Abstract: A process for the re-use of remainders or other residual Si of high purity silicon such as saw dust or kerf from manufacturing of solar cells wafers or semi-conductor devices, is characterized in that the dry kerf, chips and/or other residual Si from wafer production processes or semi-conductor devices is used as feedstock together with metallurgical grade silicon in a direct chlorination reactor (1) producing silicon tetrachloride, SiCl4. Unreacted kerf or other small particles that escape the reaction zone unreacted are repeatedly returned to the reactor for further chlorination regardless of their size.