Device and method for separating and purifying crude selenium

Abstract

The present invention discloses a device and method for separating and purifying crude selenium, and belongs to the technical field of purification of scattered metals. The present invention places crude selenium in a crucible of a vacuum distillation furnace, places an upper and lower condenser above the crucible, and fills the lower condenser with metal particles; then starts vacuum distillation, and collects selenium products in the upper condenser; the metal particles are one or two of Pb and Cu. The present invention adopts two-stage condensation combined with Pb and / or Cu metal particles, and purifies crude selenium by vacuum distillation. The purity of the refined selenium product is 99.9% to 99.99%, wherein the tellurium content can be reduced to below 0.007%.

Description

Technical Field

[0001] The invention belongs to the technical field of rare metal purification, and particularly relates to a device and method for separating and purifying crude selenium. Background Art

[0002] Selenium, a typical rare earth metal, is widely used in the electronics industry due to its unique conductivity and photoelectric effect, such as in copper indium gallium selenide thin-film photovoltaic cells. Currently, the raw materials for crude selenium extraction are copper anode mud, acid mud, and secondary selenium resources. Copper anode mud is the primary raw material, and is primarily processed through sulfuric acid roasting.

[0003] With the development of high-tech materials, selenium has become an increasingly indispensable raw material for the preparation of new materials. The demand for refined selenium is increasing rapidly, and my country's production cannot meet market demand, requiring large-scale imports. Currently, tellurium is one of the most difficult impurity elements to remove during the preparation of refined selenium. Currently, the removal of tellurium impurities is primarily achieved through chemical methods. Crude selenium is oxidized to volatilize selenium dioxide, which is then condensed and collected, absorbed in water to produce selenious acid, and finally reduced with sulfur dioxide to produce refined selenium. This method is complex.

[0004] Patent CN113277483A discloses a method for separating and recovering selenium and tellurium materials. This method involves oxidation and potential control, leaching, filtration, pH adjustment, and filtration and precipitation to obtain crude selenium and tellurium dioxide. While this process effectively separates selenium and tellurium, the resulting selenium is only crude, not highly purified, and the process is complex.

[0005] Patent CN112408339A discloses a method for purifying crude selenium containing tellurium impurities. This process involves mixing molten sodium nitrate with the raw material, stirring until the reaction is complete, and then allowing it to stand for a period of time to produce 99.99% high-purity selenium. This process offers good purification results, but the process is complex and difficult to control. Summary of the Invention

[0006] In view of the above shortcomings of the prior art, the present invention provides a device and method for separating and purifying crude selenium.

[0007] To achieve the above object, the technical solution adopted by the present invention is:

[0008] A method for separating and purifying crude selenium comprises the following steps:

[0009] (1) Place crude selenium in a crucible of a vacuum distillation furnace, place upper and lower condensers above the crucible, and fill the lower condenser with metal particles;

[0010] (2) Vacuum distillation is then started and the selenium product is collected in the upper condenser.

[0011] The metal particles are one or both of Pb and Cu.

[0012] As a preferred embodiment of the present invention, the metal particles have a particle size of 0.2-1 mm and a purity greater than 99.9%.

[0013] As a preferred embodiment of the present invention, the crude selenium comprises raw materials with the following mass percentages: 93-99% Se, 0.1-6% Te, and the rest being trace elements of Pb, Fe, S, Sn, As, Ni and Cu with a total amount not exceeding 1%.

[0014] As a preferred embodiment of the present invention, the vacuum distillation temperature is 300-500°C, the time is 60-180 minutes, and the pressure is 1-100 Pa.

[0015] The present invention also claims protection for the device for separating and purifying crude selenium, which includes a vacuum distillation furnace and a condenser body; the condenser body is located above the crucible in the vacuum distillation furnace, and an air inlet is provided below it, which is sealed with the crucible through the air inlet; a baffle is provided at the air inlet, and a through hole is provided on the baffle; a partition with distribution holes is provided inside the condenser body, dividing the condenser body into two layers of condensers, the lower condenser being filled with metal particles.

[0016] As a preferred embodiment of the present invention, the vacuum distillation furnace is a vacuum distillation furnace commonly used in the art.

[0017] As a preferred embodiment of the present invention, the diameters of the through holes on the baffle and the holes on the separator are smaller than the size of the metal particles.

[0018] As a preferred embodiment of the present invention, the diameters of the through holes on the baffle and the holes on the partition are 0.1-0.5 mm.

[0019] As a preferred embodiment of the present invention, the filling rate of the metal particles in the lower condenser is 50%-100%.

[0020] As a preferred embodiment of the present invention, the condenser body, baffles and partitions are made of quartz or stainless steel.

[0021] The invention controls the amount of raw materials so that the condenser does not generate reflux, waits for the temperature of the distillation furnace to drop to room temperature, and uses tools to scrape and collect the selenium product from the upper condenser.

[0022] Compared with the prior art, the present invention has the following beneficial effects: the present invention adopts two-stage condensation in combination with one or two of metal particles Pb and Cu, and reacts Te, Pb, Fe, S, Sn, As, Ni and Cu impurities in crude selenium with the metal particles through vacuum distillation, and the generated compounds remain in the lower condenser for condensation; the selenium that does not participate in the reaction enters the upper condenser to obtain refined selenium, and the purity of the refined selenium product is 99.9% to 99.99%, wherein the tellurium content can be reduced to below 0.007%. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the device for separating and purifying crude selenium. DETAILED DESCRIPTION

[0024] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0025] Example 1

[0026] like Figure 1 As shown, a device for separating and purifying crude selenium includes a vacuum distillation furnace and a condenser body; the condenser body is located above the crucible placed in the vacuum distillation furnace, and an air inlet is provided below the condenser body, which is sealed with the crucible through the air inlet; a baffle is provided at the air inlet, and a through hole is provided on the baffle to facilitate the steam generated during the distillation of crude selenium to enter the condenser body, and prevent metal particles from falling into the crucible; a partition with distribution holes is provided inside the condenser body to divide the condenser body into an upper and lower structure, the upper structure is an upper condenser, and the lower structure is a lower condenser, and the lower condenser is filled with metal particles.

[0027] The diameters of the through holes on the baffle and the holes on the partition are 0.1-0.5 mm; the particle size of the metal particles is 0.2-1 mm. In this embodiment, the diameters of the through holes on the baffle and the holes on the partition are 0.3 mm, and the particle size of the metal particles is 0.5 mm.

[0028] The material of the condenser body, baffles and partitions is quartz or stainless steel. In this embodiment, the material of the condenser body, baffles and partitions is quartz.

[0029] Example 2

[0030] A method for separating and purifying crude selenium using the apparatus for separating and purifying crude selenium described in Example 1 comprises the following steps:

[0031] (1) Place 10 g of crude selenium in a graphite crucible and place it in a vacuum distillation furnace. The mass fraction of Se in the crude selenium is 94.15%, the mass fraction of Te is 5.56%, and the rest are trace impurity elements such as Pb, Fe, S, Sn, As, Ni and Cu. Pure copper particles with a purity of 99.9% are placed in the lower condenser. Fill the entire lower condenser, and then place the condenser body in a vacuum distillation furnace above the crucible and seal it with the crucible.

[0032] (2) Vacuum distillation was then started at a temperature of 300°C for 180 minutes at a pressure of 1-100 Pa. After the distillation was completed, the selenium product from the upper condenser was taken out after the furnace body condensed. With reference to the provisions of the nonferrous metal industry standard of the People's Republic of China YS / T223-2007, the selenium product was quantitatively analyzed by ICP-AES and chemical titration to find that the purity was 99.965%, and the tellurium content in the selenium product was reduced to below 0.007%.

[0033] Example 3

[0034] A method for separating and purifying crude selenium using the apparatus for separating and purifying crude selenium described in Example 1 comprises the following steps:

[0035] (1) Place 10 g of crude selenium in a graphite crucible and place it in a vacuum distillation furnace. The mass fraction of Se in the crude selenium is 96.28%, the mass fraction of Te is 3.52%, and the rest are trace impurity elements. Pure copper particles with a purity of 99.9% and pure lead particles with a purity of 99.9% are placed in the lower condenser. Fill the entire lower condenser, and then place the condenser body in a vacuum distillation furnace above the crucible and seal it with the crucible.

[0036] (2) Vacuum distillation was then started at a temperature of 380°C for 110 minutes at a pressure of 1-100 Pa. After the distillation was completed, the selenium product from the upper condenser was taken out after the furnace body condensed. With reference to the provisions of the nonferrous metal industry standard YS / T223-2007 of the People's Republic of China, the selenium product was quantitatively analyzed by ICP-AES and chemical titration to find that the purity was 99.959%, ​​and the tellurium content in the selenium product was reduced to below 0.007%.

[0037] Example 4

[0038] A method for separating and purifying crude selenium using the apparatus for separating and purifying crude selenium described in Example 1 comprises the following steps:

[0039] (1) Place 10g of crude selenium in a graphite crucible and place it in a vacuum distillation furnace. The mass fraction of Se in the crude selenium is 97.28%, the mass fraction of Te is 2.56%, and the rest are trace impurity elements. Put pure lead particles with a purity of 99% into the lower condenser and fill the entire lower condenser. Then place the condenser body in the vacuum distillation furnace above the crucible and seal it with the crucible.

[0040] (2) Vacuum distillation was then started at a temperature of 500°C for 60 minutes at a pressure of 1-100 Pa. After the distillation was completed, the selenium product from the upper condenser was taken out after the furnace body condensed. With reference to the provisions of the nonferrous metal industry standard of the People's Republic of China YS / T223-2007, the selenium product was quantitatively analyzed by ICP-AES and chemical titration to find that the purity was 99.992% and the tellurium content in the selenium product was reduced to below 0.007%.

[0041] Comparative Example 1

[0042] A method for separating and purifying crude selenium comprises the following steps:

[0043] 10 g of crude selenium was placed in a graphite crucible and placed in a vacuum distillation furnace. The mass fraction of Se in the crude selenium was 94.15%, the mass fraction of Te was 5.56%, and the rest were trace impurity elements. The distillation temperature was 340°C, the temperature was kept for 140 minutes, and the pressure was 1-100 Pa. After the distillation was completed, the furnace body was condensed and the selenium product on the condenser was taken out. Referring to the provisions of the non-ferrous metal industry standard YS / T223-2007 of the People's Republic of China, the selenium product was quantitatively analyzed by ICP-AES and chemical titration to find that the purity was 96.225% and the tellurium content in the selenium product was 2.45%.

[0044] Comparative Example 2

[0045] A method for separating and purifying crude selenium comprises the following steps:

[0046] 10 g of crude selenium was placed in a graphite crucible and placed in a vacuum distillation furnace. The mass fraction of Se in the crude selenium was 96.28%, the mass fraction of Te was 3.52%, and the rest were trace impurity elements. The distillation temperature was 380°C, the temperature was kept for 110 minutes, and the pressure was 1-100 Pa. After the distillation was completed, the furnace body was condensed and the selenium product on the condenser was taken out. Referring to the provisions of the non-ferrous metal industry standard YS / T223-2007 of the People's Republic of China, the selenium product was quantitatively analyzed by ICP-AES and chemical titration to obtain a purity of 97.128% and a tellurium content of 2.16%.

[0047] Comparative Example 3

[0048] A method for separating and purifying crude selenium comprises the following steps:

[0049] 10 g of crude selenium was placed in a graphite crucible and placed in a vacuum distillation furnace. The mass fraction of Se in the crude selenium was 97.28%, the mass fraction of Te was 2.56%, and the rest were trace impurity elements. The distillation temperature was 420°C, the temperature was kept for 90 minutes, and the pressure was 1-100 Pa. After the distillation was completed, the furnace body was condensed and the selenium product on the condenser was taken out. Referring to the provisions of the non-ferrous metal industry standard YS / T223-2007 of the People's Republic of China, the selenium product was quantitatively analyzed by ICP-AES and chemical titration to find that the purity was 98.62% and the tellurium content in the selenium product was 1.24%.

[0050] Comparative Example 4

[0051] The method for separating and purifying crude selenium in this comparative example using the apparatus for separating and purifying crude selenium in Example 1 is different from that in Example 2 only in that the pure copper particles in step (1) are replaced with pure iron particles.

[0052] According to the provisions of the nonferrous metal industry standard YS / T223-2007 of the People's Republic of China, the selenium product was quantitatively analyzed by ICP-AES and chemical titration, and the purity was 97.15%, and the tellurium content in the selenium product was 2.11%.

[0053] Since Te, Pb, Fe, S, Sn, As, Ni and Cu impurities in the crude selenium cannot react with the pure iron particles, Comparative Example 4 has no purification effect.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for separating and purifying crude selenium, characterized in that: The steps include: (1) placing crude selenium in a crucible of a vacuum distillation furnace, placing an upper and lower condenser above the crucible, and filling the lower condenser with metal particles; (2) vacuum distillation is then started, and the selenium product is collected in the upper condenser; The metal particles are one or two of Pb and Cu; The crude selenium comprises the following elements in percentage by mass: 93-99% Se, 0.1-6% Te, and the rest are trace elements of Pb, Fe, S, Sn, As, Ni and Cu with a total amount not exceeding 1%.

2. The method for separating and purifying crude selenium according to claim 1, characterized in that: The particle size of the metal particles is 0.2-1 mm, and the purity is greater than 99.9%.

3. The method for separating and purifying crude selenium according to claim 1, characterized in that: The vacuum distillation temperature is 300-500° C., the time is 60-180 min, and the pressure is 1-100 Pa.

4. The device for separating and purifying crude selenium according to any one of claims 1 to 3, characterized in that: It includes a vacuum distillation furnace and a condenser body; the condenser body is fixed above the crucible in the vacuum distillation furnace, and an air inlet is arranged below the condenser body, and is sealed and connected to the crucible through the air inlet; a baffle is arranged at the air inlet, and a through hole is arranged on the baffle; a partition with distribution holes is arranged inside the condenser body, and the condenser body is divided into an upper and lower condenser layer, and the lower condenser is filled with metal particles.

5. The device for separating and purifying crude selenium as claimed in claim 4, characterized in that: The diameters of the through holes on the baffle and the holes on the partition are smaller than the size of the metal particles.

6. The device for separating and purifying crude selenium as claimed in claim 4, characterized in that: The condenser body, baffle and partition are made of quartz or stainless steel.

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