Here we have fumed silica and precipitated silica in front of us, We will find it’s difficult for us to distinguish them just by their appearance.
What can we do?
1. PH Test
Make fumed silica and precipitated silica into 4% concentration water suspension respectively, and test by pH meter.
- one pH value is around 4, another one is around 7.
- The 4 pH one is fumed silica, and the 7 pH one is precipitated silica.
2. Determination of Iron ions
Due to differences in raw materials and manufacturing process, precipitated silica has higher content of iron ions.
Make fumed silica and precipitated silica into standard solution, add chromogenic agent respectively.
The precipitated silica solution is turning red while fumed silica solution remains colorless.
HIFULL HL-200 (Fumed Silica), a common anti-caking agent which is added to table salt, etc. adsorbs both water and oil. Although they are food additives, anticaking agents have other applications too. For example, anticaking agents are popularly used in non-food items like powder coatings, road salt, fertilizers, cosmetics, synthetic detergents, and other such manufacturing applications.