A method for producing high-purity magnesium from industrial magnesium ingots

Abstract

The present invention discloses a method for producing high-purity magnesium from industrial magnesium ingots. The industrial magnesium ingots are fully melted in a melting pot filled with a protective gas, and the molten magnesium in the melting pot is sucked into a primary vacuum distillation furnace through a pipeline by using a pressure difference. Distillation is carried out in the primary vacuum distillation furnace, and magnesium and zinc volatilize into the gas phase and are condensed on the condensation plate of the vacuum furnace to obtain zinc-containing molten magnesium, which is collected by the confluence plate and then enters the secondary distillation furnace. High-boiling impurities and unvolatilized molten metal magnesium flow out of the vacuum furnace through the evaporation plate for post-treatment. Distillation is carried out on the zinc-containing molten magnesium in the secondary vacuum distillation furnace, and zinc and part of magnesium volatilize into the gas phase and are condensed on the condensation plate of the vacuum furnace to obtain high-zinc molten magnesium, and the unvolatilized magnesium is high-purity magnesium with a purity reaching 99.99%. The present invention can realize the low-cost continuous industrial production of high-purity magnesium.

Description

Technical Field

[0001] The present invention belongs to the field of metal material preparation, and particularly relates to a method for producing high-purity magnesium from industrial magnesium ingots. Background Art

[0002] Magnesium is one of the lightest metal materials in engineering applications and the preparation of industrial metal alloy materials, with a density of only 1.75 - 1.9 g / cm 3 , compared with other metals, magnesium shows great superiority. Magnesium and its alloys have low density, high specific strength, good damping performance, the function of shielding electromagnetic waves, good casting performance, easy to process, and are conducive to recycling. This makes magnesium and its alloys have unprecedented application value and broad development prospects in the fields of automobiles, electronics, electrical appliances, transportation, biology, aerospace, and national defense, and enjoy the reputation of "green engineering materials in the 21st century".

[0003] On the premise of having these advantages, high-purity magnesium also has characteristics such as low kinetic viscosity, low phase change latent heat, and good biocompatibility, and has become the main metal material for applications such as semiconductors, the electronics industry, biomaterials, coating targets, and national defense weapons. At present, the domestic market can only produce magnesium ingots of 3N5, and there is basically no large-scale production of 4N (high-purity magnesium with a magnesium content of 99.99%) or even 5N high-purity magnesium.

[0004] Existing high-purity magnesium preparation technologies include the flux method, zone melting method, and distillation method, mainly aiming to reduce impurities in magnesium to achieve high purity. Patent CN109055779A adds a series of refining agents prepared by mixing chlorides and other substances for impurity removal, and finally obtains high-purity magnesium, but ignores the generation of a large amount of chlorine gas during operation, causing secondary pollution; the semi-continuous vacuum distillation method of Patent CN207405221U has equipment divided into a crude distillation tower and a rectification tower, which is relatively complete, but has high energy consumption, and the whole set of equipment uses nickel-chromium alloy, with high cost; Patent CN109609777A is a device for purifying high-purity magnesium. Although the equipment is simple, the operation is simple, and the cost is low, due to vacuum distillation under high vacuum conditions, continuous production cannot be achieved, and the production efficiency is low.

[0005] At present, the biggest problem with these mainstream methods for preparing high-purity magnesium industrially is that they are prone to cause secondary pollution, and continuous operation and large-scale production cannot be achieved, and the purity has been unable to be improved; while the traditional vacuum distillation method operates under high vacuum, which directly changes magnesium from a solid state to a gaseous state, resulting in poor crystallization effect and inability to obtain a dense high-purity magnesium ingot; at the same time, since there is no liquid phase formation of magnesium, continuous production operation cannot be achieved, and the production efficiency of enterprises will be greatly reduced. Summary of the Invention

[0006] The present invention provides a method for producing high-purity magnesium from industrial magnesium ingots. First, the contents of various elements in the industrial magnesium ingots are detected, and based on the contents, it is determined whether to perform a single distillation or a double distillation. For the double distillation, the industrial magnesium ingots need to be completely melted into liquid magnesium in a melting pot (filled with a protective gas), and the liquid magnesium is sucked into a primary vacuum distillation furnace through a pipeline using the pressure difference. The vacuum degree in the primary vacuum furnace is controlled at 3.03×10 4 -9.11×10 4 Pa (a protective gas is introduced to stabilize the pressure). After distillation, a small part of the magnesium liquid containing high-boiling-point impurities flows out along the bottom pipeline of the furnace and is sent for post-treatment; while most of the magnesium liquid containing zinc flows into a secondary vacuum distillation furnace along the condensation cover or condensation plate. The vacuum degree in the secondary vacuum furnace is controlled at 3.03×10 4 -9.11×10 4 Pa (a protective gas is introduced to stabilize the pressure). After low-temperature distillation, the 4N high-purity magnesium liquid flows out along the bottom pipeline for ingot casting treatment; while the magnesium liquid containing zinc obtained on the condensation cover or condensation plate can be used to prepare magnesium-zinc alloy after flowing out. The entire inventive process can achieve low-cost continuous industrial production of high-purity magnesium (4N), and the obtained 4N magnesium ingots can be widely used in the preparation of top-notch alloys and biomaterials; for a single distillation, only the above single distillation operation needs to be performed.

[0007] The technical solution of the present invention:

[0008] A method for producing high-purity magnesium from industrial magnesium ingots, the specific steps including:

[0009] (1) Detecting the contents of various elements in the industrial magnesium ingots;

[0010] (2) When the zinc content in the industrial magnesium ingots meets the requirements of Mg9999 in GB / T3499-2011 (not greater than 0.003%), the industrial magnesium ingots are fully melted under a protective atmosphere, and the molten magnesium liquid is sucked into a primary vacuum distillation furnace through a pipeline using the pressure difference; adjusting the vacuum degree in the primary vacuum distillation furnace to 3.03×10 4 -9.11×10 4 Pa, the temperature is 650-1000 °C, and magnesium liquid containing high-boiling-point impurities is obtained at the bottom of the vacuum furnace and flows out through the pipeline for post-treatment; after most of the magnesium volatilizes, 4N magnesium liquid is obtained in the condensation plate and flows out along the condensation wall and is ingot-cast into 4N high-purity magnesium ingots;

[0011] (3) When the zinc content in the industrial magnesium ingots does not meet the requirements of Mg9999 in GB / T3499-2011 (greater than 0.003%), the industrial magnesium ingots are fully melted under a protective atmosphere, and the molten magnesium liquid is sucked into a primary vacuum distillation furnace through a pipeline using the pressure difference; adjusting the vacuum degree in the primary vacuum distillation furnace to 3.03×10 4 -9.11×104 pa, the temperature is 650 - 1000 °C, magnesium and zinc volatilize into the gas phase and are condensed on the condensation plate of the vacuum furnace to obtain a zinc-magnesium-containing liquid. After being collected by the manifold, it enters the secondary distillation furnace; high-boiling impurities and unvolatilized molten magnesium liquid flow out of the vacuum furnace through the evaporation plate for post-treatment; the vacuum degree in the secondary vacuum distillation furnace is 3.03×10 4 -9.11×10 4 pa, the distillation temperature is 650 - 800 °C, zinc and part of magnesium volatilize into the gas phase and are condensed on the condensation plate of the vacuum furnace to obtain a high-zinc-magnesium liquid. After flowing out along the pipeline, a magnesium-zinc alloy is obtained. The unvolatilized magnesium liquid is high-purity magnesium with a purity reaching 99.99%, and 4N magnesium is obtained after flowing out.

[0012] In step (1), the industrial magnesium ingot is the crude magnesium produced by the Pidgeon process or the electrolytic method, and the magnesium ingots conforming to the national standard with grades of Mg9998, Mg9995A, Mg9995B, Mg9990 or Mg9980.

[0013] The protective gas in step (1) includes but is not limited to argon or nitrogen.

[0014] The melting temperature in step (2) and step (3) is 650 - 750 °C.

[0015] The vacuum degree in step (2) and step (3) is controlled by the protective gas. The protective gas includes but is not limited to argon or nitrogen to ensure the stability of the pressure in the vacuum furnace.

[0016] In the high-boiling-impurity-containing magnesium liquid obtained in the primary vacuum distillation furnace, there are high-boiling impurities such as iron, copper, lead, tin, and silicon. This part of the magnesium liquid flows out along the bottom pipe orifice and can be subjected to subsequent treatment; another part of the zinc-magnesium-containing liquid flows out along the condensation cover or condensation plate and then undergoes secondary distillation.

[0017] In the secondary vacuum distillation furnace, zinc evaporates with part of the magnesium liquid and liquefies on the condensation cover and flows out along the cover wall and the condensation plate; most of the magnesium liquid remaining at the bottom of the furnace flows out along the pipeline and is cast into 4N high-purity magnesium ingots.

[0018] Compared with the prior art, the main features of the present invention are as follows:

[0019] 1. The present invention mainly adopts the distillation conditions of passing a protective gas under low vacuum, which can make magnesium appear in the liquid phase, enable the magnesium liquid to continuously enter the vacuum furnace, realize the enrichment of high-boiling impurities in the magnesium liquid during the distillation process, and not crystallize (will not cause pipeline blockage); low-boiling and high-saturated-vapor-pressure impurities such as zinc evaporate with most of the magnesium, and the obtained zinc-magnesium-containing liquid can obtain 99.99% high-purity magnesium through the second low-temperature and low-pressure distillation.

[0020] 2. The distillation process of the present invention can achieve the process of liquid phase - gas phase - liquid phase of magnesium, which can not only carry out continuous production, but also obtain dense metallic magnesium ingots, greatly reducing the production cost and improving the production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is the process flow diagram of Embodiment 1 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] The present invention will be further described below in conjunction with specific embodiments.

[0023] Embodiment 1

[0024] A method for producing high - purity magnesium from industrial magnesium ingots can reduce most impurities in magnesium, and can also reduce zinc, which is difficult to separate, to the national 4N high - purity magnesium standard without causing pollution. As Figure 1 shown, the specific implementation steps are as follows:

[0025] First step, the raw material 1 - industrial magnesium ingot of grade Mg9995B is detected by ICP - MS to obtain the impurity content in the raw material. Then the magnesium ingot is put into a melting pot with argon protection for heating and melting. The melting temperature is 750 °C, and the molten magnesium in the melting pot is sucked into a primary vacuum distillation furnace through a pipeline by using the pressure difference.

[0026] Second step, the primary vacuum distillation furnace is evacuated and filled with argon to ensure the pressure is within 3.03×10 4 -9.11×10 4 pa. Then the sucked molten magnesium is heated to 850 °C for low - vacuum distillation. Magnesium and zinc volatilize into the gas phase and are condensed on the condensation plate of the vacuum furnace to obtain zinc - containing molten magnesium, which is collected by the confluence plate and then enters the secondary distillation furnace; the molten magnesium containing high - boiling - point impurities is obtained at the bottom of the vacuum furnace and can flow out through the pipeline of the evaporation plate for post - treatment.

[0027] Third step, a large amount of zinc - containing molten magnesium flowing in is subjected to low - temperature and low - vacuum distillation in the secondary vacuum distillation furnace. Argon is filled to make the pressure 3.03×10 4 -9.11×10 4 pa, and the temperature is raised to 800 °C. Zinc and part of magnesium volatilize into the gas phase and are condensed on the condensation plate of the vacuum furnace to obtain high - zinc molten magnesium, which flows out along the pipeline to obtain a magnesium - zinc alloy. The un - volatilized molten magnesium is high - purity magnesium with a purity reaching 99.99%, and 4N magnesium is obtained after flowing out.

[0028] The content of high - purity magnesium elements in this embodiment is shown in Table 1 below. It can be seen from the table that the high - purity magnesium prepared in this embodiment meets the requirements of Mg9999 in GB / T3499 - 2011.

[0029] Table 1

[0030] Element Fe (%) Si (%) Ni (%) Cu (%) Al(％) Mn (%) Ti (%) Pb (%) Sn (%) Zn (%) Raw material 1 0.00518 0.00864 0.0017 0.0044 0.004 0.00584 0.00011 0.0018 0.00064 0.012 4N national standard 0.002 0.002 0.0003 0.0003 0.002 0.002 0.0005 0.01 0.002 0.003 Example 1 0.00057 0.00012 0.0003 0.00024 0.0013 0.00091 0.000028 0.00052 0.00045 0.0016

[0031] Example 2

[0032] A method for producing high-purity magnesium from industrial magnesium ingots, which can reduce most impurities in magnesium. For the difficult-to-separate zinc, it can also be reduced to the national 4N high-purity magnesium standard without causing pollution. The specific implementation steps are as follows:

[0033] First step, the raw material 2 - the industrial magnesium ingot with the grade of Mg9990 is detected by ICP-MS to obtain the impurity content in the raw material. Then, the magnesium ingot is put into a melting pot with nitrogen protection for heating and melting. The melting temperature is 720 °C, and the molten magnesium in the melting pot is sucked into a primary vacuum distillation furnace through a pipeline by using the pressure difference;

[0034] Second step, the primary vacuum distillation furnace is evacuated and filled with argon to ensure the pressure is within 3.03×10 4 -9.11×10 4 Then, the sucked molten magnesium is heated to 1000 °C for low-vacuum distillation. Magnesium and zinc volatilize into the gas phase and are condensed on the condensation plate of the vacuum furnace to obtain zinc-containing molten magnesium, which is collected by the confluence plate and then enters the secondary distillation furnace; The molten magnesium containing high-boiling-point impurities is obtained at the bottom of the vacuum furnace and can flow out through the pipeline of the evaporation plate for post-treatment;

[0035] Third step, a large amount of zinc-containing molten magnesium flowing in is subjected to low-temperature and low-vacuum distillation in the secondary vacuum distillation furnace. Argon is filled to make the pressure 3.03×10 4 -9.11×10 4 Pa, and the temperature is raised to 700 °C. Zinc and part of magnesium volatilize into the gas phase and are condensed on the condensation plate of the vacuum furnace to obtain high-zinc molten magnesium, which flows out along the pipeline to obtain a magnesium-zinc alloy. The un-volatilized molten magnesium is high-purity magnesium with a purity reaching 99.99%, and 4N magnesium is obtained after flowing out.

[0036] The contents of each element of the high-purity magnesium obtained in this example are shown in Table 2 below. It can be seen from the table that the high-purity magnesium prepared in this example meets the requirements of Mg9999 in GB / T3499-2011.

[0037] Table 2

[0038] Element Fe (%) Si (%) Ni (%) Cu (%) Al(％) Mn (%) Ti (%) Pb (%) Sn (%) Zn (%) Raw material 2 0.0253 0.0147 0.0015 0.0054 0.0112 0.023 0.00014 0.0016 0.008 0.01 4N national standard 0.002 0.002 0.0003 0.0003 0.002 0.002 0.0005 0.001 0.002 0.003 Example 2 0.0012 0.0014 0.00015 0.0002 0.00091 0.00087 0.00002 0.00043 0.00025 0.0021

[0039] Example 3

[0040] A method for producing high-purity magnesium from industrial magnesium ingots, which can reduce most impurities in magnesium. For the difficult-to-separate zinc, it can also be reduced to the national 4N high-purity magnesium standard without causing pollution. The specific implementation steps are as follows:

[0041] First step: Detect the impurity content in raw material 3 - industrial magnesium ingot (grade Mg9980) by ICP-MS. Then, place the magnesium ingot in a melting pot with argon protection and heat it to melt. The melting temperature is 650°C. Use the pressure difference to suck the molten magnesium in the melting pot into a primary vacuum distillation furnace through a pipeline.

[0042] Second step: Evacuate the primary vacuum distillation furnace and introduce argon to ensure the pressure is within 1.01×10 4 ~4×10 4 Pa. Then, heat the sucked molten magnesium to 650°C for low-vacuum distillation. Magnesium and zinc volatilize into the gas phase and condense on the condensation plate of the vacuum furnace to obtain zinc-containing molten magnesium. After being collected by the confluence plate, it enters the secondary distillation furnace. The molten magnesium containing high-boiling-point impurities is obtained at the bottom of the vacuum furnace and can flow out through the pipeline of the evaporation pan for post-treatment.

[0043] Third step: Perform low-temperature and low-vacuum distillation on the large amount of zinc-containing molten magnesium flowing in the secondary vacuum distillation furnace. Fill argon to make the pressure 3.03×10 4 -9.11×10 4 Pa, heat it to 650°C. Zinc and part of the magnesium volatilize into the gas phase and condense on the condensation plate of the vacuum furnace to obtain high-zinc molten magnesium. After flowing out through the pipeline, magnesium-zinc alloy is obtained. The un-volatilized molten magnesium is high-purity magnesium with a purity reaching 99.99%, and 4N magnesium is obtained after flowing out.

[0044] The contents of each element of the high-purity magnesium obtained in this example are shown in Table 3 below. It can be seen from the table that the high-purity magnesium prepared in this example meets the requirements of Mg9999 in GB / T3499-2011.

[0045] Table 3

[0046] Element Fe (%) Si (%) Ni (%) Cu (%) Al(％) Mn (%) Ti (%) Pb (%) Sn (%) Zn (%) Raw material 3 0.047 0.048 0.0017 0.018 0.026 0.045 0.000032 0.005 0.0026 0.008 4N national standard 0.002 0.002 0.0003 0.0003 0.002 0.002 0.0005 0.001 0.002 0.003 Example 3 0.0011 0.0007 0.00025 0.00023 0.0013 0.0016 0.000014 0.00051 0.00053 0.0024

[0047] Example 4

[0048] A method for producing high-purity magnesium from industrial magnesium ingots, which can reduce most impurities in magnesium, and can also reduce zinc, which is difficult to separate, to the national 4N high-purity magnesium standard without causing pollution. The specific implementation steps are as follows:

[0049] First step: Detect the impurity content in raw material 4 - crude magnesium produced by the Pidgeon process by ICP-MS. Then, place the magnesium ingot in a melting pot with argon protection and heat it to melt. The melting temperature is 750°C. Use the pressure difference to suck the molten magnesium in the melting pot into a primary vacuum distillation furnace through a pipeline.

[0050] Second step: Evacuate the primary vacuum distillation furnace and introduce argon to ensure the pressure is within 3.03×10 4 -9.11×10 4Inside the PA, then heat up the inhaled magnesium liquid to 850 °C for low-vacuum distillation. Magnesium and zinc volatilize into the gas phase and condense on the condensation plate of the vacuum furnace to obtain zinc-containing magnesium liquid. After being collected by the confluence plate, it enters the secondary distillation furnace; the magnesium liquid containing high-boiling-point impurities is obtained at the bottom of the vacuum furnace and can flow out through the pipeline of the evaporation plate for post-treatment;

[0051] The third step is to carry out low-temperature and low-vacuum distillation on the large amount of zinc-containing magnesium liquid flowing in the secondary vacuum distillation furnace, fill it with argon to make the pressure 3.03×10 4 -9.11×10 4 Pa, heat up to 800 °C, zinc and part of magnesium volatilize into the gas phase and condense on the condensation plate of the vacuum furnace to obtain high-zinc magnesium liquid. After flowing out along the pipeline, magnesium-zinc alloy is obtained, and the unvolatilized magnesium liquid is high-purity magnesium with a purity reaching 99.99%. After flowing out, 4N magnesium is obtained.

[0052] The content of high-purity magnesium elements in this embodiment is shown in Table 4 below. It can be seen from the table that the high-purity magnesium prepared in this embodiment meets the requirements of Mg9999 in GB / T3499-2011.

[0053] Table 4

[0054] Element Fe (%) Si (%) Ni (%) Cu (%) Al(％) Mn (%) Ti (%) Pb (%) Sn (%) Zn (%) Raw material 4 0.066 0.76 0.0017 0.00064 0.014 0.079 0.00002 0.0011 0.0026 0.0035 4N national standard 0.002 0.002 0.0003 0.0003 0.002 0.002 0.0005 0.001 0.002 0.003 Example 4 0.0015 0.00065 0.00023 0.00026 0.0011 0.0015 0.000014 0.00064 0.00034 0.0027

[0055] Example 5

[0056] A method for producing high-purity magnesium from industrial magnesium ingots, which can reduce most impurities in magnesium, and can also reduce the difficult-to-separate zinc to the national 4N high-purity magnesium standard without causing pollution. The specific implementation steps are as follows:

[0057] The first step is to detect the impurity content in the raw material of the crude magnesium produced by the 5-electrolysis method through ICP-MS. Then, put the magnesium ingot into a melting pot with argon protection and heat it to melt. The melting temperature is 730 °C, and use the pressure difference to suck the magnesium liquid in the melting pot into the primary vacuum distillation furnace through the pipeline;

[0058] The second step is to evacuate the primary vacuum distillation furnace and introduce argon to ensure that the pressure is 3.03×10 4 -9.11×10 4 Pa inside, then heat up the inhaled magnesium liquid to 800 °C for low-vacuum distillation. Magnesium and zinc volatilize into the gas phase and condense on the condensation plate of the vacuum furnace to obtain zinc-containing magnesium liquid. After being collected by the confluence plate, it enters the secondary distillation furnace; the magnesium liquid containing high-boiling-point impurities is obtained at the bottom of the vacuum furnace and can flow out through the pipeline of the evaporation plate for post-treatment;

[0059] The third step is to carry out low-temperature and low-vacuum distillation on the large amount of zinc-containing magnesium liquid flowing in the secondary vacuum distillation furnace, fill it with argon to make the pressure 3.03×10 4 -9.11×104 pa, heat it up to 700 °C. Zinc and part of magnesium volatilize into the gas phase and condense on the condensation plate of the vacuum furnace to obtain high-zinc magnesium liquid. After flowing out along the pipeline, magnesium-zinc alloy is obtained. The un-volatilized magnesium liquid is high-purity magnesium with a purity reaching 99.99%, and 4N magnesium is obtained after flowing out.

[0060] The content of high-purity magnesium elements in this example is shown in Table 5 below. It can be seen from the table that the high-purity magnesium prepared in this example meets the requirements of Mg9999 in GB / T3499-2011.

[0061] Table 5

[0062]

[0063]

[0064] Example 6

[0065] A method for producing high-purity magnesium from industrial magnesium ingots, which can reduce most impurities in magnesium and cause no pollution. The specific implementation steps are as follows:

[0066] In the first step, the raw material 6 - industrial magnesium ingot with the grade of Mg9980 is detected by ICP-MS to obtain the impurity content in the raw material. Since the zinc content has reached the requirements of Mg9999 in GB / T3499-2011, only one distillation is required. Put the magnesium ingot into a melting pot with nitrogen protection and heat it to melt. The melting temperature is 700 °C, and use the pressure difference to suck the magnesium liquid in the melting pot into the primary vacuum distillation furnace through the pipeline.

[0067] In the second step, evacuate the vacuum distillation furnace and introduce nitrogen to ensure the pressure is within 3.03×10 4 -9.11×10 4 pa, then heat up the sucked magnesium liquid to 750 °C for low-vacuum distillation. Obtain magnesium liquid containing high-boiling-point impurities at the bottom of the vacuum furnace, which can flow out through the pipeline for post-treatment; after most of the magnesium volatilizes, 4N magnesium liquid is obtained in the condensation plate, and after flowing out along the condensation wall, it is cast into 4N high-purity magnesium ingots.

[0068] The content of each element of the high-purity magnesium obtained in this example is shown in Table 6 below. It can be seen from the table that the high-purity magnesium prepared in this example meets the requirements of Mg9999 in GB / T3499-2011.

[0069] Table 6

[0070] Element Fe (%) Si (%) Ni (%) Cu (%) Al(％) Mn (%) Ti (%) Pb (%) Sn (%) Zn (%) Raw material 6 0.045 0.044 0.0013 0.023 0.022 0.043 0.00003 0.0045 0.0029 0.0019 4N national standard 0.002 0.002 0.0003 0.0003 0.002 0.002 0.0005 0.001 0.002 0.003 Example 6 0.0014 0.0005 0.00024 0.00021 0.0012 0.0013 0.000024 0.00041 0.00063 0.0013

[0071] Example 7

[0072] A method for producing high-purity magnesium from industrial magnesium ingots, which can reduce most impurities in magnesium and cause no pollution. The specific implementation steps are as follows:

[0073] First step, the raw material 7 - industrial magnesium ingot of grade Mg9995B is detected by ICP-MS to obtain the impurity content in the raw material. Since the zinc content has reached the requirements of Mg9999 in GB / T3499-2011, only one distillation is needed. The magnesium ingot is put into a melting pot with argon protection and heated to melt at a melting temperature of 650°C. The molten magnesium in the melting pot is sucked into a primary vacuum distillation furnace through a pipeline by using the pressure difference.

[0074] Second step, the vacuum distillation furnace is evacuated and argon is introduced to ensure the pressure is within 3.03×10 4 -9.11×10 4 Pa. Then the sucked molten magnesium is heated to 650°C for low-vacuum distillation. Molten magnesium containing high-boiling-point impurities is obtained at the bottom of the vacuum furnace and can be discharged through a pipeline for post-treatment. After most of the magnesium volatilizes, 4N molten magnesium is obtained in the condensation pan and flows out along the condensation wall and is cast into 4N high-purity magnesium ingots.

[0075] The content of each element of the high-purity magnesium obtained in this example is shown in Table 7 below. It can be seen from the table that the high-purity magnesium prepared in this example meets the requirements of Mg9999 in GB / T3499-2011.

[0076] Table 7

[0077] Element Fe (%) Si (%) Ni (%) Cu (%) Al(％) Mn (%) Ti (%) Pb (%) Sn (%) Zn (%) Raw material 7 0.0088 0.00854 0.0027 0.0034 0.003 0.00524 0.00021 0.0075 0.0006 0.002 4N national standard 0.002 0.002 0.0003 0.0003 0.002 0.002 0.0005 0.01 0.002 0.003 Example 7 0.00037 0.00022 0.00027 0.00024 0.0015 0.0009 0.00002 0.0005 0.0004 0.0017

[0078] Example 8

[0079] A method for producing high-purity magnesium from industrial magnesium ingots, which can reduce most impurities in magnesium and cause no pollution. The specific implementation steps are as follows:

[0080] First step, the raw material 8 - industrial magnesium ingot of grade Mg9990 is detected by ICP-MS to obtain the impurity content in the raw material. It is found that the zinc content has reached the requirements of Mg9999 in GB / T3499-2011. Therefore, only one distillation is needed. The magnesium ingot is put into a melting pot with argon protection and heated to melt at a melting temperature of 750°C. The molten magnesium in the melting pot is sucked into a primary vacuum distillation furnace through a pipeline by using the pressure difference.

[0081] Second step, the vacuum distillation furnace is evacuated and argon is introduced to ensure the pressure is within 3.03×10 4 -9.11×10 4Inside the PA, then heat up the inhaled magnesium liquid to 1000 °C for low-vacuum distillation. The magnesium liquid containing high-boiling impurities is obtained at the bottom of the vacuum furnace and can flow out through a pipeline for post-treatment; after most of the magnesium volatilizes, 4N magnesium liquid is obtained in the condensation pan and flows out along the condensation wall and then is ingoted into 4N high-purity magnesium ingots.

[0082] The element contents of the high-purity magnesium obtained in this embodiment are shown in Table 8 below. It can be seen from the table that the high-purity magnesium prepared in this embodiment meets the requirements of Mg9999 in GB / T3499-2011.

[0083] Table 8

[0084] Element Fe (%) Si (%) Ni (%) Cu (%) Al(％) Mn (%) Ti (%) Pb (%) Sn (%) Zn (%) Raw material 8 0.0263 0.0247 0.0025 0.0034 0.0212 0.013 0.00024 0.0026 0.006 0.0023 4N national standard 0.002 0.002 0.0003 0.0003 0.002 0.002 0.0005 0.001 0.002 0.003 Example 8 0.0012 0.00043 0.00019 0.00018 0.001 0.0012 0.000021 0.00039 0.00072 0.0019

Claims

1. A method for producing high-purity magnesium from industrial magnesium ingots, characterized in that, the specific steps include: (1) Detect the content of each element in the industrial magnesium ingot; (2)When the zinc content in industrial magnesium ingots meets the requirements of Mg9999 in GB / T 3499-2011, the industrial magnesium ingots are fully melted under a protective atmosphere, and the molten magnesium liquid is sucked into a primary vacuum distillation furnace through a pipeline by using the pressure difference; adjust the vacuum degree in the primary vacuum distillation furnace to 3.03×10 4 -9.11×10 4 pa, the temperature is 650-1000 °C, the magnesium liquid containing high-boiling-point impurities is obtained at the bottom of the vacuum furnace, and it flows out through the pipeline for post-treatment; after magnesium volatilizes, 4N magnesium liquid is obtained in the condensation pan, and it flows out along the condensation wall and is cast into 4N high-purity magnesium ingots; (3) When the zinc content in industrial magnesium ingots does not meet the requirements of Mg9999 in GB / T3499-2011, the industrial magnesium ingots are fully melted under a protective atmosphere, and the molten magnesium liquid is sucked into a primary vacuum distillation furnace through a pipeline by using the pressure difference; adjust the vacuum degree in the primary vacuum distillation furnace to 3.03×10 4 -9.11×10 4 pa. Most of the magnesium and zinc volatilize into the gas phase and are condensed on the condensation plate of the vacuum furnace to obtain zinc-containing magnesium liquid, which is collected by the confluence plate and then enters the secondary distillation furnace; high-boiling impurities and un-volatilized molten metal magnesium liquid flow out of the vacuum furnace through the evaporation plate and are sent for post-treatment; When A large amount of zinc-containing magnesium liquid flowing in is subjected to low-temperature and low-vacuum distillation in the secondary vacuum distillation furnace. The vacuum degree in the secondary vacuum distillation furnace is 3.03×10 4 -9.11×10 4 pa. Zinc and part of the magnesium volatilize into the gas phase and are condensed on the condensation plate of the vacuum furnace to obtain high-zinc magnesium liquid, which flows out along the pipeline to obtain a magnesium-zinc alloy. The un-volatilized magnesium liquid is high-purity magnesium with a purity reaching 99.99%, and 4N magnesium is obtained after flowing out; When the temperature of the primary vacuum distillation furnace in step (3) is 850 °C, the temperature of the secondary vacuum distillation furnace is 800 °C; When the temperature of the primary vacuum distillation furnace in step (3) is 1000 °C, the temperature of the secondary vacuum distillation furnace is 700 °C; When the temperature of the primary vacuum distillation furnace in step (3) is 850 °C, the temperature of the secondary vacuum distillation furnace is 800 °C; When the temperature of the primary vacuum distillation furnace in step (3) is 800 °C, the temperature of the secondary vacuum distillation furnace is 700 °C.

2. The method for producing high-purity magnesium from industrial magnesium ingots according to claim 1, characterized in that, in step (1), the industrial magnesium ingot is crude magnesium produced by the Pidgeon process or the electrolysis process, and magnesium ingots conforming to the national standard grades of Mg9998, Mg9995A, Mg9995B, Mg9990 or Mg9980.

3. The method for producing high-purity magnesium from industrial magnesium ingots according to claim 1, characterized in that, in step (1), the protective atmosphere is an argon atmosphere or a nitrogen atmosphere.

4. The method for producing high-purity magnesium from industrial magnesium ingots according to claim 1, characterized in that, in steps (2) and (3), the melting temperature is 650 - 750 °C.

5. The method for producing high-purity magnesium from industrial magnesium ingots according to claim 1, characterized in that, in steps (2) and (3), the vacuum degree is controlled by the protective gas, and the protective gas is argon or nitrogen.

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