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Silica fume(microsilica, condensed silica fume), which condenses from the gases escaping from the submerged electric arc furnaces as a by-product of the production of silicon metal or ferrosilicon, it has a very high content amorphous silicon dioxide in the form of ultrafine spherical particles typically averaging 0.1μm to 0.5 μm in diameter. Silica fume can be used in a variety of cementitious (concrete, grouts and mortars), refractory, elastomer and coating applications.
Silica fume has following features when it is applied to concrete:
Manufacturing strong concrete (about C70); improve strength and pumpover capacity of concrete remarkably.
Manufacturing high impervious (≥ P30) and structural self-waterproofing concrete, used in subway, tunnel and basement of high-rise.
Manufacturing sea engineering and chemical engineering concrete, it can stop sulphate and chloridion to permeate and corrode the concrete, that can avoid steel been corroded and prolong concrete life.
In the project of water conservancy, highway and bridge, there are not only above indexes but also rigorous anti-friction and anti weather wearing requirement for concrete. So it is necessary to mix silica fume in.
The silica fume has strong activity and high water-reducing performance, which is as an additive for rapid construction concrete, high strength sprayed concrete used as support and preserve in tunnel, subway and large foundation ditch structure, underwater construction project concrete (i.e. pier, large dam, drilling platform and so on).
Our silica fume is produced in global main ferroalloy manufacturing area, that is in the east of Helan mountain crossed by Ningxia and Inner Mongolia province located in northwest of China, where is surrounded by high energy consuming industry chain. Because of high grade silica with less impurity as well as abundant coal and electricity, it has large production of ferro-silica and metallic silicon. And gathered silica fume is in steady quality and adequate supply.
According to grade of SiO2 , the silica fume is divided to 7 levels: Grade 85, Grade 88, Grade 90, Grade 92, Grade 94, Grade 95.
Antiultraviolet and ageing resistance flexible freight bags-FIBC is adapted. Two types of 850KG and 900KG.
Grade 85
|
Chemical & Physical Analysis |
ASTM C1240-03 |
GB/T 21236-2007 |
|
SiO2 (%) |
＞85 |
≥85 |
|
C(%) |
|
≤2.5 |
|
CI(%) |
|
≤0.3 |
|
Moisture(%) |
＜3.0 |
≤3.0 |
|
L.O.I(%) |
＜6.0 |
≤6.0 |
|
Specific Surface (BET-m2/gram) |
＞15 |
≥15 |
|
Pozz. Activity Index (%) - 7 days accelerated curing |
＞105 |
|
|
Pozz. Activity Index (%) - 28 days normal curing |
|
≥85 |
|
Retained on 45 micron sieve (%) |
＜10 |
≤10.0 |
|
Variation from avg. retained on 45 micron (%-points) |
＜5 |
|
|
Water requirement ratio (%) |
|
≤125 |
Grade 88
|
Chemical & Physical Analysis |
ASTM C1240-03 |
GB/T 21236-2007 |
|
SiO2 (%) |
＞88 |
≥88 |
|
C(%) |
|
≤2.5 |
|
CI(%) |
|
≤0.2 |
|
PH value |
|
4.0-8.5 |
|
Moisture(%) |
＜3.0 |
≤3.0 |
|
L.O.I(%) |
＜6.0 |
≤4.0 |
|
Specific Surface (BET-m2/gram) |
＞15 |
≥15 |
|
Pozz. Activity Index (%) - 7 days accelerated curing |
＞105 |
|
|
Pozz. Activity Index (%) - 28 days normal curing |
|
≥85 |
|
Retained on 45 micron sieve (%) |
＜10 |
≤5.0 |
|
Variation from avg. retained on 45 micron (%-points) |
＜5 |
|
|
Water requirement ratio (%) |
|
≤125 |
Grade 90
|
Chemical and physical requirements |
GB/T 21236-2007 |
|
Item |
Spec. |
|
SiO2(%) |
＞90 |
≥90 |
|
Al2O3(%) |
|
≤1.5 |
|
Fe2O3(%) |
|
≤2.0 |
|
CaO+MgO(%) |
|
≤2.0 |
|
K2O+Na2O(%) |
|
≤2.0 |
|
C(%) |
|
≤2.0 |
|
CI(%) |
|
≤0.1 |
|
PH value |
|
4.0-8.5 |
|
Moisture（after packing）(%) |
＜1.0 |
≤2.5 |
|
L.O.I(%) |
＜3.0 |
≤3.0 |
|
Retained on 45 micron sieve (tested on Undensified, %) |
＜1.5 |
≤3.0 |
|
Specific Surface(m2/g) |
|
≥15 |
|
Pozz. Activity Index (%) - 28 days normal curing |
|
≥85 |
|
Water requirement ratio (%) |
|
≤125 |
|
Bulk Density - Undensified (when packed, kg/m3) |
200-350 |
|
|
Bulk Density - Densified (when packed, kg/m3) |
500-700 |
|
Grade 92
|
Chemical and physical requirements |
GB/T 21236-2007 |
|
Item |
Spec. |
|
SiO2(%) |
≥92 |
≥92 |
|
C(%) |
≤2.0 |
≤2.0 |
|
CI(%) |
|
≤0.1 |
|
Fe2O3(%) |
≤1.0 |
≤1.0 |
|
Al2O3(%) |
≤2.0 |
≤1.0 |
|
CaO(%) |
≤1.2 |
≤1.5 |
|
MgO(%) |
≤0.5 |
|
K2O(%) |
≤1.5 |
≤1.5 |
|
Na2O(%) |
≤0.5 |
|
Moisture(%) |
≤1.0 |
≤2.0 |
|
Loss on Ignition at 975 C |
≤3.0 |
≤3.0 |
|
Coarse Particles >45µm (325mesh) (%) |
≤1.0 |
≤3.0 |
|
PH value |
4.5-7.5 |
4.0-8.5 |
|
Specific Surface(m2/g) |
|
≥15 |
|
Pozz. Activity Index (%) - 28 days normal curing |
|
≥85 |
|
Water requirement ratio (%) |
|
≤125 |
|
Bulk Density(as packed) |
200-350kg/m3 U
500-700 kg/m3 D |
|
Grade 94
|
Analysis/Properties |
Value |
|
SiO2 Silicon Dioxide, Amorphous |
94%Min. |
|
Fe2O3 Iron Oxide |
0.19% Typical |
|
Al2O3 Aluminium Oxide |
0.27% Typical |
|
CaO |
0.26% Typical |
|
MgO |
0.49% Typical |
|
K2O Potassium Oxide |
0.50% Typical |
|
Na2O Sodium Oxide |
0.38% Typical |
|
P2O5 Phosphorus Pentoxide |
0.26% Typical |
|
MnO Manganese Oxide |
0.25% Typical |
|
TiO2 Titanium Oxide |
0.21% Typical |
|
Loss on Ignition |
2.88% Typical |
|
Coarse Particles >45µm (325mesh) |
1.2%Max. |
|
Bulk Density(as packed) |
200-350kg/m3 U
500-700 kg/m3 D |
Grade 95
|
Chemical and physical requirements |
GB/T 21236-2007 |
|
Item |
Spec. |
|
SiO2(%) |
≥95% |
≥95% |
|
Al2O3(%) |
0.21 |
≤1.0 |
|
Fe2O3(%) |
0.08 |
≤1.0 |
|
C(%) |
|
≤1.0 |
|
CI(%) |
|
≤0.1 |
|
CaO(%) |
0.11 |
≤1.0 |
|
MgO(%) |
0.21 |
|
K2O(%) |
0.32 |
≤1.0 |
|
Na2O(%) |
0.24 |
|
P2O5(%) |
0.09 |
|
|
MnO(%) |
0.035 |
|
|
TiO2(%) |
0.012 |
|
|
PH value |
|
4.5-7.5 |
|
L.O.I (%) |
2.63 |
≤1.0 |
|
Coarse Particles >45µm (325mesh) (%) |
≤1.2 |
≤2.0 |
|
Specific Surface(m2/g) |
|
≥15 |
|
Pozz. Activity Index (%) - 28 days normal curing |
|
≥85 |
|
Water requirement ratio (%) |
|
≤125 |
|
Bulk Density(as packed) |
200-350kg/m3 U
500-700 kg/m3 D |
|
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