How can I replace ; with , in an imported excel file and to delete "

Import as Table instead of CSV, and set the "FieldSeparators" option.

ImportString[
 "1;2
 3;4", 
 "Table", "FieldSeparators" -> {";"}]

(* {{1, 2}, {3, 4}} *)

"Table" is a generalization of CSV, TSV, etc. where you can customize the delimiters and separators.

ToExpression[StringReplace[ToString[file], ";" -> ","]]

{{0.0472, 120.9091}, {0.0454, 113.0303}, {0.0441, 106.6667}, {0.0442, 106.6667}, {0.0437, 103.3333}, {0.0425, 95.1515}, {0.0409, 83.6364}, {0.0387, 72.7273}, {0.0354, 59.697}, {0.0317, 45.7576}, {0.0275, 34.8485}, {0.0234, 24.8485}, {0.0155, 12.1212}, {0.0115, 6.6667}, {0.0072, 2.7273}, {0.0031, 2.1212}}

ToExpression[file /. {a_String} :> StringSplit[a, ";"]]