Method for refining metal silicon

Abstract

The embodiment of the invention provides a method for refining metal silicon, belonging to the field of chemical engineering. The method uses metallurgy principle to prepare a quasi-solar energy gradesilicon material under a condition of maintaining solid state of metallurgical silicon according to impurities affecting the service life of carriers and cell performance, and differences of physicalperformance and chemical performance of silicon; the method uses air blowing and high-temperature vacuum evaporation technology to promote the impurities inside silicon powder at high temperature tobe transferred to the surface of the silicon and removed by diffusing and segregating boron-phosphor oxide on the surface of a crystal boundary and reducing evaporation of substances with smaller vapor pressure, and leaching second phase substances of the crystal boundary by hydrofluoric acid to ensure that the purity of the metallurgical silicon is improved in a certain degree. The method has theadvantages of small energy consumption, low environmental pollution, simple equipment and the like.

Description

technical field [0001] The invention relates to the field of chemical industry, in particular to a refining method for metal silicon. Background technique [0002] With the development of the economy and the acceleration of the urbanization process, the demand for energy is also increasing, and now the main energy used is oil, which is a non-renewable resource, and the waste gas generated after use has a great impact on the environment, so All countries are stepping up research on renewable resources such as solar energy. Polysilicon is the mainstream material of solar cells, its supply and demand condition restricts the development of solar energy industry, and whether the refining process of metal silicon is advanced will directly affect the development of solar energy industry. [0003] In order to refine metal silicon into polysilicon, the prior art provides a refining method for metal silicon, the method is as figure 1 shown, including: [0004] Step 11, putting meta...

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Problems solved by technology

[0009] 1. High equipment cost

[0010] In this method, a high-purity oxide crucible must be selected to avoid the introduction of impurity contamination, but the high-purity oxide crucible is expensive and the equipment cost is high

[0011] 2. High energy consumption

[0012] This method must heat metal silicon to the range of 1450-1780 ° C, the heating temperature is high, and the energy consumption is large

[0013] 3. Big environmental pollution

[0014] The oxidizing gas used in this method is chlorine gas, which is easy to cause environmental pollution

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