Method for preparing high-purity red phosphorus from indium phosphide tailings

Abstract

The application discloses a method for preparing high-purity red phosphorus from indium phosphide tailings. The method comprises the following steps: ball milling the indium phosphide tailings to obtain indium phosphide tailing powder; performing an oxidation reaction on the indium phosphide tailing powder in an oxygen atmosphere to obtain a mixed powder containing indium oxide and diaphosphorus pentoxide; distilling and separating the mixed powder to obtain diaphosphorus pentoxide vapor and a solid phase containing indium oxide; performing a reduction reaction on the diaphosphorus pentoxide vapor in a carbon-containing environment to obtain phosphorus vapor; introducing the phosphorus vapor into pure water to condense the phosphorus vapor into liquid white phosphorus; and converting the liquid white phosphorus into red phosphorus. The method can obtain high-purity red phosphorus with a purity of 6N or above.

Description

Technical Field

[0001] This invention belongs to the technical field of red phosphorus production process, and particularly relates to a method for preparing high-purity red phosphorus by recovering indium phosphide tailings. Background Technology

[0002] High-purity red phosphorus refers to red phosphorus monomer with a purity of 99.9999% or higher. It is one of the main materials for synthesizing phosphide semiconductors and can be used to synthesize semiconductor materials such as indium phosphide (InP), gallium phosphide (GaP), aluminum gallium arsenide phosphide (AlGaAsP), indium gallium arsenide phosphide (InGaAsP), and gallium arsenide phosphide (GaAsP). It can also be used as a solid phosphorus source for IC doping and is widely used in integrated circuits, solar cells, crystalline silicon, semiconductors, TFT-LCDs, optical fiber preforms, and photochemistry, making it a very important basic semiconductor material. Yellow phosphorus can be converted into red phosphorus by heating to 200-360℃ for several days in the absence of air; industrially, yellow phosphorus is usually directly converted into red phosphorus.

[0003] The asthma (As) content in high-purity phosphorus needs to be below 0.2 ppm, or even 0.05 ppm. Currently, many methods for purifying and preparing high-purity phosphorus using industrial yellow phosphorus have been reported, including chromatographic methods and phosphine reduction methods. Both of these methods have very stringent production conditions, and even the slightest negligence can lead to an explosion.

[0004] Indium phosphide (IP) is a compound of phosphorus and indium, and it possesses excellent properties as a semiconductor material. Semiconductor devices manufactured using IPP substrates exhibit characteristics such as high saturated electron drift velocity, suitable emission wavelength for low-loss fiber optic communication, strong radiation resistance, good thermal conductivity, high photoelectric conversion efficiency, and a relatively wide bandgap. Therefore, IPP substrates can be widely used in the manufacture of optical modules, sensors, and high-end radio frequency devices.

[0005] From raw materials to ingots, and then to 2-inch or 4-inch wafers, the yield of indium phosphide is generally around 28%, making the technology extremely demanding. The production process generates a large amount of indium phosphide waste; therefore, recovering phosphorus from this waste to produce high-purity red phosphorus is of practical significance.

[0006] However, in existing technologies, indium oxide is decomposed directly to obtain indium and phosphorus. Indium phosphide requires high temperatures (above approximately 1000°C) for a significant decomposition reaction, but indium's saturated vapor pressure reaches 1 Torr (13.3 Pa) at 1082°C. During the high-temperature decomposition of indium phosphide, metallic indium vapor mixes with phosphorus vapor and may react again to form indium phosphide. Indium oxide, on the other hand, has a melting point as high as 2000°C, and phosphorus pentoxide begins to sublimate at 360°C, making it easier to separate from indium oxide. Furthermore, indium phosphide does not completely decompose during prolonged high-temperature decomposition at 1100°C; only about 50% of the indium phosphide decomposes. In addition, directly heating indium phosphide to decompose it into indium and phosphorus yields white phosphorus vapor, which is condensed to obtain white phosphorus. Conventional white phosphorus purification involves distillation to remove impurities, followed by long-term heating under oxygen-free conditions to obtain high-purity red phosphorus. Besides being highly toxic, white phosphorus is also dangerous due to its flammability. The safety and environmental protection requirements for the decomposition of indium phosphide and subsequent distillation purification processes are extremely high. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a method for preparing high-purity red phosphorus from indium phosphide tailings. The method provided by this invention is safe, environmentally friendly, and has a high recovery rate. Furthermore, it can obtain red phosphorus with a purity of 6N or higher.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] This invention discloses a method for preparing high-purity red phosphorus from indium phosphide tailings. The indium phosphide tailings are ball-milled to obtain indium phosphide tailings powder. The indium phosphide tailings powder is then oxidized under an oxygen atmosphere to obtain a mixed powder containing indium oxide and phosphorus pentoxide. The mixed powder is then distilled to separate phosphorus pentoxide vapor and an indium oxide-containing solid phase. The phosphorus pentoxide vapor is then introduced into a carbon-source environment for a reduction reaction to obtain phosphorus vapor. The phosphorus vapor is introduced into pure water and condensed to obtain liquid white phosphorus. The liquid white phosphorus is then converted to obtain red phosphorus.

[0010] This invention first grinds indium phosphide tailings, then oxidizes them in a high-temperature oxygen environment. Simultaneously, some gaseous decomposition products generated by the cutting fluid in the indium phosphide tailings at high temperature escape. The oxidized indium oxide and phosphorus pentoxide powder are separated into phosphorus pentoxide vapor through high-temperature distillation, while also separating it from high-boiling-point impurities. The phosphorus pentoxide vapor is then reduced by carbon at high temperature to obtain phosphorus vapor. Finally, the volatile phosphorus vapor is introduced into pure water and condensed into liquid white phosphorus. The white phosphorus is repeatedly washed with pure water to remove soluble impurities. The washed liquid white phosphorus enters a red phosphorus converter from underwater, where it is converted for several days under inert gas protection to obtain high-purity red phosphorus. The purity of the obtained high-purity red phosphorus reaches over 6N.

[0011] In a preferred embodiment, iron balls are used as grinding balls during the ball milling process.

[0012] In this invention, iron balls are used as grinding balls. Although the ball mill liner and iron balls are in direct contact with the indium phosphide tailings, the indium phosphide tailings will inevitably be contaminated during the ball milling process. However, after the indium phosphide tailings are oxidized and distilled at high temperature, high-boiling-point impurities such as Fe can be separated from phosphorus pentoxide vapor.

[0013] In a preferred embodiment, the ball-to-material ratio in the ball mill is 4–6:1, and the milling speed is 40–55 rpm. The inventors have found that when the milling parameters are controlled within the above range, the particle size of the obtained indium phosphide powder is ≤74 μm, at which point the oxidation effect of the indium phosphide tailings powder is optimal.

[0014] In a preferred embodiment, indium phosphide tailings powder is oxidized in an oxygen atmosphere to obtain a mixed powder containing indium oxide and phosphorus pentoxide. The flow rate of the oxygen atmosphere is 2-20 L / min, the oxidation reaction temperature is 650-1150℃, preferably 750-950℃, and the oxidation reaction time is 3-5 h.

[0015] In actual operation, indium phosphide tailings powder is placed in a corundum boat furnace tube and then heated and oxidized in an oxygen atmosphere to obtain a mixed powder containing indium oxide and phosphorus pentoxide.

[0016] In a preferred embodiment, the process of distilling and separating the mixed powder is as follows: heating the mixed powder to 360-600°C and introducing argon gas at a flow rate of 2-200 ml / min.

[0017] In actual operation, indium oxide and phosphorus pentoxide powder A are loaded into a quartz tube with an outer diameter of 80-200 mm, and argon gas is introduced from one side of the quartz tube at a flow rate of 2-200 ml / min; the quartz tube is heated to 360-600℃, and phosphorus pentoxide is obtained on the other side of the quartz tube.

[0018] In this invention, controlling the distillation temperature within a certain range ensures that phosphorus pentoxide is vaporized to form phosphorus pentoxide vapor, while avoiding the vaporization of indium oxide and other impurities, thereby achieving the separation of phosphorus pentoxide.

[0019] In a preferred embodiment, the carbon source is selected from porous carbon. The inventors have discovered that using blocky porous carbon yields the best reduction effect.

[0020] In this invention, the blocky porous carbon used is a high-purity organic material carbonized under high temperature and air-isolated conditions to obtain blocky porous high-purity carbon. In actual operation, the blocky porous high-purity carbon is loaded into a corundum tube, the air is driven away with argon gas and heated to the set temperature, and then phosphorus pentoxide vapor is passed into the corundum tube to carry out the reduction reaction.

[0021] In a preferred embodiment, the reduction reaction is carried out at a temperature of 1400–1500°C for 7–9 hours.

[0022] In a preferred embodiment, phosphorus vapor is introduced into pure water and condensed into liquid white phosphorus, which is then washed multiple times with pure water. The washed liquid white phosphorus is then introduced into a red phosphorus converter from underwater and converted for several days under the protection of inert gas to obtain red phosphorus.

[0023] In this invention, phosphorus vapor is controlled to be introduced into pure water and condensed into liquid white phosphorus. The liquid white phosphorus is then washed with pure water, which helps remove soluble impurities. The white phosphorus is collected and further purified to ultimately obtain red phosphorus with a phosphorus content of 6N or higher.

[0024] Further preferably, the temperature of the pure water is 50–90°C. The temperature of the pure water needs to be effectively controlled. If the temperature is too low, solid white phosphorus will be obtained, which will reduce the purity. If the temperature of the pure water is too high, boiling will cause the agitated liquid white phosphorus to come into contact with the outside air and burn.

[0025] In a preferred embodiment, the purity of the red phosphorus is 6N or higher.

[0026] Principles and advantages

[0027] This invention first grinds and oxidizes indium phosphide tailings. High-boiling-point impurities within the oxidized material do not affect subsequent products. The oxidized indium phosphide powder generates indium oxide and phosphorus pentoxide. Then, phosphorus pentoxide is separated from the high-boiling-point impurities and indium oxide by high-temperature distillation, yielding high-purity phosphorus pentoxide vapor. Further, a high-temperature reduction reaction is conducted to obtain high-purity white phosphorus. After multiple washings with pure water, the washed liquid white phosphorus enters a red phosphorus converter from underwater. Under inert gas protection, it is converted for several days to obtain high-purity red phosphorus. The purity of the obtained high-purity red phosphorus reaches over 6N.

[0028] This invention uses only oxygen and argon in the recycling and purification of indium phosphide tailings to obtain high-purity red phosphorus, reducing environmental impact and meeting production needs. Detailed Implementation

[0029] The present invention and its specific implementation methods will be further described in detail below with reference to the embodiments.

[0030] The present invention is characterized by the following steps:

[0031] A. Place the indium phosphide tailings into a ball mill for dry grinding. The particle size D50 after ball milling should not be less than 200 mesh (74μm). The ball-to-material ratio should be 4-6:1, and the rotation speed should be 40-55 rpm.

[0032] B. Place the indium phosphide tailings powder obtained in step A into a corundum boat furnace tube, and then place the corundum boat furnace tube into a tubular electric furnace; introduce oxygen into the tubular electric furnace at a flow rate of 2L to 20L / min, and oxidize at 650 to 1150℃ for 3 to 5 hours. After the reaction is completed, indium oxide and phosphorus pentoxide powder are obtained.

[0033] C. The indium oxide and phosphorus pentoxide powder obtained in step B are loaded into a quartz tube with an outer diameter of 80-200 mm. Argon gas is introduced from one side of the quartz tube at a flow rate of 2-200 ml / min. The quartz tube is heated to 360-600 °C, and phosphorus pentoxide vapor is obtained on the other side of the quartz tube.

[0034] D. The phosphorus pentoxide vapor obtained by distillation in step C is reduced in a high-temperature carbon environment to obtain phosphorus vapor. The carbon reduction reaction temperature is 1400-1500℃ and the reduction reaction time is 7-9h.

[0035] E. The phosphorus vapor B reduced in step D is introduced into pure water at a temperature of 50–90°C. The mixture is washed multiple times with pure water. The washed liquid white phosphorus then enters the red phosphorus converter from the bottom of the water. Under inert gas protection, it is converted for several days to obtain high-purity red phosphorus. The purity of the obtained high-purity red phosphorus reaches 6N or higher.

[0036] The tellurium dioxide scrap has a particle size D50 of not less than 200 mesh (74μm) after ball milling, a ball-to-material ratio of 4 to 6:1, and a rotation speed of 40 to 55 rpm.

[0037] The oxidation temperature of the indium phosphide tailings powder is 650–1150°C.

[0038] The distillation temperature of phosphorus pentoxide is between 360 and 600°C.

[0039] The reduction temperature of phosphorus pentoxide is 1400–1500℃.

[0040] The purity of the corundum furnace tube is not less than 99.7%.

[0041] The oxygen content of the indium phosphide tailings powder is not less than 99%.

[0042] The following are embodiments of the present invention:

[0043] Example 1

[0044] 500g of indium phosphide tailings were dry-milled in a ball mill using iron balls. The particle size D50 after ball milling was 200 mesh (74μm), the ball-to-material ratio was 4:1, and the rotation speed was 40 rpm. The obtained indium phosphide tailings powder was placed in an alumina furnace tube, which was then placed in a tubular electric furnace. Oxygen was introduced into the tubular electric furnace at a flow rate of 2L / min, and oxidation was carried out at 950℃ for 3 hours. After the reaction was completed, indium oxide and phosphorus pentoxide powders were obtained. The obtained indium oxide and phosphorus pentoxide powders were loaded into a quartz tube with an outer diameter of 80mm. Argon gas was introduced from one opening of the quartz tube at a flow rate of 150ml / min, and the quartz tube was heated to 400℃. Phosphorus pentoxide was obtained on the other side of the quartz tube. Phosphorus pentoxide vapor obtained by distillation is reduced in a high-temperature porous carbon environment to obtain phosphorus vapor. The carbon reduction reaction temperature is 1450℃, and the reduction reaction time is 7-9 hours. The reduced phosphorus vapor is introduced into pure water at 60℃ and washed multiple times with pure water. The washed liquid white phosphorus enters the red phosphorus converter from the bottom of the water and is converted for several days under inert gas protection to obtain high-purity red phosphorus. The obtained high-purity red phosphorus is analyzed by ICP-MS and its purity is 99.9999%, which meets or exceeds the 6N standard.

[0045] Example 2

[0046] 1000g of indium phosphide tailings were dry-milled in a ball mill using iron balls. The particle size D50 after ball milling was 200 mesh (74μm), the ball-to-material ratio was 5:1, and the rotation speed was 45 rpm. The obtained indium phosphide tailings powder was placed in an alumina furnace tube, which was then placed in a tubular electric furnace. Oxygen was introduced into the tubular electric furnace at a flow rate of 6L / min, and oxidation was carried out at 850℃ for 4 hours. After the reaction was completed, indium oxide and phosphorus pentoxide powders were obtained. The obtained indium oxide and phosphorus pentoxide powders were loaded into a quartz tube with an outer diameter of 80mm. Argon gas was introduced from one opening of the quartz tube at a flow rate of 50ml / min, and the quartz tube was heated to 500℃. Phosphorus pentoxide was obtained on the other side of the quartz tube. Phosphorus pentoxide vapor obtained by distillation is reduced in a high-temperature porous carbon environment to obtain phosphorus vapor. The carbon reduction reaction temperature is 1450℃, and the reduction reaction time is 9 hours. The reduced phosphorus vapor is introduced into pure water at 60℃ and washed multiple times with pure water. The washed liquid white phosphorus enters the red phosphorus converter from the bottom of the water and is converted for several days under inert gas protection to obtain high-purity red phosphorus. The obtained high-purity red phosphorus is analyzed by ICP-MS and its purity is 99.9999%, which meets or exceeds the 6N standard.

[0047] Example 3

[0048] 2000g of indium phosphide tailings were dry-milled in a ball mill using iron balls. The particle size D50 after ball milling was 200 mesh (74μm), the ball-to-material ratio was 6:1, and the rotation speed was 55 rpm. The obtained indium phosphide tailings powder was placed in an alumina furnace tube, which was then placed in a tubular electric furnace. Oxygen was introduced into the tubular electric furnace at a flow rate of 10L / min, and oxidation was carried out at 750℃ for 5 hours. After the reaction was completed, indium oxide and phosphorus pentoxide powders were obtained. The obtained indium oxide and phosphorus pentoxide powders were loaded into a quartz tube with an outer diameter of 80mm. Argon gas was introduced from one opening of the quartz tube at a flow rate of 100ml / min, and the quartz tube was heated to 600℃. Phosphorus pentoxide was obtained on the other side of the quartz tube. Phosphorus pentoxide vapor obtained by distillation is reduced in a high-temperature porous carbon environment to obtain phosphorus vapor. The carbon reduction reaction temperature is 1450℃, and the reduction reaction time is 9 hours. The reduced phosphorus vapor is introduced into pure water at 60℃ and washed multiple times with pure water. The washed liquid white phosphorus enters the red phosphorus converter from the bottom of the water and is converted for several days under inert gas protection to obtain high-purity red phosphorus. The obtained high-purity red phosphorus is analyzed by ICP-MS and its purity is 99.9999%, which meets or exceeds the 6N standard.

[0049] Comparative Example 1

[0050] Other conditions were the same as in Example 1, except that the indium phosphide tailings were not ball-milled, but were oxidized in a corundum furnace tube. Only the surface of the indium phosphide tailings was oxidized, and the interior of most of the indium phosphide tailings did not react.

[0051] Comparative Example 2

[0052] Other conditions are the same as in Example 1. The reduced phosphorus vapor is introduced into pure water at a temperature of 25°C. The white phosphorus vapor condenses and solidifies into lumps in the pure water. Trace amounts of unreduced phosphorus pentoxide are mixed in with the solid white phosphorus particles.

[0053] Comparative Example 3

[0054] Other conditions are the same as in Example 1. The phosphorus pentoxide vapor obtained by distillation is subjected to a reduction reaction in a high-temperature carbon environment. The carbon reduction reaction temperature is 900°C, and carbon phosphide is obtained from the reaction.

Claims

1. A method for preparing high-purity red phosphorus from indium phosphide tailings, characterized in that: Indium phosphide tailings are ball-milled to obtain indium phosphide tailings powder. The indium phosphide tailings powder is then oxidized in an oxygen atmosphere to obtain a mixed powder containing indium oxide and phosphorus pentoxide. The mixed powder is then distilled to separate phosphorus pentoxide vapor and a solid phase containing indium oxide. The phosphorus pentoxide vapor is then introduced into an environment containing a carbon source to carry out a reduction reaction to obtain phosphorus vapor. The phosphorus vapor is introduced into pure water and condensed to obtain liquid white phosphorus. The liquid white phosphorus is then converted to obtain red phosphorus. During the ball milling process, iron balls are used as grinding balls; The ball-to-material ratio of the ball mill is 4~6:1, and the rotation speed of the ball mill is 40~55 rpm; The flow rate of the oxygen atmosphere is 2~20L / min, the temperature of the oxidation reaction is 650~1150℃, and the time of the oxidation reaction is 3~5h; The process of distilling and separating the mixed powder is as follows: the mixed powder is heated to 360~600℃ and argon gas is introduced at a flow rate of 2~200ml / min; The reduction reaction is carried out at a temperature of 1400~1500℃ for 7~9 hours. The temperature of the pure water is 50~90℃; The purity of the red phosphorus is above 6N.

2. The method for preparing high-purity red phosphorus from indium phosphide tailings according to claim 1, characterized in that: Indium phosphide tailings powder is oxidized in an oxygen atmosphere to obtain a mixed powder containing indium oxide and phosphorus pentoxide.

3. The method according to claim 1, characterized in that: The carbon source is selected from porous carbon.

4. The method for preparing high-purity red phosphorus from indium phosphide tailings according to claim 1, characterized in that: Phosphorus vapor is introduced into pure water to condense into liquid white phosphorus, which is then washed multiple times with pure water. The washed liquid white phosphorus is then introduced into a red phosphorus converter from underwater, where it is converted for several days under the protection of inert gas to obtain red phosphorus.