Crystalline silicon solar cell resource classifying recycling method

A technology for sorting solar cells and resources, applied in the field of solid waste treatment, can solve the problems of increased difficulty in recycling aluminum flocculants, poor removal of n-type junctions, affecting the purity of polysilicon, etc., to achieve inhibition of formation and avoid excessive etching , good removal effect

CN107457250AActive Publication Date: 2017-12-12CHINESE RES ACAD OF ENVIRONMENTAL SCI
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2017-12-12

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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.
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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...

Examples

Embodiment 1

[0039] Such as figure 1 , 2 Shown, a kind of crystalline silicon solar cell piece resource classification recovery method, comprises the following steps:

[0040] 1) Clean the crystalline silicon solar cells with ultrasonic waves and rinse them with deionized water to obtain clean silicon wafers.

[0041] 2) Put the cleaned silicon wafer into the HCl solution with a volume fraction of 20%-40% at room temperature, and the reaction time is 30 minutes, and the aluminum coating on the back of the silicon wafer can be etched clean. When the volume fraction of HCl is less than 20%, the reagent concentration should be increased. When the aluminum mass concentration in the recycled solution system reaches 5%, the separated solution is filtered and used to make polyaluminum chloride products.

[0042] Adding fatty alcohol polyoxyethylene ether (JFC) W:V (mass to volume)=0.5g:1L, when the volume fraction of HCl solution is 20%, the etching reaction time of aluminum coating can be sho...