Iraqi kaolin of Duekhla and Al-Soofi valley biobleached using fungus Aspergillus niger. Major discoloring of these clays is resulted from certain impurities such as iron and titanium oxides as well as organic substances. ...

Silica sand of ardhama deposit has been biobeneficiated using fungus Aspergillus niger to upgrade its chemical properties especially those associated with the removal of iron oxide impurities. The biobeneficiated silica ...