Apparatus and method for vacuum purification of selenium residues

Abstract

The present invention relates to the technical field of crude selenium purification, and provides a vacuum purification apparatus and method for selenium residue. In the vacuum purification apparatus for selenium residue provided by the present invention, the arrangement of the oblique condensation plate and the flat condensation plate in the present invention improves the separation degree of selenium and other impurities in the crude selenium, and improves the purity of the obtained selenium. At the same time, the vacuum purification apparatus for selenium residue provided by the present invention has a simple structure. The selenium residue to be purified by the present invention is heated by the heating device to become water vapor, and the impurities in the water vapor pass through the oblique condensation plate and the flat condensation plate, and then condense and flow back into the raw material container, and the purified selenium vapor enters the cooling system through the holes in the condenser, condenses at the cooling cover, and merges into the collection plate, and is then collected in the collection system. The method provided by the present invention is simple to operate. The data in the examples show that the apparatus provided by the present invention can obtain selenium with a purity of 99.995% from selenium residue with a mass fraction of 60%.

Description

[Technical Field]

[0001] This invention claims priority from a Chinese patent application bearing application number 202210093041.4 and title "Vacuum purification apparatus and method for selenium residues" filed with the China Patent Office on January 26, 2022, the entire contents of which are incorporated by reference.

[0002] The present invention relates to the technical field of crude selenium purification, and in particular to an apparatus and method for vacuum purification of selenium residues. [Background technology]

[0003] Selenium is widely used due to its excellent physical and chemical properties. As a metal additive, it can improve the mechanical processing properties of metals. Selenide semiconductors have shown great application value in fields such as biomedicine, photocatalysis, copper indium selenide thin-film solar cells, and thermoelectric converters. New-generation optoelectronic devices such as ZnSe and CdSe can be used in the manufacture of infrared detectors, night vision devices, resource exploration equipment, and infrared window lenses. The addition of small amounts of selenium to glass can change the optical properties and color of glass, making it useful as a pigment component and a substitute for vulcanizing agents in rubber production. Selenium also has important medical value, countering the toxic effects of metallic mercury, cadmium, lead, and arsenic. With the vigorous development of the selenium industry, selenium plays an increasingly important role in metallurgy, materials, the chemical industry, medicine, and other fields.

[0004] Currently, the main methods for purifying selenium are chemical refining and physical refining. Chemical refining mainly involves oxidizing crude selenium and reducing it with appropriate chemical reagents to obtain purified selenium. Physical refining utilizes the difference in vapor pressure between selenium and impurities such as copper, lead, iron, gold, and silver in the crude selenium, and selenium, which has a higher vapor pressure and is more volatile, allowing it to be separated from the impurities. Patent Document 1 discloses an apparatus and method for removing impurities from crude selenium containing mercury, and the apparatus includes an oxidation furnace, a crystallizer, a separator, a spray tower, a filter, an ion exchange column, and a reduction tank. The structure of this device is relatively complicated. The process flow is as follows: mercury-containing crude selenium is fed into the oxidation furnace through the inlet; the crystallizer is heated; then the heating of the crystallizer is stopped; then the oxidation furnace is heated; oxygen is supplied to the oxidation furnace through the oxygen supply device; simultaneously, the induced draft fan and spray pump are started; after the oxidation furnace is kept warm, the heating of the oxidation furnace is stopped; after the oxidation furnace is cooled, the discharge door of the crystallizer is opened to discharge the material; simultaneously, the induced draft fan and spray pump of the spray tower are closed; at the same time, during the heat-keeping reaction of the oxidation furnace, the gaseous substances in the oxidation furnace are driven by the induced draft fan to flow from the air outlet at the top of the oxidation furnace to the air inlet at the top of the crystallizer; the oxidation residue is concentrated at the bottom of the oxidation furnace; the crystallized product of selenium dioxide is concentrated at the bottom of the crystallizer; the gaseous substances in the crystallizer then flow through the air outlet at the top of the crystallizer to the air inlet at the top of the separator; The crystals of the work material are concentrated at the bottom of the separator and return to the oxidation furnace through the separator's outlet. The gaseous substances in the separator then pass through the separator's air outlet, pass through a water sealer and an induced draft fan, enter the air inlet at the bottom of the spray tower, and then pass through the top of the spray tower to spray the exhaust gas at the separator's air outlet after being washed with the water sealer and discharged. The spray liquid enters the filter through the water outlet of the water tank and is filtered. The filtrate is allowed to stand and the pH is adjusted. Then, the filtrate is passed through an ion exchange column for mercury removal treatment. Finally, the mercury-removed liquid is passed through a reduction tank for reduction treatment. The resulting selenium precipitate is centrifuged, washed with water to remove salt, and dried to obtain mercury-free crude selenium, which is then returned to the oxidation furnace. However, the treatment process is relatively long, and the purity of the resulting selenium product is low, only reaching the 3N level. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Chinese Patent No. 108975290A Summary of the Invention [Problem to be solved by the invention]

[0006] In view of this, the object of the present invention is to provide a vacuum purification apparatus and method for selenium residue, which has a simple structure and a simple processing step, and the obtained selenium product has high purity. [Means for solving the problem]

[0007] In order to achieve the above objectives of the present invention, the present invention provides the following technical solutions: The present invention provides a vacuum purification device for selenium residues, comprising: a source container 1; a condenser 2 located above the raw material container 1; a cooling system 3 fitted to the outside of the condenser 2; a collection system (4) in communication with the cooling system (3); A heating device 11 for heating the raw material container 1 is disposed outside the raw material container 1, The condenser 2 includes a condenser cover 21 and a staggered condenser plate 22 installed in the condenser cover 21. The staggered condenser plate 22 includes an inclined condenser plate 221 and a flat condenser plate 222. The inclined condenser plate 221 is located below the flat condenser plate 222. Holes 23 are provided in the side walls of the condenser cover 21. The height of the holes 23 in the vertical direction is equal to or greater than the height of the flat condenser plate 222. The condenser 2 communicates with the cooling system 3 through the holes 23. The cooling system 3 includes a cooling cover 31 and a collection plate 32 located below the cooling cover 31. The cooling system 3 communicates with the collection system 4 through the collection plate 32.

[0008] Preferably, the number of the obliquely placed condenser plates 221 is one to two.

[0009] Preferably, the obliquely placed condenser plate 221 is inclined downward, and the included angle between the obliquely placed condenser plate 221 and the horizontal direction is 1 to 5 degrees.

[0010] Preferably, the vertical distance between two adjacent obliquely placed condenser plates 221 and the distance between said obliquely placed condenser plate 221 and the adjacent flatly placed condenser plate 222 is independently 5 to 10 cm.

[0011] Preferably, the diameter of the holes 23 is 0.5 to 1 cm, and the density of the holes 23 is 0.2 to 0.5 / cm. 2 is.

[0012] Preferably, the collection plate 32 and the collection system 4 are connected via a melt pipe 5, and a heating system 51 is installed outside the melt pipe 5.

[0013] Preferably, the heating device 11 is arranged at the bottom and sidewall of the source container 1 .

[0014] Preferably, the cooling cover 31 includes a furnace lid 311 and a cooling shell 312, and the furnace lid 311 and the cooling shell 312 are not in contact with each other.

[0015] The present invention further provides a method for purifying selenium residue using the vacuum purification device for selenium residue described in the above technical solution, Putting the selenium residue to be purified into a raw material container 1 and heating the selenium residue to be purified using a heating device 11; The gas generated by the heating enters the condenser 2, passes through the holes 23 into the cooling system 3 and is cooled, and the purified selenium obtained by cooling is collected on the collection plate 32 and enters the collection system 4.

[0016] Preferably, the heating temperature is 550 to 700°C and the heating pressure is 10 to 100Pa. [Effects of the Invention]

[0017] The present invention provides a vacuum purification device for selenium residue, comprising: a raw material container 1; a condenser 2 located above the raw material container 1; a cooling system 3 fitted to the outside of the condenser 2; and a collection system 4 connected to the cooling system 3. A heating device 11 for heating the raw material container 1 is disposed outside the raw material container 1. The condenser 2 comprises a condenser cover 21 and staggered condenser plates 22 installed within the condenser cover 21. The staggered condenser plates 22 include an inclined condenser plate 221 and a flat condenser plate 222. The oblique condenser plate 221 is located below the flat condenser plate 222. The condenser cover 21 has holes 23 formed in its sidewall, the vertical height of which is equal to or greater than the height of the flat condenser plate 222. The condenser 2 communicates with the cooling system 3 through the holes 23. The cooling system 3 includes a cooling cover 31 and a collection plate 32 located below the cooling cover 31. The cooling system 3 communicates with the collection system 4 through the collection plate 32. The arrangement of the oblique condenser plate and the flat condenser plate in the present invention improves the separation of selenium from other impurities in crude selenium, thereby improving the purity of the resulting selenium. At the same time, the vacuum purification apparatus for selenium residue provided by the present invention has a simple structure. Example data show that the apparatus provided by the present invention can obtain 99.995% pure selenium from a selenium residue with a mass fraction of 60%.

[0018] Furthermore, the heating device 11 is arranged at the bottom and sidewall of the raw material container 1, which changes the bottom heating method of the conventional vacuum furnace, thereby making the selenium dissolving speed much faster, improving production efficiency and reducing production costs.

[0019] Furthermore, the selenium product collected in the collection plate 32 enters the collection system directly through the melting pipe, eliminating the need for a cooling system to clean the material, making the operation simple, convenient, and easy. At the same time, the melting pipe is heated using a heating system, which prevents material clogging and further improves production efficiency.

[0020] The present invention further provides a method for purifying selenium residue using the vacuum purification device for selenium residue described in the above technical solution, The method includes the steps of placing the selenium residue to be purified in a source container 1, heating the selenium residue using a heating device 11, and then the gas generated by the heating enters a condenser 2 and enters a cooling system 3 through holes 23 for cooling. The cooled purified selenium is collected on a collection plate 32 and then enters a collection system 4. The selenium residue to be purified in the present invention is converted into water vapor by heating in the heating device. Impurities in the water vapor pass through an oblique condenser plate and a flat condenser plate, condense, and return to the source container. The purified selenium vapor enters the cooling system through holes in the condenser, condenses at a cooling cover, and merges into a collection plate before being collected in the collection system. The method provided by the present invention is simple in operation. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a schematic diagram of a vacuum purification apparatus for selenium residues provided by the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0022] The present invention provides a vacuum purification device for selenium residues, comprising: a source container 1; a condenser 2 located above the raw material container 1; a cooling system 3 fitted to the outside of the condenser 2; a collection system (4) in communication with the cooling system (3); A heating device 11 for heating the raw material container 1 is disposed outside the raw material container 1, The condenser 2 includes a condenser cover 21 and staggered condenser plates 22 installed in the condenser cover 21, the staggered condenser plates 22 including an obliquely placed condenser plate 221 and a flatly placed condenser plate 222, the obliquely placed condenser plate 221 being located below the flatly placed condenser plate 222, holes 23 being formed in the sidewall of the condenser cover 21, and the height of the holes 23 in the vertical direction is equal to or greater than the height of the flatly placed condenser plate 222, The condenser 2 communicates with the cooling system 3 via a hole 23; The cooling system 3 includes a cooling cover 31 and a collection plate 32 located below the cooling cover 31. The cooling system 3 communicates with the collection system 4 via a collection plate 32 .

[0023] In the present invention, unless otherwise specified, it is preferable to use commercially available raw materials for the raw materials used in the present invention.

[0024] The vacuum refining apparatus for selenium residues provided by the present invention includes a source container 1. In the present invention, the source container 1 preferably includes a crucible, and the crucible is preferably made of graphite or stainless steel. In the present invention, a heating device 11 for heating the source container 1 is installed outside the source container 1. In the present invention, the heating device 11 is preferably installed on the bottom and sidewall of the source container 1. By heating the source container 1 using the heating device 11 installed outside the source container 1, the present invention changes the bottom heating method of a conventional vacuum furnace and significantly improves the selenium melting rate, thereby improving production efficiency and reducing production costs.

[0025] The vacuum refining apparatus for selenium residue provided by the present invention includes a condenser 2. In the present invention, the condenser 2 includes a condenser cover 21 and staggered condenser plates 22 installed within the condenser cover 21. In the present invention, the staggered condenser plates 22 include an oblique condenser plate 221 and a flat condenser plate 222, and the oblique condenser plate 221 is located below the flat condenser plate 222. In the present invention, the number of oblique condenser plates 221 is preferably one to two. In the present invention, the oblique condenser plate 221 is preferably inclined downward, and the angle formed by the oblique condenser plate 221 and the horizontal direction is preferably 1 to 5°. In the present invention, the vertical distance between two adjacent oblique condenser plates 221 and between the oblique condenser plate 221 and the adjacent flat condenser plate 222 is preferably 5 to 10 cm. In the present invention, the areas of the oblique condenser plate 221 and the flat condenser plate 222 are preferably 1 / 2 to 2 / 3 of the cross-sectional area of the condenser cover 21. In the present invention, the inner diameter of the cooling cover preferably matches the inner diameter of the raw material container.

[0026] In the present invention, holes 23 are provided in the side wall of the condenser cover 21, and the height of the holes 23 in the vertical direction is equal to or greater than the height of the flat condenser plate 222. In the present invention, the diameter of the holes 23 is preferably 0.5 to 1 cm, and the density of the holes 23 is 0.2 to 0.5 pcs / cm. 2 It is preferable that:

[0027] In the present invention, the condenser cover and the staggered condenser plates are preferably made of stainless steel.

[0028] In the present invention, by providing an oblique condenser plate and a flat condenser plate, the degree of separation of selenium from other impurities in crude selenium is improved, and the purity of the obtained selenium is improved.

[0029] In the present invention, the contact area between the raw material container 1 and the condenser 2 is in a sealed state to prevent gas leakage.

[0030] The vacuum refining apparatus for selenium residue provided by the present invention includes a cooling system 3. In the present invention, the cooling system 3 includes a cooling cover 31 and a collection plate 32 located below the cooling cover. In the present invention, the cooling cover 31 includes a furnace lid 311 and a cooling shell 312, and it is preferable that the furnace lid 311 and the cooling shell 312 are not in contact with each other. In the present invention, a coolant 313 is filled in the gap formed by the furnace lid 311 and the cooling shell 312. In the present invention, it is preferable that the coolant includes water and / or oil, and more preferably is water. In the present invention, it is preferable that the furnace lid, cooling shell, and collection plate are made of stainless steel.

[0031] In the present invention, the condenser 2 communicates with the cooling system 3 via a hole 23 .

[0032] The vacuum purification apparatus for selenium residues provided by the present invention includes a collection system 4. In the present invention, the collection system 4 is preferably a cylindrical drum with an inner diameter of 50 to 70 cm. In the present invention, the material of the collection system is preferably stainless steel. In the present invention, one side of the collection system 4 is preferably provided with an opening 41, which is preferably connected to a vacuum pump, and the vacuum pump, collection system, melting pipe, cooling system, condenser, and crucible form a vacuum system.

[0033] In the present invention, the collection plate 32 of the cooling system 3 and the collecting system 4 are connected via a molten pipe 5. In the present invention, a heating system 51 is preferably installed outside the molten pipe 5. In the present invention, the material of the molten pipe 5 preferably includes stainless steel. In a specific embodiment of the present invention, the diameter of the molten pipe is preferably 6 cm.

[0034] The present invention further provides a method for purifying selenium residue using the vacuum purification device for selenium residue described in the above technical solution, Putting the selenium residue to be purified into a raw material container 1 and heating the selenium residue to be purified using a heating device 11; The gas generated by the heating enters the condenser 2, passes through the holes 23 into the cooling system 3 and is cooled, and the purified selenium obtained by cooling is collected on the collection plate 32 and enters the collection system 4.

[0035] In the present invention, the heating temperature is preferably 550 to 700°C, and the rate of temperature rise to the heating temperature is preferably 2 to 5°C / min. In the present invention, the heating temperature is achieved by a heating device 11. In the present invention, the heating pressure is preferably 10 to 100 Pa. In the present invention, the heating pressure is achieved through a vacuum system. In the present invention, the heating time is preferably 6 to 10 hours.

[0036] In the method of the present invention, the selenium residue before purification is heated by a heating device to form steam, and the impurities in the steam condense after passing through an inclined condenser plate and a flat condenser plate, and then flow back into the raw material container. The purified selenium vapor passes through the holes in the condenser into the cooling system, condenses on the cooling cover, and flows into the collection plate, and then passes through the melting pipe and is collected in the collection system.

[0037] The vacuum purification apparatus and method for selenium residue of the present invention will be described in detail below with reference to examples, but the present invention is not limited thereto.

[0038] In the following example, the apparatus shown in FIG. 1 was used. In FIG. 1, there were two oblique condensing plates and one flat condensing plate. The oblique condensing plates were inclined downward and at an angle of 5° to the horizontal. The vertical distance between two adjacent oblique condensing plates was 5 cm. The distance between an oblique condensing plate and an adjacent flat condensing plate was 5 cm. The raw material container was a graphite crucible. The inner diameter of the graphite crucible was 55 cm. The areas of the flat condensing plate and the oblique condensing plate were 2 / 3 of the cross-sectional area of the crucible. The hole diameter was 1 cm, and the hole density was 0.5 / cm. 2The diameter of the melting pipe is 6 cm, the condenser, cooling system, melting pipe and collecting system are made of stainless steel, and the coolant is cooling water. [Example]

[0039] 150 kg of selenium residue with a mass fraction of 60% was melted and placed in a crucible. The melting point was lowered into a heating device using an electric hoist. The heating device was then started. The selenium was purified under the following conditions: heating rate: 5°C / min, distillation temperature: 550°C, distillation time: 6 hours. The vacuum system was opened and the pressure was controlled at 20 Pa. During the heating process, the selenium in the crucible evaporated into vapor. The vapor passed through the oblique and flat condenser plates, passed through the holes, and entered the cooling system. Liquid selenium was condensed in the cooling cover of the cooling system, collected on the collection plate, and transported to the collection system through the melting pipe. The melting pipe was heated to 230°C by the heating system. Finally, 128.3 kg of selenium product was obtained, with a volatilization rate of 87.3%.

[0040] The obtained high-quality selenium was tested by inductively coupled plasma mass spectrometry (ICP-MS) in accordance with the non-ferrous metals industry standards of the People's Republic of China, YS / T223-2007 and YS / T226.13-2009. The purity of the purified selenium was found to be 99.992%. [Example]

[0041] 200 kg of selenium residue with a mass fraction of 60% was melted and placed in a crucible. The melting point was lowered into a heating device using an electric hoist and the heating device was started. The selenium was purified under the following conditions: heating rate: 10°C / min, distillation temperature: 680°C, distillation time: 8 hours. The vacuum system was opened and the pressure was controlled at 10 Pa. During the heating process, the selenium in the crucible evaporated into vapor. The vapor passed through the tilted and flat condenser plates, passed through the holes, and entered the cooling system. Liquid selenium was condensed in the cooling cover of the cooling system, collected on the collection plate, and transported to the collection system through the melting pipe. The melting pipe was heated to 230°C by the heating system. Finally, 199 kg of selenium product was obtained, with a volatilization rate of 99.5%.

[0042] The obtained high-quality selenium was tested by inductively coupled plasma mass spectrometry (ICP-MS) in accordance with the People's Republic of China's non-ferrous metals industry standards YS / T223-2007 and YS / T226.13-2009. The purity of the purified selenium was found to be 99.995%. [Example]

[0043] 300 kg of selenium residue with a mass fraction of 60% was melted and placed in a crucible. The melting point was lowered into a heating device using an electric hoist and the heating device was started. The selenium was purified under the following conditions: heating rate: 10°C / min, distillation temperature: 700°C, distillation time: 10 hours. The vacuum system was opened and the pressure was controlled at 50 Pa. During the heating process, the selenium in the crucible evaporated into vapor. The vapor passed through the oblique condenser plate and the flat condenser plate, passed through the holes, and entered the cooling system. The liquid selenium was condensed in the cooling cover of the cooling system and collected on the collection plate. The liquid selenium was then transported to the collection system through the melting pipe. The melting pipe was heated to 230°C by the heating system. Finally, 294 kg of selenium product was obtained, with a volatilization rate of 98.0%.

[0044] The obtained high-quality selenium was tested by inductively coupled plasma mass spectrometry (ICP-MS) in accordance with the People's Republic of China's non-ferrous metals industry standards YS / T223-2007 and YS / T226.13-2009. The purity of the purified selenium was found to be 99.991%.

[0045] From the above examples, it can be seen that the method provided by the present invention has a final direct selenium recovery rate of more than 99.5% and a selenium purity of more than 99.995%. The production scale of the present invention can reach more than 300 kg, and the production efficiency is high, the product purity is high, and impurities such as tellurium, copper, and lead are enriched.

[0046] It should be noted that the above are only preferred embodiments of the present invention, and those skilled in the art can make many improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered as part of the protection scope of the present invention. [Explanation of symbols]

[0047] 1 raw material container 11 heating device 2 condensers 21 Condensation Cover 22 staggered condenser plate 221 Inclined Condenser Plate 222 Flat condenser plate 23 holes 3 Cooling System 31 Cooling cover 311 hearth lid 312 cooling shell 313 Coolant 32 Collection Plates 4. Collection System 41 Opening 5 Melt piping 51 Heating System

Claims

1. A raw material container; a condenser located above the raw material container; a cooling system fitted to the exterior of the condenser; a collection system in communication with the cooling system; a heating device is disposed outside the source container for heating the source container and the selenium residue; the condenser includes a condenser cover and a staggered condenser plate installed in the condenser cover, the staggered condenser plate including an oblique condenser plate and a flat condenser plate, the oblique condenser plate being located below the flat condenser plate, holes being provided in a side wall of the condenser cover, the height of the holes being equal to or greater than the height of the flat condenser plate in a vertical direction; The condenser communicates with the cooling system through a hole, and the cooling system includes a cooling cover and a collection plate located below the cooling cover; the cooling system is in communication with the collection system through the collection plate; The source container includes a crucible. The collection plate and the collection system are connected via a molten pipe, and a heating system is installed outside the molten pipe; an opening on one side of the collection system; the opening is connected to a vacuum pump such that the collection system, the melting line, the cooling system, the condenser, and the crucible form a vacuum system by the vacuum pump; the cooling system is configured to cool the selenium vapor generated by the heating device to obtain liquid selenium; The collection system is configured to collect the liquid selenium to obtain a selenium product.

2. 2. The vacuum purification apparatus for selenium residues according to claim 1, wherein the number of the obliquely placed condenser plates is 1 to 2.

3. 3. The vacuum purification apparatus for selenium residues according to claim 1, wherein the oblique condenser plate is inclined downward, and the angle between the oblique condenser plate and the horizontal direction is 1 to 5 degrees.

4. The vacuum purification apparatus for selenium residues according to claim 1 or 2, characterized in that, in the vertical distance between two adjacent oblique condenser plates, the distance between the oblique condenser plate and the adjacent flat condenser plate is independently 5 to 10 cm.

5. The diameter of the holes is 0.5 to 1 cm, and the density of the holes is 0.2 to 0.5 / cm ２ 2. The vacuum purification apparatus for selenium residues according to claim 1, wherein

6. 2. The vacuum purification apparatus for selenium residue according to claim 1, wherein the heating devices are arranged on the bottom and sidewall of the source container.

7. 2. The vacuum refining apparatus for selenium residue according to claim 1, wherein the cooling cover includes a furnace lid and a cooling shell, and the furnace lid and the cooling shell are not in contact with each other.

8. 8. The vacuum refining apparatus for selenium residue according to claim 7, wherein a coolant is filled in a gap formed by the furnace cover and the cooling shell.

9. placing the selenium residue before purification into a crucible of a raw material container, and using a heating device to heat the selenium residue to be purified; and using the vacuum pump, the collection system, the melting pipe, the cooling system, the condenser, and the crucible form a vacuum system, the pressure of the vacuum system is 10-100 Pa, and the heating temperature is 550-700°C; 3. A method for purifying selenium residue using a vacuum purification apparatus for selenium residue according to claim 1 or 2, characterized in that the gas generated by the heating enters a condenser, impurities in the gas pass through the condenser and are condensed and returned to the raw material container, selenium vapor in the gas passes through holes in the condenser into a cooling system and is cooled in the cooling cover to become liquid selenium, the liquid selenium is collected on the collection plate and enters the collection system through a melting pipe heated to 230°C by the heating system, thereby obtaining a selenium product.

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