CN108147414B

CN108147414B - Preparation method of nano-scale silicon particles

Info

Publication number: CN108147414B
Application number: CN201711428161.0A
Authority: CN
Inventors: 王海龙
Original assignee: Ningxia University
Current assignee: Ningxia University
Priority date: 2017-12-26
Filing date: 2017-12-26
Publication date: 2020-12-01
Anticipated expiration: 2037-12-26
Also published as: CN108147414A

Abstract

The invention discloses a preparation method of nano-scale silicon particlesA method comprising the steps of: with inexpensive silica and other oxide materials such as B₂O₃The method is characterized in that the raw material is used for inducing the spontaneous strip decomposition of the Si-based oxide material by a simple sintering and heat treatment method, and the tiny nano-scale SiO is firstly realized₂Separating the particles from other element oxides, rapidly heating to prepare sublimation points by using the difference of sublimation temperatures of different oxides, removing other oxides, and finally obtaining the nano-scale silicon particles by using a reduction technology such as magnesiothermic reduction and the like.

Description

Preparation method of nano-scale silicon particles

Technical Field

The invention belongs to the technical field of chemistry, and relates to a preparation method of nano-scale silicon particles.

Background

The existing preparation technologies of the nano silicon material comprise CVD, PVD, PLD, electrolysis and the like, and have the disadvantages of large energy consumption, expensive equipment, harsh preparation conditions and low efficiency.

Disclosure of Invention

The invention aims to provide a preparation method of nano-scale silicon particles. With inexpensive silica and other oxide materials such as B₂O₃The method is characterized in that the raw material is used for inducing the spontaneous strip decomposition of the Si-based oxide material by a simple sintering and heat treatment method, and the tiny nano-scale SiO is firstly realized₂Separating the particles from other element oxides, rapidly heating to a sublimation point by using the difference of sublimation temperatures of different oxides, removing other oxides, and finally obtaining the nano-scale silicon particles by using a reduction technology such as magnesiothermic reduction and the like.

The specific technical scheme is as follows:

a method for preparing nanoscale silicon particles comprises the following steps:

step 1, SiO₂Weighing powder (with unlimited particle size) and other oxide MOx powder capable of undergoing scroll decomposition reaction according to corresponding molar ratio of scroll decomposition reaction, uniformly mixing, heating in air until the powder and the oxide MOx powder are melted to form a glass body, and cooling to room temperature.

Step 2, heating the glass body in the air until the scroll reaction is stable (Ts) and 0.85Ts, and preserving the heat for 0.1-24 hours to generate scroll decomposition reaction to obtain the ultrafine SiO distributed at intervals₂And MOx biphasic material.

Step 3, rapidly heating the glass body after the heat treatment to the sublimation temperature point of MOx at the heating speed of 400-2000 ℃ per minute, so that MOx is directly gasified at the sublimation point, and the glass body after the scroll decomposition is separated, and extremely fine SiO is left₂And (3) granules.

Step 4, mixing the obtained superfine SiO2 particles with the magnesium powder according to the molar ratio of 1: 2 to 1: 100 are uniformly mixed in inert gas or vacuum, and then are heated to 650-1050 ℃ in a closed container for 0.1-24 hours, and the nano silicon particles are obtained by reduction.

And 5, removing MgO by acid washing, and rinsing with deionized water to obtain pure nano silicon particles.

The optimum fastest temperature for the scroll decomposition is 10% below Ts, and the optimum temperature is 360 degrees taking 1 as an example.

B₂O₃After sublimation, the residue can be rinsed once with hydrochloric acid to remove B to the maximum₂O₃。

Compared with the prior art, the invention has the beneficial effects that:

the method has low requirements on the granularity, the morphology and the like of the initial raw materials, low raw material cost, simple and cheap production equipment, simple process and high production efficiency, and can be carried out in the air except the step 4.

Drawings

FIG. 1 is SiO₂And B₂O₃After mixed and melted to form a glass body, the superfine nano SiO is formed at the scroll decomposition temperature₂Transmission electron microscopy images of the particles.

FIG. 2 is an XRD pattern of a product after spinodal decomposition, showing SiO₂And phase B₂O₃Phase (1);

FIG. 3 is the removal of B by sublimation₂O₃And then carrying out magnesiothermic reduction at 650 ℃ to obtain a transmission electron microscope image of the nano Si particles.

Fig. 4 is an XRD pattern of the product after magnesiothermic reduction, which shows that pure silicon is obtained.

Detailed Description

The technical solution of the present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

Example 1

step 1, SiO₂Powders (without limitation to particle size) and other slivers capable of taking place therewithWeighing and uniformly mixing the oxide MOx powder subjected to the decomposition reaction according to the corresponding molar ratio of the banner decomposition reaction, heating the mixture in air until the oxide MOx powder and the sweep decomposition reaction are melted to form a glass body, and cooling the glass body to room temperature.

Step 2, heating the glass body in the air until the scroll reaction is stable (Ts) and 0.85Ts, preserving the heat for 0.1 hour, and performing scroll decomposition reaction to obtain the ultrafine SiO distributed at intervals₂And MOx biphasic material.

Step 3, rapidly heating the glass body after the heat treatment to the sublimation temperature point of MOx at the heating speed of 400 ℃ per minute, so that MOx is directly gasified at the sublimation point, separating the glass body after the scroll decomposition, and leaving extremely fine SiO₂And (3) granules.

Step 4, the obtained superfine SiO₂The particle and the metal magnesium powder are mixed according to the molar ratio of 1: 2, uniformly mixing in inert gas or vacuum, heating to 650 ℃ in a closed container, preserving heat for 24 hours, and reducing to obtain the nano silicon particles.

Example 2

Step 2, heating the glass body in the air until the scroll reaction is stable (Ts) and 0.85Ts, and preserving the heat for 12 hours to generate scroll decomposition reaction to obtain the ultrafine SiO distributed at intervals₂And MOx biphasic material.

Step 3, rapidly heating the glass body after the heat treatment to the sublimation temperature point of MOx at the heating speed of 1200 ℃ per minute, so that MOx is directly gasified at the sublimation point, separating the glass body after the scroll decomposition, and leaving extremely fine SiO₂And (3) granules.

Step 4, the obtained superfine SiO₂The particle and the metal magnesium powder are mixed according to the molar ratio of 1: 50 in inert gas or vacuum, then heating to 800 ℃ in a closed container, preserving heat for 12 hours, and reducing to obtain the nano silicon particles.

Example 3

Step 2, heating the glass body in the air until the scroll reaction is stable (Ts) and 0.85Ts, and preserving the heat for 24 hours to generate scroll decomposition reaction to obtain the ultrafine SiO distributed at intervals₂And MOx biphasic material.

Step 3, rapidly heating the glass body after the heat treatment to the sublimation temperature point of MOx at the heating speed of 2000 ℃ per minute, so that MOx is directly gasified at the sublimation point, separating the glass body after the scroll decomposition, and leaving extremely fine SiO₂And (3) granules.

Step 4, the obtained superfine SiO₂The particle and the metal magnesium powder are mixed according to the molar ratio of 1: 100 are evenly mixed in inert gas or vacuum, then heated to 1050 ℃ in a closed container and insulated for 0.1 hour, and the nano silicon particles are obtained by reduction.

The above description is only a preferred embodiment of the present invention, and the scope of the present invention is not limited thereto, and any simple modifications or equivalent substitutions of the technical solutions that can be obviously obtained by those skilled in the art within the technical scope of the present invention are within the scope of the present invention.

Claims

1. A method for preparing nanoscale silicon particles is characterized by comprising the following steps:

step 1, SiO₂And B₂O₃According to a molar ratio of 1: 1, uniformly mixing, heating to 900 ℃ in air, and preserving heat for 4 hours to obtain a glass body;

step 2, preserving the temperature of the glass body in the air at 400 ℃ for 2 hours to ensure that the glass body is subjected to amplitude modulation decomposition to obtain SiO distributed at intervals₂And B₂O₃；

Step 3, rapidly heating the glass body subjected to amplitude modulation decomposition to 1500 ℃ in a rapid heating furnace at the speed of 500 ℃/min to reach B₂O₃The sublimation point is evaporated and separated, and the nano SiO is left₂Particles;

and 4, mixing the rest powder and the metal magnesium powder according to the ratio of 1: uniformly mixing the mixture in an argon environment according to the molar ratio of 6, heating the mixture to 650 ℃ under a sealed vacuum condition to perform a magnesiothermic reduction reaction to obtain a mixture of nano silicon and magnesium oxide;

and 5, adding the mixture into hydrochloric acid to dissolve magnesium oxide, rinsing with deionized water to remove the magnesium oxide, and drying to obtain pure silicon nanoparticles.