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Method for grinding solids containing silicon

A solid and fluid technology, applied in the direction of chemical instruments and methods, silicon, silicon compounds, etc., can solve the problems of hydrogen formation, oxidation will be very violent, etc., to achieve the effect of reducing pollution

Active Publication Date: 2018-09-28
WACKER CHEM GMBH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the fact that fresh active silicon surfaces with open chemical bonds that are highly reactive with water are continuously formed during grinding of silicon-containing solids, there is a concern that oxidation during grinding of silicon-containing solids in the presence of steam proceeds so vigorously that in this The particles produced in this way are completely oxidized or at least oxidized to a considerable extent and are therefore no longer suitable for the desired application of silicon particles
In addition, the corresponding hydrogen gas formation during grinding is very problematic for safety reasons

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0067] 600g is made of solar silicon (Wacker BGF (sg) type PCL-NCS-F, d 10 = 100 μm, d 50 = 240 μm, d 90 = 440 μm) into the hopper of a steam jet mill s-Jet 25 (manufacturer: NetzschTrockenmahltechnik GmbH). The mill was run at 190° C. and 10 bar gauge pressure with 15 kg / h of steam. The steam jet mill was preheated by nitrogen at a temperature of 120 °C. The rotation speed of the classification wheel was 13000 rpm. After 140 minutes, stop the steam jet mill and open the collection container on the particle filter. The particles were then stored in air at room temperature and ambient pressure.

[0068] The collection container is filled with 230g of silicon powder, with d10 = 0.37 μm, d 50 = 0.83 μm, d 90 =1.9 μm (measured using a measuring instrument Horiba LA950).

[0069] The surface area calculated from the particle size distribution assuming spherical particles is 4m 2 / g.

[0070] Oxygen content (determined using an oxygen analyzer Leco TCH 600) was 2.1% by wei...

Embodiment 2

[0072] Example 2 was carried out in the same manner as Example 1 except for the following differences:

[0073] The rotation speed of the classification wheel was 4000 rpm and the steam jet mill was stopped after 20 minutes.

[0074] The collection container is filled with 350g of silicon powder and has d 10 = 2 μm, d 50 = 4.3 μm, d 90 =7.4 μm (measured using a measuring instrument Horiba LA950).

[0075] The surface area calculated from the particle size distribution assuming spherical particles is 0.82m 2 / g.

[0076] Oxygen content (determined using oxygen analyzer Leco TCH 600) is 0.44% by weight and 5.4 mg / m based on calculated particle surface area 2 .

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Abstract

The object of the invention are methods for the production of silicon particles by grinding silicon-containing solids in a jet mill using a grinding fluid containing water vapor.

Description

technical field [0001] The present invention relates to a method of grinding silicon-containing solids by means of a jet mill. Background technique [0002] In many applications, for example when silicon particles are used as active material in the anode of a lithium-ion battery, there is a need for silicon particles with a particle size in the micron range. One way of producing such particles is by comminuting larger silicon particles, for example by grinding. Thus, EP1754539 describes the pulverization of silicon particles by means of a fluidized bed jet mill, where nitrogen, argon or purified air can be used as the grinding gas flow, to produce silicon particles with a diameter of 50 to 1000 μm. However, silicon particles with an average particle size of typically less than 3 μm are required for lithium-ion batteries. In order to produce finely divided silicon powder with an average particle size of, for example, 0.02 to 10 μm, wet grinding methods are often used, as kn...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B02C19/06C01B33/021
CPCB02C19/06C01B33/02C01P2004/61H01M4/386H01M10/0525Y02E60/10B02C19/068C01P2004/51
Inventor 埃克哈德·哈内尔特米夏埃尔·弗里克
Owner WACKER CHEM GMBH