Microsilica (Silica Fume)
MST microsilica conforms to the mandatory requirements of the relevant standards :
1. american Society for Testing and Materials (ASTM C1240)
2. European committee for Standardisation (EN 13263 : 2005)
The SiO2 content ranges from 85 to 97 %.
They are classified as Grade 85, Grade 90, Grade 92, Grade 94 and Grade 97.
Including densified and undensified products.
Packaging
Microsilica is supplied in a range of packagings.
* 950-1000 jumbo PP bag with PE liner
The Jumbo bag conforms to GB/T10454 and EN ISO 21898
with UV-proof function and anti-aging character.
* 25 Kg woven bags with PE liner;
Storage & Transportation
MST set up thousands square meters of warehouse
and provides integral solution of
transport for customers.
* Bags.
* By Bulker.
Quality Control
Microsilica Collecting
Microsilica is collected from electric arc furnaces as a by-product of the production of elemental silicon or alloys
containing silicon. The production process conforms to ASTM C 1240 and EN 13263:2005.
Production Control
Before discharging the densified materals from silos, the silo level, open position of flow control gates, air and
ventilation system etc. shall be checked.
Two samples of silica fume shall be taken respectively from top and botton of silo. prior to packing into the bags.
Phisical and chemical tests are conducted to analyse specifications of SiO2, LOl, moisture and bulk density.
Inspection before Delivery
There is an inspection again before delivery.
a. Sampling from one package of each production lots.
b. broken bags shall not be delivered.
c. Material with lumps and moisture will be rejected.
| Grades | SiO2 | Applications |
|---|---|---|
| Microsilica Grade85 | SiO2>85% | For Construction |
| Microsilica Grade90 | SiO2>90% | For Construction |
| Microsilica Grade94 | SiO2>94% | For Construction & Refractory |
Quality Control and Testing Frequency
| Chemical & Physical Analysis | ASTM C1240-03 | EN 13263 : 2005 | ||
|---|---|---|---|---|
| Spec. | Frequency | Spec. | Frequency | |
| SiO2 (%) | >85,0 | 500 MT | > 85 | Weekly |
| SO3 (%) | < 2,0 | Monthly | ||
| Cl (%) | < 0,3 | Monthly | ||
| Free CaO (%) | < 1,0 | Monthly | ||
| Free Si (%) | < 0,4 | Monthly | ||
| Moisture (%) | < 3,0 | 500 MT | ||
| Loss on Ignition, LOi (%) | < 6,0 | 500 MT | < 0,4 | Weekly |
| Pecific Surface (BET - m2.gram) | > 15 | 3200MT/3 months | > 15 & <35 | Monthly |
| Bulk Density (kg/m3) -Densified | 550 - 700 | 500 MT | ||
| Bulk Density (kg/m3) -Undensified | 200 - 350 | 500 MT | ||
| Pozz Activity Index (%) - 7 days accelearated curing | > 10 | 3200MT/3 months | ||
| Pozz Activity Index (%) - 28 days normal curing | > 100 | Monthly | ||
| Retained on 45 micron sieve (%) | < 10 | 500 MT | ||
| Variation from avg. retained on 45 micron (%-points) | < 5 | avg. of last 10 tests | ||
