Main technical indexes:

si40 

1. Chroma: ≤30 APHA max.
2. Specific gravity: 1.05 –1.07 at 20° C(68° F)
3. Silicon dioxide: 40.0-42.0% by wt. as SiO₂
4. Acidity: ≤50PPm. (as HCl)
5. Ethanol: 2%
6. Iron: 0-5PPm by wt. as FeCl₂

si32

1. Chroma: ≤30 APHA max.
2. Specific gravity: 0.97 - 1.00 at 20° C(68° F) 
3.Silicon dioxide: 32.0-34.0% by wt. as SiO₂ 
4. Assay:  ≤50PPm. (as HCl) 
5.. Ethanol: 2%
6.Iron: ≤0-5PPm by wt. as FeCl₂

si28

1. Chroma: ≤30 APHA max.
2. Specific gravity: 0.93 - 0.96
3. Acidity: ≤50PP. (as HCl)
4. Silicon dioxide: 28.0-31% by wt. as SiO₂
5. Assay: 98.0%
6. Of which: Monomer 92-96%
7. Demer: 4-8%
8. Ethanol: 2%
9. Iron: ≤5PPm by wt. as FeCl₂