Colloidal Silica
Colloidal silicas are most often prepared in a multi-step process where an alkali-silicate solution is partially neutralized, leading to the formation of silica nuclei. The subunits of colloidal silica particles are typically in the range of 1 to 5 nm. Whether or not these subunits are joined together depends on the conditions of polymerization.
Initial acidification of a water-glass (sodium silicate) solution yields Si(OH)4.
If the pH is reduced below 7 or if salt is added, then the units tend to fuse together in chains. These products are often called silica gels. If the pH is kept slightly on the alkaline side of neutral, then the subunits stay separated, and they gradually grow.
Colloidal Silica Sol :
Products :
ZCS- 30 ZCS-40 ZCS-20 ACIDIC ZCS30 ACIDIC ZCS-30 NEUTRAL ZCS-30 SM ZCS-40 SM ZCS- 15 AS ZCS-30 AS ZCS 500/SM ZSC 400
Specifications
Grade |
SiO2% |
pH |
Titrable Alkali(w/w) |
Specific Gravity |
Specific Surface Area(m2/g) |
Mean Particle Size(mµ) |
Viscocity |
|
ZCS-30 |
30 |
9.75 |
0.35-0.4 |
1.2 |
220-300 |
12-9 |
3-4 |
|
ZCS-40 |
40 |
9.72 |
0.31 |
1.3 |
160 |
17 |
3.2-4 |
|
ZCS-20 ACIDIC |
20 |
4-4.6 |
----- |
1.155 |
160 |
17 |
3.05 |
|
ZCS-30 ACIDIC |
30 |
4-4.6 |
------ |
1.2 |
160 |
17 |
4 |
|
ZCS- 30 NEUTRAL |
30 |
8 |
------- |
1.204 |
220 |
12 |
3.85 |
|
ZCS-30 SM |
28.5 |
8 |
------- |
1.193 |
340 |
8 |
3.9 |
|
ZCS-40 SM |
40 |
8 |
------- |
1.303 |
220 |
12 |
7 |
|
ZCS-15 AS |
15 |
220 |
------- |
1.097 |
220 |
12 |
1.55 |
|
ZCS-30 AS |
30 |
8.68 |
------- |
1.205 |
220 |
12.4 |
3.75 |
|
ZCS 500/SM |
15 |
10.4 |
0.45 |
1.1 |
500 |
5.45 |
1.79 |
|
ZCS- 400 |
30 |
10.5 |
0.45 |
1.2 |
400-450 |
6.8-7 |
3.49 |
