Crystalline silicon solar cell resource classifying recycling method

Abstract

The invention discloses a crystalline silicon solar cell resource classifying recycling method. The crystalline silicon solar cell resource classifying recycling method comprises the following steps: cleaning crystalline silicon solar cells to obtain clean silicon wafers; removing aluminium from the surfaces of the silicon wafers; removing silver from the surfaces of the silicon wafers; removing anti-reflecting layers and N-type knots from the surfaces of the silicon wafers; at room temperature, cleaning the silicon wafers from which the aluminium and the silver are removed, and placing the silicon wafers in a mixed acid aqueous solution, wherein the mixed acid aqueous solution comprises HNO3 with the volume fraction of 39 to 41 percent and HF with the volume fraction of 5.5 to 6.5 percent; and enabling the silicon wafers to react for over 75 minutes in the mixed acid aqueous solution to obtain pure silicon wafers. According to the crystalline silicon solar cell resource classifying recycling method, the aluminium is removed by adopting hydrochloric acid; a good effect of removing the blue anti-reflecting layers and the N-type knots from the silicon wafers is achieved in a mode of mixed acid of nitric acid and hydrofluoric acid; and the silicon wafers with high purity can be obtained.

Description

technical field [0001] The invention belongs to the field of solid waste treatment, and in particular relates to a method for sorting and recycling aluminum, silver and crystalline silicon in waste crystalline silicon solar cells. Background technique [0002] Crystalline silicon solar cells are the basic components of photovoltaic modules. From top to bottom, they are front electrode, anti-reflection film, N-type layer, PN junction, P-type layer and back electrode. The front electrode is generally a silver (Ag) grid line electrode, and the anti-reflection film is silicon tetranitride (Si 3 N 4 ), the N-type layer is phosphorus (P) element doped on the silicon substrate, the P-type layer is the silicon substrate, and the electrode on the back is generally aluminum (Al) paste that is brushed on the entire surface. The production of solar cells requires processes such as texturing, diffusion, and electrode printing on the surface of the silicon wafer. When recycling a comple...

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Problems solved by technology

[0003] The Chinese patent with the publication number CN103920698A discloses a method for sorting and recycling waste crystalline silicon solar cells, using NaOH solution-HNO 3 Solution-HF solution separation and recovery step. In this patent, the NaOH solution will also etch the silicon wafer while etching the aluminum layer of the cell. It is difficult to recover the aluminum flocculant in the etching solution; and the HF solution can only etch nitrogen. Silicone anti-reflection layer, which has poor effect on removing n-type junctions and affects the purity of polysilicon

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