Aluminium Treatment — Degassing Tablets

Degassing Tablets

Degassing tablets for aluminium are pre-measured compact tablets plunged to the furnace floor using a steel rod, releasing gas consistently through the full bath depth as they dissolve — providing controlled, metered degassing of the aluminium melt to remove dissolved hydrogen and minimise gas porosity in the casting.

Unlike powder degassing flux spread on the surface, tablets release their gas at the furnace floor, generating bubbles that scavenge hydrogen throughout the entire bath depth as they rise — a more thorough degassing profile for the same bath volume. Pre-measured tablet dosing removes the variability of manual powder weighing and ensures every melt receives a consistent treatment. EGYHEX AL tablets are particularly suited to crucible furnaces, small induction melters, and ladles where plunging to bath depth is straightforward and operator proximity to the melt surface makes low surface fume preferable. CFC Egypt manufactures EGYHEX AL at our Sadat City plant to serve the aluminium casting industry across the MENA region.

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Where Degassing Tablets Are Used

Degassing tablets are preferred over powder in smaller furnace operations, crucible melting, and applications where precise dosing and lower surface fume are important.

Crucible Furnaces & Small Induction Melters

In crucible furnaces and small induction melters — the workhorse of jobbing foundries, prototype casters, and small die casting operations — the operator stands close to the furnace opening during treatment. Powder degassing spread on the surface generates visible fume at the melt surface in the operator's work zone. Tablets plunged to the crucible floor produce gas from depth; surface fume is significantly reduced because the gas has partially reacted and the hydrogen has transferred to the bubble before it reaches the surface.

Precision Casting — Consistent Per-Heat Dosing

Aerospace investment casting, precision sand casting, and other quality-critical aluminium casting processes require consistent degassing treatment across every heat. Tablets provide this consistency by eliminating the dosing variability that occurs when operators manually weigh powder — a single tablet per specified furnace size gives the same gas output every time. Process control records for quality-certified operations can reference tablet count per heat rather than powder weight, simplifying documentation and reducing operator-to-operator variation.

Ladle Degassing Before Pouring

When aluminium is transferred from the melting furnace to a pouring ladle, it is exposed to the atmosphere and absorbs additional hydrogen from the transfer turbulence and the ladle atmosphere. A degassing tablet plunged into the ladle immediately before pouring provides a final hydrogen reduction treatment at the point of use — particularly valuable in gravity and tilt-pour casting operations where the metal sits in the ladle for several minutes between taps before each pour. The compact tablet is more practical than powder in the ladle environment.

Site Casting & Remote Foundry Operations

In site casting operations — casting in field conditions, temporary facilities, or remote locations without fixed bulk handling infrastructure — pre-measured tablets are more practical than powder supplied in open bags. Tablets are individually handled, require no weighing equipment, and are less susceptible to moisture pick-up during storage than some powder formulations. For operations running with minimal equipment, EGYHEX AL tablets simplify the degassing step to a single plunge-and-wait procedure requiring no measurement or dispensing.

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CFC Aluminium Degassing Tablets

EGYHEX AL — pre-measured compact degassing tablets for aluminium, plunged to the furnace floor to provide controlled hydrogen removal from depth.

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Frequently Asked Questions

Technical questions on aluminium degassing tablets — how they work, dosing, and when to use them versus powder flux.

Aluminium degassing tablets are plunged to the bottom of the furnace or crucible using a clean, dry, preheated steel plunging rod. The tablet is held at the furnace floor for the duration of its reaction — typically one to three minutes depending on melt temperature and tablet size — allowing the gas it releases to rise as fine bubbles through the full bath depth. Once the tablet is fully consumed, the rod is withdrawn, the bath surface is lightly skimmed to remove any residual dross, and the melt is ready for pouring.

Hexachloroethane (C₂Cl₆) was historically used in degassing tablets because it is effective at releasing chlorine gas in aluminium melts, but it generates toxic chlorinated fume and is classified as a hazardous substance under environmental and occupational health regulations in many countries. Modern degassing tablet formulations use alternative active chemistries that achieve effective hydrogen removal with a reduced fume profile. Contact CFC for current product composition information and the safety data sheet for EGYHEX AL.

The number of degassing tablets required per melt depends on furnace or crucible capacity (in kg of aluminium), current hydrogen content, target hydrogen level, and melt temperature. EGYHEX AL tablets are pre-dosed to treat a specific quantity of metal — the tablet packaging indicates the recommended dosing rate. As a general guide, one tablet per 50 to 100 kg of aluminium is a common starting rate for moderate hydrogen levels. CFC technical representatives can provide a specific dosing table for your furnace size and operating conditions.

Degassing tablets (EGYHEX AL) are plunged to the furnace floor, releasing gas from depth throughout the bath — providing more consistent and thorough degassing of the full bath depth compared with powder spread on the surface, which generates gas mainly in the upper portion of the melt. Tablets produce lower visible fume at the bath surface because the reaction occurs at depth — an advantage in enclosed crucible furnaces where the operator works close to the melt. Powder flux (EGYFLUX 400) is more economical for very large furnaces where the bath area is too large for practical tablet plunging.

Bizimle konuşun

Looking for tablet degassing for your aluminium operation?

Tell us your furnace type and capacity, alloy grade, casting process, and current gas porosity challenges. Our technical team will recommend the right EGYHEX AL tablet size, dosing rate per melt, and plunging procedure for your specific operation.