Different grades of fumed silica can be obtained using an environmentally friendly thermal plasma process. In the present work, we studied the changes in the powder quality by varying the quench conditions used for the production of the powder and by agglomerating the product. Tests done before and after the agglomeration experiments showed that the agglomeration had no effect on the powder's rheological or other properties. We concluded that the inferior theological properties of the plasma produced fumed silica were due to the lack of the free hydroxyl groups on the surface of the particles. Posttreatment of plasma produced powder showed that the surface chemistry was modified and the free hydroxyl groups were introduced on the surface of the particles.