WO2013159689A1

WO2013159689A1 - Method for preparing cadmium telluride

Info

Publication number: WO2013159689A1
Application number: PCT/CN2013/074533
Authority: WO
Inventors: 朱刘; 胡智向
Original assignee: 广东先导稀材股份有限公司
Priority date: 2012-04-27
Filing date: 2013-04-22
Publication date: 2013-10-31
Also published as: CN103373715A; CN103373715B

Abstract

The present invention provides a method for preparing cadmium telluride, comprising steps of: mixing cadmium and tellurium according to a specified mole ratio, telluride being excess relative to cadmium; putting the mixture of cadmium and tellurium into a graphite barrel; putting the graphite barrel into a quartz tube; putting the quartz tube into a bomb furnace, and vacuumizing and sealing the quartz tube; putting the sealed quartz tube into a vertical gradient solidification furnace, and performing heating and heat preservation in a multistage manner, so that cadmium and tellurium are subjected to a synthetic reaction; and after the quartz tube cools to the room temperature along with the furnace, opening the quartz tube, and taking cadmium tellurium obtained from the reaction out of the quartz tube. In the method for preparing cadmium telluride provided in the present invention, the graphite barrel and the quartz tube are vacuumized and sealed, so that the heating temperature is uniform when cadmium tellurium is synthesized, and the reaction is fully performed. The method is friendly to operating personnel and the environment.

Description

Preparation method of cadmium telluride

Technical field

The present invention relates to a method for preparing a synthetic material, and more particularly to a method for preparing cadmium telluride. Background technique

Cadmium telluride is widely used in spectroscopic analysis, solar cells, infrared modulators, infrared window electroluminescent devices, photovoltaic cells, infrared detection, X-ray detection, nuclear radiation detectors, and light-emitting devices close to the visible region.

There are various methods for preparing cadmium telluride. One of the methods is to insert a hot rod into a mixed powder of cerium and cadmium and heat it to 500 °C to form. This method requires a higher temperature, the heating of the hot rod is not uniform enough, and the reaction is insufficient. Another method is to separate ruthenium and cadmium by using two separate ruthenium, and then react the formed cadmium telluride film on a heated substrate substrate. This method belongs to a film preparation method, which directly utilizes bismuth and cadmium monomer powder. . In the preparation process of the method, on the one hand, it is difficult to accurately control the evaporation of lanthanum and cadmium. On the other hand, in the process of preparing a large amount of cadmium telluride film, the worker may have more chances of contacting cadmium powder, which may be for the staff. And the environment causes pollution and damage. Summary of the invention

In view of the deficiencies in the prior art, an object of the present invention is to provide a process for preparing cadmium telluride which is capable of uniform heating temperature, sufficient reaction, and is friendly to the operator and the environment when cadmium telluride is synthesized.

In order to achieve the object of the present invention, the present invention provides a method for preparing cadmium telluride, comprising the steps of: mixing cadmium and lanthanum in a prescribed molar ratio, wherein ruthenium is excessive relative to cadmium; and mixing a mixture of cadmium and ruthenium Put into the graphite tube; put the graphite tube into the quartz tube; put the quartz tube into the sealing tube furnace, vacuum the quartz tube and seal the tube; install the sealed quartz tube into the vertical gradient solidification furnace, adopt Multi-stage heating method to heat and keep heat, so that cadmium and antimony can be synthesized. After; and then, the quartz tube is cooled to room temperature with the furnace, the quartz tube is opened, and the cadmium telluride obtained by the synthesis reaction is taken out from the graphite cylinder.

The beneficial effects of the present invention are as follows.

The preparation method of cadmium telluride provided by the invention adopts a graphite tube and a quartz tube vacuum sealing tube, which can make the heating temperature of the cadmium telluride synthesis uniform, the reaction is sufficient, and is friendly to the operator and the environment. Specific lung

First, a method of preparing cadmium telluride according to the present invention will be described.

The method for preparing cadmium telluride according to the present invention comprises the steps of: mixing cadmium and lanthanum in a prescribed molar ratio, wherein ruthenium is excessive relative to cadmium; loading a mixture of mixed cadmium and ruthenium into a graphite cylinder; Into the quartz tube; put the quartz tube into the tube sealing furnace, vacuum the quartz tube and seal the tube; install the sealed quartz tube into the vertical gradient solidification (Verdical Gradient Freezing, abbreviated as VGF) furnace The multi-stage heating method is used to heat and heat the cadmium and antimony to synthesize the reaction; and then, the quartz tube is cooled to room temperature with the furnace, the quartz tube is opened, and the cadmium telluride obtained by the synthesis reaction is taken out from the graphite tube.

In the method for producing cadmium telluride according to the present invention, the cadmium is 5N cadmium, and the ruthenium is 5N ruthenium. Preferably, the cadmium is in the form of a pellet and the crucible is a massive body. In the method for producing cadmium telluride according to the present invention, the predetermined molar ratio is 1: (1. 05~1. 1). In the method for preparing cadmium telluride according to the present invention, the vacuum degree at which the quartz tube is evacuated is (1. 0 to 4.0) X 10 - ³ Pa. In the method for preparing cadmium telluride according to the present invention, the multi-stage heating mode heating and holding program is the highest temperature rise to 1050~1100 °C for 1~3h, and the program ends. Preferably, the heating and holding of the multi-stage heating mode is: 20~40min, rising from room temperature to 250~300 °C, Bao Temperature 10~30min; After that, 30~60min rise to 450~550°C, keep warm for 5~7h; then, 30~60min rise to 650~750°C, keep warm for 7~9h; and then, 3~5h rise to 1050 ~ 1100 ° C, insulation l ~ 3h.

In the method for preparing cadmium telluride according to the present invention, preferably, the graphite cylinder is made of high-purity pure graphite, and is dried by high-temperature quenching before use, and then placed in a high-pressure furnace to be vacuum-fired. To remove volatiles contained in the graphite.

Next, an embodiment of a method for producing cadmium telluride according to the present invention will be described.

In the following embodiment of the method for preparing cadmium telluride according to the present invention, the graphite cylinder used is made of high-purity graphite, and is dried by high-temperature quenching before use, and then placed in a high-pressure furnace to be vacuum-fired. To remove volatiles contained in the graphite.

Example 1

5N cadmium ingot and 5N bismuth block were weighed in a molar ratio of 1:1.05 to a total of 500g into a graphite tube, the graphite tube was placed in a quartz tube, and the tube was taken in a sealed tube to evacuate the tube, and the vacuum was obtained. The degree of vacuum is 4.0X10 - ³ Pa.

Put the sealed quartz tube into the VGF furnace and heat it up. The heating and heating process is a stepwise heating and insulation, the highest temperature rises to 1050 ° C, and the temperature is kept at 1050 ° C for 3 h. Specifically, it is raised from room temperature to 300 ° C in 25 min, and kept at 300 ° C for 10 min. After that, it is raised to 500 ° C in 25 min and kept at 500 ° C for 6 h. After that, it is raised to 700 ° C in 30 min and kept at 700 ° C for 8 h. After that, it was raised to 1050 °C in 4h and kept at 1050 °C for 3h.

After the heating and heating program was completed, the furnace was cooled to room temperature, the quartz tube was opened, and 490 g of 5N cadmium telluride material obtained by the synthesis reaction was taken out from the graphite cylinder.

Example 2

The 5N cadmium ingot and the 5N bismuth block were weighed into a graphite tube at a molar ratio of 1:1.07, and then placed in a graphite tube. The graphite tube was placed in a quartz tube, and the tube was taken in a sealed tube to evacuate the tube. The degree of vacuum is obtained 2.3X10- ³ Pa.

Put the sealed quartz tube into the VGF furnace and heat it up. The heating and heating process is a stepwise heating and insulation, the highest temperature rises to 1085 ° C, and the temperature is kept at 1085 ° C for 2 h. Specifically, it is raised from room temperature to 280 ° C for 30 min, and incubated at 280 ° C for 20 min; after that, it is raised to 480 ° C for 30 min and 6.5 h at 480 ° C; then, it is raised to 720 ° C for 45 min, at 720 ° C for 45 min. After 9 h of heat preservation, after 4.5 h, it was raised to 1085 ° C, and kept at 1085 ° C for 2 h.

After the heating and heating program was completed, the furnace was cooled to room temperature, the quartz tube was opened, and 975 g of 5N cadmium telluride obtained by the synthesis reaction was taken out from the graphite cylinder.

Example 3

The 5N cadmium ingot and the 5N bismuth block were weighed into a graphite tube at a molar ratio of 1:1.1. The graphite tube was placed in a quartz tube, and the vacuum tube was taken in a sealed tube furnace, and the vacuum obtained by vacuuming was obtained. The degree is 1.0X10 - ³ Pa.

Put the sealed quartz tube into the VGF furnace and heat it up. The heating and heating process is a stepwise heating and insulation, the highest temperature rises to 1100 ° C, and the temperature is maintained at 1100 ° C for 1 h. Specifically, 40min is raised from room temperature to 250 ° C, and kept at 250 ° C for 30 min; then, 40 min is raised to 520 ° C, and 520 ° C is kept for 7 h; then, 60 min is raised to 680 ° C, and 680 ° C is kept. 7h; After that, it rises to 1100°C in 3h, and keeps lho at 1100°C

After the heating and heating program was completed, the furnace was cooled to room temperature, the quartz tube was opened, and 1438 g of 5N cadmium telluride obtained by the synthesis reaction was taken out from the graphite cylinder.

Finally, the test results of Examples 1-3 are given.

The detection was carried out by inductively coupled plasma mass spectrometry (ICP-MS) (manufactured by PE, model: DRC-II) to detect inorganic impurities.

The detection conditions of the device are: temperature is 18 ° C ~ 28 ° C, relative humidity is 30 ~ 70%, cleanliness is 1000. Detection principle: Inductively coupled plasma mass spectrometry detection method: to be tested After the element is ionized by the plasma at high temperature, it enters the mass analyzer in the form of a positive charge, and is received by the detector according to the difference in mass/charge ratio to generate a signal. The signal generated by the element to be tested and the reference material of the standard substance are worth the content of the element to be tested.

Table 1 Test results of Examples 1-3 (Unit: ppm)

Example 1-3 A high yield of cadmium telluride can be achieved from the weight of the raw material and the weight of cadmium telluride obtained. In addition, the method for preparing cadmium telluride provided by the invention adopts a graphite tube and a quartz tube vacuum sealing tube, which can make the heating temperature of the cadmium telluride synthesis uniform, the reaction is sufficient, and is friendly to the operator and the environment.

Claims

Claim

1. A method for preparing cadmium telluride, comprising the steps of:

Mixing cadmium and tellurium in a prescribed molar ratio, wherein ruthenium is excessive relative to cadmium;

Loading a mixture of mixed cadmium and cerium into a graphite cylinder;

Put the graphite tube into the quartz tube;

Put the quartz tube into the tube sealing furnace, vacuum the quartz tube and seal the tube;

The sealed quartz tube is placed in a vertical gradient solidification furnace, and heated by a multi-stage heating method to synthesize cadmium and strontium;

Thereafter, the quartz tube was cooled to room temperature with the furnace, the quartz tube was opened, and the cadmium telluride obtained by the synthesis reaction was taken out from the graphite cylinder.

The method for producing cadmium telluride according to claim 1, wherein the cadmium is 5N cadmium, and the lanthanum is 5N lanthanum.

The method of preparing the cadmium telluride according to claim 1, wherein the predetermined molar ratio is 1: (1. 05~1. 1).

The method of preparing the cadmium telluride according to claim 1, wherein the vacuum degree obtained by evacuating the quartz tube is (1. 0~4. 0) X 10 - ³ Pa.

The method for preparing cadmium telluride according to claim 1, wherein the heating and holding of the multi-stage heating method is performed at a maximum temperature of 1050 to 1100 ° C, and the program is terminated after 1 to 3 hours of heat preservation.

The method for preparing cadmium telluride according to claim 5, wherein the heating and holding of the multi-stage heating method is:

20~40min from room temperature to 250~300 °C, keep warm 10~30min;

After that, 30~60min rose to 450~550°C, and kept warm for 5~7h;

After that, 30~60min is raised to 650~750°C, and the temperature is kept 7~9h;

After 25, 3~5h rise to 1050~1100°C, keep warm l~3h.

The method for preparing cadmium telluride according to claim 1, wherein the graphite tube is made of high-purity graphite, and is dried by high-temperature quenching before use, and then placed in a high-pressure furnace to be evacuated.