Aluminium Dross Recovery with GHI Technology
Creating value from aluminium dross
In response to the growing interest for a circular economy, environmental restrictions and a very competitive market in terms of product quality, process productivity and profitability, the aluminum sector has been pushing the top equipment suppliers to develop competitive technologies and processes to recover the most of the aluminum dross and scrap.
When aluminium is melted, the generated dross should be removed to ensure high quality aluminium. Typically, the black dross (from secondary melting operations) can contain from 5% to 30% of aluminium. By other side, the white dross (from primary smelters) is much richer and contains a higher concentration of metal, that can be from 20% to 80%.The aluminium content in the dross, even from black or white dross, can be recovered by means of a subsequent melting process.
There are several technologies for this process, being the tilting rotary furnace the most effective way to process dross as it maximizes energy efficiency and metal recovery.
GHI’s Experience in Dross Recovery Plants
GHI Smart Furnaces, a leading European furnace supplier, with vast experience in aluminum recovery technologies has developed cutting edge equipment to increase the profitability of dross recovery plants.
As an outstanding reference, GHI supplied and designed together with Befesa, its dross recovery plant in Germany with a total input capacity of 140.000 tpy and its two aluminum recycling plants in Spain with 100.000 tpy each.
The state-of-the-art plants were developed with the efficient, safest and most sustainable technologies. The plant in Bernburg, Germany has a leading role in the Dross recovery industry. The final products are ingots and liquid aluminium which are then sold to customers, mainly from the automobile and packaging industry.
The main equipment to recover aluminum from dross is the Tilting rotary furnace.
GHI Smart Furnaces developed the ROTADROSS, a new concept in tilting rotary furnaces which provides profitable metal yields and produces significantly lower contaminant waste than traditional models, which produce high amounts of waste salts. Several references in Europe and Latin America support these facts.
The value proposition of the ROTADROSS can be resumed as:
- Oxy-fuel burners produce a high-intensity flame and better transmission of heat to load.
- The TRF is available in different sizes from 10 to 65 t capacity.
- The amount of salts required in the process can be reduced by 50% compared with other types of rotary industrial furnace.
- Lower costs of fume collection and filtration equipment since fewer combustion gases are produced.
- The tilting body of the furnace makes it easier to empty and clean.
- The proven lining designs and qualities increase the equipment lifecycle and minimize the maintenance costs.
- The 4.0 technology developed by GHI, allows the characterization of the melting process thus increasing the process control and optimizing the cycle time.
The salt-slag from the rotary tilting furnace, usually contains between 3 to 10% of residual metallic aluminum.
The salt slag cooling system designed by Befesa and supplied by GHI thanks to its technological partnership, holds the fumes and prevents the oxidation of the contained aluminium, increasing the aluminium recovery and drastically reducing the space required for cooling the traditional salt slag bins.
The fumes, undesired emissions and odours are significantly reduced with this system.
The principle of operation of GHI’s salt slag cooling system is based on the cooling down of the salt slag coming from the rotary furnaces below 400ºC in a few minutes, which is later classified depending on the size and metal content.
The cooling system is automatically fed by a fit for purpose conveyor that carries the salt slag from the tilting rotary furnaces, avoiding the use of traditional baskets.
The dross recovery plants are also equipped with reverberatory holding furnaces, specifically designed for receiving, holding, alloying and preparing molten aluminium. The open front of the furnaces, allows access to the entire chamber for cleaning and skimming operations, thus optimising finished product quality.
The furnaces have a bath agitation system by means of porous plugs that homogenize the temperature and the chemical composition of the bath, resulting in premium quality metal.
They are provided with automatic tilting systems for more efficient casting control, including a proportional valve in the hydraulic equipment, a tilt meter in the furnace and a laser system to monitor the level in the transfer channel next to each furnace.
GHI offers a new concept of complete and intelligent plant for dross recovery with the highest performance in the market and a 4.0 solution that allows customers to move from data-driven insights to data-driven actions.
All the equipment is sensorized, the captured data is analysed in the Beyond 4.0 platform with tailormade algorithms and big data systems under the most robust cybersecurity systems.
The dross recovery process is analysed by specialized GHI engineers to optimize the cycle time, improve the process control and provide predictive and preventive maintenance anywhere in the world.