The invention relates to a method for cleaning a
metallurgical silicon material, which comprises the following steps: crushing a
metal silicon material to below 3 centimeters; preparing acid-washing
impurity removing solution, and preparing mixed acid by using
hydrofluoric acid and
nitric acid in a ratio of 1:12-20; soaking the crushed
silicon material into the mixed acid, and stirring and cleaning the
silicon material for certain time;
fishing out the cleaned silicon material, cleaning the silicon material by secondary
purified water, and continually turning over the silicon material; and ultrasonically cleaning the silicon material by third-grade
purified water,
fishing out the cleaned silicon material when the pH is equal to 7, and
drying the silicon material. When the silicon material contains impurities, the
electrochemical potential energy and the surface activity in an area are changed, the impurities are enriched, the reaction
electromotive force of the impurities is large, the
reaction rate with the acid is high, then the
metal silicon material is subjected to
impurity removal to a certain degree by using the principle, and the best selective
corrosion effect is realized by allocating the acid matching ratio, concentration and reaction time so as to remove more impurities, realize the selective
corrosion effect and meet the usage requirements of solar cells on the silicon material.