Mineral Research Centre Department of Minerals and Geoscience Malaysia;
Perak Department of Mineral and Geoscience Jalan Sultan Azlan Shah Ipoh 31400 Perak Malaysia;
Mineral Research Centre Department of Minerals and Geoscience Malaysia;
Mineral Research Centre Department of Minerals and Geoscience Malaysia;
Silica rocks; acid concentration; citric acid; attrition scrubber;