A green approach for silicon separation and purification from diamond wire saw silicon powder waste slurry

During silicon wafer cutting, a significant amount of diamond wire saw silicon powder (DWSSP) waste slurry is generated, leading to severe oxidation and hindering silicon purification due to prolonged conventional processing. In this study, a green approach based on centrifugation and on-line H 2 SO 4 leaching, is proposed for the silicon separation and purification. The results indicate that under the influence of centrifugal force, rapid solid-liquid separation and impurity removal of the DWSSP waste slurry have been achieved. Direct concentrated H 2 SO 4 to the concentrated liquid eliminates acid mixing, and efficiently purifying while minimizing silicon oxidation interference, reducing total impurity content in silicon-rich powder to 54.8 ppmw. In-situ experiment verifies the total impurity content in silicon-rich powder at 99.5 ppmw, with oxygen content decreased to 2.73 %, confirming the viability of the green silicon purification approach. This study provides crucial guidance for the rapid recovery and preparation of high-purity silicon from DWSSP waste slurry. • A green combined process for disposing DWSSP waste slurry was proposed. • The impurity content in the recovered silicon is as low as 54.8 ppmw. • The oxygen content of recovered silicon in in-situ experiment is as low as 2.73 %. • The combined process can realize recovered Si quality improvement and value-added.