Degassing Tablets For Molten Aluminum · Hydrogen Removal
The small-melt answer to porosity. Liquid aluminum holds roughly twenty times more hydrogen than the same metal once it freezes, and the difference comes out as gas holes in the casting. A degassing tablet plunged to the bottom of the crucible releases gas in the melt, and the rising bubbles carry that hydrogen out with them. No rotor, no gas line, no capital spend.
Chelora Chemicals is a degassing tablet supplier and sourcing partner serving foundries and die casters across the United States. We place orders with qualified producers in both hexachloroethane-based and HCE-free grades, and every consignment carries a batch COA and SDS.
- Product type
- Melt treatment tablet
- Function
- Removes dissolved hydrogen
- Metal
- Aluminum and its alloys
- Form
- Pressed tablet
- Chemistries
- Hexachloroethane-based · HCE-free
- Application
- Plunged with a perforated bell
- Dose
- Per the producer's dosing guide
- Packaging
- Sealed moisture-barrier packs
- Documentation
- Batch COA & SDS
Note: choose the chemistry before the price. Hexachloroethane tablets work, but HCE is an EPA Group C possible carcinogen and a Clean Air Act hazardous air pollutant. HCE-free grades do the same job without that listing.
How a tablet takes hydrogen out
The tablet does in a crucible what a rotary degasser does in a holding furnace, without the equipment.
Why it matters: the gas has to start at the bottom. A tablet that floats or is dropped on the surface releases its gas into the air, not through the metal, which is why it is plunged
What degassing tablets are and do
Degassing tablets are pressed tablets of a gas-releasing compound or salt blend, made to be held under molten aluminum until they react. As the tablet decomposes it releases gas in situ, and the bubbles rise through the full depth of the melt.
Hydrogen is the target. Molten aluminum picks it up from moisture in the charge, the tools and the furnace atmosphere, and because the solid metal holds so much less of it, the excess comes out as gas porosity when the casting freezes. Hydrogen diffuses into the passing bubbles and leaves with them. The bubbles also float fine oxide films to the surface, where they are skimmed off with the dross.
The two chemistries we supply
- Hexachloroethane-based tablets. The traditional grade. Releases chlorine-bearing gas; see our hexachloroethane page for the regulatory position.
- HCE-free tablets. Salt-based formulations that release gas without hexachloroethane, so no HCE hazardous air pollutant listing.
- Tablet size. Matched to your crucible or ladle so the dose fits the melt weight.
- Dose. Set by the producer's dosing guide for the grade, not guessed per ton.
Handling character
Degassing tablets must be bone dry and preheated before plunging. Moisture meeting molten aluminum is a steam explosion risk. Details in the Safety section.
| Parameter | Typical value |
|---|---|
| Chemistry | Hexachloroethane-based or HCE-free |
| Tablet weight | Per agreed specification |
| Moisture | Per grade specification — kept low |
| Reaction behavior | Steady, non-violent release in the melt |
| Packaging seal | Moisture-barrier pack |
| Dosing guide | Supplied with the grade |
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 form | Pressed tablet |
| Function | Hydrogen removal by gas flotation |
| Metal | Aluminum and aluminum alloys |
| Application | Plunged to the bottom of the melt |
| Moisture sensitivity | High — store sealed and dry |
| By-product | Dross skimmed from the surface |
| Alternative | Rotary inert-gas degassing |
Hydrogen solubility figures are the widely cited reference values for pure aluminum at its melting point and are given for orientation. Tablet composition, weight and dose are grade-specific and are set by the producer and stated on the COA and dosing guide. Treat the table as orientation, not as a specification.
Where degassing tablets earn their place
Crucible, ladle and small-furnace melt treatment, where a rotor is not justified.
Crucible & ladle foundries
Sand and permanent mold shops melting in crucibles, where rotary degassing equipment is not worth the capital.
- Tablet size matched to melt
- HCE-free grades available
- Dosing guide supplied
Die casting
Holding furnace and ladle treatment ahead of the shot, where gas porosity rejects cost the most.
- Steady, controlled reaction
- Low-moisture packaging
- Batch traceability
Moving off hexachloroethane
Foundries replacing HCE tablets to clear an air permit or hygiene finding switch to HCE-free grades.
- Like-for-like trial packs
- Honest comparison
- HCE page for context
Operator safety
Tablets react vigorously by design. Dry, preheated plungers and fume extraction are part of the process.
- SDS with every batch
- Plunging guidance shared
- Exposure controls are yours
Small batch & R&D melts
Lab and prototype melts where a consistent, repeatable treatment matters more than volume.
- Small packs available
- Consistent tablet weight
- COA per batch
Scheduled supply
Production foundries treat every melt, so a predictable call-off matters more than spot price.
- Annual contracts with call-off
- Price held across the contract
- Second source held in reserve
Delivered to US plants and ports
We ship degassing tablets 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
A degassing tablet is a chemical mixture, so TSCA looks at each component rather than the product name. 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 Inventory status of every component with the producer 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 grade-specific transport 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 | Sealed tablet packs in cartons or drums |
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 degassing tablets
Chelora Chemicals is a degassing tablet supplier and sourcing partner, not a manufacturer. We place your order with a qualified producer whose grade fits your alloy, your melt size and how you treat the metal.
The first question we ask is which chemistry. If you are on hexachloroethane tablets and your hygiene or air-permitting team has raised it, an HCE-free grade is usually a straight swap, and we will say so before we quote.
The second is dose and fit. A tablet sized for a 500 lb crucible is wrong for a 50 lb ladle. We match tablet weight to melt weight and send the producer's dosing guide with the grade.
- Both chemistries, stated plainly. Hexachloroethane-based and HCE-free grades, with the regulatory difference set out before you choose.
- Tablet size matched to your melt. We ask for crucible or ladle size so the dose fits.
- Moisture-barrier packaging. A damp tablet is a safety hazard as well as a poor degasser.
- Dosing guide with the grade. Dose per melt weight comes from the producer, not from guesswork.
- Trial packs before a contract. Run it on your own alloy and melt practice first.
- Batch traceability to the producing plant. Full chain of custody documentation on request.
Sealed, dry and sized to your melt
Tablets in moisture-barrier packs, cartoned or drummed, with full documentation.
Sealed packs in cartons
Tablets sealed in moisture-barrier packs and cartoned, the standard format.
Lined drums
Lined drums for larger tablet counts where carton handling is not wanted.
Shrink-wrapped pallets
Cartons palletized and wrapped for container shipment.
Small trial quantities
Small packs for trial on your alloy before a commercial order.
Incoterms to suit you
Quoted on the Incoterm your purchasing team works to.
Scheduled deliveries
Annual volume released against your melt schedule.
A reactive product by design
Degassing tablets are meant to react hard in molten metal, so the hazards are as much about how they are used as what is in them. The two that matter most are moisture — any water reaching molten aluminum can cause a violent steam eruption — and fume at the melt surface. The GHS classification depends on the chemistry, so the summary below is orientation only; the safety data sheet supplied with your batch is the authoritative document.
Classified hazards
HCEHexachloroethane grades: H351 suspected of causing cancer; EPA Group C; Clean Air Act HAP.FumeReaction fume at the melt surface: use local exhaust ventilation.H₂ODamp or cold tablets in molten aluminum: risk of violent steam eruption.PPEFace shield, heat-resistant gloves and protective clothing when plunging.SDSHCE-free grades: classification per the formulation and batch SDS.
The US air rule worth knowing. EPA's secondary aluminum NESHAP, 40 CFR Part 63 Subpart RRR, defines reactive fluxing as any gas, liquid or solid flux, other than cover flux, that results in a hazardous air pollutant emission, and it defines cover flux as salt added to the melt surface without surface agitation to prevent oxidation. Foundries, die casters and extruders melting only clean charge, customer returns or internal scrap are outside the definition of a secondary aluminum production facility. Whether your fluxing practice brings you inside the rule is a determination for you and your permitting authority; we supply the composition data you need to make it.
Storage
Store in sealed original packs in a dry, covered area, away from food and feedstuffs and off the floor. Tablets are moisture-sensitive: keep packs closed until use and use part-opened packs promptly. Damp tablets should not be used.
Handling
Preheat the tablet and the perforated plunger above the melt to drive off any moisture, then plunge steadily to the bottom and hold until the reaction ends. Stand clear of the crucible during the reaction and wear a face shield, heat-resistant gloves and protective clothing. Use local exhaust ventilation at the melt. Skim the dross once the reaction is complete. Follow the batch SDS and the producer's application guide.
Transport
Transport classification is set by the formulation. Hexachloroethane-based grades may travel as UN 3077, Environmentally hazardous substance, solid, n.o.s., Class 9, depending on the producer's classification; HCE-free grades are classified on their own composition. We confirm and document the position for your grade, 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
Alloy family, melt temperature, application method and the grade chemistry confirmed against your process before the order is placed.
Producer batch testing
The producing plant tests each batch against the agreed specification before release.
Documentation review
COA, SDS, TSCA position and transport classification checked by our desk before the shipment is booked.
Traceable dispatch
Each shipment is traceable to its producing batch, with full chain-of-custody records on request.
Why porosity starts in the furnace
Hydrogen is the only gas with significant solubility in molten aluminum, and it gets in easily: from moisture on scrap and returns, damp tools, refractories and fluxes, and humidity in the combustion atmosphere. The hotter and longer the metal is held, the more it takes up.
The trouble comes at solidification. Pure aluminum holds about 0.69 mL of hydrogen per 100 g as a liquid at its melting point and only about 0.036 mL as a solid — roughly a twentyfold drop. The hydrogen that cannot stay in solution forms bubbles in the last metal to freeze, and the casting carries them as gas porosity: lost pressure tightness, poor machined surfaces and lower mechanical properties.
Degassing works by giving that hydrogen somewhere to go. Bubbles of a gas with no hydrogen in it rise through the melt and hydrogen diffuses into them. A rotary degasser does it with argon or nitrogen through a spinning rotor; a tablet does it with gas released in situ. For a crucible or ladle, the tablet is the simpler tool, as long as it goes in dry and goes in deep.
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.
| Product family | Aluminum melt treatment |
|---|---|
| Function | Hydrogen removal |
| Mechanism | Gas released in situ; hydrogen diffuses into rising bubbles |
| Chemistries | Hexachloroethane-based · HCE-free |
| Application | Plunged dry and preheated to the melt bottom |
| Equipment alternative | Rotary inert-gas degassing |
Related foundry & melt-treatment products
Other aluminum melt-treatment inputs supplied from the same desk.
Degassing tablets, answered
What do degassing tablets do?
Why does molten aluminum need degassing?
How are degassing tablets used?
How many tablets per melt?
Are your tablets hexachloroethane-based?
What is the alternative to degassing tablets?
Do degassing tablets fall under EPA rules?
What safety precautions apply?
How should tablets be stored?
Do you manufacture degassing tablets?
Get a quote on degassing tablets
Tell us your alloy, your melt size per treatment and which chemistry you use today. We will match a grade and tablet size, send the dosing guide, and quote both chemistries if you are weighing a move off hexachloroethane.