Preparation method of high-purity spherical nano silicon powder with adjustable particle size

Abstract

The invention provides a preparation method of spherical nano silicon, which comprises the following steps: under the action of electromagnetic waves and under the condition of nitrogen and / or inert gas, spheroidizing suspended silicon powder, and then cooling to obtain the spherical nano silicon. The nanoscale silicon powder is dispersed by inert gas and fed into an electromagnetic induction cavity, the resonance effect generated by microwaves acts on the inert gas, under the excitation effect of electromagnetic induction, the gas is partially ionized, high temperature is generated, heat is transferred to the surface of the silicon powder, the surface of the silicon powder reaches a solid-liquid coexistence state, and the surface of the silicon powder is heated. The spherical nano silicon powder forms a sphere under the action of surface tension, and then enters a cooling cavity, and the spherical nano silicon powder is rapidly cooled to form solid spherical nano silicon powder with uniform granularity; and the spherical nano silicon powder with controllable particle size can be obtained by adjusting the particle size of the introduced nano silicon powder and controlling the input power of microwaves. The method is high in production efficiency, low in power consumption and production cost and more suitable for large-scale production and application.

Description

technical field [0001] The invention belongs to the technical field of preparation of spherical nano-silicon materials, and relates to a preparation method of spherical nano-silicon, in particular to a preparation method of high-purity spherical nano-silicon powder with adjustable particle size. Background technique [0002] Silicon is a very common element, and there are two allotropes of amorphous silicon and crystalline silicon. Crystalline silicon is grey-black and amorphous silicon is black. Silicon is a raw material for the manufacture of glass, quartz glass, water glass, optical fiber, important components of the electronic industry, optical instruments, handicrafts and refractory materials, and is also an important material for scientific research, especially in recent years, with the rapid development of the electronics industry. , the silicon industry has also flourished. Spherical nano-silicon powder is mainly used in lithium battery anode materials, 3D printing...

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Problems solved by technology

[0003] In the prior art, the cost of the mechanical ball milling method is low, but because the particle size is reduced mainly by physical grinding, spherical nano-silicon powder cannot be obtained; the vapor phase deposition method uses silane as a raw material, which is formed by reaction in a gas phase environment, but due to Silane has stronger toxicity, so there are bigger security and environmental hazards; Plasma evaporation condensation method generally uses arc plasma method and radio frequency induction (RF) plasma method; Arc plasma method, as publication number is the invention patent of CN102910630A , because the power electrode will be in contact with the heat source during the heating process, it will cause certain pollution to the prepared material; the radio frequency induction plasma method, such as the announcement number CN203333311U, adopts an electrodeless method, which avoids the contact between the electrode and the heat source, although it will not affect The prepared materials produce pollution, but the discharge process will produce a high-voltage sheath and the resulting ion wall sputtering pollution, and considering that the radio frequency induction frequency is generally at the MHz level, the frequency is low, so the power supply is generally high. Large power consumption and relatively high cost in chemical production

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