Method for preparing 7n tellurium

Patent metadata

Field	Value
Publication number	US-2025243058-A1
Application number	US-202418770198-A
Country	US
Kind code	A1
Filing date	Jul 11, 2024
Priority date	Jan 25, 2024
Publication date	Jul 31, 2025
Grant date	—

Abstract

Provided is a method for preparing 7N tellurium, including the following steps: mixing 2N crude tellurium with concentrated sulfuric acid, and subjecting a resulting mixture to oxidation roasting to obtain a selenium dioxide vapor and a roasting residue; mixing the roasting residue with a strong base solution, and subjecting a resulting solution to electrolysis to obtain 4N electrolytic tellurium; subjecting the 4N electrolytic tellurium to vacuum distillation to obtain 5N tellurium; and melting the 5N tellurium to obtain a tellurium melt, immersing a crystallizer in the tellurium melt, and subjecting the tellurium melt to crystallization to obtain the 7N tellurium; wherein the method is performed for a total time of less than 14 days.

First claim

1 . A method for preparing 7N tellurium, comprising the following steps:
mixing 2N crude tellurium with concentrated sulfuric acid, and subjecting a resulting mixture to oxidation roasting to obtain a selenium dioxide vapor and a roasting residue; mixing the roasting residue with a strong base solution, and subjecting a resulting solution to electrolysis to obtain 4N electrolytic tellurium; subjecting the 4N electrolytic tellurium to vacuum distillation to obtain 5N tellurium; and melting the 5N tellurium to obtain a tellurium melt, immersing a crystallizer in the tellurium melt, and subjecting the tellurium melt to crystallization to obtain the 7N tellurium; wherein the method is performed for a total time of less than 14 days.

2 . The method according to claim 1 , wherein a mass ratio of the 2N crude tellurium to the concentrated sulfuric acid is in a range of (1-3):1, and a mass concentration of the concentrated sulfuric acid is 98%.

3 . The method according to claim 1 , wherein the oxidation roasting is conducted at a temperature of 350° C. to 600° C. for 0.5 h to 3 h.

4 . The method according to claim 1 , wherein in the resulting solution, a concentration of tellurium is in a range of 100 g/L to 300 g/L and a concentration of the strong base is in a range of 90 g/L to 130 g/L.

5 . The method according to claim 1 , wherein the electrolysis is conducted for 50 h to 110 h at a temperature of 30° C. to 50° C. with a current density of 45 A/m 2 to 55 A/m 2 ; and during the electrolysis, the resulting solution is in a circulating state with a circulating rate of 1 mL/s to 5 mL/s.

6 . The method according to claim 1 , wherein the vacuum distillation is conducted at a temperature of 450° C. to 600° C. and a vacuum degree of 0 Pa to 100 Pa.

7 . The method according to claim 1 , wherein the tellurium melt has a temperature of 460° C. to 560° C.

8 . The method according to claim 1 , wherein an immersion depth of the crystallizer is 50 mm to 100 mm below a liquid level of the tellurium melt.

9 . The method according to claim 1 , wherein the crystallizer has an initial temperature of 460° C. to 500° C., and after the crystallizer is immersed for 10 min to 60 min, a temperature of the crystallizer is reduced to 420° C. to 440° C.

10 . The method according to claim 1 , wherein the crystallization comprises static crystallization and rotary crystallization, and a rotational speed for the rotary crystallization is less than 120 r/min.

11 . The method according to claim 2 , wherein the oxidation roasting is conducted at a temperature of 350° C. to 600° C. for 0.5 h to 3 h.

12 . The method according to claim 4 , wherein the electrolysis is conducted for 50 h to 110 h at a temperature of 30° C. to 50° C. with a current density of 45 A/m 2 to 55 A/m 2 ; and during the electrolysis, the resulting solution is in a circulating state with a circulating rate of 1 mL/s to 5 mL/s.

13 . The method according to claim 7 , wherein an immersion depth of the crystallizer is 50 mm to 100 mm below a liquid level of the tellurium melt.

14 . The method according to claim 7 , wherein the crystallizer has an initial temperature of 460° C. to 500° C., and after the crystallizer is immersed for 10 min to 60 min, a temperature of the crystallizer is reduced to 420° C. to 440° C.

15 . The method according to claim 7 , wherein the crystallization comprises static crystallization and rotary crystallization, and a rotational speed for the rotary crystallization is less than 120 r/min.

Assignees

• Univ Kunming Science & Technology

Inventors

• Jiang Wenlong
• Yang Bin
• Luo Qijin
• Xu Baoqiang
• Zha Guozheng
• Liu Dachun
• Tian Yang
• Li Yifu
• Kong Lingxin
• Kong Xiangfeng
• Luo Huan
• Xiong Heng
• Wang Fei
• Wu Jian
• Dong Zhaowang

Classifications

• C01P2006/80

  Compositional purity · CPC title

• C01B19/02 Primary

  Elemental selenium or tellurium · CPC title

• Y02P10/20

  Recycling · CPC title

• C25B1/50

  Processes · CPC title

• C25B1/01

  Products · CPC title