Method for inhibiting antimony volatilization in a regeneration smelting process of waste antimony compound material

Abstract

The application discloses a method for inhibiting antimony volatilization in a waste antimony compound material regeneration smelting process, which is suitable for GaSb, InSb and Ga x In (1‑x) Sb waste materials. Waste antimony compounds with the same material system are loaded into a main smelting area, and high-purity antimony is used as an antimony source and placed in a side antimony source area which is in liquid-phase isolation and gas-phase communication with the main smelting area. After the furnace cavity is vacuumized, inert gas is filled to replace, smelting is carried out in a static atmosphere under near-atmospheric pressure and micro-negative pressure without continuous airflow, antimony vapor generated by the heating of the antimony source enters the upper part of the main smelting area, the actual antimony partial pressure of the melt surface is improved, and the driving force of antimony volatilization is reduced. The method does not need to directly supplement antimony to the melt, the remaining antimony source can be recycled and reused, and is beneficial to reducing antimony source consumption and lowering the regeneration smelting cost.

Description

Technical Field

[0001] This invention belongs to the technical field of smelting and resource recycling of group III-V antimony compound materials, specifically relating to a method for inhibiting antimony volatilization during the recycling and smelting of waste antimony compound materials. Background Technology

[0002] Gallium antimonide (GaSb), indium antimonide (InSb), and Ga-In-Sb ternary materials (Ga x In (1-x) Sb (0 < x < 1) belongs to the antimony-containing III-V group compound semiconductor materials and has applications in infrared detection, optoelectronic devices, and high-frequency electronic devices. During the cutting, grinding, wafer processing, and quality screening of single crystals of these materials, scrap, broken pieces, and defective wafers that do not meet dimensional or appearance requirements are generated. For waste materials that have not yet formed a functional layer for devices and whose matrix chemical system is well-defined, gallium, indium, and antimony still have high material utilization value.

[0003] Because antimony has a high saturated vapor pressure, antimony compounds are prone to antimony volatilization during regeneration smelting. Existing methods typically involve directly adding a certain amount of high-purity elemental antimony to the waste mixture or melt based on the expected antimony volatilization loss to compensate for the antimony loss during smelting. However, since the actual amount of antimony volatilization is affected by factors such as smelting temperature, furnace pressure, holding time, gas flow state, melt surface area, and charge amount, it is difficult to accurately match the amount added in advance.

[0004] GaSb, InSb, and Ga-In-Sb materials all exhibit a tendency for antimony components to volatilize during the melting process. If melting is continuously carried out under high vacuum conditions, or if protective gas is continuously introduced and evacuated during the holding process, antimony-containing vapors generated on the melt surface will be continuously carried away, easily leading to antimony loss and deviations in the stoichiometric ratio of the recycled material. Existing methods employ sealed quartz ampoules, positive pressure protective atmospheres, or molten salt sealing. While these methods can suppress volatilization to some extent, they each have limitations in terms of loading capacity, high safety requirements, insufficient equipment compatibility, and issues related to contact with the salt sealing material and subsequent cleaning. Summary of the Invention

[0005] This invention aims to address the problems of inaccurate control of antimony addition, high consumption of high-purity antimony, and difficulty in recovering and reusing residual antimony in the recycling of waste GaSb, InSb, and Ga-In-Sb materials using direct antimony replenishment. It provides a method to increase the actual antimony partial pressure above the melt and suppress antimony volatilization by utilizing a localized antimony-containing atmosphere. This method involves partitioned loading to provide an antimony atmosphere inside the crucible, achieving direct regeneration of waste antimony compound semiconductor materials in a near-atmospheric pressure environment with slight negative pressure.

[0006] To achieve the above objectives, the present invention adopts the following process scheme, and the specific steps are as follows: Step 1, Waste Pretreatment: Surface cleaning, washing, drying and crushing of the waste antimony semiconductor material mixture; Step 2, Zoned Charging and Furnace Atmosphere Control: Pre-treated waste antimony semiconductor material is charged into the main melting zone of the crucible. Antimony element with a purity of not less than 4N is then charged into the antimony source zone located on the side of the main melting zone. The main melting zone and the antimony source zone are isolated from each other in the liquid phase but maintained in gaseous connection above the liquid surface. After charging, the crucible is covered and placed in a vacuum melting furnace. The furnace cavity is evacuated and replaced with inert gas to achieve a furnace pressure of 0.5-0.9 atmospheres. Step 3, Localized Antimony-Containing Atmosphere Melting: The crucible is heated to completely melt the waste antimony compound semiconductor material in the main melting zone. Simultaneously, the antimony source in the antimony source zone is heated to generate antimony vapor. The antimony vapor enters the main melting zone through the gas-connected space above the liquid surface, forming an antimony-containing atmosphere inside the crucible. During the melting and heat preservation process, the gas inlet valve and vacuum pump are closed, and the pressure is intermittently adjusted only when the furnace pressure deviates from the set range. This allows the waste antimony compound semiconductor material to melt under a static, locally antimony-containing atmosphere, thereby suppressing the volatilization loss of antimony in the antimony melt. Step 4, Cooling: After the heat preservation is completed, stop heating and allow it to cool naturally to obtain a regenerated antimony ingot with a stoichiometric ratio that meets the requirements for single crystal growth.

[0007] In step 1, after surface decontamination of the waste antimony semiconductor material, it is cleaned with anhydrous ethanol, then vacuum dried, and finally crushed into particles.

[0008] The inert gas mentioned in step 2 is at least one of argon and nitrogen.

[0009] Preferably, the waste antimony semiconductor material in step 1 includes GaSb, InSb, or Ga x In (1-x) One or more of Sb, where 0 < x < 1.

[0010] Preferably, the waste antimony semiconductor material mixture in step 1 includes one or more of the following: scraps, broken materials, and defective wafers from different batches of antimony single crystals, different cutting parts, or different processing stages during antimony single crystal cutting.

[0011] Preferably, a fixed partition wall is provided between the main smelting zone and the antimony source zone in step 2, and the top of the fixed partition wall is higher than the highest liquid phase height of the main smelting zone and the antimony source zone; the main smelting zone and the antimony source zone are covered by the same crucible cover and are kept in gaseous communication through the space above the fixed partition wall.

[0012] Preferably, in step 2, the melting temperature is higher than the melting temperature of the corresponding antimony compound material, and the holding time is 0.5–5 hours; wherein, the melting temperature of GaSb material is 730–850°C, the melting temperature of InSb material is 550–700°C, and the melting temperature of Ga... x In (1-x) The melting temperature of Sb material is 500–850℃.

[0013] Preferably, the mass ratio of waste antimony compounds to elemental antimony in the main smelting zone is 1:0.4~1, ensuring that elemental antimony remains in the antimony source zone at the end of the holding period. The antimony source is kept in liquid phase isolation from the antimony compound melt in the main smelting zone and is not directly added to the melt as compensation antimony, but rather serves as a gaseous antimony source continuously providing antimony vapor inside the crucible.

[0014] Preferably, the antimony element in step 3 is contained in a removable inner liner located within the antimony source region; after cooling, the remaining antimony element along with the removable inner liner is removed from the antimony source region.

[0015] Preferably, the crucible body and the fixed partition are integrally formed, and the material of the crucible body and the fixed partition is selected from one of high-purity quartz, boron nitride, pyrolytic boron nitride, and high-purity graphite with a boron nitride protective layer on the surface.

[0016] Preferably, the material of the detachable inner liner is selected from one of high-purity quartz, boron nitride, or pyrolytic boron nitride, and the material of the crucible lid is selected from one of high-purity quartz, boron nitride, pyrolytic boron nitride, or high-purity graphite.

[0017] Preferably, in step 3, when the furnace pressure exceeds the set range, inert gas is briefly added or furnace gas is briefly discharged to maintain the furnace pressure at 0.5-0.9 standard atmospheres.

[0018] The mechanism by which this invention suppresses antimony volatilization is as follows: the volatilization tendency of antimony in GaSb, InSb, or Ga-In-Sb melts is related to the difference between the equilibrium antimony partial pressure at the corresponding temperature of the melt surface and the actual antimony partial pressure above the melt. The higher the antimony partial pressure above the melt, the less likely antimony in the antimonides is to volatilize. The side antimony source provides antimony vapor inside the crucible, increasing the actual antimony partial pressure in the gas phase above the main melting zone, thereby reducing the driving force for continued antimony loss from the corresponding antimonide melt. Stopping continuous gas intake and extraction during the melting and holding stages reduces the rate at which antimony vapor is carried away by the continuous gas flow and migrates to the outside of the furnace cavity; the crucible lid covering the main melting zone and the antimony source zone prolongs the residence time of antimony vapor inside the crucible. The near-atmospheric pressure with slight negative pressure in the furnace cavity mainly serves pressure safety and equipment compatibility; the actual antimony partial pressure established by the antimony source inside the crucible is the main factor suppressing antimony loss in GaSb, InSb, or Ga-In-Sb melts.

[0019] Compared with the prior art, the present invention has the following advantages: (1) It can directly produce the corresponding block-shaped recycled polycrystalline material for single crystal growth from the cutting scraps, processing crushed materials and defective wafers without device layers of GaSb, InSb or Ga-In-Sb single crystals, reducing the process of recycling and resynthesizing gallium, indium and antimony respectively; (2) The antimony loss is suppressed by using a micro-negative pressure static protective atmosphere and an antimony-containing atmosphere inside the crucible, without having to keep the vacuum melting furnace in a high vacuum or positive pressure state for a long time during the heat preservation stage; (3) The main smelting zone and the antimony source zone are liquid-phase isolated and gas-connected. The antimony source is not directly poured into the GaSb, InSb or Ga-In-Sb melt, and there is no need to set a salt seal layer on the surface of the corresponding melt. (4) The detachable inner liner makes it easy to remove, weigh and reuse the solidified remaining antimony source as a whole, and can adjust the loading of subsequent batches according to the actual consumption of antimony source. (5) By classifying and melting similar waste materials and crushing and mixing them into whole ingots, it is possible to balance the retention of the doped system and the stability of the composition of the regenerated batches; (6) Unused antimony sources can be recovered and reused as a whole, which helps to reduce the consumption of high-purity antimony and smelting costs. Attached Figure Description

[0020] Figure 1 A schematic diagram of the overall structure of the vacuum melting furnace and the partitioned crucibles; Figure 2 X-ray diffraction (XRD) pattern of regenerated gallium antimonide polycrystalline material; Figure 3 The X-ray diffraction (XRD) pattern of the regenerated indium antimonide polycrystalline material. Detailed Implementation

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments. The embodiments are used to illustrate the technical concept of the present invention and are not intended to limit the scope of protection of the present invention. Equipment and testing methods not specifically described can be conventional equipment and methods in the art.

[0022] The composition deviation of this invention refers to the degree of deviation from the ideal stoichiometric ratio of 1:1 after the atomic ratio of group III elements to Sb in antimony compounds is converted to 1:x, i.e., composition deviation = |1-x|×100%.

[0023] Example 1: Regeneration of GaSb single crystals and wafer dicing waste GaSb single crystal cutting scraps, processing fragments, and defective wafers without device functional layers are collected with the same material chemical system. Cutting fluid and particulate contaminants are removed from the surface of the waste materials. Then, organic solvents are used for cleaning and vacuum drying, and oversized waste materials are crushed.

[0024] Pretreated GaSb waste was loaded into the main smelting zone, and high-purity elemental antimony was added to the removable inner liner of the side antimony source zone. The furnace cavity was evacuated and purged with high-purity argon gas to adjust the furnace pressure to 0.6 atmospheres, and then the continuous gas inlet and continuous gas extraction channels were closed. The temperature was raised to 760℃, and after the waste was completely melted, it was held at that temperature for 1 hour. The antimony source generated antimony vapor upon heating, which entered the area above the main smelting zone through the gas-connected space.

[0025] After the heat preservation is completed and the material is cooled, the regenerated GaSb ingot is removed and crushed and mixed as a whole.

[0026] X-ray diffraction confirmed that the smelted material was a pure GaSb phase. Figure 2 According to energy-dispersive X-ray spectroscopy analysis, as shown in Table 1, the GaSb material regenerated in this embodiment has a Ga to Sb stoichiometry ratio of 1:1 and a compositional deviation of less than 5%.

[0027] Table 1. Energy dispersive X-ray spectroscopy analysis results of Example 1 Comparative Example 1: Static micro-negative pressure melting without a side antimony source Medium-mass samples were taken from the same batch of crushed and mixed waste gallium antimonide material and smelted under the same furnace cavity replacement, slight negative pressure, heating, holding, and cooling conditions as in Example 1, but without placing an antimony source in the side antimony source area. The total mass change and Ga / Sb atomic ratio of the two groups of recycled ingots were compared to evaluate the effect of the side antimony source and the antimony-containing atmosphere inside the crucible on reducing antimony loss.

[0028] As shown in Table 2, the GaSb material obtained by regeneration in this embodiment has a Ga to Sb stoichiometric ratio of 1:0.83, and the composition deviation is greater than 10%.

[0029] Table 2. Results of Energy Dispersive X-ray Spectroscopy Analysis of Comparative Example 1 Comparative Example 2: Melting with an antimony source but using a continuous gas flow Medium-mass samples were taken from the same batch of crushed and mixed waste gallium antimonide material. The same side antimony source as in Example 1 was used, but inert gas was continuously introduced and vented during the melting and holding stages. The antimony source consumption, total mass change of the recycled ingot, and Ga / Sb atomic ratio were compared between this comparative example and Example 1 to evaluate the effect of the static protective atmosphere on reducing antimony vapor carryover.

[0030] As shown in Table 3, the Ga to Sb stoichiometry ratio of the GaSb material obtained by regeneration in this embodiment is 1:0.92, and the composition deviation is greater than 5%.

[0031] Table 3. Energy dispersive X-ray spectroscopy analysis results of Comparative Example 2 Example 2: Regeneration of InSb single crystals and wafer dicing waste InSb single crystal cutting scraps, processing fragments, and defective wafers without device functional layers are collected with the same material chemical system. Cutting fluid and particulate contaminants are removed from the surface of the waste materials. Then, organic solvents are used for cleaning and vacuum drying, and oversized waste materials are crushed.

[0032] Pretreated InSb waste is loaded into the main smelting zone, and high-purity elemental antimony is added to the removable inner liner of the side antimony source zone. The furnace cavity is evacuated and purged with high-purity argon gas to adjust the furnace pressure to 0.5 atmospheres, and then the continuous gas inlet and continuous gas extraction channels are closed. The temperature is raised to 580℃, and after the waste is completely melted, it is held at that temperature for 0.5 hours. The antimony source generates antimony vapor upon heating, which enters the space above the main smelting zone through the gas-connected space.

[0033] After the heat preservation is completed and the ingot is cooled, the regenerated InSb ingot is removed and crushed and mixed as a whole.

[0034] X-ray diffraction confirmed that the smelted material was a pure InSb phase. Figure 3 Energy-dispersive X-ray spectroscopy analysis, as shown in Table 4, shows that the stoichiometric ratio of In to Sb in the regenerated InSb material obtained in this embodiment is 1:0.99, with a compositional deviation of less than 5%.

[0035] Table 4. Energy dispersive X-ray spectroscopy analysis results of Example 2

Claims

1. A method for suppressing antimony volatilization during the recycling and smelting of waste antimony compounds, characterized in that, include: Step 1, Waste Pretreatment: Surface cleaning, washing, drying, and crushing of the waste antimony semiconductor material mixture; Step 2, Zoned Charging and Furnace Atmosphere Control: Pre-treated waste antimony semiconductor material is charged into the main melting zone of the crucible. Antimony element with a purity of not less than 4N is then charged into the antimony source zone located on the side of the main melting zone. The main melting zone and the antimony source zone are isolated from each other in the liquid phase but maintained in gaseous connection above the liquid surface. After charging, the crucible is covered and placed in a vacuum melting furnace. The furnace cavity is evacuated and replaced with inert gas to achieve a furnace pressure of 0.5-0.9 atmospheres. Step 3, Localized Antimony-Containing Atmosphere Melting: The crucible is heated to completely melt the waste antimony compound semiconductor material in the main melting zone. Simultaneously, the antimony source in the antimony source zone is heated to generate antimony vapor. The antimony vapor enters the main melting zone through the gas-connected space above the liquid surface, forming an antimony-containing atmosphere inside the crucible. During the melting and heat preservation process, the gas inlet valve and vacuum pump are closed, and the pressure is intermittently adjusted only when the furnace pressure deviates from the set range. This allows the waste antimony compound semiconductor material to melt under a static, locally antimony-containing atmosphere, thereby suppressing the volatilization loss of antimony in the antimony melt. Step 4, Cooling: After the heat preservation is completed, stop heating and allow it to cool naturally to obtain a regenerated antimony ingot with a stoichiometric ratio that meets the requirements for single crystal growth.

2. The method as described in claim 1, characterized in that, The waste antimony semiconductor material mentioned in step 1 includes GaSb, InSb, or Ga x In (1-x) One or more of Sb, where 0 < x < 1.

3. The method as described in claim 1, characterized in that, The waste antimony semiconductor material mixture mentioned in step 1 includes one or more of the following: scraps, broken materials, and defective wafers from different batches of antimony single crystals, different cutting parts, or different processing stages during antimony single crystal cutting.

4. The method as described in claim 1, characterized in that, In step 2, a fixed partition wall is set between the main smelting zone and the antimony source zone. The top of the fixed partition wall is higher than the highest liquid phase height of the main smelting zone and the antimony source zone. The main smelting zone and the antimony source zone are covered by the same crucible cover and are kept in gaseous communication through the space above the fixed partition wall.

5. The method as described in claim 1, characterized in that, In step 2, the melting temperature is higher than the melting temperature of the corresponding antimony compound material, and the holding time is 0.5–5 h; specifically, the melting temperature of GaSb material is 730–850℃, the melting temperature of InSb material is 550–700℃, and the melting temperature of Ga... x In (1-x) The melting temperature of Sb material is 500–850℃.

6. The method as described in claim 1, characterized in that, The mass ratio of waste antimony compounds to elemental antimony in the main smelting zone is 1:0.4~1.

7. The method as described in claim 1, characterized in that, The elemental antimony described in step 3 is placed in a removable inner liner located within the antimony source area; after cooling, the remaining elemental antimony, along with the removable inner liner, is removed from the antimony source area.

8. The method as described in claim 4, characterized in that, The crucible body and the fixed partition wall are integrally formed, and the materials of the crucible body and the fixed partition wall are selected from one of the following: high-purity quartz, boron nitride, pyrolytic boron nitride, and high-purity graphite with a boron nitride protective layer on the surface.

9. The method as described in claim 7, characterized in that, The removable inner liner is made of a material selected from high-purity quartz, boron nitride, or pyrolytic boron nitride, and the crucible lid is made of a material selected from high-purity quartz, boron nitride, pyrolytic boron nitride, or high-purity graphite.

10. The method as described in claim 1, characterized in that, In step 3, when the furnace pressure exceeds the set range, inert gas is briefly added or the furnace gas is briefly discharged to maintain the furnace pressure at 0.5-0.9 standard atmospheres.

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