Silicon Metal Grades 553 · 441 · 3303 · 2202 · CAS 7440-21-3
The feedstock behind aluminum alloys, silicones and solar — and the one import line where US antidumping and countervailing duty orders can matter more to your landed cost than the mill price does.
Chelora Chemicals is a silicon metal supplier and sourcing partner serving aluminum producers, silicone manufacturers and foundries across the United States, with grade, sizing and origin agreed in writing before the order goes out.
- CAS Number
- 7440-21-3
- Chemical symbol
- Si
- Atomic weight
- 28.09
- Si content
- 98.5–99.5% by grade
- Commercial grades
- 553 · 441 · 3303 · 2202
- Forms supplied
- Lump · granule · powder
- Melting point
- 1,414 °C
- Transport
- Lump not DG regulated
- HS Code
- 2804 69
Note: the grade digits are maximum impurity limits. In grade 553 the figures mean Fe ≤ 0.5%, Al ≤ 0.5%, Ca ≤ 0.3%. Grade 2202 means Fe ≤ 0.2%, Al ≤ 0.2%, Ca ≤ 0.02% — tighter on every count. Confirm the exact limits against the producer specification, because interpretations vary slightly between mills.
From quartz to silicon metal
Silicon metal is smelted from quartz with a carbon reductant in a submerged arc furnace — one of the most energy-intensive processes in the metals industry.
Why it matters: smelting silicon takes roughly 11 to 13 MWh per tonne — which is why production sits where power is cheap, and why origin drives price on this line
What silicon metal is used for
Silicon metal is elemental silicon at 98.5 to 99.5% purity, smelted from quartz in a submerged arc furnace and sold as lump, granule or powder. It is not the ultra-pure silicon of a semiconductor wafer — that is made downstream — but the industrial feedstock from which everything else is built.
Three markets take most of it. Aluminum alloying is the largest, where silicon improves castability and strength in automotive and construction alloys. Silicones come next, where chemical-grade silicon reacts with methyl chloride to make the siloxane building blocks. And polysilicon for solar and semiconductors starts here, refined up through trichlorosilane.
Grades and forms we quote against
- Grade 553. Fe ≤ 0.5%, Al ≤ 0.5%, Ca ≤ 0.3%. The workhorse grade for secondary aluminum alloying.
- Grade 441. Fe ≤ 0.4%, Al ≤ 0.4%, Ca ≤ 0.1%. Tighter calcium, widely specified for primary aluminum and chemical use.
- Grades 3303 and 2202. Progressively tighter on iron, aluminum and calcium for chemical-grade and polysilicon service.
- Lump, granule or powder sized to your charge arrangement, with petroleum coke available from the same desk.
Handling character
Silicon metal lump is stable and not classed as dangerous goods, but fine powder raises dust and reactivity questions. Full detail is in the Safety section below.
| Parameter | Typical value |
|---|---|
| Appearance | Gray metallic lump, granule or powder |
| Si content | 98.5% min (553) to 99.5% min (2202) |
| Fe content | 0.2–0.5% max by grade |
| Al content | 0.2–0.5% max by grade |
| Ca content | 0.02–0.3% max by grade |
| Size range | 10–100 mm lump, or per agreed sizing |
Important: the figures above are indicative of commercial material and are offered for planning only. The batch certificate of analysis is the governing document.
| Property | Value |
|---|---|
| Physical state | Gray, lustrous, brittle crystalline solid |
| Atomic weight | 28.09 |
| Melting point | 1,414 °C |
| Boiling point | 3,265 °C |
| Density | 2.33 g/cm³ |
| Water solubility | Insoluble |
| Reactivity | Attacked by hot alkali; resists most acids |
Physical constants compiled from public reference data for elemental silicon and rounded for readability. Commercial material is 98.5 to 99.5% pure, so bulk behavior varies with the impurity profile. Treat the table as orientation, not as a specification.
Where US industry uses silicon metal
Aluminum alloying, silicones, polysilicon and steel — four very different purity requirements.
Aluminum alloying
The largest end use. Silicon improves castability, reduces shrinkage and raises strength in automotive and construction casting alloys.
- Grade 553 and 441 standard
- Sized lump for charge addition
- Bulk bag and bulk supply
Silicones & siloxanes
Chemical-grade silicon reacts with methyl chloride in the direct process to make chlorosilanes, the building blocks of every silicone.
- Grades 3303 and 2202
- Tight Ca and Al control
- Low boron and phosphorus on request
Polysilicon, solar & semiconductor
Metallurgical silicon is the starting point, refined up through trichlorosilane to solar and electronic grade polysilicon.
- Highest purity grades
- Low boron and phosphorus on request
- Documented impurity profile
Steel & foundry
Used as a deoxidizer and alloying addition in specialty steel and ductile iron where ferrosilicon is not preferred.
- Sized to the charge arrangement
- Consistent lot-to-lot assay
- Retained sample held
Origin & duty review
US antidumping and countervailing duty orders cover silicon metal from several origins, and the scope changes. Origin can move landed cost more than mill price.
- Origin confirmed before quoting
- Duty exposure flagged in writing
- Broker coordination on request
Contract & scheduled supply
Smelter output is power-dependent and seasonal. Contracted tonnage with call-off scheduling protects a continuous melt operation.
- Annual contracts with call-off
- Price held across the contract
- Second source held in reserve
Delivered to US plants and ports
We ship silicon metal to nominated delivery points across the United States. The regions below are destinations we serve — Chelora Chemicals is a sourcing and supply partner, not a US manufacturer, and does not hold US stock.
Gulf Coast
The largest US chemical cluster, and the usual entry point for bulk consignments.
- Houston & Galveston, TX
- New Orleans & Baton Rouge, LA
- Mobile, AL
Northeast
Container and bulk delivery into the mid-Atlantic and New England manufacturing belt.
- Newark & Elizabeth, NJ
- Philadelphia, PA
- Boston, MA
Southeast
Port-side delivery for the Carolinas, Georgia and Florida processing plants.
- Savannah, GA
- Charleston, SC
- Jacksonville, FL & Norfolk, VA
Midwest & Great Lakes
Inland rail and truck forwarding from the nearest coastal port to the industrial Midwest.
- Chicago, IL
- Detroit, MI
- Cleveland & Columbus, OH
West Coast
Pacific routing for West Coast processors and formulators.
- Los Angeles & Long Beach, CA
- Oakland, CA
- Seattle & Tacoma, WA
Southwest & Mountain
Inland delivery to interior states, forwarded from the Gulf or Pacific gateway.
- Dallas–Fort Worth, TX
- Phoenix, AZ
- Denver, CO
Importing into the United States
Silicon metal is a TSCA-regulated chemical substance. Under TSCA section 13 the importer of record, or its authorized agent, must certify to US Customs and Border Protection that each shipment either complies with TSCA or is not subject to it. We confirm the substance's TSCA Inventory status and agree in writing who files that certification before the first consignment moves.
Which party carries that duty follows the Incoterm. On FOB, CFR or CIF terms it is usually the US buyer; on DDP terms it can be the seller or its agent. Safety data sheets and labels are supplied to OSHA's updated Hazard Communication Standard, and the non-hazardous transport documentation is prepared before booking.
| Item | How it works |
|---|---|
| Delivery points | Any nominated US plant, terminal or port of discharge |
| Incoterms quoted | FOB · CFR · CIF · DDP |
| Importer of record | Agreed in writing before the first shipment |
| TSCA certification | Section 13 positive certification filed at entry |
| Documentation | Batch COA, SDS, packing list, certificate of origin |
| Pack formats | 1 MT bulk bags or bulk |
Note: regional coverage describes where we deliver, not where we hold inventory. Lead time depends on producer scheduling and ocean transit to your nominated US port — we confirm both in the quotation.
How we supply silicon metal
Chelora Chemicals is a silicon metal supplier and sourcing partner, not a smelter. On this line the three things that decide whether a shipment works are the impurity profile, the sizing, and the origin — and the third one is where buyers get caught.
We place your order with whichever qualified smelter best matches your grade, your price point and your delivery window, and we confirm the US import position before booking rather than after.
We keep a second qualified source on this line, because a single smelter outage — power curtailment included — should not become your melt schedule problem.
- Origin and duty exposure flagged before you commit. US antidumping and countervailing duty orders cover silicon metal from several origins and the scope changes; we confirm the position with your broker rather than guessing.
- Full impurity profile, not just Si assay. Fe, Al and Ca are what the grade designation actually controls, and they are what your process cares about.
- Sizing agreed up front. A charge bucket, a crusher feed and a direct-process reactor want different size distributions. Lump, granule and powder are not interchangeable.
- Boron and phosphorus on request. For polysilicon-bound material these trace elements matter more than the headline assay, so we ask for them when the end use needs them.
- TSCA status and import certification settled first. We confirm Inventory status and agree who files the section 13 certification before the first shipment.
- Batch traceability to the producing furnace. Full chain of custody documentation on request.
Bulk bagged or delivered in bulk
1 MT bulk bags, drums or bulk container — tell us your handling arrangement and we will quote to it.
1,000 kg bulk bags
Liner-fitted bulk bags on pallets, the standard unit for melt-shop and foundry charge handling.
Bulk container or truck
Bulk shipment for high-volume aluminum and silicone operations with mechanical handling.
25 kg bags
Smaller bagged units for powder grades and for controlled additions.
Steel or fiber drums
Sealed drums where powder grades need moisture and dust containment.
Incoterms to suit you
Quoted on the Incoterm your purchasing team works to, with origin documentation filed before booking.
Trial / sample quantities
Small sized lots dispatched for melt trials and impurity verification before a commercial order.
Stable as lump — treat the powder differently
Silicon metal lump is chemically stable, insoluble and not classed as dangerous goods for transport. Fine powder is a different proposition: it raises respirable dust and, at small enough particle size, a combustible dust question. The summary below is orientation only — the safety data sheet supplied with your specific grade and form is the authoritative document.
Classified hazards
H315Causes skin irritation.H319Causes serious eye irritation.H335May cause respiratory irritation.
Lump and powder are not the same hazard. Most US safety data sheets classify silicon metal lump as not hazardous, and apply the irritation statements above to dust and fine powder. Where you take fine powder, assess the respirable crystalline silica exposure under the OSHA silica standard and review combustible-dust controls with your process safety team. The SDS issued with your grade and form governs.
Storage
Store lump and granule in a dry, covered area; the material is stable but takes up moisture and can cake. Keep powder in sealed packaging away from moisture, strong alkali and oxidizers. Hot alkali attacks silicon and liberates hydrogen.
Handling
Handle with eye protection and gloves. Where dust is generated by crushing, screening or transfer, use local exhaust ventilation and assess respirable crystalline silica exposure. Follow the exposure controls set out in the batch SDS.
Transport
Silicon metal lump and granule are normally not regulated as dangerous goods for road, rail or sea transport, so no UN number applies. Fine powder may be classified differently depending on particle size and the producer classification. We confirm and document the position for your specific grade, form, packaging and destination before booking.
Every batch, documented
We verify documentation before dispatch so there are no surprises at your incoming-goods bench.
Specification agreed
Si assay, Fe, Al and Ca limits, sizing and origin confirmed against your requirement before order placement.
Smelter batch testing
The producing smelter tests each lot against the agreed grade specification before release.
Documentation review
COA, SDS, origin certificate and TSCA certification data checked by our desk, and duty position confirmed, before the shipment is booked.
Traceable dispatch
Each shipment is traceable to its producing furnace lot, with full chain-of-custody records on request.
How silicon metal is made
Silicon metal is made by carbothermic reduction of quartz in a submerged arc furnace. Lump quartz is charged with a carbon reductant — typically a blend of coal, charcoal, woodchip and petroleum coke — and electrodes carry current straight into the charge, holding the reaction zone above 1,800 °C.
The reaction strips oxygen from silica and releases carbon monoxide, leaving molten silicon that is tapped, refined with oxygen and air to cut aluminum and calcium, then cast, cooled, crushed and screened. Grade is set almost entirely by the purity of the quartz and the reductant blend, which is why a given smelter tends to produce a consistent grade band rather than any grade on demand.
The process takes roughly 11 to 13 MWh per tonne, which makes power the dominant cost. That economics explains the geography: production clusters where electricity is cheap, and it also explains why US antidumping and countervailing duty orders have repeatedly reshaped which origins land competitively here.
We do not publish operating process parameters here; this is background only. Full technical documentation accompanies every shipment, and any process-specific detail you need is best confirmed directly with our technical desk.
| Chemical family | Elemental metalloid |
|---|---|
| Made from | Quartz reduced with carbon |
| Process | Submerged arc furnace, above 1,800 °C |
| Energy intensity | Roughly 11–13 MWh per tonne |
| Grade driver | Quartz and reductant purity |
| Downstream | Aluminum alloys, silicones, polysilicon |
The rest of the metals & minerals range
Other metals, reductants and inorganics supplied from the same desk.
Silicon metal, answered
What is silicon metal used for?
What do the grade numbers 553 and 441 mean?
Which grade do I need?
Is silicon metal subject to US antidumping duties?
Is silicon metal the same as ferrosilicon?
What forms and sizes do you supply?
Is silicon metal hazardous?
What packing do you offer?
Do you supply silicon metal in the United States?
Do you manufacture this yourself?
Get a quote on silicon metal
Send us your required grade, impurity limits, sizing, pack type and US delivery point. We will come back with a firm quote, lead time and full documentation — and will flag the origin and duty position before you commit.