The invention relates to a method for
smelting and purifying backing material of a monocrystalline pot by
electron beams. The method comprises the following steps of respectively charging the backing material of the monocrystalline pot into a material bin, a
smelting crucible, a material delivery
cart and five condensing crucibles; after material charging is completed, sucking vacuum out of an
electron beam furnace, and preheating three
electron guns when the vacuum degree is smaller than 0.5Pa; enabling the power of each of the three electron guns to continue to maintain for 250kW, and
smelting silicon material; closing two electron guns which radiate to the smelting crucibles, pouring out the
silicon liquid, and maintaining the power of the electronic gun radiating the condensing
crucible to 250kW after the pouring is finished; finally, enabling the electron guns to maintain for 10min at the power of 250kW, 2min at the power of 200kW, 3min at the power of 150kW, 5min at the power of 120kW, 7min at the power of 100kW, 10min at the power of 80kW, 15min at the power of 50kW, 20min at the power of 30kW, and 25min at the power of 20kW, and condensing the electron beams at the power of 0kW. The method has the advantages that the
metal impurities can be effectively removed, the removal rate reaches 98% or above, and the minority
carrier lifetime in the produced polycrystalline cast
ingot can be effectively prolonged; the condition is mild, and the operation is easy.