Aluminium Treatment — Covering, Drossing & Cleaning

Covering, Drossing & Cleaning Fluxes

Covering, drossing, and cleaning fluxes are the foundational product group of aluminium melt treatment — covering fluxes form a protective barrier over the melt surface to prevent atmospheric oxidation, drossing fluxes separate entrapped metal from the oxide layer to maximise metal recovery, and cleaning fluxes disperse into the bulk melt to agglomerate and remove suspended oxide inclusions.

CFC Egypt's EGYFLUX series addresses all three functions across powder and granular forms. Powder grades spread rapidly across open-bath furnace surfaces; granular grades are preferred for dust-controlled environments or where the flux must be raked into a thick dross layer without airborne loss. Many grades combine covering, drossing, and cleaning action in a single formulation, reducing the number of products required in the treatment sequence. All are manufactured at our Sadat City plant and are suited to reverberatory furnaces, induction furnaces, crucible melters, and holding pots across aluminium casting operations.

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Where These Fluxes Are Used

Covering, drossing, and cleaning fluxes are required in every facility that melts aluminium alloys — from gravity and die-casting foundries to secondary remelters and extrusion billet casters.

Reverberatory & Induction Furnaces

Large-capacity reverberatory furnaces with open bath surfaces lose metal rapidly to oxidation if the melt surface is left unprotected during the melting and holding cycle. Covering flux is applied as soon as the charge begins to melt and is replenished after each drossing operation. Induction furnaces benefit from granular grades that do not get entrained in the bath circulation created by the induction coil.

Secondary Aluminium Remelting

Scrap-fed remelters generate significantly more dross than primary operations because scrap surfaces are highly oxidised before they enter the furnace. A combined covering and drossing flux applied from the start of the charge-down cycle protects the melt surface and prepares the dross layer for efficient metal recovery when skimming. Reducing metal loss in the dross is the single largest lever on yield in secondary operations.

Gravity & Die Casting Holding Furnaces

In production casting — whether gravity permanent mould, low-pressure, or high-pressure die casting — the holding furnace or pot sits at temperature for extended periods between pours. Continuous oxidation during this hold time builds oxide on the bath surface and introduces oxide films into the melt. Regular covering and cleaning treatment during the shift keeps the melt surface protected and the bulk metal clean enough to meet casting quality requirements.

Billet & Ingot Casting

Billet casters and ingot casters for the extrusion and rolling industries require extremely low oxide inclusion counts in the cast product, since oxide films cause surface lines, die marks, and mechanical property scatter in the downstream product. Cleaning flux treatment of the holding furnace before each casting cycle, combined with in-line filtration, delivers the melt cleanliness required for surface-critical aluminium products.

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CFC Covering, Drossing & Cleaning Flux Products

The EGYFLUX 500 series and EGYFLUX 600–800 range in powder and granular form, covering the full spectrum of melt surface protection, dross treatment, and bulk cleaning for aluminium alloys.

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Frequently Asked Questions

Technical questions on covering, drossing, and cleaning flux selection and application answered plainly. For application-specific guidance, contact our technical team.

A covering flux is spread across the surface of the molten aluminium bath to form a protective molten layer that physically separates the metal from the furnace atmosphere and prevents oxidation. A drossing flux is worked mechanically into the dross layer — the oxide-rich material that accumulates on the bath surface — to separate the entrapped metallic aluminium droplets from the oxide matrix and allow the metal to drain back into the furnace. Many CFC EGYFLUX products combine both functions in a single formulation, so one product protects the surface during the melt and is then worked into the dross during skimming.

A covering flux acts primarily at the melt surface and does not penetrate the bulk metal. A cleaning flux is designed to be dispersed into the melt — either by plunging or by mechanical agitation — where it wets and agglomerates suspended oxide films and inclusions, causing them to coalesce and float to the surface for removal. Cleaning action improves melt cleanliness indices and reduces the risk of oxide-related casting defects such as cold-shuts, non-fills, and inclusion porosity in critical castings.

Typical covering flux application rates for aluminium are in the range of 1 to 3 kg per tonne of melt, applied as a thin even layer across the bath surface at the start of the melting cycle and replenished after each drossing operation. The exact rate depends on furnace type (reverberatory, induction, crucible), alloy grade, melt temperature, and furnace atmosphere. CFC technical representatives can recommend the correct starting rate and dosing sequence for your specific operation.

CFC manufactures the EGYFLUX 501, 502, 504, 630, and 800 powder products, plus granular equivalents (EGYFLUX G 501, G 502, G 504, G 630, G 800) for covering, drossing, and cleaning applications. Powder grades disperse quickly and are suited to surface spreading on open-bath furnaces; granular grades are preferred where dust control matters or where the flux must penetrate the dross layer with minimal airborne loss. Contact CFC for selection guidance based on your alloy and furnace type.

Sprechen Sie mit uns

Need covering, drossing, or cleaning flux for your aluminium operation?

Tell us your furnace type, alloy grade, and current dross loss or melt cleanliness challenges. Our technical team will recommend the right EGYFLUX product, form (powder or granular), and dosing rate for your process — and support you through trial to volume supply.