Silicon Metal – Iranian Silicon Metal

Silicon metal or metallic silicon is an alloy consisting of a high percentage of silicon (the main component, silicon, is at least about 98 percent) and varying amounts of iron, calcium, and aluminum. This material is also known in the industry by other names such as industrial silicon and crystalline silicon. Silicon metal is prepared by melting quartz and coke in an electric furnace. To add silicon in large quantities in the iron and steel industry and as a reducing agent (deoxidizer), it sometimes is used instead of ferrosilicon. Silicon is also an important component in aluminum alloys, and most cast aluminum alloys contain silicon.

Silicon metal properties

The unique physical and chemical properties of silicon-metal have made it one of the most widely used materials in industry. High melting and boiling points, heat resistance, high hardness, and brittleness are the most important physical properties of this amazing gray compound. Silicon has relatively high chemical stability and resistance to air, and expands like water when frozen. Silicon is a semiconductor and has a shiny, metal-like surface.

Size and Classification:

In industries, silicon-metal is used in various shapes:

 

Shape	Size
Powder	16 – 240 mesh
Chips	3 – 10 mm
Lumpy	10 – 200 mm

 

Different Types of Silicon Metal

Silicon metal is classified in the industry into different types, each of which is named with a special code. The difference in the properties of each group stems from the different ratios of its constituent materials. To prepare a specific type of silicon-metal, we must know the properties of each group and select the most appropriate grade according to our working space. The classification method is based on the levels of iron, aluminum and calcium impurities in the alloy. The classification of types of SiliconMetal is given below:

 

 

Type	Content of Elements
	Si %	Fe %	Al %	Ca %	P %
1501	99.69	0.15	0.15	0.01	<0.004
1502	99.68	0.15	0.15	0.02	<0.004
1101	99.79	0.1	0.1	0.01	<0.004
2202	99.58	0.2	0.2	0.02	<0.004
2502	99.48	0.25	0.25	0.02	<0.004
3303	99.37	0.3	0.3	0.03	<0.005
411	99.4	0.4	0.1	0.1	<0.005
421	99.3	0.4	0.2	0.1	–
441	99.1	0.4	0.4	0.1	–
551	98.9	0.5	0.5	0.1	–
553	98.7	0.5	0.5	0.3	–

 

Iranian Off-grade Silicon Metal

Apart from above classification, there is some out-of-range specification which cannot be put them on beside standard grade. There for it called Off-Grade and its lower than any standard grade in terms of rice and Si rate. Here is some off-grade specification for instance:

 

“Si” Silicon

Test 1: %98.1

Test 2: %97.31

Test 3: %96.96

Test 4: %97.05

Average: %97.355

 

“Fe” Iron

Test 1: %0.31

Test 2: %1.15

Test 3: %1.4

Test 4: %1.11

Average: %0.9925

 

“Al” Aluminum

Test 1: %0.89

Test 2: %0.32

Test 3: %0.3

Test 4: %0.6

Average: %0.525

Production of Silicon Metal:

Most of the silicon-metal product is for use in aluminum industries and steelmaking. In steel making we can call it Ferrosilicon. it can contain between 15% to 90% silicon, depending on the smelter’s needs. The iron-silicon alloy is produced using a submerged arc furnace through a melting and reduction reaction. Silica-rich ore and a carbon source, such as coking coal (metallurgical coal), are crushed and fed into a furnace with scrap iron. At temperatures in excess of 1900°C, the carbon reacts with the oxygen in the ore to form carbon monoxide gas. Meanwhile, the remaining iron and silicon combine to form molten ferrosilicon, which can be collected by tapping at the base of the furnace. After cooling and solidifying, the ferrosilicon can be transported and used directly in iron and steelmaking.

The same method, excluding iron, is used to produce silicon-metal with a purity of over 99%. it’s also used in steelmaking.

Applications of silicon metal in industry:

1. It was initially used in the production of semiconductor materials, but today its range of applications has expanded from the aircraft manufacturing industry to lubricants and cosmetics.
2. The main application of silicon-metal is as an additive for non-ferrous alloys.
3. It’s used as a reducing agent in the metal smelting industry. By adding this material to metals, especially aluminum, an alloy with high strength and lower weight is obtained, which is used instead of heavy cast iron parts in the automotive and aircraft industries.
4. As an alloying agent for the production of silicon steel in demand.
5. Silicon-metal compounds are indirectly used to produce lubricants and hydrophobic compounds, paints, adhesives, polishes and cosmetics.
6. This material is also widely used in the iron core of motors, transformer reinforcement, and equipment required by the electrical, chemical, shipbuilding, and other industries.
7. It is used in the manufacture of solar cells.

MSDS:

Unlike the Ferrosilicon, Silicon Metal is generally *not classified as dangerous goods (DG)* for marine shipments under normal conditions. However, if it is in a powdered form or there is a risk of moisture exposure, it may be regulated as DG. Always consult the latest *IMDG Code* and conduct a proper hazard assessment before shipping.

H.S Code:

Silicon-metal can have multiple HS codes depending on its form, purity, and intended use. different forms or grades of silicon metal may fall under different codes. Below are some common HS codes associated with silicon metal:

1. Silicon Metal (Unwrought):

– HS Code: 28046900

– This code typically covers *unwrought silicon metal* (e.g., lumps, ingots, or blocks) with a silicon content of less than 99.99%.

– It is the most commonly used code for raw or unprocessed silicon metal.

2. High-Purity Silicon Metal:

– HS Code: 28046100

– This code applies to silicon metal with a *silicon content of 99.99% or higher.*

– High-purity silicon is often used in the electronics and solar industries.

3. Silicon Metal for Alloying:

– HS Code: 72022900

– If the silicon metal is specifically used as an alloying agent in the production of ferrous metals (e.g., steel or iron), it may be classified under these codes, which are part of the ferrous alloy category.