NOVELTY - An input gas (13) is reacted with a metal silicon alloy material (12) having silicon content of less than or equal to eutectic content of silicon defined for metal silicon alloy. A chemical vapor transport gas (15) containing silicon is generated from atomic matrix of alloy material. The vapor transport gas is directed to a filament configured to facilitate silicon deposition. Silicon is deposited from chemical vapor transport gas on the filament in purified form. Thus, silicon is purified.    USE - Purification of silicon used for solar cell and semiconductor device.    ADVANTAGE - The silicon having high purity is economically produced using vapor deposition transport gas.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) reaction chamber containing metal silicon alloy material positioned as several individual formed pieces placed adjacent to one another;    (2) production of chemical vapor transport gas for use in silicon purification, which involves reacting input gas with metal silicon alloy material, generating chemical vapor transport gas containing silicon, and outputting vapor transport gas;    (3) method of producing metal silicon alloy material, which involves melting a depleted metal silicon alloy material having concentration of silicon in atomic matrix increasing away from the exterior surface (18) of the metal silicon alloy material towards the interior of alloy material, such that weight ratio of silicon adjacent to the exterior surface is less than specified threshold fraction of the eutectic weight ratio of silicon, enhancing the weight ratio of silicon of the melt material to a selected weight ratio of silicon, and casting the melt material to produce solid metal silicon alloy material;    (4) metal silicon alloy material having silicon content at selected eutectic weight ratio such that presence of silicon crystallites in the alloy material is less than or equal to defined maximum crystallite threshold; and    (5) chemical vapor reactor containing metal silicon alloy material having silicon ratio less than or equal to eutectic ratio of silicon defined for the respective metal silicon alloy.    DESCRIPTION OF DRAWING(S) - The drawing shows the block diagram of purification apparatus.    Metal silicon alloy material (12)    Input gas (13)    Transport gas (15)    Lower grade source material (16)    Holder (17)    Exterior surface (18)    High purity silicon (27)