The most used area of Nickel is the production of Stainless Steel and high-strength alloys due to its resistance to corrosion and heat. More than 60% of the nickel produced worldwide is used in the production of Stainless Steel.
FerroNickel (FeNi) produced from lateritic nickel ores is an important input for the production of Stainless Steel. Laterite ores can be defined as magnesium and silica-rich garnierite ores or iron-rich limonite ores and contain 1-3% Nickel. Nickel Pig Iron (NPI) which has recently been used in the production of 200 and 300 series Stainless Steels is produced from Lateritic nickel ores. NPI production method is similar to FerroNickel production. Metallic nickel in the form of cathode, briquette or oxide is generally produced from sulphide nickel ores.
Secondary production of nickel has become widespread due to decreasing nickel resources. Nickel removes its slag during the melting process like in process of copper enrichment by pyrometallurgical methods. Slag is a by-product forming of oxides, silicates or borates which is separated from the molten product by the difference in density as a result of the melting process, or produced in plants that use coal/solid waste as fuel. Slag in the process of metal production; It absorbs impurities such as phosphorus and sulfur in the metal, and prevents both the pollution of the metal and the loss of heat by forming an interface with the liquid metal.
Slag produced in large quantities in pyrometallurgical processes is a source of pollution that creates air, soil and water pollution if they are not properly recycled and used. Regular stock areas are required and disposal costs increase. Since slag heaps are porous, when it meets with rain, rainwater drains down, interacts with the slag, and causes environmental pollution, affecting plants and human health. In the industry, positive steps are taken towards recycling and using slag in order to fulfill its environmental responsibility.
Due to the close geographical location of slag, the absence of blasting costs, the lack of need for large-scale equipment for primary reduction, human resources and the low initial investment costs, it is possible to talk about gains despite the disadvantages. It is also possible to recover the valuable material lost in the slag besides getting rid of waste disposal costs by establishing a Slag Recovery Plant.
By various physical processes such as crushing, screening, grinding and separation, the nickel and ferrous compounds contained in the slag are recycled into metal production and the remaining slag is brought to suitable sizes for use as a filling material such as gravel. Storage Bunker, vibro Feeder, primary and secondary Crushers, Sieves, Mills, Magnetic Separators with permanent and electromagnets, Conveyor-Belts, Electrical/Electronic equipment, Thickener and Press Filter are some of the equipments used in the Slag Recycling Plants.