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 H2SO4 leaching, is proposed for the silicon separation and purification. The results indicate that under the influence of centrifugal force, rapid solidliquid separation and impurity removal of the DWSSP waste slurry have been achieved. Direct concentrated H2SO4 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.