Bio-oxidation　technology　for　leaching　sulfide　mineral　of　refractory　gold　concentrate　is　cleaner　than　conventional　methods.　Although　liquid　agitation　can　maintain　cells　and　particles　in　suspension,　thereby　improving　the　mass　transfer　efficiency　of　oxygen,　carbon　dioxide,　and　nutrients,　it　also　generates　shear　stress,　which　can　reduce　bio-oxidation　reaction　efficiency　by　destroying　shear　sensitive　cells.　In　this　study,　a　multiphase　Eulerian　model　with　the　standard　k-epsilon　equation　and　auxiliary　models　were　evaluated　based　on　previously　conducted　experiments　investigating　two　and　three　phase　flows　of　gas-liquid,　solid-liquid　and　gas-liquid-solid.　The　predicted　shear　stress　on　bacteria,　gas　holdup,　bubble　diameter　and　turbulence　energy　dissipation　rate　were　then　calculated　by　these　models　to　reveal　the　key　factors　influencing　bio-leaching　efficiency　and　to　analyze　the　primary　region　in　which　cell　death　occurs.　The　results　showed　that　shear　stress　on　bacteria　in　the　impeller　region　is　higher　than　in　other　regions.　Based　on　the　results　of　the　study,　an　optimal　operation　condition　was　applied　to　bio-oxidation　technology　investigations.　Comparing　with　classic　roasting　technology,　bio-oxidation　technology　completely　eliminates　toxic　gas　emissions,　reduces　4.3tons　of　wastewater　per　ton　of　refractory　gold　concentrate　and　reduces　the　leaching　toxicity　of　total　arsenic　in　the　solid　waste　from　0.57　mg/L　to　0.36　mg/L.　It　is　demonstrated　that　bio-oxidation　technology　is　cleaner　and　more　eco-friendly　than　classic　roasting　technology.　This　work　provides　guidance　for　further　study　and　designation　of　the　stirred　bioreactor　scaleup　in　both　biochemical　and　environmental　engineering　applications.　(C)　2018　Elsevier　Ltd.　All　rights　reserved.