Method and device for purifying gas-phase magnesium based on nickel-based filter material
阅读说明：本技术 一种基于镍基滤材的气相镁纯化的方法与装置 (Method and device for purifying gas-phase magnesium based on nickel-based filter material ) 是由 单智伟 杨博 刘博宇 王安 毛路遥 李姣 刘飞 畅治民 于 2019-11-27 设计创作，主要内容包括：本发明提供一种基于镍基滤材的气相镁纯化的方法,所述方法采用镍基滤材对镁蒸气进行过滤,在一定的温度、真空度下,镍材一方面不与镁蒸气反应,不会给体系带来新的杂质；另一方面,镍材与镁蒸气中的杂质Al、Mn具有特殊的亲和性,能够形成稳定的固溶体；同时镍材还能够作为镁蒸气中某些杂质形核的位点,降低形核能垒,使某些杂质提前沉积,实现脱除。本发明提供的方法能够应用于工业化大批量的气相镁纯化中,成数量级的提高生产效率的同时使镁中Mn含量下降至10ppm以下,Al含量下降至10ppm以下,Si含量20ppm以下,同时可去除F、Cl、S等非金属杂质元素,提高产品纯度,得到的镁的纯度在99.99％以上。(The invention provides a gas-phase magnesium purification method based on a nickel-based filter material, which is characterized in that the nickel-based filter material is adopted to filter magnesium vapor, and under a certain temperature and vacuum degree, a nickel material does not react with the magnesium vapor and does not bring new impurities to a system; on the other hand, the nickel material has special affinity with impurities Al and Mn in the magnesium vapor, and can form stable solid solution; meanwhile, the nickel material can also be used as a nucleation site for some impurities in magnesium vapor, so that the nucleation energy barrier is reduced, some impurities are deposited in advance, and the removal is realized. The method provided by the invention can be applied to industrial large-batch gas-phase magnesium purification, the production efficiency is improved in a magnitude order, the Mn content in magnesium is reduced to be below 10ppm, the Al content is reduced to be below 10ppm, the Si content is reduced to be below 20ppm, non-metal impurity elements such as F, Cl and S can be removed, the product purity is improved, and the purity of the obtained magnesium is over 99.99%.)
1. A gas-phase magnesium purification method based on a nickel-based filter material is characterized by comprising the following steps:
(1) placing a magnesium raw material in a reaction zone in a sealed crucible, and vacuumizing the interior of the crucible;
(2) heating the magnesium raw material by a heating mechanism until magnesium vapor is generated, and condensing the magnesium vapor on a crystallizer of which the crucible is far away from the reaction zone through a nickel-based filter material to obtain high-purity magnesium.
2. The method for purifying magnesium in a gas phase based on a nickel-based filter according to claim 1, wherein in the step (1), the degree of vacuum in the crucible is 30Pa or less.
3. The method for purifying the gas-phase magnesium based on the nickel-based filter material as claimed in claim 1, wherein the heating temperature in the step (2) is 586-1300 ℃.
4. The method for purifying the gas-phase magnesium based on the nickel-based filter material as claimed in claim 3, wherein the heating in the step (2) is performed in three stages, wherein the first stage heats a reaction zone of the crucible provided with the magnesium raw material at a temperature of 700-1300 ℃; the second section and the third section sequentially heat the impurity condensation zone provided with the nickel-based filter material in the crucible, the setting temperature of the second section is 700-plus-1300 ℃, and the setting temperature of the third section is 586-plus-800 ℃.
5. The method for purifying gas-phase magnesium based on nickel-based filter material as claimed in claim 4, wherein in the step (2), the nickel-based filter material is arranged in an impurity condensation zone in a crucible, and the working temperature of the nickel-based filter material is 586-950 ℃.
6. A gas-phase magnesium purification device containing nickel-based filter materials is characterized by comprising an electric furnace body, a crucible, a heating mechanism, a thermocouple and a vacuum mechanism;
the crucible comprises a reaction zone, an impurity condensation zone and a crystallization zone which are arranged in sequence,
the reaction zone is provided with a hopper,
the impurity condensing zone is provided with a filtering component,
the filtering component is provided with a filtering material which is nickel,
the crystallization zone is provided with a crystallizer;
the vacuum mechanism is arranged in the electric furnace body, and the crucible is arranged in the vacuum mechanism;
the thermocouple is arranged on the outer wall of the crucible;
the heating mechanism is arranged in the electric furnace body to heat the crucible.
7. The apparatus for purifying magnesium in a gaseous phase comprising a nickel-based filter according to claim 6, wherein the filter is one of nickel foam, nickel fiber or nickel microsphere, and the purity of the filter is 99.5% or more.
8. The apparatus for purifying magnesium in a gas phase comprising a nickel-based filter according to claim 7, wherein when the filter is nickel foam, the pore size of the nickel foam is below 40ppi, when the filter is nickel fiber, the pore size of the nickel fiber is 100-400 mesh, and when the filter is nickel microsphere, the particle size of the nickel microsphere is 45-5000 μm.
9. The apparatus for purification of magnesium in a gaseous phase comprising a nickel-based filter according to claim 6, wherein said heating means comprises a first heating element, a second heating element and a third heating element; the first heating assembly heats a reaction zone of the crucible; the second heating assembly and the third heating assembly heat an impurity condensing region of the crucible.
10. The apparatus for purifying magnesium in a gaseous phase comprising a nickel-based filter according to claim 6, wherein the vacuum mechanism comprises a vacuum chamber, a water-cooled flange, an end cap and a vacuum pumping assembly; the vacuum cabin body is arranged inside the electric furnace body; the water-cooling flanges are arranged at two ends of the vacuum cabin body; the end cover is arranged at the end part of the water-cooling flange far away from the vacuum cabin body; the vacuumizing assembly can vacuumize the interior of the vacuum cabin; the crucible is arranged inside the vacuum cabin.
Technical Field
The invention belongs to the technical field of magnesium metal purification, and particularly relates to a method and a device for purifying gas-phase magnesium based on a nickel-based filter material.
Background
The magnesium alloy has the advantages of low density, strong damping and shock absorption, excellent electromagnetic shielding performance, relatively low recovery cost and the like, so the magnesium alloy is regarded as a green and environment-friendly engineering structure material in the 21 st century and an important strategic material. Currently, the magnesium purification field has aeipathia diseases such as low overall purity (only 99.90%), many types of impurity elements (mainly containing Mn, Al, Ca, Si, Fe, Ni and the like), large content fluctuation and the like. These maladies severely degrade the performance of the magnesium alloy, which in turn makes its practical application far less than desired.
There are two common methods for purifying magnesium metal: flux refining and vacuum distillation. The former has the advantage of realizing the large-scale purification of the raw magnesium and is the main method for purifying the industrial crude magnesium at present. The main flux used in flux refining method is only partial halide of alkali metal and alkaline earth metal, and the flux used most commonly in factory is MgCl2、KCl、CaF2And the like. The impurity removal mechanism of the refining agent comprises two aspects: firstly, the refining agent is used for carrying out oxide inclusion (MgO and SiO)2Etc.) to separate oxide inclusions from the magnesium melt by standing precipitation; secondly, by reacting the active metal impurities, e.g. K, Na, with MgCl in the melt2To remove metal impurities more active than magnesium. However, since the flux which is most commonly used at present does not react with impurity elements such as Mn, Al, Fe and Ni of the reduced magnesium ingot, it is difficult to produce the magnesium ingot with a purity of more than 99.95%In particular to magnesium with the national standard of Mg9995A and above. In addition, non-metallic impurity elements such as F, Cl, and S are often introduced into the refining flux, and the performance of the raw magnesium is also affected when the content of the impurity elements exceeds a certain threshold.
The vacuum distillation method has a long history, and the principle is that Mg is evaporated at proper temperature and pressure by utilizing the characteristic that the saturated vapor pressure difference of Mg and most impurity elements is large, and main impurities are remained in a melt, so that the separation of magnesium and the impurities is realized. The vacuum distillation method has the advantage that the ultrahigh-purity magnesium with the purity of 99.9999 percent (not counting the Zn content) can be prepared. However, in order to obtain higher purity, the distillation method is generally carried out under vacuum condition at an evaporation temperature close to the melting point of Mg (650- &
In addition, the method for purifying magnesium in the prior art also adopts a vapor deposition method of removing impurities with the aid of a filter material, but the common filter material adopts stainless steel fibers or a method of combining the stainless steel fibers with copper fibers, and the stainless steel is not suitable for the working condition of overhigh vapor pressure of magnesium and the working condition of low-temperature sublimation of heating temperature, so that the magnesium purification efficiency is low and the yield of high-purity magnesium is extremely low.
Disclosure of Invention
In order to solve the technical problems, the invention provides a gas-phase magnesium purification method and a gas-phase magnesium purification device based on a nickel-based filter material.
The invention aims to provide a gas-phase magnesium purification method based on a nickel-based filter material.
Another object of the present invention is an apparatus for carrying out the above magnesium purification process.
The invention provides a gas-phase magnesium purification method based on a nickel-based filter material, which comprises the following steps:
(1) placing a magnesium raw material in a reaction zone in a sealed crucible, and vacuumizing the interior of the crucible;
(2) heating magnesium raw material by a heating mechanism until magnesium is gasified, and condensing magnesium vapor on a crystallizer of which the crucible is far away from the reaction zone through a nickel-based filter material to obtain high-purity magnesium.
The trace impurity elements have great influence on the performance of magnesium and magnesium alloy, especially the corrosion resistance. The corrosion tolerance of nickel (Ni) element in pure magnesium is less than 10ppm, namely the mass fraction of Ni element in pure magnesium exceeds 10ppm, the corrosion rate is increased by orders of magnitude, and magnesium can show good corrosion resistance only when the Ni content is less than 10 ppm. Because of this, in the production of pure magnesium, the conventional idea is to avoid the magnesium from contacting the high nickel content container medium as much as possible, so as not to cause contamination and deteriorate the corrosion resistance. Different from the traditional thinking that the metal magnesium smelting process avoids contacting nickel element as much as possible, the invention discovers that the vapor pressure of nickel is extremely low relative to magnesium according to thermodynamic calculation, so that when magnesium vapor passes through the nickel-based filter material under the condition that the temperature is up to the temperature for gasifying magnesium into magnesium vapor under the vacuum condition, the nickel-based filter material does not react with magnesium, and the nickel and the magnesium do not form more stable substances thermodynamically, so that almost no nickel vapor enters a magnesium vapor system, and impurities such as Mn, Al, Ca, F, Cl and the like contained in the magnesium vapor are lower than the chemical potential in the magnesium vapor on one hand, and tend to form an intermediate alloy so as to separate from a gas phase system, and on the other hand, the impurities can be condensed and enriched to separate from the gas phase system by virtue of attachment sites provided by the nickel-based filter material. Because the evaporation temperature in the system of the gas-phase magnesium purification method based on the nickel-based filter material is high, the magnesium raw material can be quickly changed into magnesium vapor, and the magnesium with the purity higher than 99.99 percent can be obtained through one-time gasification-filtration-condensation process, so that the magnesium purification efficiency is high, and the method is suitable for large-scale industrial production.
The nickel-based filter material adopted in the method provided by the invention can fully utilize the excellent high temperature resistance of the nickel-based filter material in the magnesium purification process on the premise of not introducing nickel pollution, and the filter material has long service life.
Preferably, in the step (1), the degree of vacuum in the crucible is 30Pa or less.
The vacuum degree in the crucible provided by the invention is below 30Pa, and the efficiency of purifying magnesium can be ensured to be improved.
Preferably, in the step (2), the temperature of the heating is 586-1300 ℃.
The melting range of the magnesium raw material containing trace impurities is 650-700 ℃, the temperature in the crucible is set to 586-1300 ℃ under the vacuum degree below 30Pa, the magnesium raw material containing impurities can be changed into magnesium vapor, nickel as a filter material can not enter a magnesium vapor system, after magnesium passes through the nickel-based filter material, the impurities in the magnesium vapor can be well combined with the nickel-based filter material, the impurities can obtain corresponding attachment points on the nickel-based filter material, the impurities are remained in the nickel-based filter material, the magnesium vapor further rises to a crystallization area, and the magnesium vapor is condensed on a crystallizer, so that high-purity magnesium is obtained.
Further preferably, in the step (2), the heating is performed in three sections, wherein the first section heats the reaction zone of the crucible provided with the magnesium raw material, and the temperature is 700-; the second section and the third section sequentially heat an impurity condensation zone provided with the nickel-based filter material in the crucible, wherein the temperature of the second section is 700-1300 ℃, and the temperature of the third section is 586-800 ℃.
In the method provided by the invention, the heating is carried out in three sections, wherein the first section is mainly used for heating a magnesium raw material to generate magnesium vapor, and the second section and the third section are used for keeping the magnesium vapor state and heating the nickel-based filter material, so that the nickel-based filter material ensures the optimal working temperature and is beneficial to removing impurities in the magnesium vapor. In order to ensure that the heating achieves the purpose of magnesium gasification, the heating temperature of the first section and the second section is set to be 700-1300 ℃, and the heating temperature of the third section is 586-950 ℃. While the higher the temperature at which the first and second stages are heated in the appropriate range, the faster the rate at which magnesium is vaporized, and the more efficient the gas phase purification of magnesium.
Further preferably, in the step (2), the heating is performed in three sections, wherein the first section heats the reaction zone of the crucible provided with the magnesium raw material, and the temperature is 1200-1300 ℃; the second section and the third section sequentially heat an impurity condensation zone provided with the nickel-based filter material in the crucible, wherein the temperature of the second section is 1200-1300 ℃, and the temperature of the third section is 586-950 ℃. According to the method adopted by the invention, on one hand, the raw material balls can be used as the magnesium source material, and on the other hand, the metal magnesium with the purity of less than 99.99 percent can be used as the magnesium source material. When the raw material ball is used as the magnesium source material, the magnesium source material needs to be subjected to chemical reaction, so that the temperature for heating the magnesium source material needs to be over 1200 ℃, the vacuum degree is below 10Pa, and the reduced material ball can react at the temperature and the vacuum degree to obtain magnesium vapor.
Preferably, in the step (2), the heating temperature is 586-1050 ℃. Further preferably, the first section heats the reaction area of the crucible provided with the magnesium raw material, and the temperature is 700-; the second section and the third section sequentially heat an impurity condensation zone provided with a nickel-based filter material in the crucible, wherein the temperature of the second section is 700-.
The magnesium source material provided by the invention can be metal magnesium with purity lower than 99.99 percent besides the reducing material ball, when the metal magnesium is used as the magnesium source material, because the melting point of the magnesium is 649.84 ℃ and the boiling point is 1094.54 ℃, the evaporation is generally carried out by adopting a conventional vacuum distillation method under the vacuum degree of 10Pa and 750 ℃, and the magnesium source material can be heated to 750 ℃ or more and 1050 ℃ or less, thereby greatly improving the evaporation rate of the magnesium and greatly improving the purification efficiency of the gas-phase magnesium.
Preferably, in the step (2), the nickel-based filter material is arranged between the second section and the crystallization zone, and the working temperature of the nickel-based filter material is 586-.
Further preferably, in the step (2), the working temperature of the nickel-based filter material is 700-950 ℃.
Due to the high impurity content in the magnesium raw material, Ca, F and Al impurities are distributed over the respective temperatures of the condensation zone and are usually accompanied, and Mn condensate occurs at 765-832 ℃ and lower. Most impurities in the magnesium can be effectively removed on the nickel-based filter material at 586 and 950 ℃.
The principle of removing certain impurity elements by using the specific affinity of nickel materials can be illustrated by simplified thermodynamic calculations. By assuming an initial mixed steam entry: 98.6mol of Mg, 0.1mol of Al, 0.1mol of Mn, 0.1mol of Ca0 and 0.1mol of Zn. Sufficient solid Ni (1mol) is arranged in the system as a filter material, and the equilibrium state composition is determined by utilizing the Gibbs free energy minimum principle at the temperature of 1000 ℃, 900 ℃, 800 ℃, 700 ℃ and the like. As shown in figure 1, at 1000 ℃, 900 ℃ and 800 ℃, nickel can form a more stable solid solution with Mn and Al impurities contained in magnesium vapor, and the condensed substances are all solid solutions with a structure of FCC-A1#1 (; #2) according to calculation; the structure is C36#1 (; #2) at 700 ℃, but some Mg is condensed. Wherein FCC-A1#1 (; #2), C36#1 (; #2) are all crystal structure types under the Strukturbericht nomenclature rules. This shows that the impurities Mn and Al in the magnesium vapor can be condensed in the temperature range of 586-950 ℃, but below 700 ℃, magnesium also has a part of condensation behavior, so in order to improve the magnesium yield, the optimal working temperature of the nickel-based filter material is 700-950 ℃. However, the nickel-based filter material provided by the invention can remove Mn and Al impurities by utilizing a more stable solid solution formed between the nickel-based filter material and Mn and Al in magnesium vapor no matter at 586-950 ℃ or 700-950 ℃, and residual impurities in the magnesium vapor can be effectively removed by the action of the nickel-based filter material in the temperature range, so that the purity of the obtained magnesium is ensured to be more than 99.99%.
Preferably, in the step (2), the purity of the nickel-based filter material is more than 99.5%. The higher the purity of the filter material is, the more beneficial the magnesium purification is, the high-purity nickel material can not bring new impurities to the system in the magnesium purification process, and the high-purity magnesium can be obtained. The purity of the nickel-based filter material provided by the invention is more than 99.5%, wherein the nickel-based filter material does not contain a substance which reacts with magnesium and also does not contain a substance which is unstable under working conditions.
The invention provides a gas-phase magnesium purification device containing a nickel-based filter material, which comprises an electric furnace body, a crucible, a heating mechanism, a thermocouple and a vacuum mechanism, wherein the crucible is arranged in the electric furnace body;
the crucible comprises a reaction zone, an impurity condensation zone and a crystallization zone which are arranged in sequence,
the reaction zone is provided with a hopper,
the impurity condensing zone is provided with a filtering component,
the filtering component is provided with a filtering material which is nickel,
the crystallization zone is provided with a crystallizer;
the vacuum mechanism is arranged in the electric furnace body, and the crucible is arranged in the vacuum mechanism;
the thermocouple is arranged on the outer wall of the crucible;
the heating mechanism is arranged in the electric furnace body to heat the crucible.
In order to realize the purpose of purifying magnesium by utilizing the method for purifying the gas-phase magnesium by utilizing the nickel-based filter material, the invention provides a device matched with the method for use, a filtering component is arranged in a crucible impurity condensation zone in the device, the nickel-based filter material is arranged in the filtering component, and in addition, a heating mechanism for realizing magnesium gas phase change, a thermocouple and a vacuum mechanism for keeping the vacuum degree of a system are also arranged.
The device provided by the invention has a simple structure, is suitable for large-scale industrial production, improves the efficiency of purifying magnesium, and has great economic benefit.
The filter assembly in the device provided by the invention can be detached, impurities attached to the filter material can be removed in acid washing and other modes, the purpose of repeatedly using the filter material for multiple times is achieved, and the production cost is reduced.
In the device for purifying magnesium in gas phase containing the nickel-based filter material, the filter material is preferably one of foam metal nickel, nickel fiber or nickel microspheres, and the purity of the filter material is more than 99.5%. It should be noted that the purity of the nickel-based filter material of the present invention does not consider the content of non-metallic elements.
In the device for purifying magnesium in gas phase containing the nickel-based filter material provided by the invention, preferably, when the filter material is nickel foam, the pore diameter of the nickel foam is below 40ppi, when the filter material is nickel fiber, the pore diameter of the nickel fiber is 100-400 meshes, and when the filter material is nickel microsphere, the particle diameter of the nickel microsphere is 45-5000 μm.
The nickel-based filter material in the device provided by the invention has special affinity with impurities in magnesium vapor, is used as a nucleation site of the impurities in the magnesium vapor to reduce a nucleation energy barrier and enable the impurities to be deposited in advance, and has the physical interception function of the filter material. No matter the nickel material is used as a nucleation site of impurities or physical interception, the nickel material can be realized only by needing a larger contact area with magnesium vapor, and the nickel material adopts a form of foam metal nickel, nickel fibers or nickel microspheres, so that the contact area of the filter material and the magnesium vapor can be effectively increased, and the filtering efficiency is improved.
According to the device for purifying the gas-phase magnesium containing the nickel-based filter material, preferably, the crystallization zone is provided with a plurality of crystallizers arranged in a step-by-step mode.
The device provided by the invention is provided with the plurality of crystallizers, the plurality of crystallizers are arranged step by step, most impurities in magnesium are retained in the nickel-based filter material in the impurity condensation zone in the magnesium purification process, but zinc cannot be removed through the nickel-based filter material, and the zinc can be removed through the action of the multi-stage crystallizers.
The device for purifying the gas-phase magnesium containing the nickel-based filter material, provided by the invention, preferably comprises a heating mechanism, a first heating mechanism, a second heating mechanism and a third heating mechanism, wherein the first heating mechanism is arranged on the first heating component; the first heating assembly heats a reaction zone of the crucible; the second heating assembly and the third heating assembly heat an impurity condensing region of the crucible. The purpose of multistage temperature control is to accurately control the temperature and prolong the length of the proper filter material working temperature. Therefore, the multi-stage temperature control is more accurate in temperature gradient, the physical space for properly removing impurities is longer, and the high-purity magnesium can be obtained more favorably.
The device for purifying the gas-phase magnesium containing the nickel-based filter material, provided by the invention, preferably comprises a vacuum cabin, a water-cooling flange, an end cover and a vacuumizing assembly, wherein the vacuum cabin is provided with a vacuum cavity; the vacuum cabin body is arranged inside the electric furnace body; the water-cooling flanges are arranged at two ends of the vacuum cabin body; the end cover is arranged at the end part of the water-cooled flange far away from the vacuum cabin body; the vacuumizing assembly can vacuumize the interior of the vacuum cabin; the crucible is arranged inside the vacuum cabin.
According to the invention, different sections of the crucible are heated through the first heating assembly, the second heating assembly and the third heating assembly, the temperature in the crucible is monitored through the thermocouple arranged on the outer wall of the crucible, and the temperature of the crucible is used as feedback to adjust. The water-cooled flanges at the two ends mainly reduce the temperature of the flange interface, protect the flange rubber ring from being burnt by overheating, and keep vacuum. In addition, the temperature of the crystallizer can also be indirectly adjusted by adjusting the flow rate of the cooling water.
According to the device for purifying the gas-phase magnesium containing the nickel-based filter material, provided by the invention, preferably, the crucible is formed by assembling a plurality of sections of high-purity graphite pipe fittings, and the two sections of pipe fittings are connected in an insertion manner. The thermocouples in the invention are arranged on different sections of the high-purity graphite pipe fitting and are used for monitoring the temperature of each section of the crucible.
The high-purity graphite pipe fitting is prepared by taking high-purity graphite as a raw material, wherein the high-purity graphite means that the carbon content of the graphite is higher than 99.99%.
The invention has the beneficial effects that:
1. the gas-phase magnesium purification method based on the nickel-based filter material provided by the invention adopts the nickel-based filter material to filter magnesium vapor at a specific temperature and vacuum degree. The use of the nickel-based filter material breaks through the prejudice that the nickel is avoided as much as possible in the traditional magnesium purification process, on one hand, the nickel material does not react with magnesium vapor, does not form a more stable substance with magnesium thermodynamically, and does not bring new impurities to the system; on the other hand, some impurities in the magnesium vapor have special affinity with nickel, and can form a more stable solid solution with the nickel material, so that the removal of some impurities is realized; meanwhile, the nickel material can be used as a nucleation site of impurities in the magnesium vapor, so that the nucleation energy barrier is reduced, and certain impurities are deposited in advance, thereby removing the impurities in the magnesium vapor.
2. The gas-phase magnesium purification method based on the nickel-based filter material can obviously reduce the content of metal impurities, particularly Mn, Al, Ca and other impurities in magnesium vapor. The method provided by the invention can be applied to industrial large-batch gas-phase magnesium purification, the evaporation rate of the metal magnesium is exponentially increased along with the temperature rise, and the production efficiency can be improved in an order of magnitude by high-temperature magnesium vaporization. The method provided by the invention can reduce the Mn content to below 10ppm when being applied to industrial production; the Al content is reduced to below 10 ppm; the content of Si is less than 20ppm, non-metallic impurity elements such as F, Cl, S and the like can be removed, the purity of the product is improved, and the purity of the obtained magnesium is more than 99.99 percent.
3. The gas-phase magnesium purification method based on the nickel-based filter material simplifies the production process flow, impurities such as Mn, Al, Ca, F, Cl and the like are mainly enriched on the filter material, a multi-stage tower tray is not required to be arranged, the yield of high-purity magnesium is obviously improved, and therefore the production cost of the high-purity magnesium is obviously reduced.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without any creative effort.
FIG. 1 is a diagram showing thermodynamic calculations of the composition and content of condensed materials at different temperatures;
FIG. 2 is a schematic structural view of the apparatus provided in example 1;
FIG. 3a is a schematic representation of comparative example 1, high purity graphite pipe fitting Nos. 1-8 of impurity condensation zone prior to purification experiments;
FIG. 3b is a schematic view of the high purity graphite pipe fitting No. 1-8 of the impurity condensation zone of comparative example 1 after the purification experiment;
FIG. 4 is a typical Scanning Electron Microscope (SEM) topography of the collection of the inner wall of No. 8 graphite tubing of comparative example 1;
FIG. 5 is an energy dispersive X-ray spectroscopy (EDS) plot of the collection on the inner wall of No. 8 graphite tubing of comparative example 1;
FIG. 6a is a schematic representation of graphite tubes from impurity condensation zones No. 1-8 of example 4 prior to purification experiments;
FIG. 6b is a schematic representation of graphite tubes from impurity condensation zones No. 1-8 of example 4 after purification experiments;
FIG. 7 is a typical Scanning Electron Microscope (SEM) topography of the collection of the inner wall of graphite tubes Nos. 5-7 of example 4;
FIG. 8 is an energy dispersive X-ray spectroscopy (EDS) plot of the collection on the inner wall of graphite tubes Nos. 5-7 of example 4;
FIG. 9 is a typical Scanning Electron Microscope (SEM) topographical view of the inner wall collection of
FIG. 10 is an energy dispersive X-ray spectroscopy (EDS) plot of a collection on the inner wall of
FIG. 11 is a Scanning Electron Microscope (SEM) topography of the nickel-based screen prior to the experiment of example 4;
FIG. 12 is an energy dispersive X-ray spectroscopy (EDS) plot of a nickel-based screen prior to the experiment of example 4;
FIG. 13 is a Scanning Electron Microscope (SEM) topographical view of a sample taken from the center of the nickel-based screen after the experiment of example 4;
FIG. 14 is an energy dispersive X-ray Spectroscopy (EDS) plot of a sample of the central portion of a nickel-based screen after an experiment of example 4;
FIG. 15 is a Scanning Electron Microscope (SEM) topographical view of an edge sample of the nickel-based screen after the experiment of example 4;
FIG. 16 is an energy dispersive X-ray spectroscopy (EDS) plot of an edge sample of a nickel-based screen after the experiment of example 4;
FIG. 17 is an X-ray diffractometer (XRD) texture analysis of a sample of the nickel-based screen after the experiment of example 4;
FIG. 18 is a topographical view of the collected high purity magnesium of example 4;
FIG. 19 is a typical Scanning Electron Microscope (SEM) topography of the collection of the inner wall of
FIG. 20 is an energy dispersive X-ray spectroscopy (EDS) plot of the collection on the inner wall of graphite tube No. 7 of example 5;
FIG. 21 is a typical Scanning Electron Microscope (SEM) topography of the collection of the inner wall of
FIG. 22 is an energy dispersive X-ray spectroscopy (EDS) plot of a collection on the inner wall of
fig. 23 is a result of measuring the content of impurities in magnesium obtained in example 6 and comparative example 2.
In the figure 1, an electric furnace body; 2. a crucible; 3. a heating mechanism; 4. a thermocouple; 5. a vacuum mechanism; 21. A reaction zone; 22. an impurity condensation zone; 23. a crystallization zone; 211. a hopper; 221. a filter assembly; 231. a crystallizer; 31. a first heating assembly; 32. a second heating assembly; 33. a third heating assembly; 51. a vacuum cabin body; 52. water-cooling the flange; 53. an end cap; 54. and a vacuum pumping assembly.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the examples given herein without making any creative effort, shall fall within the protection scope of the present invention.
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