer the residence time. During the above-mentioned first vacuum melting treatment, low-melting point oxides such as lead and zinc are converted into single substances and evaporated with the flue, sodium evaporates with the flue in the form of oxides, and other substances still exist in the form of oxides or raw materials. It should be noted that the present invention can reduce the low-melting point substances by controlling the residence time, and evaporate them more thoroughly with the flue to achieve the purpose of removal.

[0037] Then, a second vacuum melting process is performed. The temperature of the second vacuum melting process is relatively high, specifically 1200-1400 o C, preferably 1250~1300℃; residence time is 0.2~1 h, preferably 0.5~0.8 h. During the above-mentioned second vacuum smelting treatment, oxides such as iron are reduced to simple iron and remain in the molten pool, and silicon, magnesium, vanadium, etc. form slag floating above the molten iron. At this time, gallium is reduced to simple gallium and evaporates with the flue. It should be noted that by controlling the residence time, all gallium can be volatilized. At this time, gallium is in gaseous form and the purity of gallium can reach 6N~8N.

[0038] Subsequently, the present invention performs chlorination treatment on the obtained gallium to obtain gallium trichloride. In some embodiments of the present invention, the chlorination treatment is: passing high-purity gaseous gallium into a normal pressure furnace, at which time, the high-purity gaseous gallium is directly chlorinated, and the temperature of the normal pressure furnace is controlled at 200-300 o C, preferably 220~250 o C; using one or more of the preheated dry chlorine, hydrogen chloride or other chlorine-containing gases (such as ammonium chloride) mixed with an inert gas, such as high-purity dry argon, to chlorinate the liquid high-purity gallium. The process time is 0.5~1 h, preferably 0.6~0.9 h. The oxygen content in the furnace during this process should be less than 5 ppm, preferably less than 3 ppm.

[0039] Finally, the gallium trichloride vapor obtained after chlorination will be discharged from the flue along with the excess chlorine, hydrogen chloride or other chlorine-containing gases, and as the flue cools naturally, the gallium chloride changes from gas to liquid, and then from liquid to solid, and is then separated from the gas. The gas can be recycled for chlorination treatment.

[0040] In the present invention, the transformation of the gallium trichloride form is also conducive to a more thorough separation of gallium trichloride from incompletely chlorinated gallium metal. When the gas is exhausted, the white or colorless solid in the flue is collected in a dry environment. The solid is a gallium trichloride solid with a purity of 7N to 8N.

[0041] In summary, the preparation method of gallium trichloride provided by the present invention not only has simpler steps, a shorter process flow, and a good impurity removal effect, but also can obtain gallium trichloride with a purity of 7N~8N, which is conducive to large-scale production or industrial production.

[0042] In order to further illustrate the present invention, the following examples are used to explain it in detail. The gallium-containing steelmaking refining dust used in the following examples of the present invention is provided by a steelmaking plant.

[0043] Example 1

[0044] The raw material of the gallium trichloride preparation method involved in the present invention is gallium-containing steelmaking refining dust, the main components of which are 70wt% iron oxide, 8wt% PbO, 5wt% CaO, 5wt% MnO, 2wt% MgO, and the rest are 1wt% Na2O, 0.06wt% Al2O3, 0.7wt% TiO2, 0.3wt% V2O5, 1.5wt% Cr2O3, 2.5wt% SiO2, 0.5wt% CuO, 0.8wt% NiO, 1.7wt% chloride, and the balance is sulfide. The gallium content in the raw material is 400g / t.

[0045] The specific preparation method is as follows:

[0046] (1) Gallium-containing steelmaking refining dust is mixed with coke, with the coke accounting for 5wt% of the total material mass;

[0047] (2) The gallium-containing steelmaking refining dust after carbon addition is preheated in a rotary kiln at a preheating temperature of 200 o C, the preheating time is 2 h. The purpose of preheating is to remove chlorides and sulfides in the raw materials to reduce corrosion to the subsequent vacuum furnace. The preheating equipment is a rotary kiln;

[0048] (3) The material after the second step of preheating treatment is reduced in a vacuum induction melting furnace, and the vacuum degree is controlled at 3000 Pa. This process is divided into two steps:

[0049] 3.1 The temperature of the vacuum induction melting furnace is controlled at 800 o C, stay for 2 h until the low melting point substances are reduced and evaporated through the flue;

[0050] 3.2 As the temperature continues to rise, the temperature of the vacuum induction melting furnace is 1400o C, stay for 0.2 h until all the gallium is volatilized. At this time, the gallium is in gaseous form and the purity of gallium can reach 8N;

[0051] (4) 8 N high-purity gaseous gallium is introduced into the atmospheric pressure furnace. At this time, the high-purity gallium is transformed from gaseous to liquid metal gallium. The temperature of the atmospheric pressure furnace is controlled at 200 o C, using preheated dry chlorine mixed with high-purity dry argon (10 vol% chlorine, 90 vol% argon) to chlorinate liquid high-purity gallium. The process time is 0.5 h, and the oxygen content in the furnace is 2 ppm during this process;

[0052] (5) The metallic gallium chlorinated in step (4) is gallium trichloride. Gallium chloride vapor is discharged from the flue along with the excess chlorine-containing gas. As the flue cools naturally, gallium trichloride changes from gas to liquid, and then from liquid to solid, and is then separated from the chlorine-containing gas. The chlorine-containing gas can be recycled to step (4) for use. When the chlorine-containing gas is exhausted, the white or colorless solid in the flue is collected in a dry environment. The solid is 8N gallium trichloride solid.

[0053] Example 2

[0054] The raw material of the gallium trichloride preparation method of the present invention is gallium-containing steelmaking refining dust, the main components of which are 60wt% iron oxide, 8wt% PbO, 10wt% CaO, 10wt% MnO, 5wt% MgO, and the rest are 0.6wt% Na2O, 1.1wt% Al2O3, 0.09wt% TiO2, 0.3wt% V2O5, 0.9wt% Cr2O3, 1.3wt% SiO2, 1.2wt% CuO, 0.5wt% NiO, and the remainder is chloride. The gallium content in the raw material is 100g / t. The specific preparation method is as follows:

[0055] (1) Gallium-containing steelmaking refining dust is mixed with graphite, and the carbon content accounts for 0.5 wt% of the total material mass;

[0056] (2) The gallium-containing steelmaking refining dust after carbon addition is preheated in a large muffle furnace at a preheating temperature of 400 o C, preheating time is 1 h;

[0057] (3) The material after the second step of preheating treatment is reduced in a vacuum arc melting furnace, and the vacuum degree is controlled at 1000 Pa. This process is divided into two steps:

[0058] 3.1 The temperature is controlled at 500 o C, stay for 4 hours until the low melting point substances are reduced and evaporated through the flue;

[0059] 3.2 As the temperature continues to rise, the vacuum arc melting furnace temperature is 1200 o C, stay for 1 h until all the gallium is volatilized. At this time, the gallium is in gaseous form and the purity of gallium can reach 6 N.

[0060] (4) High-purity 6N gaseous gallium is introduced into the atmospheric pressure furnace. At this time, the high-purity gallium is transformed from gaseous to liquid metal gallium. The temperature of the atmospheric pressure furnace is controlled at 280 o C, using preheated dry hydrogen chloride mixed with high-purity dry argon (30 vol% chlorine, 70 vol% argon) to chlorinate liquid high-purity gallium. The process time is 1 hour, and the oxygen content in the furnace is 1 ppm.

[0061] (5) The metallic gallium chlorinated in step (4) is gallium trichloride. Gallium trichloride vapor is discharged from the flue along with the excess chlorine-containing gas. As the flue cools naturally, the gallium chloride changes from gas to liquid, and then from liquid to solid, and is then separated from the chlorine-containing gas. After the chlorine-containing gas is separated from the byproduct hydrogen, it can be dried and recycled to step (4) for use. When the chlorine-containing gas is exhausted, the white or colorless solid in the flue is collected in a dry environment. The solid is 7N gallium chloride solid.

[0062] Comparative Example 1

[0063] The raw material of the gallium chloride preparation method of the present invention is gallium-containing steelmaking refining dust, the main components of which are 70wt% iron oxide, 8wt% PbO, 5wt% CaO, 5wt% MnO, 2wt% MgO, and the rest are 1wt% Na2O, 0.06wt% Al2O3, 0.7wt% TiO2, 0.3wt% V2O5, 1.5wt% Cr2O3, 2.5wt% SiO2, 0.5wt% CuO, 0.8wt% NiO, 1.7wt% chloride, and the remainder is sulfide. The gallium content in the raw material is 400 g / t.

[0064] The specific preparation method is as follows:

[0065] (1) Gallium-containing steelmaking refining dust is mixed with coke, with the coke accounting for 5 wt% of the total material mass;

[0066] (2) Preheat the gallium-containing steelmaking refining dust after adding carbon, the preheating temperature is 200 o C, preheating time is 2h;

[0067] (3) The second step pretreatment material is reduced using a vacuum induction melting furnace with the vacuum degree controlled at 4000 Pa. The process is divided into two steps:

[0068] 3.1 The temperature of the vacuum induction melting furnace is controlled at 800o C, stay for 2 h until the low melting point substances are reduced and evaporated through the flue;

[0069] 3.2 As the temperature continues to rise, the temperature of the vacuum induction melting furnace is 1400 o C, and stay for 0.2 h.

[0070] Since the vacuum degree in step (3) does not meet the requirement, gallium is not completely vaporized at this time, accompanied by the presence of partial gallium oxide. The purity of the gallium element is 98%, resulting in the inability to generate high-purity gallium trichloride.

[0071] Comparative Example 2

[0072] The raw material of the gallium chloride preparation method involved in the present invention is gallium-containing steelmaking and refining dust removal ash, the main components of which are 60wt% iron oxide, 8wt% PbO, 10wt% CaO, 10wt% MnO, 5wt% MgO, and the rest are 0.6wt% Na2O, 1.1wt% Al2O3, 0.09wt% TiO2, 0.3wt% V2O5, 0.9wt% Cr2O3, 1.3wt% SiO2, 1.2wt% CuO, 0.5wt% NiO, and the balance is chloride. The gallium content in the raw material is 100g / t.

[0073] The specific preparation method is as follows:

[0074] (1) Gallium-containing steelmaking refining dust is mixed with graphite, and the carbon content accounts for 0.5 wt% of the total material mass;

[0075] (2) Preheat the gallium-containing steelmaking refining dust after adding carbon, the preheating temperature is 400 o C, preheating time is 1h;

[0076] (3) The second step pretreatment material is reduced using a vacuum arc melting furnace with the vacuum degree controlled at 1000 Pa. The process is divided into two steps:

[0077] 3.1 The temperature of the vacuum arc melting furnace is controlled at 500 o C, stay for 1 hour until the low melting point substances are reduced and evaporated through the flue;

[0078] 3.2 As the temperature continues to rise, the temperature of the vacuum arc melting furnace is 1200 o C, and stay for 1 h until all the gallium is volatilized.

[0079] Since the residence time in step 3.1 is too short, some low-melting-point substances are not completely volatilized, and the purity of gallium at this time is only 3N, which fails to reach the purity required for producing gallium trichloride.

[0080] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing gallium trichloride, characterized in that: The following steps are included; S1: Gallium-containing waste is mixed with carbon and then preheated to obtain an intermediate; S2: subjecting the intermediate to vacuum melting treatment at a vacuum degree of 1000-3000 Pa to obtain gallium; S3: Chlorination treatment is performed on the gallium obtained in step S2 to obtain gallium trichloride; Wherein, the vacuum melting process includes a first vacuum melting process and a second vacuum melting process in sequence; The temperature of the first vacuum melting treatment is 500-800 o C, time is 2~4 hours; The temperature of the second vacuum melting treatment is 1200~1400 o C, time is 0.2~1 h.

2. The preparation method according to claim 1, characterized in that: The components of the gallium-containing waste include: 60~70wt% iron oxide, 2~8wt% PbO, 5~10wt% CaO, 5~10wt% MnO, 2~5wt% MgO, and a combination of any one or more of Na2O, Al2O3, TiO2, V2O5, Cr2O3, SiO2, CuO, NiO, chlorides or sulfides with a total amount less than 10wt%.

3. The preparation method according to claim 1 or 2, characterized in that: The gallium content in the gallium-containing waste is 100-400 g / t.

4. The preparation method according to any one of claims 1 to 3, characterized in that The carbon is selected from coke and / or graphite; The carbon content accounts for 0.5-5 wt% of the total mass of the gallium-containing waste and the carbon.

5. The preparation method according to any one of claims 1 to 4, characterized in that The preheating treatment is carried out at a temperature of 200-400°C and for a time of 1-2 h.

6. The preparation method according to any one of claims 1 to 5, characterized in that The purity of gallium obtained in step S2 is 6N~8N.

7. The preparation method according to any one of claims 1 to 6, characterized in that The chlorine source used in the chlorination treatment is any one or more of chlorine gas, hydrogen chloride or ammonium chloride.

8. The preparation method according to any one of claims 1 to 7, characterized in that The chlorination treatment is carried out in an inert atmosphere.

9. The preparation method according to any one of claims 1 to 8, characterized in that The method further comprises a cooling step after the chlorination treatment.

10. The preparation method according to any one of claims 1 to 9, characterized in that The purity of gallium trichloride obtained in step S3 is 7N~8N.