Table 5.

Summary table.

Obstacle	Pre-Treatment Technique	Advantages	Disadvantages
Metallic Aluminum and Zinc	Magnetic density separation	Versatile Simple	Initial cost, not for fines
	Eddy current separation	Can detect through several layers Can provide an accurate separation	Initial cost, not for fines Susceptible to magnetic permeability changes
	Wet grinding	Consumes lower power per ton of product. Enables the use of wet screening or classification for close product control. Eliminates the dust problem. Enables the use of simple handling and transport methods such as pumps, pipes and launders.	Storage of wet slurries
	Washing with alkali	Simple	Cost of alkali
Salts	Washing with water	Simple	Secondary pollution of water, unless the water in the slurry is used to make concrete from the material
	Carbonation	CO2 from stack gas can be utilized and thus reduce the emission. Can be a method for carbon sequestration.	Not a very fast process, unless the CO2 concentration is very high, which in turn will require air tight enclosures
	Thermal treatment	Simple technology	Energy Consumption Cost
Heavy metals	Washing with water	Simple	Secondary pollution of water
	Treatment with sulfide rich effluent	Simple and can utilize another waste stream	Applicable for specific heavy metals
	Wet grinding	Simple No addition of additional chemicals	Storage of wet slurries
	Phosphation	Stabilizes heavy metals	Applicable only for specific applications
	Cement stabilization	Stabilizes heavy metals	Cost of cement
	Hydrothermal treatment		Capital cost
	Electrodialytic remediation		Costly Energy Consumption