A method for producing 6n selenium from 2n selenium
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- KUNMING UNIV OF SCI & TECH
- Filing Date
- 2024-01-25
- Publication Date
- 2026-06-05
Smart Images
Figure CN117963848B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of high-purity metal preparation, and more particularly to a method for preparing 6N selenium from 2N selenium. Background Technology
[0002] Selenium is an essential trace element in living organisms and is also an indispensable element in the development and preparation of high-tech materials.
[0003] Currently, approximately 90% of crude selenium is produced from anode slime. Selenium extraction from copper anode slime mainly involves two processes: pyrometallurgical and hydrometallurgical. However, the selenium obtained through these two processes is only industrial-grade and not suitable for widespread application; further purification is needed to obtain high-purity selenium. Methods for selenium purification mainly include physical and chemical methods, such as hydrogen selenide decomposition, zone melting, sodium sulfite leaching, oxidative volatilization, and vacuum distillation. While zone melting can purify crude selenium to 5N, the process is complex, requires multiple repetitions, has high production costs, and low purification efficiency. Hydrogen selenide decomposition requires careful attention to the toxicity of hydrogen selenide gas and must be carried out in a well-ventilated environment. Vacuum distillation has specific requirements for the raw material phase and is difficult to separate metals with similar saturated vapor pressures and separation coefficients.
[0004] Patent CN112408339A discloses a method for purifying crude selenium containing tellurium impurities. This method involves heating sodium nitrate to a molten state, controlling the temperature of the molten sodium nitrate at 300℃~310℃, thoroughly mixing the crude selenium material with the molten sodium nitrate, and stirring while maintaining the temperature at 350℃~360℃ until the reaction is complete. After standing for a period of time, the melt is removed, and after cooling, refined selenium with a purity of 99.99% is obtained. This method is simple, safe, environmentally friendly, cost-effective, and does not corrode equipment; however, the purity of the crude selenium after purification does not meet the 6N standard. Summary of the Invention
[0005] The purpose of this invention is to provide a method for preparing 6N selenium from 2N selenium, which can prepare 6N selenium from 2N selenium.
[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:
[0007] This invention provides a method for preparing 6N selenium from 2N selenium, comprising the following steps:
[0008] Selenium dioxide vapor was obtained by oxidizing and roasting 2N selenium.
[0009] The selenium dioxide vapor is mixed with water to carry out a chemical reaction, resulting in a selenite solution.
[0010] The selenite solution is mixed with a reducing agent to carry out a reduction reaction to obtain 3N and / or 4N selenium.
[0011] After melting the 3N and / or 4N selenium, the crystallizer is immersed in the resulting melt for rotational crystallization to obtain 6N selenium.
[0012] Preferably, the 2N selenium comprises, by mass fraction, 0.01–0.5% Te, 0.01–0.3% Pb, 0.02–0.1% Cu, 0.01–0.2% Fe, 0.01–0.3% S, 0.01–0.05% Sn, 0.01–0.05% As, 0.01–0.06% Ni, and the balance being Se.
[0013] Preferably, the oxidative calcination temperature is 700–900°C and the time is 1–2 hours.
[0014] Preferably, the reducing agent includes sulfur dioxide and / or sodium sulfite.
[0015] Preferably, the molar ratio of the reducing agent to selenite is 1.2 to 1.8:1.
[0016] Preferably, the reduction temperature is 30–70°C and the time is 30–90 min.
[0017] Preferably, the temperature of the crystallizer is 210–300°C, and the temperature of the melt is 230–330°C.
[0018] Preferably, the rotational crystallization is a melt rotation, and the rotational speed of the melt is 80-130 r / min.
[0019] Preferably, the rotational crystallization time is 70–140 min.
[0020] This invention provides a method for preparing 6N selenium from 2N selenium, comprising the following steps: oxidizing and roasting 2N selenium to obtain selenium dioxide vapor; mixing the selenium dioxide vapor with water to carry out a chemical reaction to obtain a selenite solution; mixing the selenite solution with a reducing agent to carry out a reduction reaction to obtain 3N and / or 4N selenium; melting the 3N and / or 4N selenium and immersing a crystallizer into the resulting melt for rotational crystallization to obtain 6N selenium.
[0021] This invention involves oxidative roasting of crude selenium raw materials, where selenium reacts with oxygen to generate selenium dioxide, removing high-boiling-point impurities. Selenium is enriched by utilizing the water-soluble nature of selenium dioxide, while water-insoluble impurities (such as selenium dioxide) are removed, achieving selenium purification to obtain 3N and / or 4N selenium. Further purification of 3N and / or 4N selenium is achieved through rotational crystallization. Utilizing the different physical properties of metals during cooling and solidification, impurities such as lead, tellurium, and arsenic in 3N and / or 4N selenium tend to be concentrated in the solid phase, while selenium remains in the liquid phase, achieving further purification and yielding ultra-high purity selenium with a purity exceeding 99.9999%. Compared to traditional purification processes, this invention offers advantages such as high impurity removal rate and excellent purification effect. Attached Figure Description
[0022] Figure 1 This is a process flow diagram of an embodiment of the present invention. Detailed Implementation
[0023] This invention provides a method for preparing 6N selenium from 2N selenium, comprising the following steps:
[0024] Selenium dioxide vapor was obtained by oxidizing and roasting 2N selenium.
[0025] The selenium dioxide vapor is mixed with water to carry out a chemical reaction, resulting in a selenite solution.
[0026] The selenite solution is mixed with a reducing agent to carry out a reduction reaction to obtain 3N and / or 4N selenium.
[0027] After melting the 3N and / or 4N selenium, the crystallizer is immersed in the resulting melt for rotational crystallization to obtain 6N selenium.
[0028] This invention involves oxidizing and roasting 2N selenium to obtain selenium dioxide vapor.
[0029] In this invention, the 2N selenium preferably comprises 0.01 to 0.5% Te by mass fraction, more preferably 0.1 to 0.4%, and even more preferably 0.2 to 0.3%.
[0030] The 2N selenium preferably comprises 0.01-0.3% Pb by mass fraction, more preferably 0.08-0.2%, and even more preferably 0.1-0.12%.
[0031] The 2N selenium preferably comprises 0.02-0.1% Cu by mass fraction, more preferably 0.06-0.08%;
[0032] The 2N selenium preferably comprises 0.01-0.2% Fe, more preferably 0.1-0.16%, and even more preferably 0.12-0.15% by mass fraction;
[0033] The 2N selenium preferably comprises 0.01-0.3% by mass fraction, more preferably 0.08-0.2%, and even more preferably 0.1-0.12%.
[0034] The 2N selenium preferably comprises 0.01 to 0.05% Sn by mass fraction, more preferably 0.02 to 0.03%;
[0035] The 2N selenium preferably comprises 0.01 to 0.05% As by mass fraction, more preferably 0.02 to 0.03%;
[0036] The 2N selenium preferably comprises 0.01-0.06% Ni by mass fraction, more preferably 0.02-0.05%, and even more preferably 0.04-0.05%.
[0037] The 2N selenium preferably includes a Se balance by mass fraction.
[0038] In this invention, the oxidative calcination temperature is preferably 700-900℃, more preferably 750-800℃, and the time is preferably 1-2h, more preferably 1.2-1.5h.
[0039] After obtaining selenium dioxide vapor, the present invention mixes the selenium dioxide vapor with water to carry out a chemical reaction to obtain a selenite solution.
[0040] In this invention, the water preferably comprises deionized water. There is no particular limitation on the amount of water used; it is sufficient to completely absorb the selenium dioxide vapor.
[0041] After obtaining the selenite solution, the present invention mixes the selenite solution with a reducing agent to carry out a reduction reaction to obtain 3N and / or 4N selenium.
[0042] In this invention, the reducing agent preferably includes sulfur dioxide and / or sodium sulfite; the molar ratio of the reducing agent to selenite is preferably 1.2 to 1.8:1, more preferably 1.4 to 1.6:1.
[0043] In this invention, the temperature of the reduction reaction is preferably 30-70°C, more preferably 40-60°C; the time is preferably 30-90 min, more preferably 40-80 min, and even more preferably 50-60 min.
[0044] After obtaining 3N and / or 4N selenium, the present invention melts the 3N and / or 4N selenium and then immerses a crystallizer into the resulting melt for rotational crystallization to obtain 6N selenium.
[0045] In this invention, the crystallizer is preferably made of quartz or graphite; the temperature of the crystallizer is preferably 210–300°C, more preferably 220–280°C; and the temperature of the melt is preferably 230–330°C, more preferably 250–300°C.
[0046] In this invention, the melting and rotational crystallization are preferably carried out under the protection of a protective gas; the rotational crystallization is preferably performed by rotating the melt, the rotational speed of which is preferably 80–130 r / min, more preferably 100–120 r / min; the rotational crystallization time is preferably 70–140 min, more preferably 80–120 min, and even more preferably 90–100 min. In this invention, the rotation of the melt is preferably driven by a crucible, and the rotational speed of the melt is consistent with the rotational speed of the crucible.
[0047] The process flow diagram of the method in the embodiments of the present invention is as follows: Figure 1 As shown: crude selenium is oxidized and roasted, and then the product is reduced with sulfur dioxide to obtain refined selenium; the refined selenium is then subjected to rotational crystallization under argon protection to obtain 6N high-purity selenium.
[0048] The method for preparing 6N selenium from 2N selenium provided by the present invention will be described in detail below with reference to the embodiments, but these should not be construed as limiting the scope of protection of the present invention.
[0049] Example 1
[0050] The crude selenium raw material (Se 99.2wt%, Te 0.3wt%, Pb 0.1wt%, Cu 0.08wt%, Fe 0.1wt%, S 0.1wt%, Sn 0.05wt%, As 0.03wt% and Ni) was used. 0.04 wt% of crude selenium was placed in a roasting furnace for oxidative roasting for 1 hour, with the roasting temperature controlled at 770℃ to oxidize crude selenium into selenium dioxide. The volatilized selenium dioxide was condensed and absorbed with water to obtain a selenite solution. The selenite solution was reduced with sulfur dioxide at 40℃ (molar ratio of sulfur dioxide to selenite was 1.4:1) for 30 minutes to obtain refined selenium. The refined selenium was placed in a crystallization furnace, and the temperature of the crystallization furnace was increased under argon protection to convert the refined selenium in the crucible into molten refined selenium. After the refined selenium in the crucible was completely converted into molten refined selenium, a cold body at 230℃ was inserted into a melt at 250℃ for rotational crystallization. The crucible rotation speed was 90 r / min, and the temperature of the cold body was controlled at 230℃ during the crystallization process. After crystallization for 80 minutes, the crystallized product was taken out to obtain ultra-high purity selenium with a purity of 99.99993%.
[0051] Example 2
[0052] The crude selenium raw material (Se 99.5wt%, Te 0.2wt%, Pb 0.08wt%, Cu 0.02wt%, Fe 0.1wt%, S 0.03wt%, Sn 0.03wt%, As 0.02wt% and Ni) was used. 0.02 wt% of crude selenium was placed in a roasting furnace for oxidative roasting for 1.2 h at a controlled roasting temperature of 800 °C to oxidize crude selenium into selenium dioxide. The volatilized selenium dioxide was condensed and absorbed with water to obtain a selenite solution. The selenite solution was reduced with sulfur dioxide (molar ratio of sulfur dioxide to selenite is 1.5:1) at 45 °C for 40 min to obtain refined selenium. The refined selenium was placed in a crystallization furnace, and the temperature of the crystallization furnace was increased under argon protection to convert the refined selenium in the crucible into molten refined selenium. After the refined selenium in the crucible was completely converted into molten refined selenium, a cold body at a temperature of 245 °C was inserted into a melt at a temperature of 270 °C for rotational crystallization. The crucible rotation speed was 100 r / min, and the temperature of the cold body was controlled at 245 °C during the crystallization process. After crystallization for 100 min, the crystallized product was taken out to obtain ultra-high purity selenium with a purity of 99.99995%.
[0053] Example 3
[0054] The crude selenium raw material (Se 99.7wt%, Te 0.1wt%, Pb 0.03wt%, Cu 0.02wt%, Fe 0.07wt%, S 0.04wt%, Sn 0.01wt%, As 0.02wt% and Ni) was used. 0.01 wt% of crude selenium was placed in a roasting furnace for oxidative roasting for 1.5 h at a controlled roasting temperature of 820 °C to oxidize crude selenium to selenium dioxide. The volatilized selenium dioxide was condensed and absorbed with water to obtain a selenite solution. The selenite solution was reduced with sulfur dioxide (molar ratio of sulfur dioxide to selenite is 1.5:1) at 50 °C for 60 min to obtain refined selenium. The refined selenium was placed in a crystallization furnace, and the temperature of the crystallization furnace was increased under argon protection to convert the refined selenium in the crucible into molten refined selenium. After the refined selenium in the crucible was completely converted into molten refined selenium, a cold body at 250 °C was inserted into a melt at 280 °C for rotary crystallization. The crucible rotation speed was 110 r / min, and the temperature of the cold body was controlled at 250 °C during the crystallization process. After crystallization for 120 min, the crystallized product was taken out to obtain ultra-high purity selenium with a purity of 99.99996%.
[0055] Table 1. Test results of Examples 1-3
[0056]
[0057]
[0058] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A method for preparing 6N selenium from 2N selenium, characterized in that, Includes the following steps: 2N selenium is oxidized and roasted to obtain selenium dioxide vapor; the oxidation and roasting temperature is 700~900℃. The selenium dioxide vapor is mixed with water to carry out a chemical reaction, resulting in a selenite solution. The selenite solution is mixed with a reducing agent to carry out a reduction reaction to obtain 3N and / or 4N selenium. After melting the 3N and / or 4N selenium, the crystallizer is immersed in the resulting melt for rotational crystallization to obtain 6N selenium; The rotational crystallization is a melt rotation; The temperature of the crystallizer is 210~300℃, and the temperature of the melt is 230~330℃; The rotational speed of the melt is 80~130 r / min; The rotational crystallization time is 70~140 min.
2. The method according to claim 1, characterized in that, The 2N selenium comprises, by mass fraction, 0.01-0.5% Te, 0.01-0.3% Pb, 0.02-0.1% Cu, 0.01-0.2% Fe, 0.01-0.3% S, 0.01-0.05% Sn, 0.01-0.05% As, 0.01-0.06% Ni and the balance Se.
3. The method according to claim 1, characterized in that, The oxidative roasting time is 1-2 hours.
4. The method according to claim 1, characterized in that, The reducing agent includes sulfur dioxide and / or sodium sulfite.
5. The method according to claim 1 or 4, characterized in that, The molar ratio of the reducing agent to selenite is 1.2~1.8:
1.
6. The method according to claim 1, characterized in that, The reduction temperature is 30~70℃ and the time is 30~90min.