A method for preparing cuprous selenide

Abstract

The application belongs to the field of material preparation, and discloses a preparation method of cuprous selenide. The method comprises the following steps: (1) heating and reacting selenium powder and copper powder under a protective gas atmosphere to obtain a cuprous selenide synthesis material; the heating and reacting condition is: heating to 300-400 DEG C, keeping warm for 1-2 hours; then heating to 600-700 DEG C, keeping warm for 1-2 hours; (2) high-temperature melting reaction of the cuprous selenide synthesis material obtained in step (1) at a temperature of 1200-1250 DEG C, and then cooling to obtain a cuprous selenide product. The application can mass-produce the cuprous selenide through low-temperature powder synthesis and further high-temperature melting reaction, and solves the problem of high oxygen content caused by powder reaction. The application has low requirement on equipment, the graphite boat can be reused, and the cost is low; after powder synthesis, high-temperature melting is performed, further reaction is complete, and the effect of removing oxygen can be achieved.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of material preparation and relates to a preparation method of cuprous selenide. BACKGROUND

[0002] Commercial thermoelectric materials bismuth telluride and lead telluride have a thermoelectric value ZT of about 1, and it is particularly urgent and important to develop high-performance thermoelectric materials with less tellurium or without tellurium due to the low ZT value of the materials and the large amount of rare element tellurium.

[0003] Cuprous selenide has a molecular formula of Cu2Se, is a black cubic crystal, has a relative density of 6.749, a melting point of 1113℃, is soluble in potassium cyanide solution, and is soluble in hydrochloric acid to release hydrogen selenide, and is oxidized to copper selenite by nitric acid when reacting with sulfuric acid to generate sulfur dioxide gas. Cuprous selenide is often used as a semiconductor material. Cuprous selenide has the complexity of crystal structure, on the other hand, shows good electrical properties, and the abundance of copper and selenium on the earth is high, and the material cost is low, so cuprous selenide is a good thermoelectric alternative material.

[0004] At present, a high-temperature and high-pressure method is commonly used for the preparation of cuprous selenide, but the method has the problems of expensive equipment and small synthesis amount, resulting in high cost. SUMMARY

[0005] In view of the above problems in the prior art, the purpose of the present application is to provide a preparation method of cuprous selenide. The method can be realized by using a graphite boat, a tube furnace and a smelting furnace, has low requirements on equipment and reduces cost; the method can be batch produced by low-temperature powder synthesis and further high-temperature melting reaction, and solves the problem of high oxygen caused by powder reaction.

[0006] To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0007] A preparation method of cuprous selenide, comprising the following steps:

[0008] (1) heating and reacting selenium powder and copper powder in a protective gas atmosphere to obtain cuprous selenide synthesis material; the heating and reacting condition is: heating to 300-400℃, and keeping warm for 1-2 hours; then heating to 600-700℃, and keeping warm for 1-2 hours;

[0009] (2) high-temperature melting reaction of the cuprous selenide synthesis material obtained in step (1) at a temperature of 1200-1250℃, and then cooling to obtain cuprous selenide product.

[0010] Preferably, in step (1), the molar ratio of selenium powder and copper powder is 2.05-2.1:1.

[0011] Preferably, in step (1), -100 mesh selenium powder is used; -100 mesh copper powder is used.

[0012] Preferably, in step (1), the protective gas is nitrogen or an inert gas.

[0013] Preferably, in step (1), the heating reaction conditions are: heating at 5-10℃ per minute to 300-400℃, holding for 1-2 hours; then heating at 1-3℃ per minute to 600-700℃, holding for 1-2 hours.

[0014] Preferably, in step (1), the selenium powder and copper powder are mixed uniformly under the protection of a protective gas, then placed in a graphite boat, and then loaded into a tube furnace, and the protective gas is continuously introduced into the tube furnace and heating is started.

[0015] Preferably, in step (2), the high-temperature melting reaction is processed for 1-2 hours.

[0016] Preferably, in step (2), the cuprous selenide synthesis material obtained in step (1) is put into a melting furnace for high-temperature melting reaction, and after the reaction, the furnace is cooled to room temperature to obtain a cuprous selenide product.

[0017] Further preferably, in step (2), after high-temperature melting reaction and cooling, a cuprous selenide crude product is obtained, and 2-3 cm of material on the surface of the cuprous selenide crude product is cut off to obtain a cuprous selenide product.

[0018] Compared with the prior art, the beneficial effects of the present application are:

[0019] (1) The present application can mass-produce by low-temperature powder synthesis and further high-temperature melting reaction, and at the same time solves the problem of high oxygen caused by powder reaction.

[0020] (2) The present application can mass-produce by low-temperature powder synthesis in a tube furnace, has low requirements for equipment, and the graphite boat can be reused, so the cost is low; after powder synthesis, high-temperature melting is performed for further complete reaction, and at the same time, the effect of removing oxygen can be achieved. DETAILED DESCRIPTION

[0021] In view of the above problems existing in the prior art, the purpose of the present application is to provide a preparation method of cuprous selenide, comprising the following steps:

[0022] (1) Heating reaction of selenium powder and copper powder under a protective gas atmosphere to obtain a cuprous selenide synthesis material; the heating reaction conditions are: heating to 300-400℃, holding for 1-2 hours; then heating to 600-700℃, holding for 1-2 hours;

[0023] (2) The cuprous selenide synthesis material obtained in step (1) is subjected to high-temperature melting reaction at a temperature of 1200-1250°C, and then cooled to obtain the cuprous selenide product.

[0024] As one of the preferred solutions, in step (1), the molar ratio of selenium powder to copper powder is 2.05-2.1:1. Since the selenium vapor pressure is large, it is relatively easy to remove, and in the preparation process, the present application selects an excess of selenium.

[0025] Since the powder is too coarse, it will cause low reactivity, thereby causing incomplete reaction and low reaction efficiency. As one of the preferred solutions, in step (1), -100 mesh selenium powder is used; -100 mesh copper powder is used.

[0026] In order to protect the material or product from oxidation, as one of the preferred solutions, in step (1), the protective gas is nitrogen or inert gas.

[0027] In the present application, the low-temperature stage of the first heating is the reaction stage, and the main role is to generate the cuprous selenide synthesis material, and the high-temperature stage of the subsequent second heating is to remove selenium at high temperature, so as to ensure that the free selenium is less than 100 ppm. As one of the preferred solutions, in step (1), the heating reaction conditions are: heating at 5-10°C per minute to 300-400°C, and holding for 1-2 hours; then heating at 1-3°C per minute to 600-700°C, and holding for 1-2 hours.

[0028] As one of the preferred solutions, in step (1), the selenium powder and copper powder are mixed uniformly under the protection of the protective gas, then put into a graphite boat, and then put into a tube furnace, and the protective gas is continuously introduced into the tube furnace, and the heating is started.

[0029] As one of the preferred solutions, in step (2), the processing time of the high-temperature melting reaction is 1-2 hours.

[0030] As one of the preferred solutions, in step (2), the cuprous selenide synthesis material obtained in step (1) is put into a melting furnace for high-temperature melting reaction, and after the reaction, the furnace is cooled to room temperature to obtain the cuprous selenide product.

[0031] As one of the preferred solutions, in step (2), after the high-temperature melting reaction and cooling, the cuprous selenide crude product is obtained, and 2-3 cm of material on the surface of the cuprous selenide crude product is cut off to obtain the cuprous selenide product.

[0032] In order to facilitate the understanding of the present application, the following will combine the preferred embodiments to describe the present application more comprehensively and in detail, but the protection scope of the present application is not limited to the following specific embodiments.

[0033] Unless otherwise defined, all terms used in the description employ the same meaning as commonly understood by one of ordinary skill in the art. The professional terms used in the present document are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present application.

[0034] Example 1

[0035] The present embodiment discloses a preparation method of cuprous selenide, comprising the following steps:

[0036] (1) -100 mesh selenium powder, -100 mesh copper powder are mixed uniformly under inert gas protection according to a molar ratio of 2.05:1, the mixed material is put into a graphite boat, then is loaded into a tube furnace, nitrogen is continuously introduced into the tube furnace, heating is started; the heating gradient is: heating to 400℃ at 5℃ per minute, keeping for 1 hour; then heating to 700℃ at 3℃ per minute, keeping for 1 hour; stop heating, wait for the temperature to drop to room temperature, close the nitrogen, take out the material to obtain the cuprous selenide synthesis material;

[0037] (2) The cuprous selenide synthesis material obtained in step (1) is put into a melting furnace, the melting temperature is 1250℃, keeping for 1 hour, cooling with the furnace, after cooling to room temperature, the material is taken out, the surface 2-3 cm material is cut off, to obtain the cuprous selenide product.

[0038] Example 2

[0039] The present embodiment discloses a preparation method of cuprous selenide, comprising the following steps:

[0040] (1) -100 mesh selenium powder, -100 mesh copper powder are mixed uniformly under inert gas protection according to a molar ratio of 2.05:1, the mixed material is put into a graphite boat, then is loaded into a tube furnace, nitrogen is continuously introduced into the tube furnace, heating is started; the heating gradient is: heating to 400℃ at 5℃ per minute, keeping for 1 hour; then heating to 700℃ at 3℃ per minute, keeping for 1 hour; stop heating, wait for the temperature to drop to room temperature, close the nitrogen, take out the material to obtain the cuprous selenide synthesis material;

[0041] (2) The cuprous selenide synthesis material obtained in step (1) is put into a melting furnace, the melting temperature is 1250℃, keeping for 1 hour, cooling with the furnace, after cooling to room temperature, the material is taken out, the surface 2-3 cm material is cut off, to obtain the cuprous selenide product.

[0042] Example 3

[0043] The present embodiment discloses a preparation method of cuprous selenide, comprising the following steps:

[0044] (1) -100 mesh selenium powder, -100 mesh copper powder were mixed uniformly under inert gas protection according to a molar ratio of 2.1:1, the mixed material was put into a graphite boat, and then was loaded into a tube furnace, nitrogen was continuously introduced into the tube furnace, and heating was started; the heating gradient was: heating to 400℃ at 7℃ per minute, holding for 1.5 hours; then heating to 650℃ at 3℃ per minute, holding for 2 hours; stop heating, wait for the temperature to drop to room temperature, turn off the nitrogen, take out the material to obtain the cuprous selenide synthesis material;

[0045] (2) The cuprous selenide synthesis material obtained in step (1) was put into a melting furnace, the melting temperature was 1250℃, holding for 1.5 hours, furnace cooling, after cooling to room temperature, the material was taken out, and the surface 2-3 cm material was cut off to obtain the cuprous selenide product.

[0046] Comparative Example 1

[0047] The present comparative example discloses a preparation method of cuprous selenide, comprising the following steps:

[0048] -100 mesh selenium powder, -100 mesh copper powder were mixed uniformly under inert gas protection according to a molar ratio of 2.05:1, the mixed material was put into a graphite boat, and then was loaded into a tube furnace, nitrogen was continuously introduced into the tube furnace, and heating was started; the heating gradient was: heating to 400℃ at 5℃ per minute, holding for 1 hour; then heating to 700℃ at 3℃ per minute, holding for 1 hour; stop heating, wait for the temperature to drop to room temperature, turn off the nitrogen, take out the material to obtain the cuprous selenide product.

[0049] Comparative Example 2

[0050] The present comparative example discloses a preparation method of cuprous selenide, comprising the following steps:

[0051] (1) -100 mesh selenium powder, -100 mesh copper powder were mixed uniformly under inert gas protection according to a molar ratio of 2.1:1, the mixed material was put into a graphite boat, and then was loaded into a tube furnace, nitrogen was continuously introduced into the tube furnace, and heating was started; the heating gradient was: heating to 400℃ at 7℃ per minute, holding for 1.5 hours; then heating to 650℃ at 3℃ per minute, holding for 2 hours; stop heating, wait for the temperature to drop to room temperature, turn off the nitrogen, take out the material to obtain the cuprous selenide synthesis material;

[0052] (2) The cuprous selenide synthesis material obtained in step (1) was put into a melting furnace, the melting temperature was 1250℃, holding for 1.5 hours, furnace cooling, after cooling to room temperature, the material was taken out, and the surface 2-3 cm material was cut off to obtain the cuprous selenide product.

[0053] The cuprous selenide products obtained in Examples 1-3 and Comparative Examples 1 / 2 were detected, and the test data are shown in Table 1.

[0054] Table 1 Test data

[0055] Test item Example 1 Example 2 Example 3 Comparative Example 2 Comparative Example 3 Oxygen content 167 ppm 188 ppm 175 ppm 2380 ppm 155 ppm Free selenium < 100 ppm < 100 ppm < 100 ppm < 100 ppm 380 ppm

[0056] It can be seen that the method of the present application reduces the oxygen content of the cuprous selenide product while producing a cuprous selenide product with low free selenium content.

[0057] The above only is the preferred embodiment of the present application, and is not used to limit the present application, for the person skilled in the art, the present application can have various changes and variations. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application should be included in the scope of the present application.

Claims

1. A method for preparing cuprous selenide, characterized in that: The following steps are involved: (1) Selenium powder and copper powder in a molar ratio of 2.05 to 2.1:1 are heated to react under a protective gas atmosphere to obtain a cuprous selenide synthetic material; the heating reaction conditions are: heating to 300 to 400°C, keeping the temperature for 1 to 2 hours; then heating to 600 to 700°C, keeping the temperature for 1 to 2 hours; (2) The cuprous selenide synthetic material obtained in step (1) is subjected to a high-temperature melting reaction at a temperature of 1200-1250° C., and then cooled to obtain a cuprous selenide product.

2. The method for preparing cuprous selenide according to claim 1, wherein In step (1), -100 mesh selenium powder is used; and -100 mesh copper powder is used.

3. The method for preparing cuprous selenide according to claim 1, wherein In step (1), the protective gas is nitrogen or an inert gas.

4. The method for preparing cuprous selenide according to claim 1, wherein In step (1), the heating reaction conditions are: heating to 300-400°C at 5-10°C per minute and keeping warm for 1-2 hours; then heating to 600-700°C at 1-3°C per minute and keeping warm for 1-2 hours.

5. The method for preparing cuprous selenide according to any one of claims 1 to 4, wherein: In step (1), selenium powder and copper powder are mixed evenly under the protection of protective gas, placed in a graphite boat, and then placed in a tube furnace. Protective gas is continuously introduced into the tube furnace and heating is turned on.

6. The method for preparing cuprous selenide according to claim 1, wherein: In step (2), the high-temperature melting reaction is carried out for 1 to 2 hours.

7. The method for preparing cuprous selenide according to claim 1 or 6, wherein: In step (2), the cuprous selenide synthetic material obtained in step (1) is put into a melting furnace for high-temperature melting reaction, and is cooled to room temperature with the furnace after the reaction to obtain a cuprous selenide product.

8. The method for preparing cuprous selenide according to claim 7, wherein: In step (2), a crude cuprous selenide product is obtained after high-temperature melting reaction and cooling, and 2 to 3 cm of material on the surface of the crude cuprous selenide product is cut off to obtain a cuprous selenide product.