We're featured in the lastest edition, click to read

Salt Slag Recycling - SALTROMEX


Ultromex introduces SALTROMEX our patented plant & technology enabling aluminium smelters to treat and recycle their own salt slag wastes.

SALTROMEX is the most cost-effective method for smelters who want the option for in-situ aluminium salt slag recycling & treatment, to recover valuable metals & flux salts & avoid using third party processors.

SALTROMEX Salt Slag Recycling

SALTROMEX plants, using our patented processes, are designed to help secondary aluminium smelters of all sizes treat and recycle their own salt slag to recover valuable aluminium for re-melt, recover the flux salts to use again while leaving non-odourous, valuable aluminium oxide residues.

Scalable from 2,000 tonnes per year of salt slag to 100,000 tonnes per year, now almost all smelters can take total control of their salt slag waste. Where previously salt slag waste disposal was a significant cost, your salt slag now presents as an asset to monetize and also allows you to gain more operational control.

Our plants are designed to be low Capex & low Opex, delivering the best overall economic solution for your salt slag waste.

Contact us to learn more about how SALTROMEX can benefit your bottom line.

Salt slag recycling benefits


Recover aluminium to re melt

Salt slag contains ~5 - 12 % metal which SALTROMEX can recover, without crushing or grinding, creating no metal fines meaning maxiumum metal recovery for re melt. No other technology is as effective at recovering metal from slags or drosses. More..


Recover flux salts to use again and again

SALTROMEX removes the flux salts from the non metallic residues making it available to re-crystalise to use again over and over. Salt removal initiates hydrolysis reactions evolving malodourous, toxic and potentially explosive gases; SALTROMEX controls these gases so the process is safe and non odourous.


Un-reactive valuable oxide residues

SALTROMEX leaves the de-metalled, salt free residues (mainly aluminium oxides) un-reactive and giving no odour. They become a valuable secondary resource for other industries. 


Operational Security

Ever increasing environmental legislation puts pressure on smelters' operational effectiveness. Using SALTROMEX to treat your waste salt slag in-situ gives you more control.

To evaluate the benefits of treating your own salt slag contact us. With some basic information about your operation we can give a good idea of the costs and benefits.


We have developed a number of technology solutions to assist the aluminum industry deal with difficult wastes


For smelters processing white drosses ALTROMEX can be used to pre process the dross before melting to increase yields, reduce operating costs, increase furnace throughput and bottom line profits. The lower the quailty of the dross the bigger the gain.


The aluminum industry works hard to deal with its wastes responsibly. But in the past, when recycling technology was not so advanced, some wastes were land filled and are now causing pollution & environmental problems. TERRAMEX can resolve these problems - permanently.


Our patented solution for treating Spent Pot Liners.

CARBOMEX is an exciting new technology which represents a step change for smelters who need a sustainable option for this hazardous and problematic aluminium production waste stream.

Consulting & Lab Services

Salt slags and aluminum wastes in general are highly variable in both physical and chemical form. Our knowledge and experience of aluminium wastes is unrivalled, meaning we can help with any problems you may have.

What is Salt Slag?

Salt slag, also referred to as salt cake or black dross is a waste material generated by secondary aluminium processing (the recycling and smelting of new aluminium from aluminium scrap, dross and other industry wastes).

Due to its reactivity with water and the nature of the contaminants it contains, salt slag (or salt cake as it sometimes known) is classed as a hazardous waste in most countries and banned from landfill. Disposing of the waste in an environmentally sustainable yet cost effective way is a major challenge for the aluminium smelting industry.
Our technology turns hazardous salt slag waste into valuable resources and crucially, being deployed in-situ at your foundry, means that you are in total control.


The most common types of furnace used by the secondary aluminium industry are rotary or reverbatory furnaces. In these furnaces scrap aluminium is melted under a bath of molten salt flux which floats on the surface of the molten metal. The salt flux is a mixture of sodium chloride and potassium chloride, often with small amounts of fluorides (Cryolite).

Aluminium has a tendency to oxidize with the heat of the furnace so the salt provides an effective cover for the metallic aluminium, minimizing losses to oxidization and increasing metal recoveries. The fluoride in the salt helps break down oxide layers already on the surface of the scrap and so helps to improve separation between the aluminium and non-metal contaminants.

The molten metallic aluminium is tapped from the furnace and where it meets the salt layer this contains some residual aluminium metal, plus various metal oxides (mainly aluminium oxide) and the salts. This mixture solidifies and cools to become salt slag; sometimes known as salt cake or black dross. 

Historically, salt slag was land filled but this has caused a number of problems, including salt and other contaminants leaching into the water course and (being exothermic on contact with water) causing underground fires. As environmental awareness and regulations have developed, landfill of salt cake has been banned in many countries and the options for disposal have become a major issue for the industry. Salt slag processing and treatment for recycling is now the only sustainable option. 

Our technology allows secondary smelters to process and recycle their own salt slag wastes as they arise, recovering the small amount of trapped metal to re-melt, recovering the salts to use again and with the residual aluminium oxides becoming a useful feedstock for other industries and – crucially – leaving zero waste for landfill. 

Where landfills exist and are causing environmental problems we have unrivalled expertise is remediation these problems.

Ultromex Limited 

Mersey Wharf Business Park
Dock Road South
Bromborough, Wirral CH62 4SF
Tel: 0151 203 8377

Registered in England
Company no 07661552


Phone: +44 0151 203 8377

Our Technologies

> Salt slag recycling & treatment
> Salt cake recycling & treatment
> Salt slag land fill remediation
> Spent pot liner recycling & treatment
>  Spent pot liner in landfills
> Dross processing
> Black dross


Please send us your ideas, bug reports, suggestions! Any feedback would be appreciated.