An apparatus and method for vacuum purification of selenium residue

Abstract

The present invention belongs to the technical field of crude selenium purification, and provides a device and a method for vacuum purification of selenium residue. In the device for vacuum purification of selenium residue provided by the present invention, the inclined condensation plate and the horizontal condensation plate are arranged, which 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 device for vacuum purification of selenium residue provided by the present invention has a simple structure. The selenium residue to be purified forms vapor under the heating of the heating device; the impurities in the vapor are condensed and refluxed to the material container after passing through the inclined condensation plate and the horizontal condensation plate; while the purified selenium vapor enters the cooling system through the holes on the condenser, condenses on the cooling cover, converges into the convergence tray, and then passes through the melt pipeline and is collected in the collection system. The method provided by the present invention is simple to operate. The data of the examples show that the device 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] The present invention relates to the technical field of crude selenium purification, and in particular to a device and method for vacuum purifying selenium residue. Background Art

[0002] Selenium is widely used due to its excellent physical and chemical properties. As a metal additive, it can improve the machining performance of metals. Selenide semiconductors have shown great application value in the fields of biomedicine, photocatalysis, copper indium gallium selenide thin film solar cells, thermoelectric converters, etc. For example, new generation optoelectronic devices such as ZnSe and CdSe can be used to manufacture infrared detectors, night vision devices or resource exploration instruments and infrared window lenses. Adding a small amount of selenium to glass can change its optical properties and color, and can also be used as an ingredient in pigments and a substitute for vulcanizing agents in rubber production. Selenium also has important medical value and can weaken the toxicity of heavy metals such as mercury, cadmium, lead, and arsenic. With the booming development of the selenium industry, selenium is playing an increasingly important role in the fields of metallurgy, materials, chemical engineering, and medicine.

[0003] At present, the main methods for purifying selenium are chemical purification method and physical purification method. The chemical purification method mainly oxidizes crude selenium first, and then reduces selenium with appropriate chemical reagents to obtain refined selenium. The physical purification method utilizes the vapor pressure difference between selenium and elemental tellurium, copper, lead, iron, gold, silver and other impurity components in crude selenium. Selenium has a higher vapor pressure and is volatile, so it can be separated from impurities. Chinese Patent with Publication No. CN108975290A discloses a device and method for removing impurities from mercury-containing crude selenium. The device 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 complex, and the treatment process is as follows: Put mercury-containing crude selenium into the oxidation furnace from the feeding port. First, heat the crystallizer, then stop heating the crystallizer, then heat the oxidation furnace, and supply oxygen to the oxidation furnace through an oxygen delivery device. At the same time, start the induced draft fan and the spray pump. After the oxidation furnace keeps the temperature for reaction, stop heating the oxidation furnace. After the oxidation furnace cools down, open the discharge door of the crystallizer to discharge materials, and at the same time close the induced draft fan and the spray pump of the spray tower; At the same time, during the temperature-keeping reaction of the oxidation furnace, driven by the induced draft fan, the gaseous substances in the oxidation furnace enter the air inlet at the upper part of the crystallizer through the air outlet at the upper part of the oxidation furnace. The oxidation slag accumulates at the bottom of the oxidation furnace, and the selenium dioxide crystal product accumulates at the bottom of the crystallizer. The gaseous substances in the crystallizer further enter the air inlet at the upper part of the separator through the air outlet at the upper part of the crystallizer. The rework material crystals accumulate at the bottom of the separator and are returned to the oxidation furnace through the discharge port of the separator. The gaseous substances in the separator further enter the air inlet at the lower part of the spray tower through the air outlet of the separator by means of a water seal and an induced draft fan. The spray pump extracts the spray liquid from the water tank at the bottom of the spray tower and sprays the tail gas discharged after washing the air outlet of the separator through the water seal at the top of the spray tower. The spray liquid enters the filter through the water outlet of the water tank for filtration. After the filtrate is left standing and the pH value is adjusted, the filtrate enters the ion exchange column for mercury removal treatment. Finally, the mercury-removed liquid after mercury removal treatment enters the reduction tank for reduction treatment. The obtained selenium precipitate is centrifuged, washed with water to remove salt, and dried to obtain mercury-removed crude selenium, which is returned to the oxidation furnace. The treatment process is relatively long, and the purity of the obtained selenium product is relatively low, only reaching the 3N level. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a device and method for vacuum purifying selenium slag. The device for vacuum purifying selenium slag provided by the present invention has a simple structure, a simple treatment process, and a high purity of the obtained selenium product.

[0005] In order to achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0006] The present invention provides a device for vacuum purifying selenium slag, including a material container 1;

[0007] A condenser 2 located above the material container 1;

[0008] A cooling system 3 nested outside the condenser 2;

[0009] A collection system 4 communicated with the cooling system 3;

[0010] A heating device 11 is arranged on the outer side of the material container 1 for heating the material container 1;

[0011] The condenser 2 includes a condensation cover 21 and staggered condensation plates 22 arranged inside the condensation cover 21; the staggered condensation plates 22 include inclined condensation plates 221 and horizontal condensation plates 222; the inclined condensation plates 221 are located below the horizontal condensation plates 222; holes 23 are arranged on the side wall of the condensation cover 21; measured by the height in the vertical direction, the height of the holes 23 is greater than or equal to the height of the horizontal condensation plates 222;

[0012] The condenser 2 is communicated with the cooling system 3 through the holes 23;

[0013] The cooling system 3 includes a cooling cover 31 and a confluence plate 32 located at the lower part of the cooling cover 31;

[0014] The cooling system 3 is communicated with the collection system 4 through the confluence plate 32.

[0015] Preferably, the number of the inclined condensation plates 221 is 1 to 2.

[0016] Preferably, the inclined condensation plates 221 incline downward, and the included angle between the inclined condensation plates 221 and the horizontal direction is 1 to 5°.

[0017] Preferably, measured by the distance in the vertical direction, the distance between two adjacent inclined condensation plates 221 and the distance between the inclined condensation plates 221 and the adjacent horizontal condensation plates 222 are independently 5 to 10 cm.

[0018] Preferably, the aperture of the holes 23 is 0.5 to 1 cm, and the density of the holes 23 is 0.2 to 0.5 per cm 2 .

[0019] Preferably, the confluence plate 32 and the collection system 4 are communicated through a melt pipeline 5; a heating system 51 is arranged on the outer side of the melt pipeline 5.

[0020] Preferably, the heating device 11 is located at the bottom and side wall of the material container 1.

[0021] Preferably, the cooling cover 31 includes a furnace cover 311 and a cooling shell 312, and the furnace cover 311 and the cooling shell 312 are not in contact.

[0022] The present invention also provides a method for purifying selenium residue by using the device for purifying selenium residue described in the above technical solution, comprising the following steps:

[0023] Place the selenium residue to be purified in the material container 1, and heat the selenium residue to be purified by using the heating device 11;

[0024] The gas generated by the heating enters the condenser 2, and enters the cooling system 3 through the hole 23 for cooling. The purified selenium obtained by cooling is collected in the confluence plate 32 and enters the collection system 4.

[0025] Preferably, the heating temperature is 550-700 °C; the heating pressure is 10-100 Pa.

[0026] The present invention provides a device for vacuum purifying selenium residue, comprising a material container 1; a condenser 2 located above the material container 1; a cooling system 3 nested outside the condenser 2; a collection system 4 communicated with the cooling system 3; a heating device 11 is arranged on the outer side of the material container 1 for heating the material container 1; the condenser 2 comprises a condensation cover 21 and staggered condensation plates 22 arranged in the condensation cover 21; the staggered condensation plates 22 comprise inclined condensation plates 221 and horizontal condensation plates 222; the inclined condensation plates 221 are located below the horizontal condensation plates 222; a hole 23 is arranged on the side wall of the condensation cover 21; measured by the height in the vertical direction, the height of the hole 23 is greater than or equal to the height of the horizontal condensation plate 222; the condenser 2 is communicated with the cooling system 3 through the hole 23; the cooling system 3 comprises a cooling cover 31 and a confluence plate 32 located at the lower part of the cooling cover 31; the cooling system 3 is communicated with the collection system 4 through the confluence plate 32. In the present invention, the arrangement of the inclined condensation plate and the horizontal condensation plate 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 device for vacuum purifying selenium residue provided by the present invention has a simple structure. The data of the embodiment show that the device provided by the present invention can obtain selenium with a purity of 99.995% from selenium residue with a mass fraction of 60%.

[0027] Furthermore, the heating device 11 is located at the bottom and side wall of the material container 1, changing the bottom heating mode of the traditional vacuum furnace, greatly improving the melting speed of selenium, thereby improving the production efficiency and reducing the production cost.

[0028] Furthermore, the selenium product collected in the confluence plate 32 directly enters the collection system through the melt pipeline, without the need for the cooling system to clear the material, which is simple, convenient and easy to operate. At the same time, the heating system is used to heat the melt pipeline, avoiding material blockage and further improving the production efficiency.

[0029] The present invention also provides a method for purifying selenium residue by using the device for purifying selenium residue according to the above technical solution, including the following steps: placing the selenium residue to be purified in the material container 1, and heating the selenium residue to be purified by the heating device 11; the gas generated by the heating enters the condenser 2, and enters the cooling system 3 through the hole 23 for cooling, and the purified selenium obtained by cooling is collected in the confluence tray 32 and enters the collection system 4. Under the heating of the heating device, the selenium residue to be purified in the present invention forms vapor; the impurities in the vapor are condensed and refluxed to the material container after passing through the inclined condensation plate and the horizontal condensation plate; while the purified selenium vapor enters the cooling system through the hole on the condenser and condenses on the cooling cover, and converges into the confluence tray; and then is collected in the collection system. The method provided by the present invention is simple to operate. Description of the Drawings

[0030] Figure 1 It is a schematic diagram of the device for purifying selenium residue provided by the present invention;

[0031] Wherein, 1 is the material container, 11 is the heating device, 2 is the condenser, 21 is the condensation cover, 22 is the staggered condensation plate, 221 is the inclined condensation plate, 222 is the horizontal condensation plate, 23 is the hole, 3 is the cooling system, 31 is the cooling cover, 311 is the furnace cover, 312 is the cooling shell, 313 is the coolant, 32 is the confluence tray, 4 is the collection system, 41 is the opening, 5 is the melt pipeline, and 51 is the heating system. Detailed Embodiments

[0032] The present invention provides a device for purifying selenium residue, including a material container 1;

[0033] A condenser 2 located above the material container 1;

[0034] A cooling system 3 nested outside the condenser 2;

[0035] A collection system 4 communicated with the cooling system 3;

[0036] A heating device 11 is arranged on the outer side of the material container 1 for heating the material container 1;

[0037] The condenser 2 includes a condensation cover 21 and a staggered condensation plate 22 arranged inside the condensation cover 21; the staggered condensation plate 22 includes an inclined condensation plate 221 and a horizontal condensation plate 222; the inclined condensation plate 221 is located below the horizontal condensation plate 222; a hole 23 is arranged on the side wall of the condensation cover 21; measured by the height in the vertical direction, the height of the hole 23 is greater than or equal to the height of the horizontal condensation plate 222;

[0038] The condenser 2 is communicated with the cooling system 3 through the hole 23;

[0039] The cooling system 3 includes a cooling cover 31 and a collecting tray 32 located at the lower part of the cooling cover 31;

[0040] The cooling system 3 communicates with the collecting system 4 through the collecting tray 32.

[0041] In the present invention, unless otherwise specified, the raw materials used in the present invention are preferably commercially available products.

[0042] The device for vacuum purification of selenium residue provided by the present invention includes a material container 1. In the present invention, the material container 1 preferably includes a crucible; the material of the crucible preferably includes graphite or stainless steel. In the present invention, a heating device 11 is provided outside the material container 1 for heating the material container. In the present invention, the heating device 11 is preferably located at the bottom and side walls of the material container 1. The present invention uses the heating device 11 provided outside the material container 1 to heat the material container 1, changing the bottom heating mode of the traditional vacuum furnace, greatly increasing the melting speed of selenium, thereby improving production efficiency and reducing production costs.

[0043] The device for vacuum purification of selenium residue provided by the present invention includes a condenser 2. In the present invention, the condenser 2 includes a condensation cover 21 and staggered condensation plates 22 arranged inside the condensation cover 21. In the present invention, the staggered condensation plates 22 include inclined condensation plates 221 and horizontal condensation plates 222; the inclined condensation plates 221 are located below the horizontal condensation plates 222. In the present invention, the number of the inclined condensation plates 221 is preferably 1 to 2. In the present invention, the inclined condensation plates 221 preferably incline downward, and the angle between the inclined condensation plates 221 and the horizontal direction is preferably 1 to 5°. In the present invention, in terms of the vertical distance, the distance between two adjacent inclined condensation plates 221, and the distance between the inclined condensation plates 221 and the adjacent horizontal condensation plates 222 are independently preferably 5 to 10 cm. In the present invention, the areas of the inclined condensation plates 221 and the horizontal condensation plates 222 are preferably 1 / 2 to 2 / 3 of the cross-sectional area of the condensation cover 21. In the present invention, the inner diameter of the cooling cover is preferably the same as the inner diameter of the material container.

[0044] In the present invention, holes 23 are provided on the side wall of the condensation cover 21; in terms of the vertical height, the height of the holes 23 is greater than or equal to the height of the horizontal condensation plates 222. In the present invention, the aperture of the holes 23 is preferably 0.5 to 1 cm, and the density of the holes 23 is preferably 0.2 to 0.5 per cm 2 。

[0045] In the present invention, the materials of the condensation cover and the staggered condensation plates are independently preferably stainless steel.

[0046] In the present invention, the provision of the inclined condensation plate and the horizontal condensation plate improves the separation degree of selenium and other impurities in crude selenium and enhances the purity of the obtained selenium.

[0047] In the present invention, the part where the material container 1 contacts the condenser 2 is in a sealed state to prevent gas leakage.

[0048] The device for vacuum purification of 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 confluence plate 32 located at the lower part of the cooling cover. In the present invention, the cooling cover 31 preferably includes a furnace cover 311 and a cooling shell 312, and the furnace cover 311 and the cooling shell 312 do not contact. In the present invention, a coolant 313 is filled in the gap formed by the furnace cover 311 and the cooling shell 312. In the present invention, the coolant preferably includes water and / or oil, and more preferably water. In the present invention, the materials of the furnace cover, the cooling shell and the confluence plate are independently preferably stainless steel.

[0049] In the present invention, the condenser 2 communicates with the cooling system 3 through a hole 23.

[0050] The device for vacuum purification of selenium residue provided by the present invention includes a collection system 4. In the present invention, the collection system 4 is preferably a cylindrical barrel with an inner diameter of 50 - 70 cm. In the present invention, the material of the collection system is preferably stainless steel. In the present invention, an opening 41 is preferably provided on one side of the collection system 4, and the opening 41 is preferably connected to a vacuum pump; the vacuum pump, the collection system, the melt pipeline, the cooling system, the condenser and the crucible form a vacuum pumping system.

[0051] In the present invention, the confluence plate 32 in the cooling system 3 and the collection system 4 are connected through a melt pipeline 5. In the present invention, a heating system 51 is preferably provided on the outer side of the melt pipeline 5. In the present invention, the material of the melt pipeline 5 preferably includes stainless steel. In a specific embodiment of the present invention, the diameter of the melt pipeline is preferably 6 cm.

[0052] The present invention also provides a method for purifying selenium residue by using the device for vacuum purification of selenium residue according to the above technical solution, including the following steps:

[0053] Place the selenium residue to be purified in the material container 1 and heat the selenium residue to be purified by using a heating device 11;

[0054] The gas generated by the heating enters the condenser 2 and enters the cooling system 3 through the hole 23 for cooling. The purified selenium obtained by cooling is collected in the confluence plate 32 and enters the collection system 4.

[0055] In the present invention, the heating temperature is preferably 550 - 700 °C, and the rate of increasing the temperature to the heating temperature is preferably 2 - 5 °C / min. In the present invention, the heating temperature is achieved by the heating device 11. In the present invention, the heating pressure is preferably 10 - 100 Pa. In the present invention, the heating pressure is achieved by the vacuum pumping system. In the present invention, the heating time is preferably 6 - 10 h.

[0056] In the method of the present invention, the selenium residue to be purified forms vapor under the heating of the heating device; the impurities in the vapor are condensed and refluxed into the material container after passing through the inclined condensation plate and the horizontal condensation plate; while the purified selenium vapor enters the cooling system through the holes of the condenser, condenses on the cooling cover, and then converges into the convergence tray; and then is collected in the collection system through the melt pipeline.

[0057] The device and method for vacuum purification of selenium residue provided by the present invention are described in detail below in conjunction with embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0058] The following embodiments use Figure 1 the device shown, Figure 1 in which, the number of inclined condensation plates is 2, the number of horizontal condensation plates is 1, the inclined condensation plate inclines downward and forms an angle of 5° with the horizontal direction; measured by the vertical distance, the distance between adjacent inclined condensation plates and between the inclined condensation plate and the horizontal condensation plate is 5 cm; the material container is a graphite crucible, and the inner diameter of the graphite crucible is 55 cm; the areas of the horizontal condensation plate and the inclined condensation plate are 2 / 3 of the cross-sectional area of the crucible, the aperture of the hole is 1 cm, and the density of the holes is 0.5 per cm 2 , the diameter of the melt pipeline is 6 cm, the materials of the condenser, the cooling system, the melt pipeline and the collection system are stainless steel, and the coolant is cooling water.

[0059] Example 1

[0060] After melting 150 kg of selenium residue with a mass fraction of 60%, it is put into the crucible, lifted into the heating device by an electric hoist, the heating device is started, the conditions for purifying selenium are set as the heating rate of 5 °C / min, the distillation temperature of 550 °C, and the distillation time of 6 h, the vacuum system is turned on, and the pressure is controlled to be 20 Pa. During the heating process, the selenium in the crucible evaporates to form vapor, passes through the inclined condensation plate, the horizontal condensation plate, passes through the holes, enters the cooling system, condenses into liquid selenium in the cooling cover of the cooling system, gathers in the convergence tray, and is transported to the collection system through the melt pipeline; the melt pipeline is heated to 230 °C by the heating system, and finally 128.3 kg of selenium product is obtained, and the volatilization rate reaches 87.3%.

[0061] The obtained high-quality selenium was tested for purity of refined selenium using an inductively coupled plasma mass spectrometer (ICP-MS) with reference to the non-ferrous metal industry standards YS / T 223-2007 and YS / T 226.13-2009 of the People's Republic of China. The purity of selenium was 99.992%.

[0062] Example 2

[0063] After melting 200 kg of selenium residue with a mass fraction of 60%, it was placed in a crucible and dropped into the heating device using a hoist. The heating device was started, and the conditions for purifying selenium were set as follows: the heating rate was 10 °C / min, the distillation temperature was 680 °C, and the distillation time was 8 h. The vacuum system was turned on, and the pressure was controlled at 10 Pa. During the heating process, the selenium in the crucible evaporated to form vapor, passed through the inclined condensation plate, the horizontal condensation plate, and through the holes, and entered the cooling system. It condensed into liquid selenium in the cooling hood of the cooling system, gathered in the confluence plate, and was transported to the collection system through the melt pipeline; the melt pipeline was heated to 230 °C by the heating system, and finally 199 kg of selenium product was obtained, and the volatilization rate reached 99.5%.

[0064] The obtained high-quality selenium was tested for purity of refined selenium using an inductively coupled plasma mass spectrometer (ICP-MS) with reference to the non-ferrous metal industry standards YS / T 223-2007 and YS / T 226.13-2009 of the People's Republic of China. The purity of selenium was 99.995%.

[0065] Example 3

[0066] After melting 300 kg of selenium residue with a mass fraction of 60%, it was placed in a crucible and dropped into the heating device using a hoist. The heating device was started, and the conditions for purifying selenium were set as follows: the heating rate was 10 °C / min, the distillation temperature was 700 °C, and the distillation time was 10 h. The vacuum system was turned on, and the pressure was controlled at 50 Pa. During the heating process, the selenium in the crucible evaporated to form vapor, passed through the inclined condensation plate, the horizontal condensation plate, and through the holes, and entered the cooling system. It condensed into liquid selenium in the cooling hood of the cooling system, gathered in the confluence plate, and was transported to the collection system through the melt pipeline; the melt pipeline was heated to 230 °C by the heating system, and finally 294 kg of selenium product was obtained, and the volatilization rate reached 98.0%.

[0067] The obtained high-quality selenium was tested for purity of refined selenium using an inductively coupled plasma mass spectrometer (ICP-MS) with reference to the non-ferrous metal industry standards YS / T 223-2007 and YS / T 226.13-2009 of the People's Republic of China. The purity of selenium was 99.991%.

[0068] As can be seen from the above embodiments, for the method provided by the present invention, the direct recovery rate of selenium is finally greater than 99.5%, and the purity of selenium exceeds 99.995%. The production scale of the present invention can reach more than 300 kg, with high production efficiency and high product purity, and impurities such as tellurium, copper, and lead are enriched.

[0069] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A device for vacuum purification of selenium residue, characterized in that, it includes a material container (1); a condenser (2) located above the material container (1); a cooling system (3) nested outside the condenser (2); a collection system (4) communicated with the cooling system (3); a heating device (11) is arranged on the outer side of the material container (1) for heating the material container (1); the condenser (2) includes a condensation cover (21) and staggered condensation plates (22) arranged in the condensation cover (21); the staggered condensation plates (22) include inclined condensation plates (221) and horizontal condensation plates (222); the inclined condensation plates (221) are located below the horizontal condensation plates (222); holes (23) are arranged on the side wall of the condensation cover (21); measured by the height in the vertical direction, the height of the holes (23) is greater than or equal to the height of the horizontal condensation plates (222); the condenser (2) is communicated with the cooling system (3) through the holes (23); the cooling system (3) includes a cooling cover (31) and a confluence plate (32) located at the lower part of the cooling cover (31); the cooling system (3) is communicated with the collection system (4) through the confluence plate (32); the cooling cover (31) includes a furnace cover (311) and a cooling shell (312), and the furnace cover (311) and the cooling shell (312) do not contact; a coolant (313) is filled in the gap formed by the furnace cover (311) and the cooling shell (312).

2. The device according to claim 1, characterized in that, the number of the inclined condensation plates (221) is 1 to 2.

3. The device according to claim 1 or 2, characterized in that, the inclined condensation plates (221) are inclined downward, and the included angle between the inclined condensation plates (221) and the horizontal direction is 1 to 5°.

4. The device according to claim 1 or 2, characterized in that, measured by the distance in the vertical direction, the distance between two adjacent inclined condensation plates (221), and the distance between the inclined condensation plates (221) and the adjacent horizontal condensation plates (222) are independently 5 to 10 cm.

5. The device according to claim 1, characterized in that, The aperture of the hole (23) is 0.5 to 1 cm, and the density of the holes (23) is 0.2 to 0.5 holes / cm 2 .

6. The device according to claim 1, characterized in that, the confluence plate (32) and the collection system (4) are communicated through a melt pipeline (5); a heating system (51) is arranged on the outer side of the melt pipeline (5).

7. The device according to claim 1, characterized in that, the heating device (11) is located at the bottom and side wall of the material container (1).

8. A method for purifying selenium residue by using the device for vacuum purifying selenium residue according to any one of claims 1 to 7, characterized in that, it includes the following steps: placing the selenium residue to be purified in the material container (1), and using the heating device (11) to heat the selenium residue to be purified; the gas generated by the heating enters the condenser (2), and enters the cooling system (3) through the holes (23) for cooling, and the purified selenium obtained by cooling is collected in the confluence plate (32) and enters the collection system (4).

9. The method according to claim 8, It is characterized in that the heating temperature is 550 to 700 °C; the heating pressure is 10 to 100 Pa.

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