... of residual oil 5)Certificate:ISO9001:2008 Activated Clay for Corn Oil1)Raw Material:High quality ... burning oil & asphalt approach),%≥95Activity(NaAc approach)≥180Free acid (H2SO4),%≤0.15Water content before leaving factory,%≤12 ... harmful pigment,aflatoxin,phosphatide,saponin,colloid,and cotton acid from the oil to make it high- ... to its high water absorption ability. acid activated clay for corn oil