The invention relates to a method for recycling a waste
silicon solution, in particular to a method for recycling a waste
silicon solution generated in
cutting silicon chip sheets. The method is characterized by comprising the following steps: carrying out
centrifugal separation on the waste silicon solution generated in
cutting silicon bars by filter cloth with the
pore diameter of 800-1,500 meshes, and then obtaining silicon
powder; putting the silicon
powder obtained after separation in a reaction kettle; adding a strong oxidizer to react, and then filtering the reaction solution so as to remove organic
carbon impurities, wherein the strong oxidizer is one of concentrated
sulfuric acid,
hydrogen peroxide and
nitric acid or a
mixed solution prepared from concentrated
sulfuric acid,
hydrogen peroxide and
nitric acid; putting the silicon
powder obtained after secondary
filtration in the reaction kettle; adding diluted
aqua fortis to react, and then filtering and
drying the reaction solution so as to remove
metal and
metal oxide impurities; and putting the silicon powder obtained after third
filtration in a Czochralski
single crystal furnace; sufficiently reacting in the
single crystal furnace in vacuum at the temperature of 800-1,000 DEG C so as to remove surface impurities, then cooling, and finally obtaining solar-grade silicon sheets. Applying the method can recycle most silicon powder in the waste silicon solution, and the silicon powder can be used for manufacturing solar batteries by
downstream processing, thereby not only saving resources, but also not generating environmental
pollution.