NOVELTY - The silicon melting apparatus has a rectangular chamber (5) that is provided with a crucible holding melting silicon (2). The rectangular chamber is connected to the cylindrical chamber (6) through an openable and closable element (12). A detection mechanism is arranged in the cylindrical chamber and provided with a specific resistance measuring device to detect concentration of impurity contained in the solidification silicon. A rotational cooling structure (7) is arranged inside the chambers to process silicon.    USE - Silicon melting apparatus for silicon purifier (claimed) used during manufacturing of crystalline silicon used for solar cell and semiconductor integrated circuit.    ADVANTAGE - Concentration of impurity contained in solidification silicon can be detected appropriately. Purification time of the solidification silicon can be managed reliably and silicon purification efficiency can be improved. Temperature and pressure in the melting furnaces can be adjusted appropriately. Influence of the radiant heat from the melting silicon can be excluded and sample for detecting impurity density in the silicon can be collected reliably.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) silicon purifier which removes impurity contained in the melting silicon inside the rectangular chamber whose pressure is reduced; and    (2) silicon purification method which involves immersing a rotational cooling structure in the melting silicon in the crucible accommodated in the rectangular chamber. The rotational cooling structure is rotated to form solidification silicon in the outer peripheral surface of the rotational cooling structure. The rotational cooling structure is removed from the rectangular chamber so that the specific resistance of the solidification silicon formed in the outer peripheral surface of the rotational cooling structure is determined. The density of boron and phosphorus in the melting silicon is determined and pressure inside the chambers is set to be identical.    DESCRIPTION OF DRAWING(S) - The drawings show schematic views explaining operating mode of silicon purifier and sealed state of the chambers of the silicon melting apparatus.    Melting silicon (2)    Rectangular chamber (5)    Cylindrical chamber (6)    Rotational cooling structure (7)    Openable and closable element (12)