Industry information
Uses, ingredients, and industrial requirements of silica
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  • 作者:admin
  • 发布时间:2020-01-18 15:19
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I. Use
 
Silica is mainly used in the metallurgical industry to make acid refractory bricks—silica bricks and fluxes for smelting various metals. Silica brick has good resistance to acid slag erosion, and it also has a certain resistance to the erosion of calcium oxide slag and iron oxide slag. The biggest advantage of silica bricks is that the load softening starting temperature is high (generally above 1620 ℃), so it is widely used in building furnace linings such as coke ovens, electric furnaces, heating furnaces, glass melting furnaces and refractory kiln.
 
 
 
Pure silica can be used for making quartz glass and refining crystalline silicon. Crystalline silicon is the raw material for refining single crystal silicon, and it can produce silicon aluminum and organic silicon. In the chemical industry, silica is used to make various silicon compounds and silicates. It is also used as a filler for sulfuric acid towers. In the building materials industry, it can be used as a raw material for glass, ceramics and portland cement. Can also be used for grinding stones, oil stones, sandpaper and so on.
 
 
 
Mineral composition and chemical composition
 
In the industry, the quartzite, quartz sandstone, and vein quartz that meet the requirements of silicon dioxide and impurity content are called silica. The main mineral component is quartz, and the chemical composition is mainly silicon dioxide. , Calcium oxide, phosphorus pentoxide and other impurities.
 
 
 
3. General industrial requirements
 
(I) Requirements for chemical composition and main physical properties
 
 
 
1.For refractory products
 
Grade
 
chemical composition(%)
 
Refractory
 
 
Water absorption
 
(%)
 
SiO2
 
Al2O3
 
CaO
 
Fe2O3
 
Super
 
Grade I
 
Grade II
 
≥98
 
≥97
 
≥96
 
≤0.5
 
≤1.0
 
≤1.3
 
≤0.4
 
≤0.5
 
≤1.0
 
≤0.5
 
≤1.0
 
≤1.5
 
1750
 
1730
 
1710
 
≤3
 
≤4
 
≤4
 
 
 
2.For ferroalloys and industrial silicon
 
Grade
 
chemical composition(%)
 
SiO2
 
Al2O3
 
Fe2O3
 
CaO
 
P2O5
 
Super
 
Grade I
 
Grade II
 
≥99
 
≥98
 
≥97
 
≤0.3
 
≤0.5
 
≤1.0
 
≤0.15
 
 
 
≤0.2
 
≤0.3
 
≤0.5
 
≤0.02
 
≤0.02
 
≤0.03
 
Note: The lump of ore is generally 20-250 mm, and those below 20 mm generally require no more than 10%.
 
 
 
3.For flux, etc.
 
Use
 
chemical composition(%)
 
SiO2
 
Al2O3
 
Fe2O3
 
CaO
 
P2O5
 
For flux
 
For silicon aluminum
 
For crystalline silicon
 
For quartz glass
 
≥90—95
 
≥98.5
 
≥98—99
 
≥99.95
 
≤2—5
 
≤0.5
 
≤0.5
 
Minimal
 
≤1—3
 
 
≤0.5
 
Minimal
 
≤3
 
 
≤0.5
 
Minimal
 
 
 
≤0.03
 
Minimal
 
 
 
(2) Requirements for mining technical conditions:
 
Available thickness: 2 meters,
 
Stone removal thickness: 1-2 meters,
 
Mining and stripping ratio: 1: 3-5 meters.
 
 
 
 
 
4. Examples of deposits
 
(I) Quartzite (for silica brick)
 
grade
 
chemical composition(%)
 
Refractory
 
(℃)
 
Minable thickness
 
(Meter)
 
Strip ratio
 
SiO2
 
Al2O3
 
Fe2O3
 
CaO
 
Super
 
Grade I
 
Grade II
 
> 98
 
> 98
 
> 98
 
<0.5
 
<1.0
 
<1.2
 
<0.5
 
<1.0
 
<1.5
 
<0.5
 
<1.0
 
<1.2
 
> 1750
 
> 1730
 
> 1710
 
2
 
<1
 
 
 
(II) Shimen quartzite in Liaoning
 
use
 
grade
 
chemical composition(%)
 
Refractory
 
(℃)
 
Minable thickness
 
(Meter)
 
Strip ratio
 
SiO2
 
Al2O3
 
Fe2O3
 
CaO
 
For silicon brick
 
Grade I
 
Grade II
 
Class III
 
> 98
 
> 97
 
> 98
 
<1.0
 
<1.3
 
<1.6
 
<0.5
 
<1.0
 
<1.5
 
 
> 1770
 
> 1750
 
> 1730
 
1
 
1
 
For ferrosilicon
 
Grade I
 
Grade II
 
> 97
 
> 98
 
<1.0
 
<1.5
 
<0.3
 
<1.0
 
<0.02
 
<0.03
 
 
 
V. Appendix
 
(I) Quality Standard for Silica YB2416-81 issued by the Ministry of Metallurgical Industry on May 1, 1982
 
1.For refractory products
 
grade
 
chemical composition(%)
 
Refractory
 
(℃)
 
Water absorption (%)
 
SiO2
 
Al2O3
 
CaO
 
Premium
 
First grade
 
Second grade
 
≥98
 
≥97
 
≥96
 
≤0.5
 
≤1.0
 
≤1.3
 
≤0.4
 
≤0.5
 
≤1.0
 
1750
 
1730
 
1710
 
≤3
 
≤4
 
≤4
 
 
 
2.For ferroalloys and industrial silicon
 
grade
 
chemical composition(%)
 
SiO2
 
Al2O3
 
Fe2O3
 
CaO
 
P2O5
 
Premium
 
First grade
 
Second grade
 
≥98
 
≥97
 
≥96
 
≤0.3
 
≤0.5
 
≤1.0
 
≤0.15
 
 
 
≤0.2
 
≤0.3
 
≤0.5
 
≤0.02
 
≤0.02
 
≤0.03
 
Note: The product size is divided into the following five specifications (excerpts)
 
20-40 mm, 40-60 mm, 60-120 mm, 120-160 mm, 160-250 mm.
 
 
 
(II) Quality requirements for silica raw materials of Baosteel
 
1. For steelmaking: SiO2> 95%, Al2O3 <2%, moisture <5%, particle size 10-30 mm.
 
2. For ironmaking: chemical composition is the same as that for steelmaking; particle size is less than millimeter.