Index denomination

Characteristics and norms for grades

Methods of

analysis

60

90

120

150

175

200

300

380

1. Appearance:                noncompacted*)

Loose blue-white powder

visually

compacted

White mass in the form of porous pieces

-

visually

2. Mass part of silicone dioxide (SiO₂) in recalculation on burnt substance, %, not less

99,9

99,9

99,9

99,9

99,9

99,9

99,9

99,9

GOST 14922

3. Mass part of Fe₂O₃, %, not more

0,003

0,003

0,003

0,003

0,003

0,003

0,003

0,003

GOST 14922

4. Mass part of Al₂O₃, %, not more

0,05

0,05

0,05

0,05

0,05

0,05

0,05

0,05

GOST 14922

5. Mass part of TiO₂, %, not more

0,03

0,03

0,03

0,03

0,03

0,03

0,02

0,02

GOST 14922

6. pH of suspension

3,8 -4,5

3,8 -4,5

3,8 -4,5

3,8 -4,5

3,8 -4,5

3,7 -4,5

3,6 -4,5

3,6 -4,5

GOST 14922

7. Mass part of moisture, %, not more**)

1

1

1

1

1,5

1,5

1,5

1,5

GOST 14922

8. Mass loses at burning, %, not more

1

1

1

1

1

1

2

2

GOST 14922

9.Bulk density, gr/dm³:

GOST 14922

noncompacted

40-60

40-60

40-60

40-60

40-60

40-60

40-60

40-60

compacted

120-140

120-140

120-140

120-140

120-140

120-140

110-140

Is not to be compacted

10. Specific surface, m²/gr by BET method

60±20

90±20

120±20

150±20

175±25

200±25

300±30

380±40

GOST 14922

11. Mass part of big particles (grit), %, not more

0,04

0,04

0,04

0,04

0,04

0,04

0,04

0,05

GOST 14922

*) In noncompacted silica there can be easily decomposable/breakable loose pieces

**) Increase of moisture mass part is allowed for grades 60, 90, 120, 150, 175 and 200, not more than up to 2%; for grades 300 and 380 not more than up to 3 and 4% accordingly, during the shelf life at relative air humidity of not more than 60%.