Slag Beneficiation Plants

Aluminum Slag Beneficiation Applications

Aluminum slag consists of aluminum, aluminum oxide, scrap and alloying elements and other metal oxides, alkali and halogenated compounds depending on the used fluxes. The main feature of aluminum slag is that it forms lattice-like structures from existing oxide films and traps metal droplets with its thixotropic behavior during melting. Metal droplets trapped in the slag are the main cause of metallic aluminum loss in the melting process. However, the amount of metal contained in the slag and the amount of metal that can be recovered from the slag differ depending on the metal melting, slag cooling and slag melting processes. In other words, it is impossible to recover all the metal trapped in the slag. During cooling, there is typically a 1-2% loss of metallic aluminum per minute as a result of thermite reaction (reactions of fine powdered aluminum particles releasing large amounts of heat).

Types of aluminum slag can be listed as follows:

• White dross: It is the slag formed by the use of flux at a low rate, that is to say 1.5-3% of the melted scrap charge. Metal content is between 25-45%.

• Rich Slag (Skimm): The slag taken from the melting furnace before fluxing, the slag taken from the melting and reverberator furnaces after refining and, the slag that is scraped from the ingot surface formed in the runner and tundish during transfer and ingot casting. Metal content is between 50-90%. It can be evaluated separately in different literatures, or it can be classified as white dross.

• Black dross: It is slag that is difficult to melt in terms of physical form and is formed by use of excessive flux (5-10% of the melted charge). Metal content is between 15-35%.

• Rotary Kiln Slag (Salt Cake): The slag formed in rotary kilns, melting processes under molten flux and by excessive flux usage (between 8-20% of the melted charge) and with cryolite (up to 0.05-0.07% of the melted charge after melting). The metal content is between 8-15%.

Aluminum slag is not a waste, it is a by-product with economic value due to its metallic aluminum content. In other words, the main purpose of slag recycling processes is to recover the aluminum in the slag and to produce an economic value from it by transforming the secondary slag that is formed into a non-hazardous form for the environment.

Size reduction is necessary in order to liberate metallic aluminum and aluminum minerals from the slag. By the liberation process, the comminuted aluminum slag is subjected to magnetic separation, and generally, over-band metal separators, dry magnetic drum separators and perm-roll magnetic separators are preferred. Finally, the desired final product and waste is obtained with the ecs eddy current non-ferrous metal separator. The engineering and design of the facility, which provides the separation of the obtained aluminum concentrate from the impurities and also produces the final product with the desired physical and chemical values, is carried out by BAS laboratories and engineers as 7 days and 24 hours conditions. Mineralogical studies and laboratory productions of all aluminum slags for each application are provided by us. Since aluminum slags differ with application process and raw material recipe, laboratory studies and test productions are so importatnt to detect right solution. BAS produces results with limited tolerance for site applications according own laboratory results on a customer sample studies. You can contact us for the most economical studies in all kind of aluminum slags. The correct mineralogical analysis of the slag, grain liberation degree, particle size distribution and the correct enrichment tests applied to the sample are the main criteria for the success of the project.

As we are BAS; we do all laboratory studies, general and detalied engineering, correct magnetic separation methods are provided on a turnkey basis.